Please see the [Transcriber’s Notes] at the end of this text.

THE AUTOMOBILE
OWNER’S GUIDE

THE AUTOMOBILE
OWNER’S GUIDE

BY
FRANK B. SCHOLL

D. APPLETON AND COMPANY
NEW YORKLONDON
1920

COPYRIGHT, 1920, BY
D. APPLETON AND COMPANY

PRINTED IN THE UNITED STATES OF AMERICA

PREFACE

The automobile has taken its place as one of the most successful and useful inventions of the day. It is equaled only by the internal combustion gas engine, which is a factor in making it practical and efficient.

Gasoline-propelled vehicles have become one of man’s greatest aids in business efficiency, but nevertheless it is very important that we consider the facts, that the adoption of the automobile by man for business, commerce and pleasure is on a very large scale, and that the production by manufacturers is so great that very little thought is given to proper care, which is an ever-present factor in economical operation and a fair return for the investment.

The purpose of this book is to serve as a practical guide for those who own, operate, or contemplate purchasing an automobile.

The contents of this book cover the entire field that would be of value to the owner or chauffeur in making his own repairs. The parts and expressions are given in their simplest form; technical terms, tables and scales have been entirely eliminated, as they mean little or nothing to the average owner, and are of value only to the mechanical engineer and draftsman.

The illustrations, drawings and diagrams are intended only for the purpose of bringing out points that are more readily understood and explained in this manner. No attempt has been made to conform to proportionate exactness or scale accurateness.

Since there are many different makes of cars, motors, and equipment, the functional action of all is practically the same, therefore we use for illustration only those which are used by the majority of manufacturers.

While, as a general rule, you will find all automobiles efficient and reliable, troubles and conditions are bound to arise that are somewhat puzzling; therefore, to assist the owner, we have written a [chapter] on trouble hints conveniently arranged in three columns, headed troubles, cause, and remedy.

The entire book is worked out along such lines, and so arranged, that a man or a boy with a common school education can easily master it and become an efficient mechanic.

INTRODUCTION

After twelve years’ experience with the automobile, I find that only one-third of the present-day owners understand the mechanical operation, care and proper upkeep of their cars; the other two-thirds know little or nothing of their cars, and are unable to locate or detect trouble, or make the slightest adjustment necessary to remedy it. This fact remains as the chief cause of the present high depreciation in cars, and the loss of millions of dollars annually to automobile owners.

After two years of observation and close investigation, I find the vast majority of the present owners are eager to acquire mechanical knowledge, but they have not accomplished their aim, chiefly because the available books to attain that end are too technical, dry, and overdescriptive for the average owner and beginner in mechanics.

The automobile is not an individually constructed piece of machinery, but a combination of individual inventions, each adapted to a functional purpose, which is necessary to the harmony of successful operation. A great many of these mechanical achievements are of delicate construction, and very apt to get out of adjustment. This, however, is not always the case, as grease, dirt and foreign matter with which the various parts come in contact often prevent them from operating properly.

Therefore a little common knowledge of operation and a little care will enable an owner to operate his car successfully, thereby avoiding unnecessary trouble, damage and expense.

One of the chief aims of the writer is to make this book interesting and thorough, in order to hold the reader until he understands the entire contents, after which he should be able to make any necessary repairs and adjustments, or to hold a position as automobile mechanic.

In order to accomplish the foregoing and prevent a student from becoming discouraged we use functional principle as the base for explanation whenever possible.

The instructions set forth in this book are not taken merely from theory, but have been put into successful operation by the writer, who for several years sold cars in outlying districts where garage facilities were limited, and where it was necessary to make a mechanic of every purchaser in order to sustain the high reputation of the car sold. Later on his plan of instructions was used in an automobile school where he was chief instructor, and still later they were developed into a note system which he used in establishing an automobile school in the city of Toledo, Ohio.

The students turned out by this school were very efficient and successful, and finished the course in less than one-half the time usually required for the average automobile course.

This book was written during the twenty months that the writer spent in the U. S. Army, from the note system used in his automobile school.

F. B. S.

CONTENTS

PAGE
Preface[v]
Introduction[vii]
INTRODUCTORY CHAPTER.
History of the Gasoline Engine and Early Automobileconstruction[1]
Purchasing a new car[3]
Purchasing a used car[4]
Selecting and testing a used car[5]
Driving instructions[6]
Road rules for city and country[9]
What to do in case of accident[10]
CHAPTER I.
Gasoline Engine Construction, and Parts[12]
The engine block castings, cylinders, pistons, connecting rods, bearings, crank shaft,cam shaft and fly-wheel.
CHAPTER II.
Valve Construction and Operation[21]
Valve construction. Types and operation of the valves in an 8-cylinder V-type engine. Valvelocations and valve grinding. Valve care.
CHAPTER III.
The Operation of a 4-Cycle 4-Cylindered Gasoline Engine[29]
Explaining the cycle. The 4-, 6-, 8-, 12-cylindered engine—The Knight sleeve valve engine—S. A. E.Horse Power scale—Displacement-Engine charts—Lubrication oils and greases—Lubrication systems—Care—Cleaning—and adjustingof lubrication systems.
CHAPTER IV.
Brief Treatise on Carburetion[45]
The Stromberg plain tube Model M carburetor. Principle of action—Installation—Adjustment andmaintenance—Stromberg Model L adjustment.
CHAPTER V.
Nitro Sunderman Carburetor[60]
Principle of action, action of venturi, adjustment and general care.
The Schebler Model R carburetor, action and adjustment points.
CHAPTER VI.
Stewart Carburetor[65]
Principle of operation—Adjustment and maintenance.
CHAPTER VII.
Carter Carburetor[70]
Operating principle—Adjustment and care.
CHAPTER VIII.
Schebler Plain Tube Carburetor[72]
Operation—Instructions for installing, adjustment and maintenance.
CHAPTER IX.
Kerosene Carburetors[76]
Operating principle—Installation and adjustment.
CHAPTER X.
Heated Manifolds and Hot Spots[79]
Action—Advantage and design.
CHAPTER XI.
Cooling Systems[82]
Purpose of cooling system—Circulating systems—The force pump circulating system—Overheating—Radiatorcleaning—Freezing—Freezing solutions—Radiator repairing—The air cooling system.
CHAPTER XII.
Muffler Construction[86]
Purpose—Advantage—Type—Assembly and Maintenance.
CHAPTER XIII.
Vacuum Systems[89]
Operating principle—Purpose of the air vent—Failure to feed gasoline to carburetor—Removingtop—Cleaning gasoline strainer screen—Operating principle and general maintenance.
CHAPTER XIV.
Electrical Dictionary of Parts, Units and Terms[95]
Voltage—Amperage—Ohms—Current—Circuit—Low tension Current—High Tension Current—Inductioncoil—Commutator—Insulation—Shunt or choking coil—Fuse—Condenser—Dynamo—Voltaic cell—Accumulator—Storagebattery—Electrolyte—Hydrometer—Ammeter—Circuit breaker—Switch—Generator—Regulator—Contact-breaker—Non-vibratingcoil—Distributors.
CHAPTER XV.
The Magneto[101]
Parts—Assemblage—Operating principle.
CHAPTER XVI.
Bosch High Tension Magneto, Type ZR[105]
Operating principle—Primary or low tension circuit—Secondary or high tension circuit—Timingmagneto gears—Timing magneto with engine—The condenser—Safety spark gap—Interrupter timing range—Cutting outignition—Caution—Care—Maintenance.
CHAPTER XVII.
Magneto Washing, Repairing and Timing[111]
Magneto cleaning—Magneto repairing—Magneto assembling—Magneto timing to engine.
CHAPTER XVIII.
North East Ignition System[114]
Wiring ignition distributor—Ignition coil—Breaker box and distributor head assembly—Condenser—Breakercontacts—Breaker cam—Distributor head—Automatic spark advance mechanism—Manual spark control—Timing the distributor—Generalcare.
CHAPTER XIX.
Atwater Kent Ignition Systems[126]
Type CC system—Operating principle—Setting or timing—Adjustment—Oiling—General care.
CHAPTER XX.
Atwater Kent Battery Ignition System[132]
Type K-2-Operating principle—Operation of contact maker—Contactless distributor—Wiring diagram ofcurrent flowage—Setting and timing the unisparker—Timing with engine—Automatic spark advance—Contact point adjustment—Oilingdiagram—Condenser—Testing for ignition trouble.
CHAPTER XXI.
Philbrin Single Spark, and High Frequency Duplex Ignitioystems[141]
Operation of contact maker—Current induction—Duplex system—Duplex switch—Duplex switchaction—Wiring diagram—Adjustment of contact points—General care.
CHAPTER XXII.
Electrical Starting and Lighting Systems[147]
The generator—The regulator—The automatic cut-out—One unit system—Two unit system—Three unitsystem—The starting motor—Lubrication—Maintenance.
CHAPTER XXIII.
Electric Lighting and Starting Systems[154]
Wiring diagram Bijur system—Operation of Bijur system—Starting motor—Operation of startingmotor—Wiring circuits—Fuse—Ground fuse—Lamp controller—Oiling—Battery testing—General care.
CHAPTER XXIV.
North East Starter Used on Dodge Brothers’ Cars[161]
Model G starter-generator operation—Wiring diagram—Starter-generator action—Mounting—Drive—Chargingrate adjustment—Fuse—Locating trouble—Starting switch and reverse current cut-out—Running with battery disconnected.
CHAPTER XXV.
The Delco Electrical System[167]
Motoring the generator—Cranking the engine—Generating electrical energy—Diagram of motor generatoroperation—Lubrication—Ignition switch—Circuit breaker—Ignition coil—Distributor—Contact breaker and timer—Care.
CHAPTER XXVI.
Storage Battery[180]
Construction—Chemical action—Cells—Electrolyte solution—Battery charging—Care andmaintenance—Hydrometer testing—Battery idle—Battery freezing—General care.
CHAPTER XXVII.
Spark Plugs and Care[186]
Type—Construction—Connections—Assembling—Repairing—Cleaning—General care.
CHAPTER XXVIII.
Clutch Construction, Type and Care[189]
Clutch operation—Gear shifting—Change speeds—Cone clutch—Cone clutch care—Cone clutchadjustment—Multiple disc clutch—Borg and Beck clutch—Borg and Beck clutch adjustment—Disc clutch cleaning, wet plate,dry plate—Cone clutch leather—Cone clutch leather patterns—Cutting—General care.
CHAPTER XXIX.
Transmissions, Types, Operation and Care[198]
Operation of—Planetary type—Progressive type—Selective type—Gear shifts—Unit-power-plant—Transmissioncleaning—Lubrication—Care.
CHAPTER XXX.
Universal Joints[204]
Universal joints—Slip joints—Operation—Construction diagram—Tightening—Lubrication—Care.
CHAPTER XXXI.
Differential Gears[207]
Bevel gear action—Construction—Adjusting—Gearless differential—Action—Adjustment—Advantage—Wormgear drive differential—Operation—Adjustment—Lubrication—General care.
CHAPTER XXXII.
Axle Types, Operation and Care[212]
Dead axles—The semi-floating axle—Adjustment—Lubrication—The full-floatingaxle—Construction—Adjustment—Lubrication—The I-beam front axle—The spindle—Steering knuckle—Care of all types.
CHAPTER XXXIII.
Brake Types, Operation and Care[218]
Brake adjustment—Brake re-lining—Brake care—Brake cleaning.
CHAPTER XXXIV.
Springs and Spring Care Tests[223]
Spring types—Spring lubrication—Weekly spring care—Bi-monthly spring care—Spring wrapping.
CHAPTER XXXV.
Alignment[229]
Wheel alignment—Lengthwise—Crosswise—Axle alignment—Lengthwise—Alignment tests—Mechanicalalignment—Lengthening wheelbase.
CHAPTER XXXVI.
Steering Gears, Type and Construction[232]
Operation of worm and sector type—Adjustment of worm and sector type—Worm and nut type—Adjustmentof worm and nut type—Rack and pinion type—Connections—Drag link—General care.
CHAPTER XXXVII.
Bearing Types, Use and Care[236]
Plain bearings—Bushings—Roller bearings—Flexible roller bearings—Radial ball bearings—Thrust ballbearings—End thrust—Double thrust—Cleaning—Care—Maintenance.
CHAPTER XXXVIII.
Car Arrangement[243]
Showing location and names of parts—Adjustment—General care.
CHAPTER XXXIX.
Overhauling the Car[247]
Instructions showing how to go about it—And how to give the car a thorough overhauling.
CHAPTER XL.
Repair Equipment[251]
Road repair necessities—Shop repair necessities.
CHAPTER XLI.
Car Cleaning, Washing and Care[253]
Body construction—Body washing—Running gear washing—Engine cleaning—Cleaning upholstering—Rugcleaning—Windshield cleaning—Sedan or closed body cleaning—Tire cleaning—Rim cleaning—Light lens cleaning—Caution.
CHAPTER XLII.
Tires, Build, Quality and Care[256]
Tire care—Tire chains—Cross chains—Tube care—Tube repairing—Tire and tube storage.
CHAPTER XLIII.
Electrical System[259]
General overhauling and tuning hints.
CHAPTER XLIV.
Automobile Painting[262]
CHAPTER XLV.
Carbon Removing[263]
Trouble Hints[264]
FORD SUPPLEMENT.
IThe car—its operation and care[269]
IIThe Ford Engine[277]
IIIThe Ford Cooling System[287]
IVThe Gasoline System[290]
VThe Ford Ignition System[295]
VIThe Ford Transmission[301]
VIIThe Rear Axle Assembly[307]
VIIIThe Ford Muffler[310]
IXThe Ford Running Gear[311]
XThe Ford Lubrication System[316]
XICare of Tires[320]
XIIPoints of Maintenance[323]
XIIIThe Ford One Ton Truck[325]
XIVThe F. A. Starting and Lighting System Installed on Sedans and Coupés[328]
Index[335]

ILLUSTRATIONS

FIGUREPAGE
[1].Typical Four-Cylinder Block13
[2].Cylinder Block with Head Removed13
[3].Removable Cylinder Head (Reversed)14
[4].Typical Cylinder Piston15
[5].Typical Piston Ring15
[6].Typical Connecting Rod16
[7].Counter-Balanced Crank Shaft17
[8].5-M-B Crank Shaft17
[9].Cam Shaft18
[10].Flywheel19
[11].8-Cylinder Valve Arrangement22
[12].Poppet Valve23
[13].Valve Types, Location and Operation24
[14].Valve Timing Marks25
[15].Knight Valve-Timing Marks—4-Cylinder27
[16].Knight Valve-Timing Marks—8-Cylinder28
[17].4-Stroke Cycle29
[18].Diagram of Action, 4-Cylinder 4-Cycle Engine31
[19].Power Stroke Diagram32
[20].Buick Engine—Parts Assembly36
[21].Buick Engine—Location Inside Parts Assembly37
[22].Buick Motor—End View38
[23].Liberty U. S. A. Engine39
[24].Splash Oiling41
[25].Plunger Pump Oiling System42
[26].Stromberg Model M Carburetor—Sectional View46
[27].Stromberg Carburetor Model M—Air Bleeder Action47
[28].Stromberg Carburetor Model M—Accelerating Well49
[29].Stromberg Carburetor Model M—Idling Operation51
[30].Stromberg Carburetor—Throttle 1⁄5 Open52
[31].Stromberg Carburetor—Throttle Wide Open53
[32].Stromberg Model M—Adjustment Points55
[33].Stromberg Model “L”—Adjustment Points58
[34].Sunderman Carburetor60
[35].Sunderman Carburetor61
[36].Sunderman Carburetor62
[37].Sunderman Carburetor63
[38].Schebler Model R Carburetor Assembled64
[39].Stewart Carburetor66
[40].Carter Carburetor70
[41].Schebler Carburetor Model Ford A—Sectional View72
[42].Schebler Carburetor Model Ford A—Adjustment Points73
[43].Holley Kerosene Carburetor76
[44].Holley Kerosene Carburetor Installment77
[45].Hot Spot Manifold79
[46].Holley Vapor Manifold—Ford Cars80
[47].Thermo-Syphon Cooling System82
[48].Muffler—Three Compartment86
[49].Muffler87
[50].Vacuum System—Top Arrangement89
[51].Vacuum System Installation90
[52].Vacuum System Diagram—Stewart Warner91
[53].Vacuum System—Inside View of Parts94
[54].Coil Diagram96
[55].Dynamo—Diagram of Action98
[56].Magnets—Pole Blocks101
[57].Armature Core—Wound Armature102
[58].Primary and Secondary Winding and Current Direction102
[59].Breaker—Slip Ring—Distributor103
[60].Bosch M Distributor and Interruptor—Housing Removed106
[61].Wiring Diagram Bosch Magneto, Type ZR-4107
[62].Wiring Diagram, North-East System—on Dodge Car115
[63].North-East Distributor—Model O—Ignition116
[64].North East Breaker-Box118
[65].Automatic Spark Advance Mechanism—North East121
[66].Atwater Kent Circuit Diagram—Type C. C.127
[67].Atwater Kent Contact Breaker—Type C. C.128
[68].Atwater Kent Distributor and Contactless Block128
[69].Distributor Wire Connections to Distributor129
[70].Atwater Kent Type C. C. Wiring Diagram130
[71].Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System133
[72].Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System133
[73].Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System134
[74].Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System134
[75].Atwater Kent Distributor and Contactless Block135
[76].Atwater Kent Wiring Diagram Type K-2136
[77].Atwater Kent K-2 Wiring137
[78].Atwater Kent Automatic Spark Advance Mechanism—A-K Type K-2138
[79].Atwater Kent Contact Breaker—Oiling Diagram—A-K Type K-2139
[80].Philbrin Contact Maker—Point Adjustment141
[81].Philbrin Contact Maker and Distributor Blade142
[82].Switch Case143
[83].Duplex High Frequency Switch144
[84].Philbrin Wiring Diagram145
[85].Bijur 2-V System Mounted on Hupmobile Engine149
[86].Bijur Starter Mechanism Showing Action151
[87].Bijur Starter Mechanism Showing Action152
[88].Wiring Diagram Model N—Hupmobile153
[89].Wiring Diagram—Jeffrey-Chesterfield Six155
[90].Wiring Diagram—Jeffrey Four158
[91].Hydrometer Syringe159
[911⁄2].Dodge Wiring Diagram162
[92].North East Model G Starter Generator164
[93].Delco Motor Generator—Showing Parts168
[94].Delco Motor Generator—Diagram of Operation170
[95].Delco Ignition Switch Plate173
[96].Delco Ignition Switch Circuit Breaker—Mounted173
[97].Delco Ignition Coil175
[98].Delco Wiring Diagram—Buick Cars176
[99].Delco Ignition Distributor177
[100].Delco Ignition Contact Breaker and Timer178
[101].Storage Battery, Sectional View180
[102].Storage Battery, Sectional View182
[103].Hydrometer Syringe183
[104].Spark Plug187
[105].Cone Clutch and Brake190
[106].Multi-Disc Unit Power Plant, Clutch and Transmission192
[107].Borg and Beck Clutch193
[108].Cone Clutch Leathers—Pattern—Cutting196
[109].Friction Transmission199
[110].Selective Type of Gear Shifts200
[111].Sliding Gear Transmission—Sectional View201
[112].Clutch and Transmission Assembly—Unit Power Plant203
[113].Slip Joint and Universal204
[114].Universal Joint Construction Diagram205
[115].Differential Action Diagram207
[116].Differential Assembly208
[117].Differential Adjusting Points209
[118].Allen Gearless Differential210
[119].Semi-Floating Rear Axle213
[120].Full-Floating Axle—Wheel-End Arrangement214
[121].Full-Floating Axle214
[122].Steering Knuckle and Front Axle Parts215
[123].I-Beam Front Axle216
[124].Brake—Types and Adjustment219
[125].Brake—Showing Toggle Arrangement220
[126].Transmission Brake—Equalizer220
[127].Brake—Arrangement and Adjustment—“Buick”221
[128].1⁄2-Elliptical Front Spring226
[129].Full-Elliptic Spring226
[130].3⁄4-Elliptical Rear Spring227
[131].Platform Spring227
[132].Cantilever Spring, Front228
[133].Cantilever Spring, Rear228
[134].Wheel Alignment Diagram230
[135].Worm and Sector Steering Gear233
[136].Worm and Nut Steering Gear234
[137].Rack and Pinion Type Steering Gear234
[138].Steering Wheel235
[139].Plain Bearings or Bushings236
[140].Shims237
[141].Bock Roller Bearing237
[142].Hyatt Roller Bearing238
[143].Double Row Radial Ball Bearing239
[144].Double Row Thrust Bearing241
[145].End Thrust Bearing241
[146].Car Arrangement245
[147].Ford Motor—Sectional View278
[148].Ford Motor—Valve and Cylinder Assembly279
[149].Ford Fuel System290
[150].Ford Transmission Assembly303
[151].Ford Rear Axle System308
[152].Ford Brake309
[153].Ford Spindle311
[154].Ford Chassis Oiling Chart317

THE AUTOMOBILE OWNER’S GUIDE

INTRODUCTORY CHAPTER
HISTORY OF THE GAS ENGINE AND EARLY AUTOMOBILE CONSTRUCTION

A great many experiments were conducted with the explosive type of motor between 1840 and 1860. These motors were very heavy and crude affairs and furnished little or no power. They were either abandoned or given up by those conducting the experiments, and had all but disappeared in the later 50’s. The chief difficulties that they could not overcome were, the finding of a suitable and combustible fuel, a way to distribute it to the explosion chambers in proper proportion, and a device to ignite it at the proper time. Many of these early inventions used coal tar gases and gunpowder as fuel.

The first designs for an internal combustion engine of the four stroke cycle type were devised in 1862 by M. Beau de Rochas. These designs were taken in hand by a German by the name of Otto, and many experiments were conducted by him and two other Germans, Daimler and Benz, which resulted in a fairly successful engine. The Otto Gas Engine Co., of Deutz, Germany, was then formed with Daimler as general manager. Experiments were carried on which resulted in many improvements, such as valve adjusting and electrical spark ignition. Many other smaller improvements were worked out which overcame many of the difficulties of the former and cruder devices.

The first gas engines were all of the single cylinder type, very heavily constructed and produced from three to five horse power. In 1886, Daimler conceived the idea of constructing the multiple type of engine with water-jacketed cylinders. Benz also completed a very successful motor in the late fall of 1886, which embodied the water cooling idea. The practical beginning of the gas engine as a factor in vehicle propulsion began in the fall of 1886, when Daimler applied his motor to a two-wheeled contrivance, which greatly resembled our present-day motorcycle. While this machine ran, it was not considered a very great success. Benz in the early part of 1887, connected his motor to a three-wheeled vehicle with which he was able to travel at the rate of three miles per hour.

The real beginning of the present-day automobile took place in Paris, France, in 1890, when M. Panhard secured the patent rights from Daimler to use his engine. He then built a four-wheeled vehicle, which carried some of the ideas of present-day construction, such as a steering device and brakes. To this he applied his engine and was able to travel at the rate of six miles per hour. In 1891 Peugeot Frères completed their vehicle and installed a Benz engine. This vehicle or car, as it was then called by the French government on account of its being mechanically driven, was able to make from seven to eight miles per hour.

The perfecting of the automobile was hampered very much between the years 1891 and 1898 by stringent laws that had been enacted by the French government, which all but prohibited the driving of a car on the public thoroughfare.

The first American-made automobile of the gas propelled type was completed in the year 1892 by Charles Duryea. This car embodied many of our present-day ideas but was very lightly constructed and under-powered.

In 1893 another car made its appearance in America. This car was built by Edward T. Haynes and was the beginning of the present-day Haynes’ line of famous cars.

The first automobile club was organized in Paris, France, in the year 1894 with the Marquis de Dion as president. The purpose of this club was to secure a reformation of the laws that had been enacted when the automobile made its first appearance on the public thorough-fare, and to make laws and rules to govern automobile racing.

At that time it was necessary when driving on a public highway to have some one run seventy-five feet in advance of a car waving a red flag, and to shout a warning at street intersections. These stringent laws, however, were repealed by the government through influential aid brought to bear on it by the automobile club assisted by the rapid progress of the automobile industry.

PURCHASING A NEW CAR
Things to be Considered to Make the Investment Safe

When you are going to buy a new car go about it in this manner and protect your investment.

First.—Choose the car that suits you best in regard to cost, operation, and appearance.

Second.—Inquire as to the financial status of the manufacturer. If there is anything wrong with the car, or the management of the company, it will show up here.

Third.—Orphaned cars may run as well and give as good service as anybody could ask for, but when a company fails or discontinues to manufacture a model, the car immediately loses from one-third to one-half of its actual value. That is, providing you wish to trade it in or sell it as a used car.

Fourth.—What kind of service does the agency in your vicinity give? Do they take any interest in the cars they sell after they are in the hands of the purchaser?

Fifth.—The amount of interest taken in your purchase by the agent or service station usually determines the amount of depreciation at the end of the season.

Sixth.—If you are purchasing your first car some little adjustments will be required, and conditions will arise that require understanding and attention. You, therefore, must acquire either a functional and mechanical knowledge of the operation, or depend on the agent or service station for help.

Seventh.—You will probably say that you can get along without such help. You probably can, but what will be the results? Will you be required to stand a loss in the long run resulting from excessive repair bills and depreciation which could have been prevented to a great extent?

Eighth.—Remember that an agent can fool you when you are buying, but that you cannot fool him if you wish to sell or trade in.

Ninth.—Remember that this book, The Automobile Owners’ Guide, was written to assist you in just such cases as we have presented, and that by spending a little time in study you can acquire a working knowledge of your car, and become independent of the service station and the agent, which will result in a big saving in both repair bills and depreciation.

PURCHASING A USED CAR
How to Estimate Its Value

The question is often asked, Does it pay to invest money in a second-hand car? The answer may be either yes or no, and depends entirely upon the condition of the car.

For example, A and B purchase a new car at the same time. A is rather conservative. He is also a careful driver and gives his car the best of attention. B is a careless driver and pays little or no attention to adjustments and lubrication.

A has seen to proper lubrication and has kept the parts properly adjusted and tightened up, and his careful driving has kept the alignment in perfect condition. His car at the end of the first season requires a little overhauling which will put it in as good condition as it was when it was new as far as service is concerned, and it is worth 85 to 90 per cent of its original value.

B has not seen to proper lubrication and has allowed his motor to overheat. The cylinders and pistons are scored and worn, and the valves are warped and do not seat properly. He drove into deep ruts and chuck-holes, and bumped into curbs and posts while turning around. His axles and wheels are out of line; the frame and all the running parts which it supports are out of alignment. Overhauling will not put this car in A-1 condition, and it is not worth more than 30 per cent. of the original cost price. It would be a poor investment at any price to an owner who is buying it for his own use.

Selecting and Testing a Used Car.—First.—If you are buying from a dealer who trades in cars, judge his statement of the condition of a car according to his ability as a mechanic and according to his reputation for accuracy. If you are buying from a reputable used car dealer his word can usually be taken as a correct statement of conditions as his business depends upon the accuracy of his statements and he knows the condition of a car before he buys it.

Second.—See the former owner. Get his statement of the condition of the car and the care it has had, and judge it by his appearance, and the general appearance of his home and property.

Third.—If the car is listed as Rebuilt or Overhauled, see if the oil-pan, differential, and transmission covers have been removed. If this has been done the old grease will either have been cleaned off or show marks of the removal. If these marks are found the proper adjustments and replacements have probably been made.

Fourth.—Don’t judge the mechanical condition of a car by its outward appearance.

Fifth.—Examine the tires and figure the cost of replacement if any are found in poor condition.

Sixth.—Jack up the front axle and test the wheels for loose or worn bearings.

Seventh.—Grasp the wheel at the top and bottom and wiggle it to determine whether the spindle bolts or steering device connections are worn.

Eighth.—Jack up the rear axle, set the gear shift-lever into high-speed, move the wheel in and out from the bottom to discover worn bearings, and move the wheel, forward and backward, to determine the amount of back-lash in the differential and universal joints.

Ninth.—Test the compression of the cylinders while the engine is cold using the hand crank. If one cylinder is found weak, a leak exists and the escaping compression can be heard.

Tenth.—Run the motor until it is warm. If any weakness in compression is noticeable the cylinders are probably scored, or the rings may be worn. The valves may also be warped, thereby preventing them from seating properly.

Eleventh.—Examine the shoulders of the cross-members supporting the engine, radiator, or transmission to see if they are cracked or broken.

Twelfth.—The battery may have deteriorated through improper attention. Test the solution with a hydrometer. If it is found well up, it can be passed as O. K.

Thirteenth.—Don’t judge the condition of the car by the model, as a two or three-year-old model may be in better mechanical condition than a six-month or year-old model.

DRIVING INSTRUCTIONS

A new driver should remain cool and take things in a natural way as a matter of course. There is nothing to get nervous or excited about when learning to drive a car. Any one can master the art of driving quickly by remaining cool and optimistic.

First.—Acquire some definite knowledge of the operation of the engine and its accompanying devices.

Second.—Have some one explain the operation of the accelerator, spark, and throttle levers.

Third.—Study the relative action of the clutch and gear-shifting pedal.

Fourth.—The new driver takes the wheel and assumes a natural and calm position with the muscles relaxed.

Fifth.—He adjusts the motor control levers. The throttle lever is advanced one-fourth its sliding distance on the quadrant. The spark lever is set to one-half the sliding distance on the quadrant.

Sixth.—Push the ignition-switch button, IN, or ON, and press the starter button, letting it up as soon as the engine begins to fire.

Seventh.—Not all gear-shifts are marked, consequently it is a good idea to let the new driver feel out the different speed changes. This is accomplished by pushing out the clutch and placing the shift-lever into one of the four slots. Now let up the clutch pedal until it starts to move the car, continue the feeling-out process until the reverse speed gear is located, and at this point impress on him that first and reverse speeds, are always opposite each other, lengthwise either on the right or left side of neutral, while second speed is always crosswise opposite reverse, and high-speed is opposite first on the other side of neutral.

Eighth.—Starting the car with engine running, advance the spark-lever three-fourths the distance on the quadrant, advance the throttle until the engine is turning over nicely (not racing). Place one hand on the steering-wheel and with the other grasp the gear-shift-lever, push in the clutch pedal, hold it for five seconds, in order that the clutch brake may stop rotation. Place the shift-lever into the first-speed slot and let up on the clutch pedal. The car should be driven four or five hundred feet on this speed until the driver acquires the “nack” of steering.

Ninth.—To shift to second speed advance the gas throttle until the car gathers a smooth rolling motion, press in the clutch pedal and allow three to five seconds for the brake to retard the speed of the clutch, then shift the lever to second speed and release the clutch pedal easily.

Tenth.—To shift into high-speed retard the throttle lever a trifle (to prevent the engine from racing), throw out the clutch and shift the lever into the high-speed slot. Perform these operations slowly but without hesitation.

Eleventh.—To shift to reverse speed go through the same operation that you followed when first was used, except that the shift-lever is placed in the reverse slot.

Twelfth.—The reverse speed-gear is never engaged unless the car is at a “stand-still,” as this gear turns in an opposite direction.

Thirteenth.—Always test the emergency brake lever and the speed shift-lever, to be sure that they are in a neutral position before starting the engine.

Fourteenth.—Remember that in case of emergency the car can be stopped quickly by pushing in both foot-pedals. Pressure on the clutch pedal disconnects the engine from the car, while pressure on the “foot” or service brake pedal, slows up the motion of the car and will bring it quickly to a stand-still.

Fifteenth.—Always push the clutch out when using the service brake to check the rolling motion of the car.

Sixteenth.—When you wish to stop the car and motor kick out the clutch and hold it in this position while you stop the rolling motion of the car with the service brake and shift the gears to neutral. Then set the emergency brake and turn off the switch to stop the motor.

If the engine cannot take the car up a steep grade in low speed (due to defective motor or gravity fuel feed) stop, engage reverse speed, turn off the ignition switch, and let the car back down to level or a place where you can turn around, and back up the hill. The reverse speed is geared from one and a half to two times lower than first speed.

Nineteen.—To stop the back wheels from skidding turn the front wheels in the direction which the back wheels are sliding and release the brakes. Turning away or applying the brakes adds momentum to the sliding motion.

Twenty.—If for any reason you must or cannot avoid driving into the ditch unless the ditch is very shallow, turn the car directly toward the opposite bank. The front or rear springs will lodge in the bank and prevent the car from rolling over and crushing the occupants, and the car can be drawn out more easily from this position.

ROAD RULES FOR CITY AND COUNTRY

1.—Be courteous to all whom you meet and give your assistance if necessary.

2.—When encountering a bad stretch of road, with the track on your side, don’t drive in and force another machine coming towards you to get out of the track. WAIT.

3.—Never block a track. In case you wish to stop and talk to some one, drive to one side.

4.—Keep on the right hand side of the road at all times, whether moving or standing, except as prescribed in Paragraph 5.

5.—In passing vehicles traveling in the same direction, always pass on the left and blow the horn.

6.—In passing a vehicle that has just stopped, slow down and sound the horn.

7.—In changing your direction, or stopping, always give the appropriate hand signal.

8.—Hand signals, straight up or up on 45° angle, STOP. Straight out or horizontal, TURNING TO THE LEFT. Down at an angle of 45°, TURNING TO THE RIGHT.

9.—The distance between vehicles outside of towns and cities, 20 yards; between vehicles passing through towns and cities, 5 yards; between vehicles halted at the curb, 2 yards.

10.—Bring all vehicles under easy control at street and road intersections.

11.—A maximum driving speed should not exceed 7 miles in business sections of cities, 15 miles in residential sections, 25 miles on country roads.

12.—Form the habit of slowing down and looking both ways before crossing tracks.

13.—Always pass a street car on the right side.

14.—Always stop 8 feet from a street car when passengers are getting off, unless there is a safety zone, then drive slowly.

15.—Never drive over the side-walk line while waiting for signal of traffic officer.

16.—Notify traffic officer which way you wish to turn with hand signal.

17.—Always stop and wait for an opening when driving from a side street or road into a main thoroughfare.

18.—Make square turns at all street corners unless otherwise directed by traffic officer.

19.—If you wish to turn from one street into another wait until the traffic officer gives the straight ahead signal, then give the appropriate signal to those in the rear.

20.—Always drive near the curb when you wish to turn to the right, and to the right of the center line of the street when you wish to turn to the left.

21.—Drive straight ahead at 42nd St. and 5th Ave., N. Y., and at Market and Broad St., Newark, N. J. These corners handle more traffic than any two corners in the United States. No turns are made at either corner.

22.—Exercise care not to injure road ways.

23.—Do not damage improved roads by the use of chains when unnecessary.

24.—In case the car is not provided with chains, rope wrapped around the tires will make a good substitute.

25.—In case of fire, do not try to put it out with water as the gasoline will only float and spread the fire. Use a fire extinguisher or smother with sand or with a blanket.

WHAT TO DO IN CASE OF ACCIDENT

1.—In case of injury to person or property stop car and render such assistance as may be needed.

2.—Secure the name of person injured or of owners of said property.

3.—Secure names and addresses of witnesses to the accident.

4.—Draw diagram of streets as shown in [Fig. A]. Show relative positions of the colliding vehicles and the object of pedestrian just before the accident.

Fig. A. Street Intersection

5.—Label streets and every object depicted and add measurements and line showing course followed by vehicles, etc., and any explanatory statements which would aid an understanding of the occurrence.

6.—File this report at police headquarters.

CHAPTER I
GAS ENGINE CONSTRUCTION, AND PARTS

We will use for purposes of illustration the common four-cylinder, four cycle, cast en bloc, “L”-head type of motor, as this type is used probably by 90% of the automobile manufacturers. The block of this type of motor is cast with an overlapping shoulder at the upper left hand side which contains a compartment adjoining the combustion chamber in which the intake and exhaust valves seat, and the casting is made, in the shape of the Capital letter L turned upside down. This arrangement allows both valves to seat in one chamber and to operate from one cam shaft.

The operation of each cylinder is identically the same whether you have a one or a many cylindered motor, consequently when you have gained a working knowledge of one cylinder, others are a mere addition. This may sound confusing when the eight or twelve cylindered motor is mentioned, but is more readily understood when we consider the fact that an eight or twelve cylindered motor is nothing more than two fours or two sixes, set to a single crank-case or base in V-shape to allow the connecting rods of each motor to operate on a single crank shaft. This arrangement also allows all the valves to operate from a single cam shaft, thereby making the motor very rigid and compact, which is an absolute necessity considering the small space that is allowed for the motor in our present-day designs.

[Fig. 1]. The casting or block, which is the foundation of the whole motor or engine, usually has a removable head which allows for easy access to the pistons and valves. The block is cast with a passage or compartment through the head and around the cylinders through which water circulates for cooling the adjoining surfaces of the cylinders. This alleviates the danger from expansion and contraction caused by the tremendous heat generated in and about the combustion chambers. This block also contains the cylinders and valve seats. The pistons and valves are fitted to their respective positions as construction progresses.

Det. Head
Exhaust Pt.
Intake Pt.
Re. Plate		Cyl. Block
Upper Crankcase
Lower Crankcase

Fig. 1. Typical Four-cylinder Block

[Fig. 2]. The block with head removed shows the smooth flush surface of the block face and the location of the cylinders in which the pistons operate or slide, with each power impulse or explosion. When the piston is at its upper extreme it comes within a sixteenth of an inch of being flush with the top of the block, while the valves (also shown in Fig. 2) rest on ground-in seats, in their respective chambers, and are operated by a stem which extends downward from the head through a guide bushing in the block to the cam shaft.

Pistons
Water Vents
Intake Valve
Exhaust Valve

Fig. 2. Cylinder Block With Head Removed

The location of the water vents is also shown, through which water is circulated to prevent the cylinders from overheating which would cause the pistons to “stick” from expansion.

[Fig. 3]. The top or head of the motor is removed, exposing the combustion chambers. These chambers must be absolutely air-tight as the charge of gas drawn in through the inlet valve is compressed here before the explosion takes place, and low compression means a weak explosion, which causes the motor to run with an uneven-jumpy motion, and with an apparent great loss of power. A copper fiber insert gasket is placed between the top of the block and the head before it is bolted down. This gasket prevents any of the compression from escaping through unevenness of the contact surfaces, as metal surfaces are prone to warp when exposed to intense heat. It is necessary to turn the bolts in the head down occasionally, as the heat causes expansion. The following contraction, which loosens them, results in a loss of compression and a faulty operation of the motor.

Combustion Chamber
Spark Plug Vent
Water Circulating Vent
Bolt Holes

Fig. 3. Removable Cylinder Head (Reversed)

The spark-plug vents through the head are usually located directly over the piston although in some cases they are over the valve head and in some motors which are cast without a removable head they may be at one side of the combustion chamber. The location of the spark-plug does not materially affect the force of the explosion, although when it is located directly over the piston a longer plug may be used, as the pistons do not come up flush with the top of the block, and a spark-plug extended well into the combustion chamber will not become corroded with carbon or burnt oil as is usually the case with a plug which does not extend beyond the upper wall surface of the combustion chamber.

[Fig. 4]. The plunger or piston is turned down to fit snugly within the cylinder and is cast hollow, with two shoulders extending from the inside wall.

Head
Ring
Wrist Pin
Oil Ring		Ring Groove
Bushing
Wrist Pin
Set Screw
Ring Groove		Set Screw
Bushing
Wrist Pin

Fig. 4. Typical Cylinder Piston

[Fig. 4A] shows a split piston. Three grooves are cut into it near the head to receive the piston rings. The width and depth of these grooves vary according to the size of the piston. A hole is bored through the piston and shoulders about half way from each end. The bushing or plain bearing shown in [Fig. 4B] is pressed into this hole and forms a bearing for the wrist pin also shown in [Fig. 4B]. Wrist pins are usually made of a much softer metal than the bearing, and are subjected to severe duty, which often causes them to wear and produce a sharp knock; this may be remedied by pressing out the pin, giving it a quarter turn, and replacing it in that position.

Fig. 5. Typical Piston Ring

[Fig. 5] shows a split joint piston ring. Piston rings are usually made from a high grade gray iron, which fits into the grooves in the piston and springs out against the cylinder walls, thereby preventing the compressed charge of gas from escaping down the cylinder, between the wall and the piston. [Fig. 5A] shows a piston equipped with leak-proof rings; this type of piston ring has overlapping joints, and gives excellent service, especially when used on a motor which has seen considerable service. [Fig. 5B] illustrates how piston rings may line up, or become worn from long use, or from faulty lubrication. This trouble may be easily detected by turning the motor over slowly. The escaping charge can usually be heard and the strength required to turn the motor will be found much less uniform on the defective cylinder.

The motor should be overhauled at least once every year, and by applying new rings to the pistons at this time new life and snappiness may be perceived at once.

The connecting rod shown in [Fig. 6] has a detachable or split bearing on the large end, and takes its bearing on the crank pin of the crank shaft. The small or upper end may have either a hinge joint or press fit to the wrist pin. This rod serves as a connection and delivers the power stroke from the piston to the crank shaft. These rods are required to stand very hard jars caused by the explosion taking place over the piston head. The bearings are provided with shims between the upper and lower half for adjusting. Piston or connecting rod bearings must be kept perfectly adjusted to prevent the bearings from cracking or splitting which will cause the rod to break and which may cause considerable damage to the crank case.

Wrist Pin BearingUpper Half
Crank Pin Bearing		Lower Half
Bearing End Overlaps
Shims
Bolts
BushingRodShims

Fig. 6. Typical Connecting Rod

[Fig. 7] shows a counter balanced crank shaft. This type of crank-shaft is provided with weights which balance the shaft and carry the momentum gathered in the revolution.

Rear Main BearingWeightCenter
Main Bearing		Front Main Bearing
Fly Wheel
Attached to
this Ring		 Timing Gear
Attached
Here
Crank Pin Crank Pins

Fig. 7. Counter-Balanced Crank Shaft

Main Bearings

Fig. 8. 5-M-B Crank Shaft

[Fig. 8] shows the plain type of crank shaft with the timing gear attached to the front end and the fly-wheel attached to the rear end. The crank shaft shown is carried or held by five main bearings, which is an exception, as the majority of motor manufacturers use only three main bearings to support the crank shaft, while in some of the smaller motors only two are used. These bearings are always of the split type, the seat for the upper half is cast into the upper part of the crank-case, and the lower half is usually attached to the upper half by four bolts which pass through the flange at each side of the bearing. Small shims of different sizes are employed between the flanges of each half of the bearing in order to secure a perfect adjustment which is very essential, as these bearings are subjected to heavy strains and severe duty. A shim may be removed occasionally as the bearing begins to show wear. A worn main bearing can be detected by placing the metal end of a screw-driver or hammer on the crank-case opposite the bearing and the other end to the ear. If the bearing is loose or worn a dull bump or thud will be heard. This looseness should be taken up by removing a shim of the proper thickness.

Cam GearBearingsCams
Cams

Fig. 9. Cam Shaft

Main bearings run loose for any length of time will be found very hard to adjust as the jar which they are subjected to invariably pounds them off center which makes readjustment a very difficult task to accomplish with lasting effect. New main bearings in a motor should always be scraped to secure a perfect fit. A loose piston or connecting rod bearing will produce a sharp knock which can easily be determined from the dull thud produced by a loose main bearing. ([Fig. 9].) The cam shaft revolves on bearings and is usually located at the base of the cylinders on the left hand side looking toward the radiator and carries a set of cams for each cylinder. The cam pushes the valve open, and holds it in this position, while the piston travels the required number of degrees of the cycle or stroke.

The cam shaft is driven from the crank shaft usually through a set of timing gears, and operated at one-half the speed of the crank shaft in a four cycle motor, as a valve is only lifted once, while the crank shaft makes two revolutions or four strokes. The cam-shaft bearings, and the timing gears are usually self-lubricating and require very little attention. Timing of the cam shaft is a rather difficult matter and will be treated in a following [chapter] under the head of valve timing.

Start GearKey-Seat
Shaft-Seat
Cone Clutch
Seat		Disc Clutch
Small Disc
Bolt on Here

Fig. 10. Flywheel

The oil pan or reservoir forms the lower half or base of the crank case. The lubricating oil is carried here at a level which will allow the piston rods to dip into it at each revolution of the crank shaft. The timing gears receive their lubrication from the supply carried in the reservoir by means of a plunger or piston pump which is operated from the cam shaft. The balance of the motor is usually lubricated by a splash system taken up in a later [chapter] on lubrication. The oil is carried at a level between two points marked, high and low, on a glass or float gauge which is located on the crank case. A gasket made of paper or fiber is used between the union or connection of the oil reservoir and the upper half of the crank case to prevent the oil from working out through the connection.

[Fig. 10] represents the flywheel. The flywheel is usually keyed to the crank shaft directly behind the rear main bearing. This wheel is proportionate in weight to the revolving speed of the motor, which it keeps in balance by gathering the force of the power stroke. The momentum gathered by it in this stroke carries the pistons through the three succeeding strokes called the exhaust, intake, and compression strokes. The flywheel also serves as a connection between the power-plant and the running gear of the car, as a part of the clutch is located on it, and the connection takes place either in the rim or on the flange.

CHAPTER II
VALVE CONSTRUCTION, TYPES, AND OPERATION

The proper and accurate functional operation of the valves is as necessary to successful motor operation as the proper adjustment of a hairspring is to a watch, for if a hairspring becomes impaired in any way, a watch will not keep correct time. This is the case in a motor when a valve becomes impaired. The valves in a motor, therefore, must be considered the most vital part conducive to successful and economical operation of the motor.

The valves are manufactured from a high grade tungsten or carbon steel, and are designed to withstand the intense heat which the heads located in the combustion chambers are subjected to, without warping. A perfect seat is required to prevent leaking, which will cause low compression and a weak power impulse, thus reducing the power and harmony of successful operation.

The poppet valve is used by about ninety-five per cent. of motor manufacturers. This type of valve is mechanically operated from the cam shaft at one-half the crank shaft speed, as a valve is lifted only once in every four strokes, or two revolutions of the crank shaft. The reduction in speed is accomplished by using a gear on the cam shaft, twice the size of that on the crank shaft.

The heads and chambers must be kept free from carbon which forms and bakes into a shale and has a tendency to crack and chip as the temperature changes in the combustion chambers. These chips are blown about in the cylinders until they lodge or are trapped by the descending valves. It then forms a pit on the seat and prevents the valves from seating properly. This leaves an open space which attracts more carbon, and the entire functional action of the valve is soon impaired, necessitating regrinding in order that it may properly seat again.

Carbon is generated from a poor gas mixture or from excessive use of lubricating oil and may be considered the chief cause of improper functional action of the valves.

VALVE CONSTRUCTION, TYPES, AND OPERATION 8-CYLINDERED V-TYPE ENGINE

Valve Head
Removable Plates		Cam ShaftValve Head
Valve Seat Valve Seat
Tappet for
Adjusting Valves		 Tappet for
Adjusting Valves

Fig. 11. 8-Cylinder Valve Arrangement

[Fig. 11] shows the location of the cam shaft, valves, and tappet adjustment, on a V-shaped engine. The cylinders of this type of engine are arranged in two blocks, consisting of four cylinders in each, set directly opposite each other on an angle of 90°. The connecting rods from opposite cylinders are yoked and take their bearing on the same crank pin. This arrangement allows the intake and exhaust valves of each opposite cylinder to operate from a single cam shaft, or in other words the entire sixteen valves are operated by a single cam shaft carrying eight cams. Consequently an eight or twelve cylindered engine is identical in regard to valve timing to either a four or six cylindered engine.

Valve Head

Valve Seat

Valve Guide

Valve Stem

Valve Spring

Sp. Seat

Cap Screw

Tappet

Lock Nut

Guide Bushing

Push Block

Roller

Cam

Fig. 12. Poppet Valve

[Fig. 12] shows a poppet valve. This type of valve has only one adjustment, called the tappet. The adjustment is made by turning the cap-screw out of the push block until the head comes into contact with the valve stem. The lock nut on the cap screw is then turned down tightly to the push block to hold the adjustment. A strong spring is placed on the valve stem which causes it to close quickly and remain closed until it comes into contact with the cam.

Valves are set and operate in three different positions as shown in [Fig. 13]. The exhaust valve in this case seats on the floor of the combustion chamber and is operated by the stem which extends through the casting to the tappet, while the intake valve seats on the upper wall of the combustion chamber and is operated from over head by a push-rod extending from the tappet to a rocker-arm. When both valves are operated from above and seat on the upper wall of the combustion chamber the motor is referred to as the overhead valve type of motor. In the majority of motors both valves seat on the floor of the valve chamber.

Rocker Arm
Valve Stem
Valve OpenValve Seat
Combustion
Chamber		Tappets
Cam
Cam Shaft
Overhead
Type Valve		Push Rod
Poppet-Type
Valve

Fig. 13. Valve Types, Location and Operation

Valve Timing.—Valve timing is usually accomplished by setting the first, or exhaust valve cam, to correspond with a mark on the flywheel and cylinder (shown in [Fig. 14]).

This is accomplished by lining up the 1⁄4, or 1⁄6 D-C mark on the flywheel rim with the center mark on the cylinder block, and means that 1⁄4, or 1⁄6, pistons are on upper dead center of the compression stroke, the flywheel is then turned a trifle until the marks E-C, or Ex-C, is at upper dead center and in line with the mark on the cylinder block. This means that the exhaust valve closes at this point. The cam shaft is then turned in the running direction and the cam shaft gear meshed at the valve closing or seating point. This is all that is necessary as the other cams take up correct operation when any one cam is set properly.

Another method of valve timing used by some motor manufacturers is shown in [Fig. 14]. It is simply necessary in this case to line up the prick punch marks on the timing gears—after getting the first position on upper D-C of the compression stroke—to acquire correct valve time. No definite or average scale can be given for valve timing, as all different types of motors are timed differently. These instructions must be secured from the manufacturer when the motor is not marked.

Cylinder Marks Camshaft
Gear
1-4 Pistons
on Upper
Dead Center
FLY-WHEEL MARKS
Running Direction of
Fly Wheel
MARKS LINED UP
Timing Gear
Punch Marks		Crankshaft
Gear

Fig. 14. Valve Timing Marks

Valve Grinding.—A valve-grinding compound can be purchased at any garage or service station or one may be compounded by mixing emery dust with a heavy lubricating oil until a thin paste is formed. The valve spring is released next by forcing up the tension with a screw driver or valve lifter. A small H-shaped washer is drawn from a groove near the end of the stem, which frees the valve; it can then be pushed up and raised through the guide. A small spring is placed over the valve stem. This spring should be strong enough to raise the valve one-half inch above the seat. A thin film of the grinding compound is evenly applied to the seating face of the valve head, a screw driver or ratchet fork is set in the groove on the head of the valve, and the handle rolled between the palms of the hands, covering about one-third of the distance around the valve seat; the valve is let up after the motion has been repeated four or five times, and repeated at another angle until the entire surface of the valve is smoothly ground and allows the valve to seat perfectly.

Valves.—The sleeve valve type of motor was invented several years ago by Charles A. Knight. He met with some difficulty in having it manufactured in this country because the lubrication system was thought to be inadequate and the poppet valve was then at the height of its popularity with the manufacturer of engines.

Knight took his engine to Europe and made some slight improvements on it. It was then taken over and manufactured by one of the large automobile manufacturing companies of that continent and is now being used by many of the celebrated automobile manufacturers of every country.

The principle of operation does not differ in any respect from the ordinary type of four cycle motor, except, that instead of having the poppet type of valves it has a set of sleeves which slide up and down on the piston. The sleeves are operated from an eccentric shaft by a short connecting rod and carry ports which are timed to line up with the ports of the intake and exhaust manifold ports at the proper time in the cycle of operation.

[Fig. 15] shows the method of timing the sleeves on the four cylinder engine. First, turn the motor over in the running direction until the marks (I-4-T-C) on the flywheel are in alignment with the marks on the cylinder casting. Turn the eccentric shaft in the running direction until the marks A, B, C, shown in [Fig. 15] are lined up, and then apply the chain.

Timer
Shaft
Sprocket

Crank Shaft Sprocket

Fig. 15. Knight Valve-Timing Marks—4-Cylinder

To check up on the timing, back the flywheel up an inch or two and insert a thin piece of tissue paper into the exhaust port and turn the engine in the running direction until the paper is pinched, which signifies that the valve is closed. The marks on the flywheel, timing gears, and the crank case should be in alignment. [Fig. 16] shows a diagram of the timing marks on the eight cylinder Knight engine. The method of timing this engine is as follows: (1) Turn the engine over until the marks I-4-R-H—D-C align with the marks on the crank case. (2) Turn the eccentric shaft and sprocket until the arrows shown in [Fig. 16] are in line with the guide marks on the front end of the chain housing. Then put on the chain and check up the timing, using the thin piece of tissue paper.

Eccentric Shaft
Sprocket Hub

Mark on
Eccentric Shaft
Sprocket

Guide Mark on
Crank Case

Crank Shaft
Sprocket

Fig. 16. Knight Valve-Timing Marks—8-Cylinder

VALVE CONSTRUCTION

If the sleeve rods are removed for some reason, the bearings should be fitted very loosely to the eccentric shaft when they are put back. A looseness of about .008 of an inch is permissible.

CHAPTER III
THE OPERATION OF A 4-CYCLE, 4-CYLINDERED ENGINE

The four-cycle or Otto stroke type of gasoline engine should rightly be called the four-stroke-cycle engine, as it requires four strokes and two revolutions of the crank shaft to complete one cycle of operation.

This type of motor is used almost universally by the manufacturers of pleasure cars due to its reliability, and to the ability it has to furnish continuous power at all speeds with the minimum amount of vibration.

Firing
Stroke		Exhaust
Stroke		Intake
Stroke		Compression
Stroke
1234

Fig. 17. 4-Stroke Cycle. 1—Cylinder in Action

[Fig. 17] shows a diagram of one cylinder in the four strokes of the cycle, and the distance traveled by the crank shaft during each stroke. No. 1 begins with a charge of compressed vapor gas in the cylinder and is called the firing or power stroke. The ignition system (explained in a later chapter) furnishes a spark at from five to fifteen degrees early or before the piston reaches top dead center. Although the stroke theoretically starts before the piston reaches its highest point of ascent, the actual pressure or force of the explosion is not exerted until the piston has crossed dead center. This is due to the fact that the piston travels very rapidly, and that it requires a small fraction of a second for spark to ignite the compressed charge of gas. It may, therefore, be easily seen that, if the spark did not occur until the piston is on or has crossed dead center, the piston would have traveled part of the distance of the stroke, and as it is moving away from the highest point of compression the pressure is reduced by allowing more volume space which causes a weak explosion and a short power stroke. The intake and exhaust valves are closed through the duration of the power stroke.

No. 2. The exhaust stroke begins from fifteen to thirty degrees early, or before the piston reaches lower dead center on the firing stroke. The exhaust valve opens at the start of this stroke allowing the pressure of the burnt or inert gas to escape before the piston begins to ascend on the upward part of the stroke, and closes seven to ten degrees late to allow the combustion chamber to clear out before the next stroke begins.

No. 3. The intake or suction stroke begins with the piston descending from its highest level to its lowest level. The intake valve opens ten or twenty degrees late, and as the piston is traveling on its descent, considerable vacuum pressure has formed which draws suddenly when the valve opens and starts the gas from the carburetor in full volume. The entire length of this stroke creates a vacuum which draws a full charge of vaporized gas into the cylinder through the open intake valve. The intake valve closes from ten to twenty degrees late in order that the full drawing force of the vacuum may be utilized while the piston is crossing lower center.

No. 4. The compression stroke begins at the end of the intake stroke with both valves closed. The piston ascends from its lowest extreme to its highest level, compressing the charge of gas which was drawn into the cylinder on the intake or suction stroke; and at the completion of this stroke the cylinder is again in position to start No. 1, the firing stroke, and begin a new cycle of operation. The cam shaft is driven from the crank shaft through a set of gears or a silent chain, and operates at one-half the speed of the crank shaft as a valve is lifted once through the cycle of operation, or two revolutions of the crankshaft.

1234
Firing
Val. Closed		Compressing
Val. Closed		Exhausting
Ex. Val. Open		Intake
In. Val. Open

Fig. 18. Diagram of Action, 4-Cylinder 4-Cycle Engine

[Fig. 18] shows the operation of a four-cylindered motor as it would appear if the cylinder block were removed. The timing or firing order of the motor shown in this diagram is 1-2-4-3. No. 1 cylinder is always nearest the radiator and on the left in this diagram. No. 1 cylinder is firing. The intake and exhaust valve remain closed while this stroke is taking place. This causes the entire force of the explosion to be exerted on the head of the receding piston. The cylinders, as may be seen in the diagram, are timed to fire in succession, one stroke behind each other. While No. 1 cylinder is on the firing stroke, No. 2 cylinder is compressing with both valves closed and will fire and deliver another power impulse as soon as No. 1 cylinder completes and reaches the lowest extreme of its firing stroke. No. 3 cylinder, being fourth in the firing order, has just completed the firing stroke and is starting the exhaust stroke which forces the burnt and inert gases out of the cylinder through the open exhaust valve. No. 4 cylinder which is third in the firing order has just completed the exhaust stroke and is about to start the intake or suction stroke with the exhaust valve open. This diagram should be studied and memorized as it is often necessary to remove the wires which may easily be replaced if the firing order is known, or found by watching the action of the exhaust valves and made to conform with the distributor of the ignition system. (Note the running direction of the distributor brush and connect the wires up in that direction.) For the firing order given above connect No. 4 wire to No. 3 distributor post, and No. 3 wire to No. 4 post, as this cylinder fires last.

1-CYL. 2-CYL.
4-CYL. 8-CYL.

Fig. 19 Power Stroke Diagram

[Fig. 19] shows a diagram of the power stroke impulse delivered to the cycle in a one, two, four, and eight cylindered motor. A complete cycle consists of 360 degrees, and as there are four strokes to the cycle an even division would give a stroke of ninety degrees, which is not the case, however, owing to the fact that the valves do not open and close at the theoretical beginning and ending point of each stroke which is upper dead center and lower dead center. The firing or power impulse stroke begins at approximately five to seven degrees before the piston reaches upper dead center on the compression stroke and ends from fifteen to thirty degrees before the piston or cycle of rotation of the crankshaft reaches lower dead center. This results in a power impulse of less than ninety degrees, which varies accordingly with valve timing in the different makes of motors. Consequently we have a power stroke of a little less than ninety degrees in a one-cylinder motor; two power strokes of a little less than 180 degrees in a two cylinder motor, while the power impulse of the four-cylinder motor very nearly completes the cycle. In the six, eight, and twelve cylinder motor the power strokes overlap, thereby delivering continuous power of very nearly equal strength.

Twin, Four, and Six Cylindered Motors.—The operation of the twin cylindered motor varies very little from the single four or six. It is simply a case where two, four, or two six cylindered motors are set to a single crank case at an angle which will allow the piston or connecting rods from the opposite cylinders to operate on a single crank shaft. When the cylinders are set directly opposite each other the connecting rods are yoked and take their bearing on a single crank pin of the crank shaft. This, however, is not always the case, for in some motors the connecting rods take their bearing side by side on the crank pin. The cylinders in this case are set to the crank case in a staggered position to allow the connecting rods from each cylinder to operate in line with the crank shaft.

The cylinder blocks are usually set to the crank case at an angle of ninety degrees and are timed to furnish the power impulse or stroke opposite each other in the cycle of operation. The advantage of this formation is that two power strokes are delivered in one cycle of operation, which increases the power momentum and reduces the jar or shock of the explosion causing a sweet running vibrationless motor.

The valves are usually operated by a single cam shaft located on the upper inside wall of the crank case. Valve timing is accomplished by following the marks on the flywheel or lining up the prick punch marks on the gears, as shown in [Chapter II] on valves.

When a magneto is used to furnish the current for ignition on an eight cylinder motor it has to be operated at the same speed as the crank shaft, as a cylinder is fired at each revolution of the crank shaft and an interruption of the current is required at the breaker points to produce the secondary or high tension current at the spark plug gaps.

Twelve cylindered motors are usually equipped with two distributors or a dual system, or two magnetos driven separately through a set of timing gears.

Knight or Sleeve Valve Motor.—The Knight or sleeve valve motor operates on the same plan as the ordinary type of motor except that the valves form a sleeve and slide over the piston. The sleeves are operated by an eccentric shaft and are provided with ports which are timed to conform with the ports of the intake and exhaust manifolds at the proper time.

MOTOR HORSEPOWER
S. A. E. Scale
FOUR-CYCLE HORSEPOWER RATING

Bore1 cyl.2 cyl.4 cyl.6 cyl.
23⁄4 3.00 6.0012.0018.00
27⁄8 3.00 6.5013.0020.00
3.00 3.50 7.0014.5021.50
31⁄4 4.00 8.5017.0025.50
31⁄2 5.0010.0020.0029.50
33⁄4 5.5011.0022.5034.00
4.00 6.5013.0025.5038.50
41⁄4 7.0014.5029.0043.50
41⁄2 8.0016.0032.5048.50
43⁄4 9.0018.0036.0054.00
5.0010.0020.0040.0060.00
51⁄411.0022.0044.0066.00
51⁄212.0024.0048.0073.00
53⁄413.0026.5053.0079.50
6.0014.5029.0057.5086.50

This scale gives the nearest equivalent to the whole or half horsepower, as is required by State where licenses are paid at so much per horsepower.

Formula—S. A. E. D2 times N 2.5 equals horsepower.

For sleeve valve timing see [Chapter II] on Valves.

DISPLACEMENT

There are probably few men operating cars to-day who fully understand what is meant by the term displacement, often used in referring to automobile races. It is one of the main factors or points in determining the class in which a car is qualified to enter under the laws that govern races. In looking over a race program, you will note that there are usually two or more classes, one of which is open, and another with a limited piston displacement, which gives the smaller cars a competing chance in their class.

Consequently piston displacement is merely the volume displaced by all the piston in moving the full length of the stroke. The volume of a single cylinder is equal to the area of the bore multiplied by the length of the stroke, and the total displacement of a four cylinder motor will be four times this and that of a six cylinder motor, six times this.

Piston displacement:

D2 times S times N times 3.14 4

WhereD equals bore in inches
S equals stroke in inches
Where N equals number of cylinders
Example:Required to find the piston displacement of a 31⁄2 × 5 inch four-cylindered motor. D equals 3.5 S equals 5. and N equals 4.

Piston Displacement

3.52 times 5 times 4 times 3.14 4

3.5 times 3.5 times 5 times 4 times 3.14 4

equals 173.58 cubic inches.

IGNITION COIL DELCO GENERATOR
DISTRIBUTOR
CONTROL
LEVER
PEDALS FAN
BRAKE LEVER FAN BELT
STARTER SLIDING
GEAR CASE
UNIVERSAL
HOUSING		 STARTING
CRANK SHAFT
TRANSMISSION
END PLATE		 TIMING GEAR
CASE
TRANSMISSION TIMING GEAR
HOUSING
CLUTCH RELEASE BEARING
RETAINER GREASE CUP		 WATER PUMP
MOTOR ARMFLY WHEEL
HOUSING		LOWER
CRANK CASE		DRAIN COCK

Fig. 20. Buick Engine—Parts Assembly

VALVE KEYVALVE ROCKER ARM PINOIL FILLER
WING PLUG		VALVE ROCKER ARM
VALVE SPRING CAPVALVE ROCKER ARM WICK WATER OUTLET
VALVE SPRING SPARK PLUG
VALVE FAN
VALVE GAGE VALVE PUSH ROD
WATER JACKET
COMBUSTION SPACE WATER INLET
VALVE LIFTER VALVE LIFTER GUIDE
PISTON PIN
PISTON VALVE LIFTER CLAMP
OIL PUMP
DRIVING GEAR		 FAN BRACKET STUD
FAN BELT
CONNECTING ROD
CRANK SHAFT TIMING GEARS
CONNECTING
ROD BEARING		 FAN PULLEY
CAM SHAFT
CRANK SHAFT
BEARING		 CAM SHAFT BEARING
STARTING NUT
OIL PUMP GEAR COVER
UPPER CRANK CASE
FLY WHEEL TIMING GEAR HOUSING
FLY WHEEL HOUSING CHECK VALVEWATER PUMP
DRAIN PLUGOIL DIPPERSPLASH OIL TROUGH VALVE ROLLER
LOWER CRANK CASECRANK CASE OIL PIPE

Fig. 21. Buick Engine—Location Inside Parts Assembly

ROCKER ARMOIL WICK
WING PLUGVALVE STEM
ROCKER ARM COVERVALVE SPRING
ADJUSTING BALLVALVE CAGE
NUT
LOCK NUT
VALVE CAGE
WATER JACKET VALVE
SPARK PLUG COVER EXHAUST
MANIFOLD
COMBUSTION
SPACE		 INTAKE
MANIFOLD
PUSH ROD HOT AIR
CHAMBER
VALVE PUSH
ROD COVER		WRIST PIN
CYLINDER
VALVE LIFTER CAPPISTON
VALVE LIFTER
GUIDE CLAMP
VALVE LIFTER SPRING
VALVE LIFTER GUIDE
VALVE LIFTER
CAM ROLLER PIN
CAM ROLLER CONNECTING ROD
CAM SHAFT
CRANK CASE
CRANK SHAFT

Fig. 22. Buick Motor—End View

Fan Belt
Adjustment

Split Collar
with Locking Cup

Valve Tappet
Adjustment

Cam Shaft End
Thrust Adjustment

Shims for
Adjustment of
Connecting Rods

Oil Passage to
Connecting Rod

Oil Pipe to
Piston Ring

Oil Pump
Filter Screen

Oil Sump
Filter Screen

Oil Pump

Felt Gasket

Oil Drain Plugs

Fig. 23. Liberty U. S. A. Engine

LUBRICATION SYSTEMS, OILS, AND GREASES

Special attention should be given to regular lubrication, as this, more than any one thing, not only determines the life but also the economic up-keep of the car.

Whenever you hear an owner say that his car is a gas eater, or that it uses twice or three times as much oil as his neighbor’s, which is the same model and make, you know at once that he, or some one who has used the car before him, either did not give sufficient attention to lubrication, or used a poor grade of oil. It is almost impossible to impress the importance of the foregoing facts upon the minds of the average motorist, and we have, as a direct result, a loss of millions of dollars annually through depreciation.

The manufacturers of automobiles and gasoline engines have earnestly striven to overcome this negligence by providing their products with automatically fed oiling systems which alleviate some of the former troubles. These systems, however, also require some attention to function properly.

Grease.—A medium grade of light hard oil grease is best adapted for use in grease cups, universal joints, and for packing wheel bearings and steering gear housings. The transmission and differential operate more successfully when a lighter grade of grease is used, such as a graphite compound, or a heavy oil known as 600 W.

Oils.—Great care should always be exercised in purchasing lubricants. None but the best grades should be considered under any circumstances. The cheaper grades of oil will always prove to be the most expensive in the end. The ordinary farm machinery oils should never be used in any case as an engine lubricant, for in most cases they contain acids, alkalies, and foreign matter which will deteriorate and destroy the bearings of the motor.

An oil to give the best satisfaction must be a purely mineral or vegetable composition which will flow freely at a temperature of 33° Fahrenheit and also stand a temperature of 400° Fahrenheit without burning. Always choose an oil which is light in color as the darker oil usually contains much carbon.

Lubrication (Lat. Lubricus, meaning slippery).—-Lubrication is provided on all types of automobile engines, and at various other places where moving parts come in contact or operate upon each other.

Three different types of lubricating systems are found in common use.

[Fig. 24] shows the splash system. The oil is placed into the crank case and maintained at a level between two points, marked high and low, on a float or glass gauge at the lower left-hand side of the crank case. The oil is usually poured directly into the crank case through a breather pipe provided to prevent excessive vacuum pressure.

The lower end of the connecting rod carries a spoon or paddle which dips into the oil at each revolution and splashes it to the cylinder walls and various bearing surfaces within the motor.

Fig. 24. Splash Oiling

Care of the Splash System.—This type of oiling system does not require any adjustments, or special care, except that the oil level be constantly kept between the high and low level marked on the gauge.

Cleaning the Splash System.—Lubricating oils lose their effectiveness and become thin and watery after a certain period of use due to a fluid deposit called residue which remains in the combustion chambers after the charge of gas has been fired. This fluid generally works its way into the crank case, thinning the oil.

The crank case should, therefore, be drained, cleaned, and refilled with fresh oil every fifth week or thousand miles that the car is driven. This will prevent much wear and give a quiet and satisfactory running motor. Draining and washing out the crank case is accomplished by removing a drain plug at the bottom of the crank case. The old oil is drained off and thrown away. Kerosene is then poured into the crank case through the breather pipe until it flows out of the drain clear in color. The plug is then replaced and the crank case replenished with fresh oil until the three-quarter from low level is reached on the gauge. The oil level should be carried as near this point as possible to obtain the most satisfactory result.

[Fig. 25] shows the plunger or piston pump pressure system usually used in conjunction with the splash system. The oil is carried in a reservoir at the bottom of the crank case and is drawn through a fine meshed screen by the oil pump, which is of the plunger type operated off the cam shaft. It forces the oil through copper tubes in the three main bearings. The front and center bearings have an outlet which furnishes the oil to the gears in front and to the troughs in which the connecting rods dip. The troughs have holes drilled to keep the level of the oil, the surplus being returned to the reservoir.

PLUNGER PUMP AND STRAINEROIL PRESSURE ADJUSTMENTFRONT
BEARING
LINE
REAR
BEARING
LINE		CENTER BEARING
LINE		OIL FLOAT LEVEL

Fig. 25. Plunger Pump Oiling System

There is a pipe line running from the pump to the gear case with a screw adjustment to regulate the oil pressure by turning either in or out. There is a pipe line running to a gauge on the dash which gives the pressure at all times. The cam shaft and cylinder walls get the oil by the splash from the connecting rods. The bottom rings of the pistons wash the oil back into the crank case. The overflow from the front bearings falls into a small compartment immediately under the crank shaft gear where it is picked up by this gear and carried to the other gears and the bearings of the water pump shaft. A small oil throw washer on the pump shaft prevents any surplus oil from being carried out on the shaft or the hub of the fan drive pulley. Any overflow from the gear compartment is carried immediately to the splash pan where it provides for the splash lubrication of the connecting rod bearings and the cylinder walls. The dippers on the connecting rod bearings should go 1⁄4 in. beneath the surface of the oil. The upward stroke of the oil pump plunger draws the oil through the lower ball check into the pump body and the downward stroke discharges it through the upper ball check into the body of the plunger which is hollow and has outlets on either side. This allows the oil to flow from the plunger into the by-pass in the oil pump body and then into the lines running to the main crank shaft bearings. The next upward stroke forces the oil through the lines to the main bearings.

The oil pressure regulator is located on the body of the pump and connects to the by-pass. It consists of a hollow sleeve screwed into the body of the pump which has a small ball check held by a short coiled spring the tension of which determines the oil pressure. The tension and the pressure may be increased by turning the nut to the right. The nut should not be given more than one turn at a time in either direction as it is very sensitive. A loose main bearing will allow more oil to pass through it. Consequently the pressure registered on the oil gauge will be reduced. This will come about gradually. It is not advisable to attempt to adjust the oil pressure without first noting the condition of the main crank shaft bearings.

The most common cause of failure to operate is the collection of dust and dirt on the sleeve at the lower end of the pump or from an accumulation of sediment back of the ball check. This needs to be cleaned from time to time.

Force and Gravity Oiling System.—The force and gravity oiling system operates in much the same manner as the plunger pump system, except that the oil is pumped into an elevated tank from which it flows through lines by gravity to the various bearings. Oil pumps, however, differ in construction and some manufacturers use eccentric, centrifugal, and gear pumps. Oil pumps are very simple in construction and action and can be readily understood by recalling their functional action.

Oil pumps rarely give any trouble, and if they fail to function properly, dirt should be immediately suspected, and the ball valves and pipes inspected and cleaned.

CHAPTER IV
BRIEF TREATISE ON CARBURETION

A carburetor is a metering device whose function is to mechanically blend liquid fuel with a certain amount of air to produce as nearly a homogeneous mixture as possible, and in such proportions as will result in as perfect an explosive mixture as can be obtained.

If a gas is used as a fuel it is of course not so difficult to obtain a homogeneous mixture due to the intimacy with which a gas will mechanically mix with air. This intimacy is a result of the minuteness of the molecules of both the gas and the air. With a liquid fuel, such as gasoline, however, it is quite different, especially with low test gasoline. If it were possible to completely transfer the liquid fuel into its vapor the latter would act as a gas and would, therefore, mix with the air to form a homogeneous mixture. It should be, and is, therefore, the aim of the carburetor designer to produce an instrument which will atomize the fuel and break it up into small particles so that every minute particle of the fuel will be surrounded by a correct proportion of air when it is discharged into the intake manifold of the motor. To facilitate the vaporization of these minute particles of fuel it is advisable to preheat the air taken into the carburetor, thereby furnishing the necessary heat units required to vaporize the fuel by virtue of its physical property known as its latent heat of evaporation.

There is a range of proportions of air to vapor, for a given fuel, between which combustion will obtain. This range extends from that proportion known as the upper limit of combustion to that known as the lower limit of combustion. The upper limit is reached when the ratio of air to vapor is a maximum at which combustion will take place; that is to say, any addition of air in excess of this maximum will render the mixture non-combustible. The lower limit is reached when the ratio of air to vapor is a minimum at which combustion will take place, any decrease of air below this minimum producing a non-combustible mixture. It should be remembered that the limits of combustion of any fuel with air are dependent upon the temperature and pressure.

Carburetor FlangeThrottle Valve
Throttle Stem
or Shaft
Large VenturiIdle Discharge Jet
Idle Adjustment Needle
High Speed Adjustment Needle
Small Venturi Float Needle
Air
Bleeder
Mixture Control
Valve or Choker
Float
Accelerating Well
Idling Tube Strainer
Float
Needle
Seat
High Speead
Needle Seat
Strainer Body Gasoline
Connection
Drain Plug

Fig. 26. Stromberg Model M Carburetor—Sectional View

Under given temperature and pressure the rate at which the combustible mixture will burn depends upon the ratio of air to vapor. This rate of burning is known as the rate of propagation, and it is apparent that it is desirable to obtain a mixture whose rate of propagation is a maximum, because the force of the explosion will depend upon the rapidity with which the entire mixture is completely ignited.

The limits of combustion of gasoline (.70 sp. gr.) can be taken approximately as follows: lower limit, 7 parts air (by weight) to 1 part gasoline, upper limit, 20 parts air to 1 part gasoline.

The Stromberg Plain Tube Model M Carburetor.—A plain tube carburetor is one in which both the air and the gasoline openings are fixed in size, and in which the gasoline is metered automatically, without the aid of moving parts by the suction of air velocity past the jets.

[Fig. 26] shows a longitudinal section of a type M plain tube carburetor, and shows the location of the gasoline when the motor is at rest. The various parts are indicated by names and arrows. An elementary requirement of a carburetor is that as a metering device it shall properly proportion the gasoline and air throughout the entire operating range.

Fig. 27. Stromberg Carburetor Model M—Air Bleeder Action

In the carburetor under discussion this mixture proportioning is properly maintained by the use of what is termed the air bleed jet. [Fig. 27] shows the principle of the action of the air bleeder. The gasoline leaves the float chamber, passes the point of the high speed adjusting needle, and rises through a vertical channel “B.” Air is taken in through the air bleeder “C,” and discharged into the gasoline channel before the latter reaches the jet holes in the small venturi tube “E.” The result is that the air thus taken in breaks up the flow of gasoline and produces a finely divided emulsion. Upon reaching the jet holes of the small venturi tube this emulsion is discharged into the high velocity air stream in the form of a finely divided mist. If the reader will recall how thoroughly a soap bubble divides itself when it bursts, he will readily appreciate how completely the air bleed jet will atomize the fuel.

Before explaining the operation of the accelerating well it is advisable to know the reason for its existence. Suppose we had a large tube such as the intake manifold of a motor through which air and particles of gasoline were flowing due to a certain suction at one end. What would be the result if we suddenly increased the suction? It would be this: Due to the fact that air is so much lighter than gasoline, the air would respond almost instantly to the increased suction and its flow would be accelerated very suddenly, whereas the particles of gasoline, owing to that characteristic known as inertia, would not respond so rapidly, and due to its heavier weight its flow would not accelerate as much as the air. This would mean that the air would rush ahead of the gasoline particles, and the proportion of air to gasoline would be greater until the inertia forces had been overcome and the gasoline particles responded completely to the increased suction. This very thing will take place in a carburetor unless provision is made for it. That is to say a sudden opening of the throttle will tend toward producing a very lean mixture at the motor due to the lagging of the gasoline explained above. A lean mixture at this time, when acceleration is desired, would obviously be detrimental to the result wanted. It is at this particular time that additional gasoline is most desirable in order to compensate for the lagging gasoline and maintain the proper mixture at the motor. In the Stromberg carburetor this is accomplished by means of the accelerating well shown in [Fig. 28]. The operation is as follows: The action is based upon the principle of the ordinary U tube. If a U tube contains a liquid, and if pressure is applied to one arm of the tube, or what is the same, if suction is applied to the other arm, it is self-evident that the level of the liquid will rise in the arm on which the suction is applied and will drop in the other arm. So it is in the construction of the accelerating well. Referring to the illustration, [Fig. 28], the space “F” forms the one arm of the U tube, and the space “B” the other arm. These spaces communicate with each other through the holes “G” thus forming a modified form of U tube.

Fig. 28. Stromberg Carburetor Model M—Accelerating Well

When the motor is idling or retarding in speed, the accelerating well or space “F” fills with gasoline. Now when the throttle is opened, thereby increasing the suction in the venturi tube, the following takes place: atmospheric pressure at the bleeder “C” exerts itself on the gasoline in the space “F” forcing the liquid down to join the regular flow from “H” and passing up the space “B” and out into the high velocity air stream through the small venturi tube. While the well acts the flow of gasoline is more than double the normal rate of flow, thereby compensating for the lagging of the gasoline referred to previously.

Upon close observation it will be noticed that there is a series of small holes down the wall of the well. Referring to the analogy of the U tube, these holes directly connect the two arms of the U tube. It is obvious that the smaller and fewer these holes, the faster will the well empty, due to the U tube suction, and the larger and more these holes, the slower will the well empty. It is therefore apparent that the rate of discharge of the well can be regulated as required by different motors, different grades of gasoline, different altitudes, etc., by inserting wells of different drillings. The action of the well is also dependent upon the size of the hole in the bleeder “C” because it is the relative area of this hole in the bleeder as compared to the area of the holes in the well which determine the rate at which the well will empty.

The foregoing characteristics of the model M carburetor have dealt more with the open throttle or high speed operation. We shall now consider the operation when the motor is idling. Earlier types of carburetors, when high test and very volatile gasoline was employed, were designed with a mixing chamber in which the gasoline, after being discharged from the nozzle, would mix with the air and evaporate very freely. Present day gasoline, however, is considerably heavier and very much less volatile, and we therefore cannot depend upon its volatility to accomplish its vaporization.

Fig. 29. Stromberg Carburetor Model M—Idling Operation

[Fig. 29] shows the arrangement and idling operation of the model M Stromberg carburetor. Concentric and inside of the passage “B” is located the idling tube “J.” When the motor is idling, that is, when the throttle is practically closed, the action which takes place is as follows: the gasoline leaves the float chamber, passes through the passage “H” into the idling tube through the hole “I,” thence up through the idling tube “J” to the idling jet “L.” Air is drawn through the hole “K” and mixes with the gasoline to form a finely divided emulsion which passes on to the jet “L.” It will be noted that this jet directs the gasoline-air emulsion into the manifold just above the lip of the throttle valve. Inasmuch as this throttle valve is practically closed the vacuum created at the entrance of the jet “L” is very high and exceeds 8 pounds per square inch. It is obvious, therefore, with this condition existing, that the gasoline will be drawn into the manifold in a highly atomized condition. It is well to call attention here to the fact that the low speed adjusting screw “F” operates a needle valve which controls the amount of air which passes through the hole “K,” and it is the position of this needle valve which determines the idling mixture.

Fig. 30. Stromberg Carburetor—Throttle 1⁄5 Open

As the throttle is slightly opened from the idling position a suction is created in the throat of the small venturi tube as well as at the idling jet. When idling the suction is greater at the idling jet, and when the throttle is open the suction is greater at the small venturi tube. At some intermediate position of the throttle there is a time when the suction at the idling jet is equal to that at the small venturi, and, therefore, at this particular time the gasoline will follow both channels to the manifold. This condition which is illustrated in [Fig. 30] lasts but a very short while, because as the throttle is opened wider the suction at the small venturi tube rapidly becomes greater than that at the idling jet. The result is that the idling tube and idling jet are thrown entirely out of action, the level of the gasoline in the idling tube dropping as illustrated in [Fig. 31], where the throttle is shown to be wide open, in which case all of the gasoline enters the manifold by way of the holes in the small venturi tube.

Fig. 31. Stromberg Carburetor—Throttle Wide Open

It will be remembered that at this position of the throttle the accelerating well has emptied, and therefore there is a direct passage for air from the bleeder to the gasoline in the main passage giving the air bleed jet feature explained before. This is being mentioned again in order to call attention to the fact that care should be taken not to use too large a bleeder, because the air which enters through the bleeder partly determines the mixture, and if the bleeder hole is too large the mixture is very apt to be too lean at high speeds.

[Fig. 32] shows an exterior photograph of one of the type M Stromberg carburetor. Before discussing the installation and adjusting of this carburetor it will be well to say a few words concerning the use of the venturi tube and its construction.

The object in using the venturi tube in carburetor design is to produce a maximum air velocity at the jet and at the same time not cause undue restriction. This high air velocity creates the suction necessary to properly atomize the gasoline. The use of the double venturi tube construction has developed the best possible results. In this construction the mouth of the smaller venturi tube is located at the throat of the larger one, and with this arrangement the highest degree of atomization is attainable, and at the same time the air restriction is held down to a minimum.

In order that any carburetor may do justice to what is claimed for it, it is absolutely essential that the motor on which it is installed is in good condition in other respects because, besides poor carburetion, there are numerous things about an internal combustion engine which will cause its poor operation. Therefore, assuming that the following conditions exist, we can proceed with the installation of the carburetor and after adjusting it we can expect very good results as to the operation of the motor.

1. The ignition should be properly timed so that with a retarded spark the explosion takes place when the piston of the cylinder in which the explosion occurs is at its upper dead center.

2. The inlet and exhaust valves should be so timed that they open and close at the proper time during the cycle. In this respect a motor is usually timed when it comes from the manufacturer.

3. The valves should be ground in so that they form a perfect seal with the valve seat. Any accumulation of carbon on the upper part of the exhaust should be removed so as to prevent the valve stem from sticking in the guide and thereby not permitting the valve to close upon its seat.

4. Any undue wear of the valve stem guides should be corrected because the clearance between the stem and the walls of the guide will permit air to be drawn up into the motor thus ruining the mixture from the carburetor. Similarly any leaky flange at any joint along the intake system will produce the same detrimental result.

Fig. 32. Stromberg Model M—Adjustment Points

5. All piston rings should be tight and leak proof in order to insure good and even compression in all the cylinders. Without good and even compression in all the cylinders it is impossible to obtain the maximum power from the motor, and it is also impossible to obtain good idling of the motor.

6. It should be seen that the ignition system is delivering a spark to each spark plug without missing.

7. The spark plugs should be clean, and the accumulation of carbon on the inside of the plug should not be sufficient to cause fouling or short-circuiting of the plug. In the case of a short circuited plug it is impossible to obtain a spark at the end of the high tension cable, but this does not indicate that the plug is firing. For best results the gap of the spark plug should never be less than .020″ nor more than .032″. A good setting is at about .025″.

The foregoing constitute some of the more important troubles to look for when the motor is not performing satisfactorily.

Installation and Adjusting.—We are finally ready to proceed with instructions for installing and adjusting Model M carburetors.

1. Try the throttle lever and the air horn lever by moving same with the hand before the carburetor is installed, and be sure that the butterfly valves are open to the limit when the respective levers come in contact with their stops. Also be sure that when the throttle valve is closed, the lower side of the butterfly is adjacent to the hole through which the idling jet projects.

2. Prepare a paper gasket about .020″ thick to fit the flange of the carburetor. Shellac same and then attach the carburetor to the flange of the intake manifold very securely by means of proper cap screws.

The attaching of the gasoline line, hot-air stove, hot air flexible tubing, and choke control need not be discussed in detail as these installations are very simple.

After having properly installed the carburetor on the motor, turn both the high and low speed adjusting screws, A and B, completely down clockwise so that the needle valves just touch their respective seats. Then unscrew (anti-clockwise) the high speed adjusting screw A about three turns off the seat, and turn the low speed adjusting screw B anti-clockwise about one and one-half turns off the seat. These settings are not to be considered as final adjustments of the carburetor. They are merely to be taken as starting points because the motor will run freely with these settings.

After the motor has been started, permit it to run long enough to become thoroughly warm then make the high speed adjustment. Advance the spark to the position for normal running. Advance the gas throttle until the motor is running at approximately 750 r. p. m. Then turn down on the high speed screw A gradually notch by notch until a slowing down of the motor is observed. Then turn up or open the screw anti-clockwise until the motor runs at the highest rate of speed for that particular setting of the throttle.

To make the low speed adjustment B proceed as follows: Retard the spark fully and close the throttle as far as possible without causing the motor to come to a stop. If upon idling the motor tends to roll or load it is an indication that the mixture is too rich and therefore the low speed screw B should be turned away from the seat anti-clockwise, thereby permitting more air to enter into the idling mixture. It is safe to say that the best idling results will be obtained when the screw B is not much more or less than one and one-half turns off the seat.

After satisfactory adjustments have been made with the motor vehicle stationary, it is most important and advisable to take the vehicle out on the road for further observation and finer adjustments. If upon rather sudden opening of the throttle the motor backfires, it is an indication that the high speed mixture is too lean, and in this case the high speed screw A should be opened one notch at a time until the tendency to backfire ceases. On the other hand if when running along with throttle open, the motor rolls or loads, it is an indication that the mixture is too rich, and this condition is overcome by turning the high speed screw A down (clockwise) until this loading is eliminated.

STROMBERG MODEL L CARBURETOR

There are three adjustments; the high speed, the extremely low speed or idle, and the “economizer.”

The high speed is controlled by the knurled nut “A” which locates the position of the needle “E” past whose point is taken all the gasoline at all speeds. Turning nut “A” to the right (clockwise) raises the needle “E” and gives more gasoline, to the left, or anticlockwise, less.

Fig. 33. Stromberg Model “L”—Adjustment Points

If an entirely new adjustment is necessary, use the following practice. Put economizer “L” in the 5th notch (or farthest from float chamber) as an indicator, turn nut “A” to the left, anticlockwise, until needle “E” reaches its seat, as shown by nut “A” not moving when throttle is opened and closed. When needle “E” is in its seat it can be felt to stick slightly when nut “A” is lifted with the fingers. Find adjustment of “A” where it just begins to move with the throttle opening, then give 24 notches to the right or clockwise (the notches can be felt). Then move the economizer pointer “L” back to the 0 notch (toward float chamber). This will give a rich adjustment. After starting and warming up the motor, thin out the mixture by turning “A” anticlockwise, and find the point where the motor responds best to quick opening of the throttle, and shows the best power.

The gasoline for low speed is taken in above the throttle through a jet at “K” and is regulated by dilution with air as controlled by the low speed adjusting screw “B.” Screwing “B” in clockwise gives more gasoline; outward, less. The best adjustment is usually 1⁄2 to 3 turns outward from a seating position. Note that this is only an idling adjustment and does not effect the mixture above 8 miles per hour. When motor is idling properly there should be a steady hiss in the carburetor; if there is a weak cylinder or manifold leak, or if the idle adjustment is very much too rich, the hiss will be unsteady.

The economizer device operates to lean out the mixture by lowering the high speed needle “E” and nut “A” a slight but definitely regulated amount at throttle positions corresponding to speeds from 5 to 40 miles per hour. The amount of drop and consequent leaning is regulated by the pointer “L.”

After making the high speed adjustment for best power, with pointer “L” in 0 notch, as above described, place throttle lever on steering wheel to a position giving about 20 miles per hour road speed. Then move pointer “L” clockwise (away from float chamber), one notch at a time, till motor begins to slow down. Then come back one notch.

The amount of economizer action needed depends upon the grade of gasoline and upon the temperature.

In the mid-west the best economizer adjustment will usually be the third or fourth notch. With Pennsylvania gasoline and in the South, the 2nd notch; while on the Pacific coast no economizer is necessary unless distillate (which should not be below 59 degrees Baume) is used. Also fewer notches economizer action will be necessary in summer than in winter.

CHAPTER V
“NITRO”-SUNDERMAN CARBURETOR

Fig. 34. Sunderman Carburetor

[Fig. 34] shows a through section of the new “Nitro”-Sunderman carburetor. This is practically a new model presented to the automobile industry for 1919 and 1920. It is claimed that it is an exact fulfillment of the long sought method of accurate compensation. It is of the single plain tube design with a single gasoline nozzle in the shape of a mushroom placed in the center of the air passage. Around this nozzle, however, rests the floating venturi which is a large end and small center floating air tube seen in [Fig. 35] which hurries the air at low speeds and checks the rush at high velocities. [Fig. 35] shows the commencement of action at idling speeds, and as the gasoline for idling comes from the same nozzle which furnishes the maximum power, an air by-pass is provided to reduce the suction on the nozzle at low speeds. The one single adjustment on this type of carburetor is shown at (X) in [Fig. 36], and is used only to control the passage of air through the by-pass at idling or low speeds. In [Fig. 34] the engine’s demand has increased to a point where the suction is greater than the weight of the venturi, which causes it to rise on the air stream, and open up the air passage around the head of the nozzle. This allows the compensation for the correct ratios of the air and gasoline mixtures.

Fig. 35. Sunderman Carburetor

In [Fig. 37] the venturi closes the air by-pass and under full suction, gives the maximum area around the nozzle for leaner mixtures and full volumetric. The unrestricted air passage in the plain tube type of carburetor is here worked out to its fullest development.

Fig. 36. Sunderman Carburetor

The Venturi.—This is a stream line air passage tapered to a narrow throat near the center which increases the velocities without offering a restriction to the free air passage, and being of a very loose fit in the carburetor, is allowed to float up and down on the air stream around the nozzle over which it automatically centers at all times. The venturi goes into action slowly as it is retarded by the action of the air by-pass, but rises fast when the latter is cut off. It rides on the air stream at a perfect balance and offers no resistance to the air passage because of its stream line taper, and as the venturi float is sensitive to a fine degree, it is ready for any change in the motor suction and compensates accordingly. The jet tube running up into the mushroom head contains a jet which is drilled for the particular requirements of the motor on which the carburetor is installed. This jet feeds into the mushroom head which is drilled with four small holes which spread the gasoline by capillary action in a fine fan film to all sides of the under surfaces of the slot. Here the ascending air picks it off at right angles to its path in a very fine vapor. This vapor is carried up the stream line venturi without cross currents and is in a finely mixed state of flame-propagation. The heavier fuels are readily broken up with this nozzle and straight kerosene has been used with success. This carburetor does not require any other care than a thorough cleaning out once or twice in a season.

Fig. 37. Sunderman Carburetor

THE SCHEBLER MODEL “R” CARBURETOR

[Fig. 38] shows a section view of operation and adjustment on the model “R” Schebler carburetor. This carburetor is designed for use on both four and six cylindered motors. It is of the single jet raised needle type, automatic in action, the air valve controlling the needle valve through a leverage arrangement. This leverage attachment automatically proportions the amount of gasoline and air mixture at all speeds. This type of carburetor has but two adjustments. The low speed adjustment which is made by turning the air valve cap and an adjustment on the air valve spring for changing its tension. (A) shows the air valve adjusting cap. (B) is the dash control leverage attachment. (C) is the air valve and jet valve connection. (D) is the boss that raises the jet valve needle and lowers the spring tension on the air valve giving a rich mixture in starting. The needle valve seats in E and controls the nozzle spray. (F) is the air valve spring tension adjusting screw.

Fig. 38. Schebler Model R Carburetor Assembled

Model R Adjustment.—To adjust this carburetor turn the air valve cap to the right until it stops, then to the left one complete turn, start the motor with the throttle 1⁄4 open; after it is warmed up turn the air valve cap to the left until the motor hits perfectly. Advance throttle 3⁄4 on quadrant. If the engine backfires turn screw (F) up, increasing the tension on the air spring until acceleration is satisfactory.

CHAPTER VI
THE STEWART CARBURETOR

[Fig. 39] shows the Stewart carburetor used on Dodge Brothers cars, which is of the float feed type in which a fine spray of gasoline is drawn from an aspirating tube by a current of air induced by the engine pistons. The supply of gasoline being regulated by a float which actuates a needle valve controlling the outlet of the feed pipe. This tube is also called the spray nozzle. This type of carburetor is commonly used on automobile engines.

It consists of a float chamber containing a float, functions of which are described below, a mixing chamber in which the gasoline spray is reduced to vapor and mixed with air (i. e., “carbureted” in proper proportion).

The float and valve maintain a constant or even supply of gasoline for the carburetor.

The gasoline flows from the filter Z into the float chamber C through the inlet valve G, which is directly actuated by the float F, so that it closes or opens as the float rises or falls. As the float rises the valve is closed until the float reaches a certain predetermined level, at which the valve is entirely closed. If the float falls below this level because of a diminishing supply of gasoline in the float chamber, the valve is automatically opened and sufficient fresh gasoline is admitted to bring the level up to the proper point. From the foregoing it will be seen that the float chamber in reality serves as a reservoir of constant supply, in which any pressure to which the gasoline has been subjected in order to force it from the tank is eliminated. When the engine is running gasoline is, of course, being constantly drawn off from the float chamber through the aspirating tube L, as will be described later, to meet the requirements of the motor, but in practice the resulting movement of the inlet valve is very slight and hence the flow of gasoline into the float chamber is nearly constant.

The gasoline inlet valve is also called the “needle valve.”

Fig. 39. Stewart Carburetor

Between the float chamber C and the engine connection of the carburetor is an enclosed space called the mixing chamber O. This compartment is provided with a valve for the ingress of free air.

Extending into the mixing chamber from a point below the surface of the gasoline in the float chamber is a passage, L for gasoline, ending with a nozzle, so constructed that gasoline drawn through it will come forth in a very fine spray. This is called the aspirating tube, atomizer, or more commonly, the spray nozzle.

The air inlet AA to the mixing chamber on the carburetor used on the Dodge is in the shape of a large tube extending from the carburetor to a box on the exhaust manifold. Air supplied from this source is heated in order that vaporization of gasoline may be more readily accomplished.

A cold air regulator is interposed between this tube and the carburetor proper so that in hot weather cool air may be admitted. This should always be closed when the temperature of the atmosphere is below 60 F.

The action of the carburetor is as follows: The suction created by the downward stroke of the pistons draws air into the mixing chamber through the air ducts (drilled holes HH). The same suction draws a fine spray of gasoline through the aspirating tube L (spray nozzle) into the same compartment, and the air, becoming impregnated with the gasoline vapor thus produced, becomes a highly explosive gas. In order that the proportion of air and gasoline vapor may be correct for all motor speeds, provision is made by means of a valve A for the automatic admission of larger quantities of both at high motor speeds. The ducts are open at all times, but the valve is held to its seat by its weight until the suction, increasing as the motor speed increases, is sufficient to lift it and admit a greater volume of air. The valve A is joined to the tube L, hence the latter is raised when the valve is lifted and the ingress of proportionately larger quantities of gasoline is made possible. This is accomplished by means of a metering pin P normally stationary, projecting upward into the tube L. The higher the tube rises the smaller is the section of the metering pin even with its opening, and hence the greater is the quantity of gasoline which may be taken into the tube. The carburetor thus automatically produces the correct mixture and quantity for all motor speeds.

The metering pin is subject to control from the dash, as will be explained later, by means of a rack N, and pinion M. To change the fixed running position of the pin, turn the stop screw to the right or left. Turning this screw to the right lowers the position of the metering pin and turning it to the left raises it. As the pin is lowered more gasoline is admitted to the aspirating tube at a given motor speed, thus enriching the mixture.

A wider range of adjustment of the position of the metering pin may be had by releasing the clamp of the pinion shaft lever and changing its position with relation to the shaft. This should never be attempted by any save experts in this class of work.

The carburetor used on the Dodge Brothers car is so nearly automatic in its action that it is not effected by climatic conditions, or changes in altitude or temperature. It automatically adjusts itself to all variations of atmosphere. It is, therefore, wise to see if the causes of any troubles which may develop are not due to derangements elsewhere than at the carburetor before attempting any changes of its adjustment.

Make all adjustments with dash adjustment all the way in.

The metering pin should not be tampered with unless absolutely necessary.

If replacement of this pin should become necessary, it may be accomplished as follows: First, remove the cap nut at the bottom of the rack and pinion housing. Next, turn pinion shaft slowly from right to left (facing toward the carburetor) until the bottom of the metering pin appears at the bottom of the pinion shaft housing. Continue to turn the shaft slowly in the same direction, releasing the connection to the dash control if necessary, until the rack to which the pin is fastened drops out. The palm of the hand should be held to receive this as the parts are very loosely assembled. The pinion shaft should be retained at the exact position at which the rack is released. Install a new metering pin, the way to do this will be obvious, and return the rack to its proper mesh with the pinion. Replace dash attachment (if detached), replace cap, adjust per instructions given on previous page.

The loose assembling of the metering pin in the rack is for the purpose of providing for freedom of movement of the metering pin and in order that binding in the aspirating tube may be avoided.

The gasoline filter is installed on the carburetor at a point where the fuel pipe is connected.

The pressure within the gasoline tank forces the fuel through the pipe, through the filter screen (ZO in the filter) and thence out through the opening to the carburetor.

The filter cap CC may be removed by turning the flanged nut on the bottom of carburetor to the left, thus releasing the inlet fitting.

The filter screen or strainer should occasionally be cleaned. This may be readily accomplished by removing the filter cap to which the screen is attached.

The filter should be screwed up tight when replaced.

CHAPTER VII
THE CARTER CARBURETOR

Fig. 40—Carter Carburetor

[Fig. 40] shows the Carter carburetor which embodies a radically new principle. It belongs to the multiple-jet type, but possesses this striking difference, variations in fuel level are utilized to determine the number of jets in action at any time. The variations in fuel level occur in a vertical tube known as the “stand pipe.” They take place in instant response to the slightest change in the suction exerted by the engine. As this suction depends directly on the engine’s speed, it can clearly be seen that this provides a marvelously sensitive means of automatic control. A large number of exceedingly small jets are bored spirally around the upper portion of this tube. As a result, the level at which the fuel stands within it, determines the number of jets from which delivery is being made at any instant and the gasoline supply is always directly proportioned to the engine speed, however suddenly changes in speed take place. Owing to the comparatively large number of these jets, their exceedingly small size, and their correspondingly short range of action, the flow of fuel is absolutely uninterrupted.

The instrument is permanently adjusted for low and intermediate speeds at the time of installation. An auxiliary air valve controlled from dash or steering post forms the high speed adjustment as well as affording a means of securing absolute uniformity of mixture under widely varying conditions of weather, temperature, or altitude, directly from the driver’s seat. A simple method of enabling each cylinder to such a rich priming charge direct from the float chamber is another valuable feature that obviates all need of priming and insures easy starting in the coldest winter weather.

CHAPTER VIII
THE SCHEBLER PLAIN TUBE CARBURETOR MODEL “FORD A”

Fig. 41. Schebler Carburetor Model Ford A—Sectional View

D—CHOKER OR SHUTTER IN AIR BEND.
BE—LEVERS CLOSING CHOKER, OPERATED FROM STEERING COLUMN AND FRONT OF RADIATOR.
H—LOW SPEED GASOLINE ADJUSTING NEEDLE.
I—HIGH SPEED GASOLINE ADJUSTING NEEDLE.
K—IDLE AND LOW SPEED BYPASS.
M—ACCELERATION WELL.
P—PILOT OPENING.

The Pilot tube principle is introduced for the first time in the carburetor and this Pilot tube or improved type of gasoline nozzle is so designed or built that it automatically furnishes a rich mixture for acceleration and thins out this mixture after the normal motor speed has been reached. This furnishes a very economical running mixture at all motor speeds, together with a smooth and positive acceleration.

The importance of this Pilot tube or nozzle principle cannot be over emphasized, as it furnishes a flexible, powerful and economical mixture, without the addition of any complicated parts. The Ford “A” carburetor has no parts to wear or get out of adjustment.

Fig. 42. Schebler Carburetor Model Ford A—Adjustment Points

Two gasoline needle adjustments are furnished. One for low speed and idling and one for high speed. These adjustments have been found advisable and necessary to properly handle the present heavy grades of fuel and the variations in the motor due to wear, etc. Those adjustments also insure the attaining of the widest range of motor speed.

A double choker is furnished, and with these controls the Ford can be easily started under the most severe weather conditions and the mixture controlled from the driver’s seat.

With the Ford “A” carburetor a low speed of four to five miles an hour can be secured without any loading or missing. Also, with this carburetor the maximum speed and power of the motor are obtained.

INSTRUCTIONS FOR INSTALLING AND ADJUSTING THE SCHEBLER FORD “A” CARBURETOR

First, remove the Ford carburetor from the manifold, also the dash board control, the hot air drum, and tubing, and the radiator choke wire. Be sure to save the cotter pin used in the throttle control.

Install the Schebler carburetor, using gasket and cap screws which are furnished with the equipment. The gasoline connection is the same as regularly furnished on the Ford equipment and no other connections are necessary. Screw the connections on the Ford gasoline line onto the connection furnished on the carburetor. Attach the hot air drum and the tubing to the exhaust manifold and run the choke wire through the radiator.

Before adjusting carburetor, see that the spark plugs are clean and set about .035, or nearly the thickness of a new dime. See that the compression is good and equal on all four cylinders. See that the timer is clean and in good shape, as an occasional miss is due to the roller in the timer becoming worn. Also, be sure that there is no leak in the intake manifold.

The steering post control must be set so that the tubing is fastened into set screw (A) and the control wire is fastened through the binding post in lever (B) with steering post control or plunger pushed clear in and the butterfly shutter (D) in the hot air horn or bend open, so that when the plunger control is pulled out the wire (C) in the binding post (B) on lever closes the shutter (D) almost completely. This will furnish a rich mixture for starting and warming up the motor under normal weather conditions.

The wire running to the front of the radiator must be attached to lever (E) so that when the motor is cold, the shutter (D) can be closed tight, thus insuring positive starting. However, this wire must be released immediately upon starting the motor or the motor will be choked by excess of gasoline.

To start the motor, open low speed needle (H) and high speed needle (I) about four or five complete turns. You will note that the needles have dials which indicate turning needle to the right cuts down the gasoline supply.

Pull out steering post control, open throttle about one-quarter way, retard the spark, pull out radiator choke wire which will close shutter and crank the motor. After motor is started, immediately release radiator choke wire and gradually push in the steering post control or plunger and let the motor run until it is warmed up. Then first adjust the high speed needle (I) until the motor runs smoothly and evenly with retarded spark. Close throttle part way and adjust idle needle until motor runs smoothly at low speed.

In order to get the desired low throttle running, use the throttle stop screw (L) which will control the throttle opening and give you the desired low speed running.

A strainer is furnished on the carburetor which prevents dirt or sediment getting into the bowl of the carburetor and choking up the gasoline nozzle or causing flooding.

CHAPTER IX
KEROSENE CARBURETORS

Experiments have been carried on for quite some time pertaining to the development of a more successful carburetor which will burn the heavier fuels. The chief difficulty encountered is to find a more suitable way to vaporize these low grade fuels.

Kerosene can be used, only with an application of heat to the manifold to aid in the evaporation of the heavier parts of this fuel. The exhaust pipes are available for this source of heat, but as there is no heat from this source until the engine is running, it is necessary to start the engine on gasoline and switch over to the heavier fuels after the warming-up process.

Fig. 43. Holley Kerosene Carburetor

[Fig. 43] shows the Holley kerosene carburetor which is adaptable to any type of engine by making simple changes in the exhaust manifold to include the heating coil tube. This carburetor will operate successfully on any hydro-carbon fuel with a boiling point below 600° F. Two float chambers are provided to take care of the starting and running fuels. The engine is started on the gasoline part of the carburetor and after a short warming-up period the feed is switched to the kerosene part of the device.

Fig. 44. Holley Kerosene Carburetor Installment

The principle upon which this device operates is to provide a primary mixture by means of a needle valve and a very small aspirating jet which gives a mixture that is too rich for combustion. This rich mixture of atomized fuel is carried through a coil tube of very thin wall thickness, which is exposed to the exhaust gases, directly in the exhaust manifold.

The temperature in this coil tube reaches as high as 500 degrees F. The globules of the over rich mixture are broken up here and flow directly into the mixing chamber, where additional air enters, diluting the mixture to make it combustible. The opening of the air valve is controlled by the suction of the engine and by the throttle valve. The shifter valve for changing the operation from gasoline to kerosene is conveniently arranged for dash control, when the engine becomes warm. A primer is arranged in the manifold just above the carburetor and aids in cold weather starting.

[Fig. 44] shows the installation of the Holley kerosene carburetor. In this case it was necessary to add a compartment on the exhaust manifold to contain and heat the coil tube. There are some details that must be taken care of on installation. A small auxiliary tank must be provided to hold the gasoline for starting, while a larger tank must be provided to carry the main supply of kerosene.

The adjustments of this type of carburetor is through a needle valve located in each fuel chamber, and as it is impossible to give any set adjustment that would apply to the many different types of motors, the proper adjustment must be worked out. This is done by shifting to the gasoline and turning the needle valve to the right and left and noting the point at which the engine runs the smoothest. The needle valve is then set at this point. The fuel shifter valve is turned to feed the kerosene, and this adjustment is made in the same manner.

CHAPTER X
HEATED MANIFOLDS AND HOT SPOTS

Heat added to the manifold is the probable solution of the present low-test fuel supplied to the motorist. In the first place you may be satisfied if your motor runs and does not give any noticeable loss of power. But the question is, are you getting full power out of your motor in accordance with the amount of fuel consumed? And are you getting the proper amount of mileage out of each gallon? The answer to both questions would probably be in the negative, if both questions were taken up individually by owners.

EXHAUSTINTAKE
EXHAUST
GOVERNOR
GOVERNOR
CARBURETOR

Fig. 45. Hot Spot Manifold

One of the best solutions, if not the best, is the new hot-spot manifold used on the Liberty engine, which was designed for Army use. [Fig. 45] shows the hot-spot Liberty engine manifold. The intake manifold is external but short, therefore does not offer much opportunity for the liquid to condense. From the carburetor it rises up straight to a point well above the valve ports and the cylinder blocks, and at the top of the rise it touches the exhaust pipe and divides, the two branches sweeping downward quite clear of the exhaust manifold to each block of cylinders. About three inches of the intake passage is exposed to the exhaust manifold top.

The advantage of this design is that the heating element affects practically only the liquid fuel and does not have much effect on the fuel already vaporized. Naturally the liquid fuel is heavier than the vapor, and as the mixture rushes up the manifold at a high rate of speed and turns to the right or left, the heavier liquid particles are thrown straight against the hot-spot, where they are boiled off in vapor.

Thus, although the total amount of heat supplied to the incoming charge is small, vaporization is good, since pains have been taken to supply the heat where it is needed.

Fig. 46. Holley Vapor Manifold—Ford Cars

[Fig. 46] shows the Holley vapor manifold for Ford cars which is intended to completely vaporize gasoline by applying heat at the proper point. As will be noted by the arrows, the exhaust gases pass down, striking a hot-spot at the top of the internal intake passage. The exhaust gases flow along this passage and finally pass out at the bottom. The heavier particles of fuel, after leaving the carburetor, strike against the wall at point (A) and there are broken up by the exhaust gases. Should any of the globules not be broken up at this point, they will be vaporized when they strike the hot-spot at (B) as this is directly in contact with the exhaust gases. It will be noted that the heavier globules are subjected to a rising temperature. Starting at (A) and finishing at (B) a control valve regulates the amount of heat supplied to the intake manifold.

CHAPTER XI
COOLING SYSTEMS
Type, Operation and Care

Cooling systems are provided on all types of gasoline engines. As the heat generated by the constant explosions in the cylinders would soon overheat and ruin the engine were it not cooled by some artificial means.

Circulation Systems.—There are two types of water circulating systems. The Thermo Syphon, and the Force Pump circulating systems.

Fig. 47. Thermo-Syphon Cooling System

[Fig. 47] shows how the water circulates in the Thermo-Syphon system. It acts on the principle that hot water seeks a higher level than cold water, consequently when the water reaches a certain temperature, approximately 180° F., circulation commences and the water flows from the lowest radiator outlet pipe up through the water jackets into the upper radiator water tank, and down through the thin tubes to the lower tank to repeat the process.

The heat is extracted from the water by its passage through the thin metal tubing of the radiator to which are attached scientifically worked out fins which assist in the rapid radiation of the heat. The fan just back of the radiator sucks the air through the small tubes which connect the upper and lower radiator tanks. The air is also driven through between these tubes by the forward movement of the car.

The Force Pump Circulation System.—The Force Pump circulating system is constructed in the same manner as the Thermo Syphon Cooling System. The only difference in the two systems is that a small pump is attached to the lower radiator pipe to force the circulation of the water.

The pump is usually of the centrifugal type and consists of a fan-shaped wheel operated in a snugly fitted housing. The water enters at the hub and is thrown out against the housing and is forced on by the rapid action of the fan blades. Another type of pump is used by some manufacturers which consist of two meshed gears of the same size, which operate in a snugly fitted housing. These gears operate in a direction toward each other, the water is carried forward or upward in the space between the teeth, and is forced on when the teeth mesh and fill the space.

Overheating.—Overheating may be caused by carbonized cylinders, too much driving on low speed, not enough or a poor grade of lubricating oil, spark retarded too far, racing the engine, clogged muffler, poor carburetor adjustment, a broken or slipping fan belt, jammed radiator tube, leaky connection, or low water.

Radiator Cleaning.—The entire circulation system should be thoroughly cleaned occasionally. A good cleaning solution is made by dissolving one-half pound of baking soda in three and one-half to four gallons of soft water. The radiator is filled with the solution and left to stand for twenty to thirty minutes. The hose is then removed from the lower pipe, water is then turned into the radiator through the filler spout until the system is thoroughly flushed out.

Freezing.—Unless an anti-freezing solution is used through the cold months you are bound to experience trouble. The circulation does not commence properly until the water becomes heated. It is apt to freeze at low temperatures before circulation commences. In case any of the small tubes are plugged or jammed they are bound to freeze and burst open if the driver attempts to get along without a non-freezing solution.

Freezing Solution.—Wood or denatured alcohol can be used to a good advantage. The following table gives the freezing point of solutions containing different percentages of alcohol.

20% solution freezes at 15° above zero.
30% solution freezes at  8° below zero.
50% solution freezes at 34° below zero.

A solution composed of 60% of water, 10% of glycerine, and 30% of alcohol is commonly used, its freezing point being 8° below zero.

Evaporation.—On account of evaporation, fresh alcohol must be added frequently in order to maintain the proper solution.

Radiator Repairs.—A small leak may be temporarily repaired by applying brown soap, or white lead, but the repair should be made permanent with solder as soon as possible. A jammed radiator tube is a more serious affair. While the stopping up of one tube does not seriously interfere with circulation, it is bound to cause trouble sooner or later, and the tube will freeze in cold weather. Cut the tube an inch above and below the jam and insert a new piece soldering the connection. If the entire radiator is badly jammed or broken, it will probably be advisable to install a new one.

Air Cooling System.—Air cooling has been developed to a point where fairly good results are attained. This system has an advantage over the circulating systems, in that the weight of the radiator and water is done away with, and no trouble is experienced with stoppage of circulation and leaky connection. This system, however, has its drawbacks, in that it cannot be used successfully on the larger and more compact engines. In order to allow the necessary large space for radiation, the cylinders are heavily flanged and set separately. The fan is placed in a much higher position than usual, in order that the air current may strike the heads of the cylinders and circulate downward. Compression is also lowered considerably to prevent heat generation and pre-ignition. On account of the small size of the cylinders and low compression, it is necessary to operate an air cooled engine at a very high rate of speed to produce sufficient power for automobile locomotion.

The fan must be kept in good working condition, and care should be exercised in not allowing the engine to run idle for any length of time.

CHAPTER XII
MUFFLER CONSTRUCTION, OPERATION AND CARE

The muffler was designed to silence the otherwise loud report of the exploding charge of gas, which is released from the cylinders by the sudden opening of the exhaust valves.

While these devices are differently shaped and formed, the functional purpose and action is practically the same in all designs.

The burnt or inert gases are forced from the cylinders on the exhaust stroke. It passes into the exhaust manifold which absorbs some of the heat before it reaches the muffler.

HangerTie Rod
Split Clamp NutMuffler
Shell		Spacer
Spacer		Nozzle
Center Pipe

Fig. 48. Muffler—Three Compartment

[Fig. 48] shows a three compartment muffler. The burnt gases enter compartment No. 1 from the exhaust pipe. This compartment is sufficiently large to spread the volume which lessens the pressure and force. It then enters the rear compartment No. 3, through the center pipe; it expands again and passes through the perforated spacer plate, enters compartment No. 2, and escapes through the nozzle in an even silent flow.

The muffler at all times produces a certain amount of back-pressure on the engine which results in a slight loss of power. The back pressure exerted by the majority of mufflers, however, is very slight and has a tendency to counter balance or equalize the sudden shock delivered to the bearings by the explosion over the piston head.

The muffler may also become fouled by the use of too much or too heavy a grade of lubricating oil, which will cause the expansion space and the small holes in the spacer plates to become clogged with carbon and soot. This carbon and soot soon bakes into a hard crust causing much back pressure which results in a considerable loss of power. This condition will become noticeable first by a loss of considerable power caused by an overheated motor. If this condition is not remedied, the exhaust manifold and pipe leading to the muffler will soon become red-hot, causing much danger of a serious damage loss to the car from fire.

Fig. 49. Muffler

Muffler.—To eliminate or remedy this condition, disconnect manifold pipe from the muffler, remove the muffler from hangers, and disassemble it by removing the nuts from the tie rods which release the end plates. This will allow the compartment walls and spacer plates to be drawn from the sleeve. Each compartment and spacer plate should be removed sectionally, and its position carefully noted, in order that it may be replaced correctly in re-assembling. The walls of the sleeve, and the compartment end plates are scraped and rubbed with a piece of sandpaper. A small round file may be used in cleaning the center pipe. The spacer plates are scraped and sandpapered. The small holes in the spacer plates may be opened by using the tapered end of a small file. [Fig. 49] shows a muffler of another design. The burnt gas enters a compartment containing three saucer shaped spacers which retard and break up the volume. It then passes through an open compartment and enters reversed spacers through small holes near the sleeve wall. It centers or forms slightly in volume and escapes to the next compartment through a small hole in the center of the second spacer. This action of forming and breaking is kept up until the outlet is reached.

CHAPTER XIII
VACUUM SYSTEMS
Construction, Operation and Care

The vacuum systems have proved to be one of the important inventions pertaining to successful motor operation. They are self contained, simple in construction and automatic in operation. They do away with the troublesome power and hand pressure pumps and their connections.

AIR VENT
FROM
INTAKE MANIFOLD
FROM
GASOLINE
SUPPLY TANK

Fig. 50. Vacuum System—Top Arrangement

[Fig. 50] shows the top arrangement and connections. R is the air vent over the atmospheric valve. The effect of this is the same as if the whole tank were elevated, and is for the purpose of preventing an overflow of gasoline, should the position of the car ever be such as to raise the fuel supply tank higher than the vacuum tank. D shows the pipe connection from the fuel supply tank. C shows the pipe connection to the intake manifold. W shows a tap or vent through which gasoline may be fed into the upper chamber, in case the fuel supply tank is damaged or put out of commission. R shows the air vent connection from the lower tank.

[Fig. 51] shows a general diagram of vacuum system installation. One of the chief advantages is that it allows the carburetor to be placed near the head of the motor and does away with the long manifold connections required with the gravity feed systems. This also reduces the frictional resistance, gives a richer mixture and greater volume of flow.

AIRVENT
A—CONNECTION
BETWEEN INTAKE
MANIFOLD AND
VACUUM TANK
C—CONNECTION
FROM VACUUM
TANK TO CARBURETOR		B—
CONNECTION
BETWEEN
MAIN GASOLINE
SUPPLY TANK AND
VACUUM TANK

Fig. 51. Vacuum System Installation

[Fig. 52] shows a sectional view of the Stewart Vacuum System and explains the operative value of each part. A is the suction valve for opening and closing the connection to the manifold through which a vacuum is extended from the engine manifold to the gasoline tank. B is the atmospheric valve, and permits or prevents an atmospheric condition in the upper chamber. When the suction valve A is open and the suction is drawing gasoline from the main supply tank, the atmospheric valve B is closed. When the suction valve A is closed, the atmospheric valve B must be open, as an atmospheric condition is necessary in the upper tank in order to allow the gasoline to flow through the flapper valve H into the lower chamber. C is a pipe connecting the tank to the intake manifold of the engine. D is a pipe connecting the tank to the main fuel supply tank. E is the valve control lever and has two coil tension springs S attached to operate the short valve lever F. G is the metallic air-containing float, which controls the action of the valves through the spring and lever arrangement. H is the flapper valve at the outlet of T, and it closes by suction when the vacuum valve A is open. When the vacuum valve A closes, the atmospheric valve B opens and relieves the suction in the upper tank, the flapper valve H opens and allows the fuel to flow from the upper tank into the lower chamber.

AIR VENT
TO INTAKE
PASSAGE
FROM
GASOLINE
TANK
FLOAT VALVE
UPPER
CHAMBER
LOWER
CHAMBER
TO CARBURETOR

Fig. 52. Vacuum System Diagram—Stewart Warner

J is a plug in the bottom of the tank which can be removed to clean or drain the tank. This plug can be removed and replaced with a pet-cock for drawing off gasoline for priming or cleaning purposes. K is the line to the carburetor. It is extended on the inside of the tank to form a pocket for trapping water and sediment. L is a channel space between the inner and outer shells and connects with the air vent R, thus admitting an atmospheric condition to exist in the lower chamber at all times, and thereby permitting an uninterrupted flow of gasoline to the carburetor. R is an air vent over the atmospheric valve; the effect of this valve is the same as if the whole tank was elevated. It is also for the purpose of preventing an overflow of gasoline should the position of the car ever be such as would raise the fuel supply tank higher than the vacuum tank. Through this tube the lower or reservoir chamber is continually open to atmospheric pressure. T is the outlet at the bottom of the float chamber in which the flapper valve H is located. U is the float stem guide. V is a strainer which prevents foreign matter from passing into the vacuum chamber. W is a tap or vent through which gasoline may be fed into the upper chamber if the fuel tank is damaged or put out of commission.

The simple and durable construction of this system makes it unlikely that the car owner will ever need to make internal repairs. Before attempting to repair this tank make sure that the trouble is not due to some other cause.

Air Vent.—A small amount of gasoline may escape through the air vent occasionally. This will do no harm and no adjustment is needed. However, if the vent tube continues to overflow, one of the following conditions will be responsible: 1. The air hole in the main supply tank is stopped up, or the hole is too small. Enlarge the hole or clean it out. 2. If gasoline leaks from the system except from the vent tube, it can only do so from one of the following causes: a. A leak may exist in the outer wall of the tank. If so soldering it up will eliminate the trouble. b. The carburetor connection on the bottom of the tank may be loose. c. There may be a leak in the tubing at the head of the tank. d. The cover of the tank may be loose.

Failure to Feed Gasoline to the Carburetor.—This condition may be due to other causes than the vacuum system. Do not tinker with it until you are sure that the trouble is not elsewhere. Flood the carburetor. If gasoline runs out of the float chamber you may be sure that the vacuum system is performing its work properly.

To Remove Cover.—To remove the cover for inspection, take out the screws and run a knife blade carefully around the top to separate the gasket without damaging it. Shellac the gasket before you replace it to make the tank air-tight.

Faulty Feed.—If faulty feed is traced to the vacuum tank, one of the following conditions may be the cause. The float valve G may have developed a leak. To repair, remove the top of the tank to which it is attached. Dip the float into a pan of hot water. Bubbles will show the leak. Punch two small holes, one at the top, and one at the bottom, and blow the gasoline out. Then solder up the holes and the leak. Use solder carefully in order not to add too much weight to the float. A small particle of dirt may be lodged under the flapper valve. This trouble can usually be remedied by tapping the side of the tank. In order to determine whether or not the flapper valve is working properly, plug up the air vent tube and remove the pipe extending from the bottom of the tank to the carburetor. Start the engine and place a finger over the opening (from which you removed the tube). If continual suction is felt, it is evident that the flapper valve is being held off its seat. If tapping the side of the tank will not remedy this condition, remove the cover and withdraw the upper chamber. The valve is attached to the pipe projecting from the bottom.

Strainer.—Remove and clean the strainer screen located at V, [Fig. 52], every five or six weeks. This screen collects all the dirt and foreign matter in the gasoline, and often becomes stopped up.

CONNECTION TO
GASOLINE TANK		SUCTION TUBE
CONNECTION TO INTAKE
MANIFOLD
STRAINERVENT TUBE
CONNECTION
COVER
ATMOSPHERIC
VALVE
SUCTION VALVE
VALVE LEVER
INNER TANK
SPRINGS
OUTER TANK
FLOAT LEVER
FLOAT
GUIDE
FLAPPER VALVE
DRAIN PLUGCONNECTION TO
CARBURETOR

Fig. 53. Vacuum System—Inside View of Parts—Stewart Warner

Filling the Vacuum Tank.—To fill the tank after it has been cleaned or repaired, leave the spark off, close the gas throttle, and crank the engine over a few times with the starter or by hand. It takes less than ten seconds to create sufficient vacuum to fill the tank.

CHAPTER XIV
ELECTRICAL DICTIONARY OF PARTS, UNITS AND TERMS

Before taking up the study of automobile ignition systems and electrical appliances, we will first devote a little time to study, in order to become familiar with the different electrical parts, functions, terms and names applied to the various units, and machines.

In the first place electricity is not a juice or fluid that flows through a wire, but is a generated electro-motive force that may be held in storage or conducted from one place to another. It will not flow without a round circuit and seeks ground return at the slightest opportunity. It is designated in terms which express quality, quantity, force and action.

Voltage.—A volt is an electrical unit, expressing the force or pressure of the current. The voltage of a system simply means the difference of pressure exerted on the system measured in volts.

Ampere.—An ampere is an electrical unit expressing the quality or intensity of the current.

Ohm.—An ohm is an electrical unit expressing resistance; or the resistance of conductors to the flow of current.

Current.—The current is the generated electro-motive force.

Circuit.—Electricity will not flow unless there is a circuit or ground return to its original source.

Low Tension Current.—Low tension current is generated in the primary winding or coil by placing it in a magnetic field. It will flow from one point to another but has very little strength and will not jump the gap at the spark plug. It is used for lighting purposes, or conducted to an induction coil which transforms it into a high tension alternating current.

High Tension Current.—High tension current is generated in the secondary coil by interruption of the primary current or by the rapid magnetization and demagnetization of the core and primary coil.

Direct Current.—Direct current is produced by placing a coil or wire in a magnetic field. It is usually conducted to an induction coil where it is transformed into a high tension alternating current.

Alternating Currents.—Alternating currents are produced by the rapid breaking down and building up of the primary current. An alternating current flows forward from zero to its highest point of strength and back again to zero. The alternating action takes place so rapidly that a light can be connected in this circuit and it will burn steadily without any noticeable fluctuation.

Fig. 54. Coil Diagram

Induction Coil.—An induction coil consists of a soft iron core; a primary and secondary winding, and a set of platinum points. The primary winding is wound directly over the core and consists of a few turns of thick wire. The secondary wire is wound over the primary and consists of a great many turns of thin wire. [Fig. 54] shows the functional action of an induction coil. Both of the coils are wound on the soft iron core A-B. The primary current which is supplied in this case by a cell or number of cells, C and D, is broken at frequent intervals of time. The method of doing this is as follows: One terminal of the primary coil is connected to the fixed platinum stud D, the other terminal to a spring which carries a piece of soft iron, E. When the spring is unbent it touches the stud D, and a current passes in the primary. The core of soft iron becomes magnetized and attracts the soft iron disc, E, thus breaking contact at D. The current is stopped and the core immediately becomes unmagnetized, the spring flies back and the contact is again made. The process is then repeated. When the contact in the primary is broken the current flows in one direction in the secondary coil, when it is made the current flows in the opposite direction in the secondary. Thus an alternating current is set up in the secondary current of great frequency.

Commutator.—The commutator or timer as it is commonly called is used only in connection with the induction coil to complete the circuit when a spark is required at the plug in the cylinder.

Insulation.—Insulating is the act of covering a conductor with a non-conducting substance to prevent the spark from jumping or seeking ground.

Choking Coil.—A choking coil in simple form consists of a coil and iron core to increase self-induction. It is used to reduce currents of high pressure and is commonly called a bucking coil.

Fuse.—A fuse is used to prevent conductors or coils from being damaged by heat generated from high pressure currents. It consists of a metal and glass tube which contains a fine wire. This wire being much thinner than the wire of the cable, the heat naturally develops faster at this point, and is soon high enough to melt the wire and break or open the circuit, and thus any further damage to the insulation is prevented.

Condenser.—A condenser usually consists of a few strips of folded tin foil insulated from each other with paraffined or oiled paper. It absorbs, restricts and distributes high pressure currents and also prevents excessive sparking at the contact points.

Fig. 55. Dynamo—Diagram of Action

Dynamo.—A dynamo is a machine which converts mechanical energy into electric energy, and must consist of at least two separate parts; the field magnets to create the magnetic field, and the armature or conductor in which the current is generated. One or the other of these must be in motion in order to cut the lines of magnetic force crossing the field. [Fig. 55] shows the operation of the most common or simplest type of alternating current producing machine, which is similar and conforms in action to the high tension magneto and generator. Field pieces magnetize the pole pieces N and S. A wire coil is placed in the field at right angles to the magnetic lines of force turned to the right. It takes up the position of the dotted lines and no lines of force are cut, whereas in its original position, as many lines of force as possible are cut. Turning the coil on its axles, a-b, causes the lines of force cut by c-d, and e-f to vary from the highest number of lines that it is possible to cut to zero and back again, thus constantly changing the flowing direction of the current. The reversal of the current takes place at the instant that the coil passes the point where it cuts the greatest number of lines of force. The ends of the coil are connected to a commutator on the shaft a, b. Steel insulated brushes pick the current from the commutator ring and conduct it to the brush post; an insulated wire conductor is attached to this post and conducts the current to the place of use or storage.

Voltaic Cell.—The source of energy of a voltaic cell is the chemical action. (See [accumulator]).

Accumulator.—The standard accumulator or storage battery is composed of three cells or hard rubber jars in which a number of lead plates are immersed in a solution of sulphuric acid and water known as electrolyte. The plates are stiff lead grids which hold a paste made of various oxides of lead. Six plates in each cell are joined to the positive terminal, and seven plates in each cell are joined to the negative terminal. Thin wooden separators are inserted between the plates to prevent them from touching one another. In the forming process the material on the positive plates becomes converted into brown peroxide of lead; the negative plates assume the form of gray metallic lead. The material on both plates is known as active material. When current is taken from the cells the sulphuric acid in the electrolyte combines with the active material of the plates to form sulphate of lead, and when the battery is recharged the lead sulphate is again converted into the original active material and the acid set free in the solution.

Storage Battery.—For construction and action see [Accumulator]. For care see chapter on [storage batteries].

Electrolyte.—A chemical solution used in voltaic cells consisting of two parts sulphuric acid added to five to seven parts of water by volume.

Hydrometer.—A hydrometer is used to test the electrolyte solution in the cells of storage batteries. It consists of a weighted float and a graduated stem, and as sulphuric acid is heavier than water, the specific gravity reading will be proportional to the amount of acid. The hydrometer thus measures the relative amount of acid in the electrolyte and consequently reveals the condition of the battery.

Ammeter.—An ammeter is an electrical instrument which indicates the amount of current that the generator is supplying to the storage battery, or the amount of current that the storage battery is supplying for ignition, lights and horn.

Circuit Breaker.—The circuit breaker is a device which prevents excessive discharging of the storage battery. All the current for lights is conducted through the circuit breaker (Delco system). Whenever an excessive current flows through the circuit breaker it intermittently opens the circuit causing a clicking sound. This will continue until the ground is removed or the switch is operated to open the circuit on the grounded wire. When the ground is removed the circuit is automatically restored, there being nothing to replace as is the case with fuses.

Switch.—A switch opens and closes the various circuits and is for the purpose of controlling the light, ignition, generator and storage battery circuits.

Generator.—See chapter on [electrical starting systems].

Regulation.—(Delco). On account of the various speeds at which the generator must operate it is necessary that the output be regulated so that sufficient current is obtained at the low engine speeds without excessive current at the higher speeds. The regulation in this case is what is known as the third brush excitation in which the current for magnetizing the frame is conducted through the auxiliary or third brush on the generator commutator. With this arrangement the natural function of the generator itself causes less current to flow through the shunt field winding at the higher engine speeds. This weakens the magnetic field in which the armature is rotating and decreases the output of the generator.

Contact-breaker.—See chapter on [Atwater Kent ignition systems].

Coil, nonvibrating.—See chapters on [Atwater Kent ignition systems] and [Philbrin electrical systems].

Distributors.—See chapters on [Magnetos] and [Atwater Kent ignition systems].

CHAPTER XV
MAGNETO PARTS AND OPERATION

Fig. 56. Magnets—Pole Blocks

The purpose of the magneto is to furnish electrical current at regular intervals, to jump the spark plug gaps and to ignite the gas which has been compressed in the combustion chambers. The discovery was made years ago that, by placing a coil of wire between two magnetic poles, current would be present at once. But it is only while the wire coil is in motion that the current will flow or circulate, and while there are many theories why this takes place only while the coil is in motion, none seem to explain the fact satisfactorily. The strength of the current depends on the size of the magnetic field, and the number of wraps of wire in the coil. Consequently the larger the coil the more intense the current. [Fig. 56] represents the magnets, of which there are from three to six. The U-shaped pieces are made of steel which has been case hardened and charged with electricity which causes them to become magnetized. Magnets have two poles or axes, one of which is positive from which the current flows, and one of which is negative to which the current flows or passes. [Fig. 56A] shows the pole pieces which are located on the inside of the lower or open end of the magnets. The pole pieces are channel ground, leaving a round space or tunnel in which the armature revolves.

[Fig. 57] shows the soft iron core which is shaped like the block letter H, and wound with fine wire, making up the coil shown in [Fig. 57A] of the wound armature.

Fig. 57. Armature Core—Wound Armature

Fig. 58. Primary and Secondary Winding and Current Direction

[Fig. 58] shows the primary and secondary winding. The primary or heavy wire is wound on the core lengthwise, each strand being separated from the other with rubber or tin foil insulation. The current passes from the top of the left pole piece to the top of the core until it passed out of range, crossing the upper gap between the two pole pieces. As the top of the core leaves or breaks the contact flow of current, the bottom of the core comes in contact range, leaving an open space which breaks the current and changes the direction of flowage as shown in [Fig. 58A and 58B]. This current is of a low tension nature, and will not jump the gap at the spark plugs when the engine is running slow. The secondary winding, shown in [Fig. 58], is made up of many more windings of a finer wire. The low tension or primary current is led through the armature shaft to a contact breaker at the rear of the magneto.

[Fig. 59] shows the contact breaker, which consists of a housing in which two platinum points are arranged, one point stationary, the other attached to an arm on a pivot. The points are held together by spring tension.

Fig. 59. Breaker—Slip Ring—Distributor

A cam on the armature shaft comes into contact with the arm on which the second point is located, forcing it from the stationary point, thus breaking the low tension current which returns to the secondary coil, the magnetizing and demagnetizing caused by the break in the low tension current, and sets up a rapid alternating current. One end of the secondary is led to a collector ring on the front of the magneto. [Fig. 59A] shows the collector ring. A carbon brush collects the current from the ring and conducts it to the distributor’s centrally located arm. [Fig. 59B] shows the distributor. The centrally located arm is timed to deliver the current, or comes into contact with one of the segments or brushes and allows the current to flow from the segment to the gap at the spark plug, where it jumps the gaps and ignites the gas in the cylinders at the proper time. Then it returns through the ground (the engine and the frame) to the magneto, where it passes back into the secondary coil, passing through an insulated condenser consisting of small plates of steel insulated from one another. This regulates the flowage of the returning current, by reducing it through resistance, and prevents the armature from heating.

A safety spark gap is provided on some magnetos which causes the spark to jump and lose some of its force through resistance when the plugs become shorted. This also restricts the current and greatly aids the condenser in performing its purpose.

CHAPTER XVI
BOSCH HIGH TENSION MAGNETO
Operation, Adjustment and Care

Like all other types of high tension magnetos, the Bosch Type ZR. Ed. 16 explained in this chapter, generates its own current and is usually employed as sole ignition on an engine.

The timer and distributor are integral; and the rotation of the armature, between the poles of strong permanent field magnets, sets up or induces a current in the armature primary circuit, which is farther augmented at every one hundred and eighty degrees of revolution of the armature shaft, by the abrupt interruption of the primary circuit by means of the magneto interruptor. At the opening of the primary circuit the resulting discharge of current from this circuit induces a current of high voltage in the armature secondary circuit. The high tension current thus created is collected by a slip ring on the armature and passes to the slip ring brush then to the various magneto distributor terminals each of which is connected to a spark plug in its respective cylinder.

The operation of the instrument will be more clearly understood from a study of the complete circuits, primary and secondary, which follows.

The Primary or Low Tension Circuit.—The beginning of the armature primary circuit is in metallic contact with the armature core, and the end of the primary circuit is connected by means of the interruptor fastening screw to the insulated contact block supporting the long platinum contact on the magneto interruptor. The interruptor lever carrying a short platinum contact, shown in [Fig. 60] at C is mounted on the interruptor disc, which in turn, is connected to the armature core. The primary circuit is completed whenever the two platinum contacts of the interruptor are brought together, and separated whenever these contacts are separated.

From the latter point the high tension current passes to the distributor brush ([shown] at D) which is held in a brush holder on the distributor gear, and consequently rotates with the distributor gear. Metal segments are imbedded in the distributor plate and as the distributor brush rotates it makes successive contacts with the segments, passing the current onto the spark plug gaps through the high tension cables which are attached to the segment terminal posts.

Fig. 60. Bosch M Distributor and Interruptor—Housing Removed

[Fig. 61] shows a circuit diagram of the Type ZR. Ed. 16. Bosch Magneto. Note that the spark plugs must be connected up in accordance with the firing order of the engine. The metal segments imbedded in the distributor plate are connected with the terminal studs on the face of the plate, and the latter are connected by cable to the spark plugs in the various cylinders. In the cylinders the high tension current produces a spark which produces ignition, and then returns through the ground and the engine to the magneto armature, thus completing the circuit.

Timing the Magneto.—With the average four cycle engine the proper operating results are obtained by timing the magneto as follows: The crank shaft is rotated to bring the piston in No. 1 cylinder (in automobile practice this is the cylinder nearest the radiator) exactly on top dead center of the compression stroke. The timing control lever on the housing is then placed in the fully retarded position. With this done, the magneto distributor plate should be removed by withdrawing the two holding screws, or by releasing the two holding springs as the case may be.

DISTRIBUTOR
BRUSH
HOLDER		SAFETY
SPARK GAP
SLIPRING CONDENSER
ARMATURE INTERRUPTER
GROUND GROUND

Fig. 61. Wiring Diagram Bosch Magneto, Type ZR-4

The operation of the platinum contact points is controlled by the action of the interruptor lever as it bears against the two steel segments secured to the inner surface of the interruptor housing.

In [Fig. 60], A shows the distributor with the face plate removed to show the position of the distributor segments which are connected to the terminal posts on the back of the plate. B shows the interruptor housing and cover removed from its position on the magneto. C shows the complete assembly of the distributor and interruptor. Note that the face plate of the distributor is fastened on with a set of screws while the interruptor cover is held in position with a latch.

The Secondary or High Tension Current.—The high tension current is generated in the secondary circuit only when there is an interruption of the primary circuit, the spark being produced at the instant the platinum interruptor contact points separate. The armature secondary circuit is a continuation of the armature primary circuit, the beginning of the secondary circuit being connected to the primary, while the end of the secondary is connected to the insulated current collector ring mounted on the armature just inside the driving shaft end plate of the magneto. The slip ring brush is held in contact with the slip ring by a brush holder at the shaft end of the magneto which receives the high tension current collected by the slip ring by means of a connecting bar which passes under the arch of the magnets, and passes the current to the center of the distributor plate, thus exposing the distributor brush and gear. The cover of the interruptor housing is also to be removed to permit observation of the interruptor points.

The armature should then be rotated by means of the exposed distributor gear in the direction in which it is driven until the platinum contact points are about to separate, which occurs when the interruptor lever begins to bear against one of the steel segments of the interruptor housing. Timing or installation is completed by replacing the interruptor housing cover and distributor plate, and connecting the cables between the magneto and the spark plugs.

Exact Magneto Timing.—The foregoing will establish the desired relationship between the magneto armature shaft and the engine crank shaft. It should be noted, however, that while these instructions cover the average engine, the exact magneto timing for individual engines is best determined by trial.

When specific instructions for magneto timing are given by the engine manufacturer, it is recommended that such instructions be followed in preference to those herein given.

It must always be borne in mind that while making connections the distributor brush travels in the opposite direction to the rotation of the armature shaft.

The Condenser.—The condenser consists of a set of metal discs, insulated from one another with tin foil. It is carried at the interruptor end of the magneto. It is connected in the primary current and forms a shunt connection with the interruptor contact points, and through resistance to the returning ground current prevents excessive sparking at the interruptor contact points which would soon burn the points and ruin the coils.

The Safety Spark Cap.—A safety spark cap is provided to protect the armature and other current carrying parts. Under normal conditions the current will follow its path to the spark plug, but if for any reason the resistance in the secondary wire is increased to a high point, as when a cable becomes disconnected, or a spark gap too wide, the high tension current will discharge across the safety spark gap.

Caution.—The current should never be allowed to pass over the safety spark gap for any length of time, and if the engine is operated on a second or auxiliary ignition system, the magneto must be grounded in order to prevent the production of high tension current. The snapping sound by which the passage of current across the safety spark gap may be noted should always lead to an immediate search for the cause of the difficulty.

The Safety Spark Gap.—The safety spark gap consists of a pointed metal electrode projecting from the mounting flange of the slip ring holder, inside the shaft end hood. The tip of the electrode extends to within a short distance of the connecting bar, extending from the brush holder to a magneto distributor plate center post.

Timing Range.—The magneto interruptor housing is arranged so that it may be rotated through an angle of thirty-four to thirty-seven degrees with respect to the armature shaft. The movement of this housing in one direction or another causes the interruptor lever to strike the steel segments earlier or later in the revolution of the armature, the spark occurring correspondingly earlier or later in the cylinder. The spark can be advanced by means of moving the interruptor housing which is connected to the spark lever on the steering gear, in the direction opposite the rotation of the armature. The armature rotation is usually indicated by an arrow on the cover at the driving end of the magneto.

Cutting Out Ignition.—Since a high tension current is generated only on the interruption of the primary circuit, it is evident that in order to cut out the ignition, it is merely necessary to divert the primary current to a path that is not affected by the action of the magneto interruptor. This is accomplished as follows: An insulated grounding terminal is provided on the cover of the magneto interruptor housing with its inner end consisting of a spring with carbon contact pressing against the head of an interruptor fastening screw. The outer end of the grounding screw is connected by low tension cable to one side of the switch, and the other side of the switch is grounded by connecting a cable between it and the engine or frame. When the switch is open the primary current follows its normal path across the interruptor points, and is interrupted at each separation of these contact points. However, when the switch is closed, the primary current passes from the head of the interruptor fastening screw to the carbon contacts of the grounding terminal, thence through the switch to the engine and back to the magneto, and as the primary current remains uninterrupted when following this path, no ignition current is produced.

Care and Maintenance.—Aside from keeping the magneto clean externally, practically the only care required is the oiling of the bearings. Of these there are two sets supporting the armature, and a single plain bearing supporting the shaft of the distributor gear. Any good light oil may be used for this purpose (never cylinder oil), and each of the bearings should receive not more than two or three drops about every thousand miles. Apply the oil through the oil ducts at each end of the armature shaft. The interruptor is intended to operate without oil, as oil on the interruptor platinum points prevents good contact, and causes sparking, burning, and misfiring. Care should be taken to prevent oil entering these parts.

CHAPTER XVII
MAGNETO WASHING, REPAIRING AND TIMING

One point that cannot be over sufficiently emphasized is the warning that only those who are thoroughly familiar with the magneto should attempt to disassemble it. Therefore every part should be studied, and its functional action fully understood before any repairs or adjustments are undertaken.

The manufacturers of magnetos have developed their product to a point of high efficiency and dependability, and if they are properly lubricated and washed occasionally to prevent gumming up, very little trouble may be expected from this type of ignition system.

Magneto Cleaning.—Magneto parts should be washed with gasoline as it has the ability to remove grease and dirt and evaporates rapidly leaving a perfectly dry surface. Care should be exercised to prevent fire, for the present grade of gasoline does not evaporate as readily as it did some time ago when refiners furnished a high test grade of fuel and the surface of the armature and indentures of the magneto may retain a pool or film which may be ignited by a short circuit, or from the breaker box, and cause a fire which would ruin the magneto. There is, however, little danger from fire if the gasoline is used sparingly, and each part wiped dry before reassembling the magneto.

It is considered a good point when the magneto has been taken apart to be cleaned to go over every part with a cloth dampened in kerosene, because gasoline leaves a very dry surface which is liable to rust. The bearings especially are most easily affected in this way.

The armature may be washed with a brush which has been dipped into gasoline, but should not be immersed as that would soften the insulation and cause it to rot.

The way in which the parts come off should be carefully noted in order to avoid trouble in reassembling, and the gears operating the distributor should be carefully marked to assure correct timing, which will result in a saving of time and trouble.

When the magnets are removed, close the ends with a file or piece of steel to prevent them from becoming demagnetized.

Magneto Repairing.—As previously stated, it is not likely that a magneto will require any further attention than the regular monthly oiling. Two or three drops of light sewing machine oil should be dropped into the oil wells which supply the bearings at each end of the armature shaft.

If any trouble arises that can be traced directly to the magneto, examine the breaker box mechanism first; the locknut at the point adjustment may have worked loose, and the points may be closed, or some abnormal condition may exist that has caused the points to pit and stick.

Breaker point adjustment varies from the thickness of a sheet of writing paper to one sixty-fourth of an inch; an adjustment anywhere between these two points usually results in satisfactory operation.

If the magneto does not function properly after the breaker box and external wire connections have been examined, the trouble is probably due to an internal short circuit, and repairs of this nature should only be undertaken by an expert magneto mechanic.

To remove the magneto, disconnect the high tension wires leading to the spark plugs from the distributor terminal posts, tag and number each wire to correspond with the number stamped below the post. If the engine fires 1-2-4-3, number three wire will be attached to number four terminal post. Then remove the ground wire and disconnect the universal joint and remove the metal strap, or the set screws, from the base.

To Time the Magneto.—Place the timing control lever in a fully retarded position; remove the plates from the distributor housing to expose the distributor brush and gear, then remove the cover from the interruptor housing to permit observation of the points, and rotate the armature in the direction which it is driven until the point begins to open. At this point mesh the distributor gear so that the distributor lever will just be touching one of the segments which connect to the distributor terminal posts.

Timing the Magneto with the Engine.—Rotate the crank shaft until No. 1 cylinder is up on dead center on the compression stroke; rotate the armature, with the spark lever in full retard until the distributor arm begins to make contact with No. 1 segment, and mesh the timing gear at this point.

CHAPTER XVIII
NORTH EAST IGNITION SYSTEM

The N.-E. Model O Distributor Ignition System is used on Dodge Brothers cars. This system provides high tension ignition for the engine by transforming the low voltage of the starter generator or the battery into a high voltage capable of jumping freely between the spark plug electrodes. This is accomplished through the agency of an induction coil, the primary winding of which, in series with an interruptor or contact breaker, receives current under normal running conditions from the starter generator. The starting and lighting battery, however, supplies this current instead of the generator whenever the engine is starting or running very slowly.

At each interruption of the primary current there is set up in the secondary winding of the coil a high tension current, and this current flows from the coil through a high tension cable to the distributor rotor from which point it is selectively conducted to the proper spark plug. Upon reaching the spark gap in the plug, it jumps from the inner electrode to the outer one, which is grounded, and then returns through the engine frame to the grounded end of the secondary winding on the ignition coil. The high tension spark thus produced in the cylinder ignites the gas and so brings about the necessary combustion.

Wiring ([Fig. 62]).—As will be evident upon reference to the accompanying wiring diagram, the primary circuit of the ignition system leads from the positive terminal of the battery through the charging indicator to the ignition switch binding post marked “Bat.,” thence, when the switch is turned on, through the switch to one of its binding posts marked “Ign. Coil.” Continuing on from this point through the ignition coil and the breaker contacts, it returns to the second switch binding post marked “Ign. Coil,” where it passes through the switch again. It then finally reaches the grounded negative terminal of the battery through the grounded terminal of the switch and the car frame.

CHARGING
INDICATOR		IGNITION AND
LIGHTING SWITCH		 SPARK PLUGS
GROUNDED
THROUGH CASE
CONTACT-STUD LOCK NUT
STATIONARY CONTACT-STUD
MANUAL CONTROL LEVER
BREAKER-ARM
GROUND
CONNECTION		 BREAKER-CAM
STARTING SWITCH AND
REVERSE CURRENT
CUT-OUT		BREAKER-CAM NUT
CONDENSERBREAKER-
CONTACTS
IGNITION
COIL		 BREAKER BOXDISTRIBUTOR
HEAD
BATTERYSECONDARY COIL
PRIMARY COILSAFETY SPARK GAP
GROUND CONNECTION GROUNDED
THROUGH CASE

Circuit Diagram of the Model O Ignition System on the Dodge Brothers Motor Car

Fig. 62. Wiring Diagram, North-East System—on Dodge Car

The ignition switch is so constructed that it produces a reversal of polarity in the distributor circuit each time the switch is turned off and then on again. For this reason there is no necessity of making a distinction between the two wires leading from the distributor to the two switch binding posts marked “Ign. Coil,” because the operation of the system cannot be affected by the transposition of these wires. With this one exception, however, the ignition circuit connections must always be made exactly as indicated in the diagrams, if satisfactory operation of the system is to be maintained.

HIGH TENSION
DISTRIBUTOR TERMINALS
DISTRIBUTOR-BRUSH DISTRIBUTOR-HEAD
DISTRIBUTOR-ROTOR BREAKER-CAM NUT
BREAKER-ARM LOCK WASHERS
VERTICAL SHAFT BREAKER-CAM
VERTICAL SHAFT
BEARING SLEEVE		 STATIONARY CONTACT-STUD
SUPPORT
PRIMARY COIL
TERMINALS
GREASE CUP
COUPLING YOKE
HIGH TENSION
COIL TERMINAL		 HORIZONTAL SHAFT
ADVANCE PLATE
COIL HOUSING VERTICAL SPIRAL GEAR
ADVANCE WEIGHTS
IGNITION COIL HORIZONTAL SPIRAL GEAR

Fig. 63. North-East Distributor—Model O—Ignition

Ignition Distributor. ([Fig. 63]).—The model O ignition distributor is mounted on the right-hand side of the Dodge Brothers engine where it is held rigidly in position by means of four bolts. The horizontal shaft of the distributor is connected directly to the engine pump shaft through a flexible coupling, and runs, therefore, at engine speed. The vertical distributor shaft is driven from the horizontal shaft by means of spiral gears which reduce its speed to one-half that of the engine.

The complete distributor unit consists essentially of three self-contained assemblies: The ignition coil, the breaker box and distributor base assembly which include the automatic spark advancing mechanism. Each one of these three elements is so constructed as to be readily detachable from the distributor unit independently of the others.

Ignition Coil.—The ignition coil, which is contained in a separate housing, forming part of the distributor unit, is constructed for 12 volt service and operates directly on the starting and lighting circuit. The coil housing is attached to the distributor base by means of four screws and serves also as a cover for the automatic advance compartment. The high tension terminal located on the coil housing is designed to provide a safety spark gap, as well as to act as a binding post for the high tension cable which connects the coil to the distributor head.

Breaker Box and Distributor Head Assembly. ([Fig. 64]).—The breaker box and distributor head assembly is mounted in an upright position near the center of the distributor base and is secured in place by a large-headed screw in the vertical portion of the base. This screw projects into the annular groove in the vertical shaft bearing sleeve, thereby preventing the breaker box assembly from becoming detached from the distributor base and yet at the same time permitting it to turn freely from side to side. The short lug projecting downward from the manual control lever on the breaker box extends into the round hole near the middle of the distributor base and acts as a stop to limit the travel of the breaker box.

In case it should become necessary to remove the breaker box and distributor head assembly, the distributor head should first be detached from the breaker box and then, with the breaker box in the position of full retard, the exact location of the distributor rotor should be marked accurately on the edge of the box. This mark should be made with special care, because it has to serve as the sole guide for the correct position of the vertical shaft when the assembly is put back in place again on the distributor base. Moreover, while the breaker box assembly is separated from the base, the horizontal shaft in the base must not be turned from the position it occupied at the time when the location of the rotor was marked. If either of these precautions is neglected, the correct relationship between the several moving parts of the system will be likely to be disturbed to such an extent that the complete retiming of the distributor will become necessary.

Fig. 64. North-East Breaker-Box

Condenser.—The condenser, shunted across the breaker contacts to absorb the inductive surges that occur in the primary circuit at each interruption, serves to intensify the effect produced in the secondary circuit by these interruptions, and also to protect the breaker contacts from injurious arcing. It is contained in a sealed case which protects it against possible external injury, and is located in the breaker box close to the breaker contacts where its maximum effectiveness is obtained.

Being very substantially constructed, the condenser ordinarily requires no attention. If for any reason it should become inoperative, the best course is always to replace it with a new one, because condenser repairs are not economically practicable. The entire condenser unit can be easily removed, whenever desired, by disconnecting the two condenser leads from the breaker box binding posts, and then unscrewing the two nuts on the under side of the breaker box that hold the condenser case in place.

Breaker Contacts.—The breaker arm, which carries one of the two breaker contacts, is mounted on a pivot post from which it is thoroughly insulated by a fiber bushing. The helical spring, which is attached to the lug at the pivot end of the arm, holds it normally in such a position that the breaker contacts are kept closed. But the fiber block near the middle of the breaker arm lies in the path of the breaker cam and is consequently struck by each lobe of the cam as the vertical shaft revolves. Each of these blows from the cam cause the breaker contacts to be forced apart, and thereby produce the necessary interruptions in the primary circuit. The second contact is carried by the stationary contact stud, which is adjustably mounted in an arched support. With this stud properly adjusted the difference between the contact points when they are fully separated by the cam, is twenty thousandths of an inch (.020″).

If it should ever become necessary to renew the breaker contacts, a complete replacement of the entire breaker arm and the contact stud assemblies will in general be found to be the most effectual method of handling the work. The breaker arm can be removed by simply lifting it off its pivot bearing after its pigtail has been disconnected from the breaker box binding post. The spring attached to the breaker arm lug will slip off of its own accord as soon as the arm is raised sufficiently from its normal position. After the breaker arm has been taken off, the stationary contact stud can be removed by releasing its lock nut and unscrewing it from its support. To replace the breaker arm it is merely necessary to insert the lug in the spring, and then, with the spring held taut, to push the arm firmly down upon its pivot post until it snaps into position.

Breaker Cam.—The breaker cam, by which the interruptions in the primary circuit are produced has four projections on its working surface, so spaced that one of them strikes the breaker arm and causes the breaker contacts to be abruptly separated each time a spark is required. The cam is held in place on the upper end of the vertical shaft by means of a slotted nut and set of special lock washers. It should never be disturbed if avoidable, because its accurate setting is absolutely essential to the correct operation of the entire system. If, at any time, however, its position should become altered accidentally, it must be carefully reset at once in accordance with the timing directions given later on.

The breaker cam and the distributor rotor are both mounted on the vertical shaft and are rotated at exactly one-half engine speed. Accordingly, since the engine is of the usual four-cycle type requiring two revolutions of the crank shaft for one complete cycle of operation, the distributor rotor and breaker can make one revolution during the completion of each full cycle of the engine.

Distributor Head.—The distributor head contains five high tension terminals. The central terminal receives the current from the secondary winding of the ignition coil and transmits it to the rotor arm by which it is distributed to the four outer terminals. These outer terminals are numbered 1, 2, 3, 4 respectively, corresponding to the firing order of the engine, and are connected to the four spark plugs in accordance with their markings. The distributor rotor in completing one full revolution establishes contact successively between the rotor brush and each one of these four outer distributor terminals, each contact being made at the same moment that the primary circuit is interrupted by the action of the breaker cam. Thus when the spark plug leads are properly connected, the high tension current, as soon as produced in the secondary circuit, is conducted to the spark plug of the proper cylinder just at the moment when the gas in that particular cylinder is ready for firing. If, therefore, the spark plug leads ever have to be removed from the distributor head, they must always be attached again carefully in the correct order.

Automatic Advance Mechanism. ([Fig. 65]).—Combustion does not follow instantaneously upon the occurrence of the spark, however, because a small time interval is always needed for the gas in the cylinder to ignite. Consequently, unless some means are provided for offsetting the lag between spark and combustion, the explosion of the gas could not always be made to take place at exactly the correct moment under varying conditions of engine speed.

Fig. 65. Automatic Spark Advance Mechanism—North East

To compensate for this lag, therefore, there is incorporated in the distributor a centrifugally actuated mechanism, which is capable of automatically advancing or retarding the time of the spark in exact accordance with the rate of speed at which the engine is running.

The operating characteristics of the automatic advance are accurately proportioned to conform throughout the entire speed range with the requirements of the engine; and in order to insure the permanence of this relationship the device is so constructed as to be practically nonadjustable.

Manual Spark Control.—Besides this automatic advance there is also the usual manual control mechanism for changing the time of the spark independently of the centrifugal device. This manual control is for use principally for retarding the spark when starting or idling the engine or for facilitating carburetor adjustments. During normal operation of the engine, the spark lever on the steering wheel quadrant should be advanced as far as permissible without causing the engine to knock, and the actual regulation of the spark position be left entirely to the automatic advance mechanism. The arrangement of the manual control is such, provided the breaker cam is properly set, that when the spark lever is in the position of full retard, and the engine is running very slowly, the spark will occur in each cylinder at 5 engine degrees after the piston has passed the upper dead center of its compression stroke. With the spark lever advanced to the limit of its travel on the quadrant, the spark will occur 15 degrees before the upper dead center position has been reached by the piston on its compression stroke.

Timing the Distributor.—Whenever it becomes necessary to disconnect the distributor shaft from the engine pump shaft the exact relative positions of the two halves of the coupling joining these two shafts, as well as the location of the distributor rotor, should be carefully noted and marked. This is necessary in order to make possible the reëstablishment of the correct relations between the distributor shaft and the pump shaft when original conditions are being restored. Moreover, care must be taken to avoid turning the engine while the distributor is disconnected, because the proper timing relations can only be retained by keeping the position of the pump shaft unchanged during this time.

Should it ever happen, however, that the distributor has been taken off without the proper precautions having been observed, or that the timing arrangement has been disturbed in any other fashion, it will thereupon become necessary to make a complete readjustment of the timing relations of the distributor and the engine. This is to be done always after the distributor has been reconnected to the engine, the first step being to ascertain definitely the relative position of the engine pistons and valves. With this done, the positions of the breaker cam and the distributor rotor are then to be reset as directed below.

Since all the parts of the engine follow a regular sequence of operation, only the position of the piston and valves in the No. 1 cylinder need be considered in this process, and the three remaining cylinders may be practically disregarded. There are numerous methods, varying in their degree of accuracy, for locating the position of the engine pistons, but the most dependable one is that of removing the cylinder head so as to expose the pistons and valves to full view. With the head thus removed, the engine should be cranked slowly by hand until the No. 1 piston has risen to the top of its compression stroke and has just started to descend on its combustion stroke. At this moment the spark, when fully retarded, should normally occur in No. 1 cylinder.

Under circumstances where it is not convenient or desirable to remove the cylinder head the following approximate method for determining the location of No. 1 piston may be employed with a fair degree of success. Open the cocks of the priming cups on all the cylinders, and crank the engine slowly by hand until the No. 1 piston has just reached the top of its compression stroke. This can be ascertained by holding the thumb over the No. 1 priming cup and noting carefully the moment when the compression ceases to increase. After locating the dead center position of No. 1 piston in this way, turn the crank shaft a very slight distance further until the No. 4 exhaust valve is just at the point of closing. Under these conditions, provided the No. 4 exhaust valve lifter is in correct adjustment, the No. 1 piston should be approximately in the desired position of 5 engine degrees beyond dead center.

With the No. 1 piston thus carefully set in accordance with one of the above methods, preferably the former, bring the distributor into the position of full retard. To do this, disconnect the manual control attachment and turn the break-box as far as it will go in the direction in which the vertical shaft rotates. Then after making sure that the ignition switch is turned off, remove the distributor-head and the distributor rotor and the breaker box, and with a broad bladed screw driver back off the breaker cam nut until the cam is free to turn on its shaft. Next, replace the rotor temporarily, and turn the cam slowly until the breaker contacts just begin to open when the rotor occupies the position where it normally makes contact with the No. 1 distributor terminal. This adjustment can be made to the best advantage by turning the cam forward to separate the contacts then back again slowly until the contacts just come together, at which point the cam should be allowed to remain.

After the proper setting has thus been obtained, remove the rotor again and lock the cam securely in position by tightening the slotted nut that holds it. Finally, replacing the rotor, rock the vertical shaft backward and forward as far as the slack in the gears will permit, and note carefully the action of the break contacts. The setting of the cam must be so accurate that when the gears are rocked forward to take up the slack, the contacts will be just held apart and yet when the gears are rocked backward as far as the slack permits, the contacts will be actually closed.

A convenient method of verifying this adjustment is to turn on the ignition current and connect an ordinary 14 or 16 volt 2. c. p. lamp across the two binding posts of the breaker box. The lamp thus attached, will serve as a sensitive indicator for representing the action of the contact-points when the vertical shaft is rocked forward and backward to take up the slack in the gears. The moment the contacts begin to be separated, the lamp will light; but as soon as they are allowed to come together the lamp will at once go out again.

Should the test prove the first setting to be inaccurate, the cam must be readjusted, and the test repeated several times if necessary until the correct setting is finally obtained. Too much care cannot be employed in making this adjustment, because even a very slight inaccuracy in the setting of the cam will produce a considerably magnified effect upon the operation of the engine. This is due to the fact that the engine speed is twice as great as that of the vertical shaft.

General Care.—Under normal operating conditions the ignition system requires very little care aside from the usual precautions against moisture and dirt. There are, in fact, but three points of importance that need attention during service:

1. Lubrication.

2. Cleaning and adjustment of the breaker contacts.

3. Inspection of the wiring and the spark plugs.

CHAPTER XIX
ATWATER KENT IGNITION SYSTEMS
Construction, Operation and Care

Atwater Kent ignition systems have been adopted of late by many prominent automobile manufacturers as a means of distributing or conveying electrical spark to the cylinders at the proper firing time.

This type of quick break distributing system has proved very efficient and dependable, and will usually outlast the life of the motor as there are very few moving parts, which eliminates troubles caused by worn parts getting out of adjustment.

This type of ignition system operates in much the same manner as the high tension magneto, and differs only in that the parts have been taken from the compact magneto case and distributed in other locations in separate units. As this type takes its current from the lighting and starting battery, it does not contain an armature or field magnets to manufacture the electrical force.

[Fig. 66] illustrates the principles of operation of the type CC Atwater Kent closed circuit system, which consists of the unisparker containing the contact maker and distributor. The only moving parts are located in this unit. The coil consists of a soft iron core, with a primary and secondary winding sealed in an insulated tube or container. A resistance unit is located in the top and regulates the current automatically. The system is controlled by a switch located on the dash. The contact breaker shown in [Fig. 67] consists of an exceedingly light steel contact arm. One end rests on a hardened steel cam which rotates one-half as fast as the crank shaft. This cam has as many sides as the engine has cylinders. When the contact points are opened by the movement of the cam the primary circuit is broken and produces a discharge of secondary high tension current at one of the spark plug gaps.

CONTACT
MAKER		TO PLUG TO PLUG
DISTRIBUTOR
CONDENSER
TO PLUG
CONTACT MAKER
GROUNDED
SPARK PLUG
BATTERY
GROUND
PRIMARY
BATTERYGROUND
SWITCH
SECONDARY
GROUND
REGULATING
RESISTANCE

Fig. 66. Atwater Kent Circuit Diagram—Type CC

[Fig. 68] shows the simple Atwater Kent contactless distributor. The high tension distributor of the Atwater-Kent system forms the top of the contact maker. Each spark plug wire terminates in an electrode, which passes through the distributor cap. A rotating distributor block takes the high tension current from the central terminal and distributes it to the spark plugs in proper firing order. The distributor block or arm does not make direct contact with the distributor posts. The current jumps the small gap between the distributor block and the terminal electrodes and does away with frictional wear resulting from actual contact.

Fig. 67. Atwater Kent Contact Breaker—Type CC

Fig. 68. Atwater Kent Distributor and Contactless Block

[Fig. 69] shows the method of connecting the high tension wires to the distributor; the insulation is removed, or the wire bared in a space 11⁄4″ long. The removable terminal cover is pushed up on the wire as shown at A, the bared end of the wire is then passed through the hole in the secondary terminal as shown at B. The end of this wire is then twisted back on itself, for two complete turns as shown at C, so that the end will not project beyond the diameter of the insulation. The wire will then be tightly held when the terminal covers are screwed down as shown in Fig. D. Never use pliers to tighten these covers and do not solder the wires to the terminal posts.

Fig. 69. Distributor Wire Connections to Distributor

Adjustment.—The only parts of this system that are adjustable are the contact points. These need to be adjusted only for natural wear. Do not adjust the points unless you are convinced, by trying everything else, that it is the points that need attention.

In making adjustments, note the following directions. The normal gap between the points should not be less than .005″, or more than .008″, the standard setting is .006″, which is about the thickness of two ordinary sheets of writing paper.

TO UNGROUNDED
TERMINAL OF BATTERY

SWITCH

COIL

DISTRIBUTOR

GROUND

CONTACT
MAKER

Fig. 70. Atwater Kent Type CC Wiring Diagram

The contact points are made of tungsten steel, the hardest known metal. When contact points are working properly small particles of tungsten steel will be carried from one point to the other, which sometimes causes a roughness and a dark gray coloring of the surfaces. This roughness does not in any way effect the proper working of the points, owing to the fact that the rough surfaces fit into each other perfectly.

It should not be necessary to file or redress the points unless they become burned, due to some abnormal condition or accident. The dark gray appearance is the natural color of the tungsten steel.

Oilings.—A very small amount of ordinary vaseline or grease applied to the cam and a drop or two of oil applied to the cups every few weeks, is all the lubrication necessary. Do not get oil on the contact points, and wipe off any free oil or grease on the contact maker.

The springs in this system are set at exactly the right tension. Do not try to bend or tamper with them.

The wiring of the type CC ignition system is very simple, as shown in [Fig. 70], and is known as the one wire with ground return method. Well insulated primary wire is used for the primary circuit between the coil and the ignition switch. The best quality of five-sixteenth inch secondary wire is used to conduct the high tension current from the coil to the distributor, and from the distributor to the spark plug.

Setting or Timing the Type CC System.—The piston in number one cylinder should be raised to high dead center, between the compression and firing strokes, the clamp which holds the unisparker should be loosened and the unisparker turned backward, or opposite the rotating direction of the timer shaft until the contact points commence to open. The spark occurs at the exact instant of the opening of the point.

After completing the electrical connection the current can be turned on, and the unisparker timed exactly from the spark at the plugs. For this purpose the plugs should be removed from the engine and laid on top of the cylinders.

CHAPTER XX
ATWATER KENT IGNITION SYSTEM, TYPE K-2

The operating principle of the Atwater Kent ignition system type K-2, differs from type CC system in that it operates on the open circuit plan, whereas the type CC system explained in the preceding chapter, operates on the closed circuit plan.

A-K ignition system type K-2 consists of three parts:

No. 1. The unisparker combining the special contact maker, a condenser, and a high tension distributor.

No. 2. The coil, consisting of a simple primary and secondary winding, and a condenser. These parts are all imbedded in a special insulating compound. The coil has no vibrator or other moving parts.

No. 3. The ignition switch. This switch controls the system by opening and closing the primary current.

The Principle of the Atwater Kent System.—The function of this system is to produce a single hot spark for each power impulse of the motor. It differs from other types of battery ignition systems in that the contact points do not touch except during the brief instant of the spark. The ignition circuit is, therefore, normally open, whence the name “open circuit” results. The contact maker consists of a pair of contact points, normally open, which are connected in series with a battery, and the primary circuit of the non-vibrating induction coil. The mechanism for operating the contacts consists of a notched shaft having one notch for each cylinder, rotating at one-half the engine speed, a lifter which is pulled forward by the rotation of the shaft, and a coil spring which pulls the lifter back to its original position after it has been drawn forward and released by the notched shaft; hardened steel latch, against which the lifter strikes on its recoil and which in turn operates the contact points.

LATCH
CONTACT
SCREW		 NOTCHED
SHAFT
LIFTER
CONTACT
SPRING		 LIFTER
SPRING

Fig. 71. Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System.

Fig. 72. Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System

Fig. 73. Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System

Fig. 74. Atwater Kent Contact Breaker—Diagram of Action—Type K-2 System

Operation of the Contact Maker.—It will be noted in [Fig. 71] that the lifter is being pulled forward by the notched shaft. When pulled forward as far as the shaft will carry it ([Fig. 72]), the lifter is suddenly pulled back by the lifter spring. In returning, it strikes against the latch, throwing this against the contact spring and closes the contact for a brief instant. This movement is far too quick for the naked eye to follow ([Fig. 73]).

[Fig. 74] shows the lifter ready to be pulled forward by the next notch.

Note that the circuit is closed only during the brief instant of the spark. No current can flow at any other time, not even if the switch is left on when the motor is not running. No matter how slow or how fast the notched shaft is turning, the lifter spring will always pull the lifter back at exactly the same speed, so that the operation of the contact, and therefore the spark, will always be the same no matter how fast or how slow the engine is running. The brief instant that the contact points touch, results in very little current consumption. The high tension current from the coil is conveyed to the rotating distributor block, which seats on the end of the unisparker shaft to each of the spark plug terminals in the order of firing.

Fig. 75. Atwater Kent Distributor and Contactless Block

The important advantage which the distributor possesses is the fact that there are no sliding contacts or carbon brushes. The distributor blade is so arranged that it passes close to the spark plug terminals without quite touching (as shown in [Fig. 75]), thus permitting the spark to jump the slight gap without any loss of current pressure. This also eliminates all wear and trouble caused by sliding or rubbing contacts.

[Fig. 76] shows the wire connections and direction of current flowage. The distributor blade is about to make contact with the terminal leading to the spark plug in No. 2 cylinder. At the instant that contact is made the breaker points in the contact maker shown in the lower part of the diagram close, thus allowing a primary or low tension current to flow between the contact maker, coil, and battery. The sudden breaking of this current occurs when the points open again, thereby creating a current of high tension voltage in the secondary coil which is conducted to the center terminal of the distributor where it is distributed to the spark plug terminals through the rotation of the distributor blade. The high tension cables leading from the distributor are heavily insulated, thus the current in seeking ground return chooses the easiest path, by jumping the slight gap at the spark plugs.

DISTRIBUTOR

GROUND

COIL

BATTERY

CONTACT MAKER

Fig. 76. Atwater Kent Wiring Diagram Type K-2

Setting and Timing the Unisparker.—The type K-2 unisparker is installed, so as to allow a small amount of angular movement or, in other words, the socket into which the unisparker fits is provided with a clamp which will permit it to be turned or locked in any given position.

Timing.—The piston in No. 1 cylinder is raised to high dead center between the compression and power stroke. Then loosen the clamp which holds the unisparker and turn the unisparker backward, or contrary to the direction of rotation until a click is heard. This click happens at the exact instant of the spark. Clamp the unisparker tight at this point being careful not to change its position. Note that current for this system is usually supplied by the starting and lighting battery. When changing batteries be sure that the voltage of the battery is the same as that marked on the coil.

To Plugs
To Plugs
Contact-
maker
SwitchContact Maker
BAT.
S & INT. INT. S.INT. INT.
COILSEC
Ground To Motor
Ground to MotorPOS NEG
BATTERY

Fig. 77. Atwater Kent K-2 Wiring—Cut 1, Under Hood Coil; Cut 2, Kick Switch Coil

The external wiring of the A-K type K-2 is very simple, as shown in the diagrams, [Figs. 77 and 77A]. Fig. 77 shows the wire connections, when the reversing switch and under-hood coil is used. Fig. 77A shows the connections, when using plate or kick switch coil. A well insulated braided primary wire is used for the primary or battery circuit. See that this wire is well protected against rubbing or abrasion wherever it comes into contact with metal parts of the car. When the starting and lighting battery is used to furnish the ignition current, two wires should run directly to the battery terminals.

The two types of Atwater Kent systems described are provided with automatic spark advance mechanism. Provisions are also made for manual lever control, by simply connecting the unisparker to the throttle lever at the base of the steering gear.

Fig. 78. Atwater Kent Automatic Spark Advance Mechanism—A K Type K-2

[Fig. 78] shows the automatic spark advance mechanism. It is located on the underside of the contact maker base plate, and consists of a set of weights which swing out from the center against spring tension, and advances the unisparker on the shaft, according to the amount of centrifugal action or speed of the shaft. When the shaft is not in motion the springs draw the weights toward center, which automatically shifts the unisparker on the shaft until the spark is in a fully retarded position.

Contact Point Adjustment.—The only adjustment aside from the initial timing is in the contact points. They are adjustable only for natural wear, and one adjustment should last at least six months. The contact screw is provided with a number of shim washers against which it is set up tight. When the points eventually become worn, they should be dressed flat and smooth. A sufficient number of the washers should be removed so that when the contact screw is set up tightly it will maintain the proper gap between the points. The distance between the contact points should be about the distance of a thin visiting card. They should never touch when at rest.

Oil lightly every
1000 miles

Oil

Fig. 79. Atwater Kent Contact Breaker—Oiling Diagram—A-K Type K-2

[Fig. 79] shows an oiling diagram of the contact maker. The latch, lifter, and lifter spring are not adjustable or subject to wear. They should be well cleaned and oiled every five hundred miles. Use a light oil and avoid getting it on the contact points.

The Condenser.—The condenser of this system acts somewhat like a shock absorber to the contact points. It absorbs the spark or arc and makes the break in the primary current, clean and abrupt. The condenser is very accessible, but should never be tampered with, as it does not require any attention.

Testing for Ignition Trouble.—If the engine misses without regard to speed, test each cylinder separately by short circuiting the plug with a screw driver, allowing a spark to jump. If all cylinders produce a good regular spark the trouble is not with the ignition system.

If any cylinder sparks regularly this will indicate that the ignition system is in working order so far as the unisparker and coil are concerned. The trouble is probably in the high tension wiring between the distributor and plug, or in the plugs themselves. Examine the plugs and wiring carefully. Leaky secondary wiring is frequently the cause of missing and backfiring.

Frequently, when high tension wires are run from the distributor to the spark plugs through a metal tube, trouble is experienced with missing and backfiring, which is due to induction between the various wires in the tube. This is especially likely to happen if the main secondary wire from the distributor to the coil runs through this tube with the spark plug wires.

Whenever possible the distributor wires should be separated by at least one-half inch of space. They should be supported by bracket insulators, rather than run through a tube. In no case should the main distributor wire run through a conduit with other wires.

If irregular sparking is noted at the spark plugs, examine the battery and connections.

If the trouble commences suddenly, it is probably due to a loose connection in the wiring, if gradually, the battery may be weakening or the contact points may require attention.

CHAPTER XXI
PHILBRIN SINGLE SPARK IGNITION SYSTEM
Operation, Adjustment and Care

The Philbrin ignition system consists of a specially designed contact maker and interrupter, a distributor mounted on the same shaft, a nonvibrating heat and moisture proof coil, an armored heat, moisture, and puncture proof condenser, and a special Duplex switch.

Fig. 80. Philbrin Contact Maker—Point Adjustment

[Fig. 80] shows an illustration of the Philbrin contact maker which operates in this manner. The cam A strikes against the end of the plunger B and forces the points together at C, and holds the contact for approximately three and one-half degrees of the revolution of the cam. The spark occurs simultaneously with the separation of the contact points. The contact maker has but one adjustment; that of the adjustable contact screw, which is in direct line with the contact plunger. The contact points are brought together gradually by the surface formation of the cam. When the point of ample saturation of the coil is reached, the breaking of the contacts is instantaneous. The duration of the spark is in proportion to the speed of the engine, but breaking of the points is always instantaneous and entirely independent of the engine’s speed thereby producing the required spark at all speeds without any spark lag.

Fig. 81. Philbrin Contact Maker and Distributor Blade

[Fig. 81] shows the distributor blade mounted over the contact maker. The distributor blade is so arranged that it clears the spark plug lead terminals in the cover by a slight margin, and does not make actual contact, thereby eliminating all friction due to such contacts.

Operation.—Turning on the switch sets up a low tension current in the coil and primary wire coil when the contact points close. The sudden breaking of this current causes demagnetism of the core and the primary coil to set up a high tension current in the secondary coil. This current is led to the distributor blade and passes to the spark plug terminals as the blade comes in contact range.

The Philbrin high frequency system uses the same coil and distributor as the single spark system. But as the circuits of the two systems are entirely distinct and separate, they do not conflict with each other. The high frequency system has its own condenser and interrupter located in the switch case, and supplies a continuous flow of sparks.

Fig. 82. Switch Case

[Fig. 82] shows the interior of the switch case. This part of the mechanism controls the interruption of the battery current. The current is supplied to the interruptor through a polarity reverser, which reverses the direction of the current each time the switch button is turned. This equalizes the wear on the contact points.

Attention is again called to the distributor blade shown in [Fig. 82], which is used for both systems. Because of the shape of this blade, there is a continuous flow of sparks after the explosive spark has been delivered to one cylinder until the forward edge of the distributor blade is within range of the distributing point of the next terminal. By this action the first spark delivered to the cylinder is an efficient one, and the follow up continues at intervals of approximately one-thousandth of a second. These sparks are all perfectly synchronous.

The operation of the high frequency system does not differ in function action from the single spark system explained on the foregoing page. Either system may be had singly, or in duplex formation. Consequently either the single or the double system may be encountered. When the duplex system is used the driver has his choice and can use either the high frequency or single spark system, by turning the rubber roll switch on the distributor to the system indicated.

This follow-up feature has been found particularly advantageous for starting in cold weather, or where a poor grade of gasoline is encountered, and in case of a poor carburetor adjustment or foul spark plugs. The high frequency system also has the unique feature of keeping the spark plugs clean without disintegrating the electroids, as is often the case with the high tension magneto.

Fig. 83. Duplex High Frequency Switch

[Fig. 83] shows the Duplex switch. Ordinarily a storage battery is used for one source of current, and a set of dry cells for the other. This is so arranged that either source of current can be used with either the single spark system or the high frequency system at will. One source of current only can be used if so desired, that is, the storage battery only or the dry cells alone. Where the source of current is dry cells only, the single spark system is used as it is more economical in current consumption. All of the switch contacts are of the pressure plunger type, thereby eliminating the uncertainty of brush contacts. Each switch is provided with a lock operating through the hub of the lever. When the switch is locked in the off position it is impossible to remove the cover without breaking it as the cover of the switch locks to the back.

Ratchet buttons select which one of the systems is to be used, by a movement of 45°. This button operates only in a clock-wise direction.

C-2 Circuit 2
C-1 Circuit 1
Bat.-1 Battery 1
Bat-2 Battery 2
Sec-Secondary
C-Circuit
Sec. Gr. Secondary
Ground
To
Spark
Plugs		 BAT. (SEC.GR.) C
BAT.-2
BAT.-1 Coil
C.R.
Distributor

Fig. 84. Philbrin Wiring Diagram

[Fig. 84] shows a wiring diagram of the Philbrin system. The wire connections come to the contact maker directly from the switch, instead of from the coil. This provides for control of the current to the contact maker in such a manner that if a short circuit occurs in either of the systems, by turning a button it is entirely cut off and the other system put into operation.

Tungsten contact points are used on the single spark system as they are not effected by the use of light oil. The contact points for the high frequency system are platinum-iridium. They are mounted inside of the switch case and need little or no attention. The contacts, due to the reversed polarity, have an extremely long life and can be used without attention until they are worn down to the base metal. The duel type of system, however, may be purchased in separate units, and an owner may choose either the high frequency system or the single spark system separately if so desired.

This type of ignition system is manufactured for four, six, eight, and twelve cylindered cars.

CHAPTER XXII
ELECTRICAL STARTING AND LIGHTING SYSTEMS
Construction, Operation and Care

A great many different types of mechanical, and compressed air starters were devised and tried out as equipment by the manufacturers of automobiles a few years ago. These devices were either mechanically imperfect, or required considerable attention from the owner to keep them in working order and have all but disappeared from the market, being supplanted by the electrical starter, which has been perfected to a high state of efficiency and dependability.

The general principle of all electrical starters is much alike and they usually operate in much the same manner. The electrical force or current is produced by a generator driven from the engine. This current is collected, or held in storage by chemical reproduction plates in a storage battery. The battery, in turn, is connected to a small electric motor carried at the side of the engine.

The Generator.—The operating principle of current production of the generator is practically the same as explained in the magneto, which may also be termed a generator or dynamo.

A generator consists of an iron frame, a set of magnetic field windings, a wound armature with a commutator on the end, and a brush which collects the current from the commutator.

The current is induced in the armature by rotating it in a magnetic field. The amount of voltage induced in the armature-coil depends on its rotating speed, as the faster the armature turns, the greater the number of magnetic field lines cut, and the greater the amount of voltage induced in the armature coil.

The Regulator.—The generator is provided with a regulator to control the output rate of voltage when the engine is running at excess speeds. This is necessary to prevent the higher charging rate from overcoming the capacity of the storage battery. The regulating of the voltage output may be accomplished by mechanical or electrical means. The mechanical regulator usually consists of a governor which is timed to release the armature from the drive shaft when the engine reaches a certain rate of speed. The electrical regulator usually consists of a reversed series of field winding which acts against the force of the magnetic field, or of a bucking coil.

The Automatic Cut-out.—All types of generators which supply current to a storage battery are equipped with an automatic cut-out arrangement which is entirely automatic in action and requires no attention.

The function of the automatic cut-out is to prevent the current from flowing back to the generator when the current production of the generator is less than the charged strength of the storage battery. The cut-out may be located anywhere on the conductor, between the storage battery and the generator, and consists of a simple electro-magnet, which is operated by the direction of current flowage.

One Unit System.—The generator furnishes the current for ignition and starting, and is also reversible to act as a starting motor. The system is referred to as a one unit system.

Two Unit System.—When the starting motor and the generator act singly, and are contained in a separate casting, the system is referred to as a two unit system.

Three Unit System.—When the generator and starting motor are located as a separate unit, and when the ignition current is supplied by a magneto, this system is referred to as a three unit system.

The Starting Motor.—The starting motor is constructed in the same manner as the generator, and is simply a reversal of action. When cranking, the current from the storage battery flows through the motor winding and magnetizes the armature core. This acting upon the magnetism of the frame causes the turning effort.

Lubrication.—Regularly every two weeks, or every five hundred miles, two or three drops of thin neutral oil should be dropped into the oil wells supplying the armature bearings and usually located at each end of the armature shaft.

Fig. 85. Bijur 2-V System Mounted on Hupmobile Engine

Care.—Regularly every two weeks, inspect all connections as a full volume of current will not flow over a loose or corroded connection. Never allow any oil or dirt to collect on the motor or generator, as it interferes with the terminal connection and misdirects the current, and the instrument soon becomes inoperative.

[Fig. 85] shows the location of the two unit Bijur electrical starting and generating system mounted on an engine. The starting motor is bolted to the flywheel housing, and is provided with a square armature shaft which carries a pinion which can be moved horizontally on the shaft. This pinion meshes directly with teeth cut in the steel flywheel ring. No intermediate gears or roller clutches are used. The control lever connects through linkage to the shifting fork which shifts the pinion on the square shaft of the motor. The same foot pedal linkage operates the starting switch. Normally a spring holds the motor pinion out of mesh with the flywheel teeth and also holds the starting switch in the “off” position.

The Generator.—The generator is bolted to an extension on the crank case at the front side of the gas motor, and is driven by a silent chain from the crank shaft. After the gas motor attains a speed equivalent to a car speed of ten miles per hour on high speed, the generator begins to generate, and will generate a current which is highest at low speeds, and diminishes somewhat at higher speeds.

The machines are both self-contained as there are no regulators or automatic switches which require separate mounting.

The automatic switch for opening and closing the circuit between the generator and storage battery is mounted inside the generator. This switch is properly adjusted before the generator leaves the factory, and no further adjustments are necessary.

Two wires lead from the generator. One of these is connected at the starting motor to one of the heavy cables coming from the storage battery, while the other generator wire is grounded on the chassis, the chassis forming a part of the circuit. The generator polarity is reversible and the connections at the machine may be made haphazard and without regard to polarity. If connections are reversed at the generator, no damage will result, as the machine will automatically assume the correct polarity to charge the battery.

[Fig. 86] shows the position of the Bijur starting system, and the relative neutral positions of starting pedal, motor pinion, and starting switch, when the starting equipment is not in action.

[Fig. 86A] shows the normal position of the various parts after the starting pedal has been depressed and just before the starting motor begins to operate. The pinion is now in full mesh with the flywheel ring and further depressing the starter pedal will close the switch.

FOOT PEDAL
POSITION 1--OUT OF ACTION. STARTING
SWITCH OFF. PINION UP AGAINST MOTOR
HEAD.		FLYWHEEL
SHIFTING FORK STARTING SWITCH
MOTOR SHAFT
OIL HEREMOTOR OIL HERE
COLLAR
CLEVIS PIN
SHIFTING ROD
STOPSHIFTER SPRING
RELEASE SPRING
OIL DRAIN
KEEP THIS HOLE CLEAR		PINION OIL HERE
CRANK CASE

POSITION 2--ABOUT TO CRANK.
GEARS HAVE MESHED BUT
SWITCH HAS NOT YET MADE CONTACT.

Fig. 86. Bijur Starter Mechanism Showing Action

[Fig. 87] shows all the parts in their positions for cranking. The small gap between the collar on the shifting rod and clevis pin permits the switch rod to move and thus open the starting switch without moving the motor pinion when the starting pedal is released.

POSITION 2A—ABOUT TO CRANK.
GEARS NOT YET MESHED, TEETH
ARE BUTTING, BUT SWITCH HAS
MADE CONTACT. SHIFTER SPRING
STRONGLY COMPRESSED READY
TO DRAW PINION INTO MESH.

POSITION 3—CRANKING, NOTE
GAP BETWEEN COLLAR ON
SHIFTING ROD AND CLEVIS PIN.
SHIFTING FORK IS UP AGAINST
STOP AND SHIFTER SPRING IS
SLIGHTLY COMPRESSED.

Fig. 87. Bijur Starter Mechanism Showing Action

[Fig. 87A] shows the condition when on depressing the foot pedal, and sliding the pinion on the motor shaft towards the flywheel the pinion does not mesh with the flywheel, and the teeth butt. Depressing the foot pedal will close the starting switch strongly compressing the shifter spring. After the switch is closed the motor will begin to rotate and allow the pinion to slip into mesh with the flywheel. The motor will then crank in the normal way.

HEAD LAMP MOTORSWITCH TERMINAL
GROUNDED
GENERATOR STARTING
SWITCH		BATTERY
IGNITION SWITCH
INTERRUPTOR
AND
DISTRIBUTOR
SPARK PLUGS
REAR LAMP
HORN COIL
INSTRUMENT LAMP
HEAD LAMP HORN BUTTONLIGHTING SWITCH

Fig. 88. Wiring Diagram Model N—Hupmobile

[Fig. 88] shows a complete diagram of the Model N Hupmobile wiring system.

CHAPTER XXIII
ELECTRIC STARTING AND LIGHTING EQUIPMENT

[Fig. 89] shows a diagram of the Bijur lighting and starting system on the Jeffrey “Chesterfield-six.” The generator supplies current for the lights and charges a storage battery when the gas motor is running at speeds equivalent to ten or more miles per hour on high gear.

When the gas motor is running at speeds corresponding to less than ten miles per hour, all currents for lamps are drawn from the storage battery.

The starting motor is in operation only during the period of starting, and remains idle at all other times. The appliances shown in the [diagram] constituting the equipment are a six volt constant voltage generator, a six volt starting motor, starting switch, six volt hundred ampere hour battery, lamp controller, and a high tension magneto. Due to the reversible characteristics of the generator, no attention need be paid to the polarity of the wiring when it is removed and again replaced.

The starting motor pinion meshes with teeth on the flywheel when the starting switch mounted on the housing covering the motor pinion is compressed.

Operation of System Shown in Diagram.—After the gas motor reaches a speed equivalent to a car speed of approximately ten miles per hour on the third speed gear, the generator will generate and maintain a constant voltage, or electrical pressure at higher speeds and will also maintain this pressure constant at all loads.

The current output from the generator at any time will depend upon the condition of the storage battery. If a car has been left standing for some time with the lights burning, the storage battery will become more or less discharged and its voltage lowered. Under these conditions the generator voltage or pressure will be higher than that of the battery, forcing a comparatively high charging current into the battery. This current may be from 5 to 20 amperes, and the battery will rapidly approach the fully charged condition.

3⁄8 LOOM No. 14No. 103⁄8 LOOMNo. 14No. 101⁄4 LOOM
No. 14
RIGHT HEAD LIGHT TERMINAL POSTS FUSES 10 AMPERES
NEGATIVE
STORAGE
BATTERY
GENERATORMAGNETO POSITIVE
SWITCH
CYLINDERS BATT -LIGHTING
SWITCH		No. 14
No. 14BATT + TONNEAU LIGHT
GROUNDNo. 10GROUND FUSE
MAGNETO SWITCH
No. 18 DUPLEX No. 14
DASH & EXTENSION
LIGHT
No. 10
AMMETERNo. 0
HORN BUTTON REAR LIGHT
HEAD LIGHT MOTORSTARTING SWITCH
HORN
25⁄8 LOOM

Fig. 89. Wiring Diagram—Jeffrey-Chesterfield Six

As a battery becomes charged its voltage increases reducing the difference in pressure between the generator and battery and decreasing the charging current to the battery.

ELECTRIC STARTING AND LIGHTING OPERATION

Current from the generator passes through an ammeter and this meter shows the current being supplied to the battery and the lights, or to the battery only when no lights are in operation.

Starting Motor.—The starting motor is provided with a square shaft and carries a pinion which can be moved horizontally on this shaft. This pinion meshes directly with teeth cut on the flywheel.

The starting pedal located at the driver’s seat connects through linkage to fork which shifts the link on the square shaft of the motor. The same foot pedal linkage operates the starting switch. Normally a spring holds the motor pinion out of mesh with the flywheel teeth, and also holds the starting switch in an “off” position.

Operation of the Starter.—Depressing the starter, one pedal operates the starting switch and makes a preliminary contact which connects the starting motor to the storage battery through a resistance located inside of the starting switch. This resistance permits a small amount of current to pass through the starting motor, causing its armatures to rotate at relatively slow speed. This slow rotation insures proper meshing of the pinion and flywheel teeth when they are brought into engagement. Depressing the foot pedal also shifts the pinion on the square shaft of the motor so as to bring it into contact with the teeth on the flywheel.

When the pinion is in full mesh with the teeth on the fly, the moving contact in the starting switch has traveled to a position where the resistance is cut out of the circuit, connecting the storage battery directly to the starting motor. The starting motor will then spin the gas motor.

Starting.—First see that the necessary adjustments have been made, then depress the starting foot pedal as far as it will go and hold it firmly in place until the gas motor starts. The instant the gas motor begins firing the foot pedal should be released. The starting pedal should be pressed as far as it will go without any pausing on the downward stroke.

[Fig. 90] shows diagram of operation and wiring of the Bijur electrical system used on Jeffery 4-cylinder car.

If the pinion and flywheel teeth do not mesh properly do not hold the starting pedal down, release it and after a few seconds pause, depress the pedal again.

If the gas motor does not start firing promptly after spinning it with the electric motor, do not continue to spin it, but see that the proper adjustments for starting have been made and that there is gasoline in the carburetor, and that the ignition is in working order.

Continued spinning of the gas motor by the electric motor will not damage the electrical equipment but constitutes a useless drain on the storage battery and should be avoided.

Wiring.—[Fig. 90] shows the circuits for all electric appliances on the Jeffrey-4 car. The various units are wired on the two-wire system. The “out of focus” filaments in the head lamp bulbs are wired on the three-wire system, the chassis acting as a neutral wire, one side of the “out of focus” filament being grounded in the head lamps. The “in focus” filaments are on the two-wire system.

The dash lamp is on the tail lamp circuit and is so arranged that these two lamps are always in operation when any combination of head lamp filaments are in use.

Fuse Circuits.—Each head lamp is separately fused, the current for both filaments in each head lamp bulb passing through one fuse.

GROUND TO OIL PIPE
GROUNDED TO INSTRUMENT
ASSEMBLY
RIGHT HEAD LIGHTGENERATOR
DASH LAMP
SWITCH INDICATOR
CYLINDERS
1 2 3 4		 CONNECTIONS THROUGH SWITCHIN “DIM” POSITION
FUSE AND
JUNCTION BLOCK
HORNCONNECTIONS THROUGH SWITCHIN “ON” POSITION
MAGNETOHORN BUTTON
MOTORSTARTING SWITCHBATTERYWIRING FOR 6-CYLINDER MODEL661 IS THE SAME AS FOR 4-CYLINDERMODEL 462, EXCEPT FOR HIGH TENSIONLEADS BETWEEN MAGNETOAND SPARK PLUGS.
LEFT HEAD LIGHT
NOTE:—DOTTED LINES INDICATE PERMANENTCONNECTIONS BETWEEN FUSECABINET, DASH LAMP, CURRENT INDICATORAND SWITCH. CONNECTIONS AS SHOWNFACING FUSE CABINET.SWITCH GROUNDEDREAR

Fig. 90. Wiring Diagram—Jeffrey-Four

Separate fuses are provided for the electric horn circuit and for the rear lamp circuit. The push button for operating the electric horn is mounted on the center of the steering post.

Ground Fuse.—A fuse is located in the ground circuit between the lamp controller and the magneto top to ground.

Fig. 91. Hydrometer Syringe

Lamp Controller.—A pair of wires from the terminals of the storage battery connect to the five position lamp controller. All lighting circuits connected to this controller which may be locked in any of the five positions.

Oiling should be practiced regularly every two weeks or every five hundred miles. Two or three drops of thin neutral oil should be put in each of the two oilers of the motor and in each of the two oilers of the generator. Do not flood the bearings with oil.

At the same time the starting motor shaft should be oiled. An oil hole is provided in the top of the starting motor gear case and about ten drops of cylinder oil should be used.

[Fig. 91] shows a hydrometer syringe used for determining the specific gravity or density of the solutions in the battery cells.

To take specific gravity readings unscrew the filler or vent plug and insert the tube into the cell and release bulb slowly to draw the acid solution into the chamber until the hydrometer floats. The enlarged graduated stem shows a reading of 1.280 at the point where it emerges from the solution. After testing, the solution must be returned to the cell from which it was taken. Specific readings above 1200 show the battery more than half charged.

Gravity below 1.150 indicates battery completely discharged or run down.

Should the gravity fall below 1.150 the gas motor should be given a long run to restore the battery.

CHAPTER XXIV
NORTH EAST STARTER SYSTEM USED ON DODGE BROTHERS’ CARS

The North East starter system shown in [Fig. 911⁄2] comprises the North East Model G starter-generator and the combined starting switch and reverse current cut-out. This equipment serves to start the engine and provide current for the lamps and other electrical accessories as well as for the ignition system. The battery as the source of current while the engine is not in operation or is running slowly; but at all engine speeds above 350 R. P. M. the starter-generator supplies current for the entire electrical system.

Wiring.—In the accompanying wiring diagrams the starting circuit is represented by the very heavy cables; the charging circuit, where it does not coincide with the starting circuit, by the cables of medium weight, and the lighting and the ignition circuits by the light cables. As will be seen from the diagrams, the starting circuit extends from the positive terminal of the battery to the starting switch, and thence, when the switch is closed, through the starter-generator armature and field coils back to the negative terminal of the battery by way of the grounded negative starter-generator terminal, the car frame, and the battery ground connections. The charging circuit is identical with the starting circuit except at the starting switch, where instead of passing from one switch terminal to the other through the switch contactor it extends through a parallel path which includes the reverse current cut-out and the charging indicator. The cable leading to the lighting and ignition switch is attached to the positive terminal of the indicator. From this switch the lighting and the ignition circuits become distinct, and each, after passing through its proper course, reaches the car frame and returns through it to the source of supply.

Charging
Indicator		Lighting & Ignition
Switch		 Dash
Lamp
Horn
Head Lamp GroundTail
Lamp
GroundHorn ButtonStarting Switch
and
Reverse Current
Cut-out
Ground Ground
Connection		 Ground
Head Lamp
Battery
GroundStarter-GeneratorGround Connection

Fig. 911⁄2. Dodge Wiring Diagram

Without exception all the connections of the starting and lighting system must be made as indicated in this diagram if entirely satisfactory results are to be obtained from the equipment.

Starter-Generator ([Fig. 92]).—The starter-generator is mounted on the left side of the engine by means of an adjustable support and a clamping strap. It runs at three times engine speed, operating directly from the crank shaft through a silent chain drive. Being a single unit machine, it employs but one armature with only one commutator, one set of field windings and one set of brushes for the performance of all of its functions both as a starter and as a generator.

While starting the engine it acts as a cumulatively compounded motor; but while serving as a generator it operates as a differentially compounded machine with its output positively controlled through the agency of a Third Brush Regulating system, supplemented by the differential influence of the series field upon the shunt field.

The machine is designed for 12 volt service and, when driven by the engine, normally begins to deliver current to the battery as soon as the car speed is brought up to approximately 10 miles per hour. From this point on, the charging rate rises rapidly with increasing speed until the standard maximum rate of 6 amperes is reached at a car speed of 16 or 17 miles per hour. From this speed to 20 or 21 miles per hour it remains practically constant, but above 21 miles per hour it decreases gradually until at the upper speed limit of the engine it may become as low as 3 amperes.

This charging rate conforms throughout with the standard recommendations of the battery manufacturers. The early maximum reached by the starter-generator output provides amply for the demands of current at ordinary driving speeds; while the tapering characteristic, which comes into effect at high speeds, serves to protect the battery from superfluous charging in instances where cars may be subjected to continuous high speed service.

FIELD COIL TIE ROD
ARMATURE FIELD RING FUSE
RETAINING PLATE
CORK PACKING WASHERCOMMUTATOR
ARMATURE SHAFT
BALL BEARING
SPROCKETCOMMUTATOR-END
HOUSING
3RD BRUSH PLATE
ADJUSTING-STUD
SPRING END-PLAY
WASHER
BALL BEARING
LOCKING SLEEVE
BEARING-CAP
FELT
OILING-WASHERS
BALL BEARING
OIL SLINGER.CLAMP-SCREW
3RD BRUSH PLATE
CLAMP
CRIMPED SPACERCOVER-BAND
SPROCKET-END HOUSINGBRUSH-HOLDER STUD
BRUSH
BRUSH HOLDER

Fig. 92. North East Model G Starter-Generator

Adjustment of Charging Rate.—The third brush system is so constructed as to permit the charging rate to be changed when desired to a higher or to a lower value than that for which it is normally adjusted. Such adjustments should not be attempted by the car owner himself, and should never be made except in cases of actual necessity where the normal charging rate does not meet the special service conditions under which the equipment may be required to operate permanently. In every instance where there is any reason to believe that a modification of the rate would be beneficial, the car owner should refer the equipment to the North East Electric Company or its nearest branch or service station.

Fuse.—The fuse is located on the commutator end of the starter-generator. Its purpose is to protect the electrical system if possible by rendering the starter-generator inoperative whenever abnormal operating conditions may occur. Due to its protective function the fuse is always the first point in the system to be inspected in case the starter-generator ever failed to produce current. If the fuse is found to be “blown” or missing, a new one should be applied and the machine given a preliminary test before further search for trouble is made. Should the generator fail to deliver current even after a new fuse has been installed or should the new fuse “blow” when the machine is in operation, the entire electrical system should then be inspected thoroughly for possible faults such as open circuits, improper connections or abnormal grounds. Under such circumstances the difficulty should always be corrected before any further attempt is made to operate the equipment.

Precautions Necessary for the Operation Without Battery in Circuit.—The third brush regulating system requires a closed charging circuit for the successful performance of its duties. The battery, therefore, forms an indispensable link in the system and its presence in circuit is always essential to the proper operation of the starter-generator. Should the machine ever have to be operated with the battery disconnected or with the charging circuit otherwise incomplete, the electrical system must be protected by rendering the machine inoperative. This is to be done by removing the fuse from its clips.

When the starter-generator thus rendered incapable of producing current, no ignition current will be available from the usual sources. Under such circumstances, therefore, the engine cannot be operated without some provisional source of ignition current. A battery of nine or ten dry cells will serve satisfactorily as a temporary substitute provided they are used for ignition only.

Starting Switch and Reverse Current Cut-out.—The reverse current cut-out is located in the same case with the starting switch. This combined switch and cut-out is mounted near the center of the toe-board where the switch push-rod button is within convenient reach from the driver’s seat.

CHAPTER XXV
THE DELCO ELECTRICAL SYSTEM—BUICK CARS

The motor generator which is located on the right side of the engine is the principal part of the Delco System. This consists essentially of a dynamo with two field windings, and two windings on the armature with two commutators and corresponding sets of brushes, in order that the machine may work both as a starting motor, and as a generator for charging the battery and supplying the lights, horn and ignition. The ignition apparatus is incorporated in the forward end of the motor generator. This in no way affects the working of the generator, it being mounted in this manner simply as a convenient and accessible mounting. The motor generator has three distinct functions to perform which are as follows:

1.—Motoring the generator.

2.—Cranking the engine.

3.—Generating electrical energy.

Motoring the generator is accomplished when the ignition button on the switch is pulled out. This allows current to come from the storage battery through the ammeter on the combination switch, causing it to show a discharge. The first reading of the meter will be much more than the reading after the armature is turning freely. The current discharging through the ammeter during this operation is the current required to slowly revolve the armature and what is used for the ignition. The ignition current flows only when the contacts are closed, it being an intermittent current. The maximum ignition current is obtained when the circuit is first closed and the resistance unit on the front end of the coil is cold. The current at this time is approximately 6 amperes, but soon decreases to approximately 31⁄2 amperes. Then as the engine is running it further decreases until at 1000 revolutions of the engine it is approximately 1 ampere.

LEAD TO SWITCH.
TO SHUNT FIELD. IGNITION COIL.RESISTANCE UNIT.
TO THIRD BRUSH.
TO POS. BATTERY.DIS. HEAD LOCATING TONGUE.
TO NO 1 TERMINAL.
TO NO 2 TERMINAL.
BRUSH OPERATING ROD.OILER A.
TO STARTING PEDAL.
STARTING GEARS.
A FIELD COIL.
OILER B.DISTRIBUTOR
SHAFT GEAR.
FLY WHEEL.PUMP SHAFT.
ARMATURE.
LUBRICATOR C.
GENERATOR
CLUTCH.
ROLLER BEARING.BALL BEARING.
OIL DRAIN.
ONE WAY CLUTCH BUILT IN
THIS GEAR.		MOTOR COMMUTATOR.GENERATOR COMMUTATOR.

Fig. 93. Delco Motor Generator—Showing Parts

This motoring of the generator is necessary in order that the starting gears may be brought into mesh, and should trouble be experienced in meshing these gears, do not try to force them, simply allow the starting pedal to come back giving the gears time to change their relative positions.

A clicking sound will be heard during the motoring of the generator. This is caused by the overrunning of the clutch in the forward end of the generator which is shown in [Fig. 93].

The purpose of the generator clutch is to allow the armature to revolve at a higher speed than the pump shaft during the cranking operation and permitting the pump shaft to drive the armature when the engine is running on its own power. A spiral gear is cut on the outer face of this clutch for driving the distributor. This portion of the clutch is connected by an Oldham coupling to the pump shaft. Therefore its relation to the pump shaft is always the same and does not throw the ignition out of time during the cranking operation.

The cranking operation takes place when the starting pedal is fully depressed. This causes the top motor brush to come in contact with the motor commutator. As this brush arm lowers, it comes in contact with the gear in the generator brush arm raising the generator brush from its commutator. At the same time the current from the storage battery flows through the heavy series field winding, motor brushes and motor winding on the armature. The switching in this circuit is accomplished by means of the top motor brush which is operated from the starting pedal. (Shown in [Fig. 94]).

This cranking operation requires a heavy current from the storage battery, and if the lights are on during the cranking operation, the heavy discharge from the battery causes the voltage of the battery to decrease enough to cause the lights to grow dim. This is noticed especially when the battery is nearly discharged; it also will be more apparent with a stiff motor or with a loose or poor connection in the battery circuit. It is on account of this heavy discharge current that the cranking should not be continued any longer than is necessary, although a fully charged battery will crank the engine for several minutes.

Brush Operating Rod

Motor Brush

Generator Brush

Generator
Commutator

Motor Commutator

Third Brush

Plate Slotted To Permit
Third Brush Adjustment

Fig. 94. Delco Motor Generator—Diagram of Operation

During the cranking operation the ammeter will show a discharge. This is the current that is used both in the shunt field winding and the ignition current; the ignition current, being an intermittent current of comparatively low frequency, will cause the ammeter to vibrate during the cranking operation. If the lights are on the meter will show a heavier discharge.

The main cranking current is not conducted through the ammeter, as this is a very heavy current and it would be impossible to conduct this heavy current through the ammeter and still have an ammeter that is sensitive enough to indicate accurately the charging current and the current for lights and ignition.

As soon as the engine fires the starting pedal should be released immediately, as the overrunning motor clutch is operating from the time the engine fires until the starting gears are out of mesh. Since they operate at a very high speed, if they are held in mesh for any length of time, there is enough friction in this clutch to cause it to heat and burn out the lubricant. There is no necessity for holding the gears in mesh.

The motor clutch operates between the flywheel and the armature pinion for the purpose of getting a suitable gear reduction between the motor generator and the flywheel. It also prevents the armature from being driven at an excessively high speed during the short time the gears are meshed after the engine is running on its own power.

This clutch is lubricated by the grease cup A, shown in [Fig. 93]. This forces grease through the hollow shaft to the inside of the clutch. This cup should be given a turn or two every week.

When the cranking operation is finished the top brush is raised off the commutator when the starting pedal is released. This throws the starting motor out of action ([Fig. 94]). The top brush comes in contact with the generator commutator, and the armature is driven by the extension of the pump shaft.

At speeds above approximately 7 miles per hour the generator voltage is higher than the voltage of the storage battery which causes current to flow from the generator winding through the ammeter in the charge direction to the storage battery. As the speed increases up to approximately 20 miles per hour this charging current increases, but at the higher speeds the charging current decreases.

Lubrication.—There are five places to lubricate the Delco System:

1. The grease clutch for lubricating the motor clutch.

2. Hole at B ([Fig. 93]) for supplying cup grease for lubricating the generator clutch and forward armature bearing.

3. The oiler C in the rear end cover for lubricating the bearing on the armature shaft. This should receive a few drops of oil once a week.

4. The oil hole in the distributor at A ([Fig. 93]) for lubricating the top bearing of the distributor shaft. This should receive oil once a week

5. This is the inside of the distributor head. This should be lubricated with a small amount of vaseline, carefully applied two or three times during the first 2000 miles running of the car, after which it will require no attention. This is to secure a burnished track for the rotor brush on the distributor head. This grease should be sparingly applied and the head wiped clean from dust and dirt.

The combination switch ([Figs. 95] and [96]) is for the purpose of controlling the lights, ignition, and the circuit between the generator and the storage battery. The button next to the ammeter controls both the ignition and the circuit between the generator and the storage battery, the latter circuit being shown in the heavier line as shown on the circuit diagram ([Fig. 98]). The button next to this controls the head lights. The next button controls the auxiliary lamps in the head lights. The button on the left controls the cowl and tail lights.

The circuit breaker is mounted on the combination switch as shown in [Fig. 96]. This is a protective device, which takes the place of a fuse block and fuses. It prevents the discharging of the battery or damage to the switch or wiring to the lamps, in the event of any of the wires leading to these becoming grounded. As long as the lamps are using the normal amount of current the circuit breaker is not affected. But in the event of any of the wires becoming grounded an abnormally heavy current is conducted through the circuit breaker, thus producing a strong magnetism which attracts the pole piece and opens the contacts. This cuts off the flow of current which allows the contacts to close again and the operation is repeated, causing the circuit breaker to pass an intermittent current and give forth a vibrating sound.

Fig. 95. Delco Ignition Switch Plate

Circuit Breaker

Numbers of Lower Terminals

Fig. 96. Delco Ignition Switch Circuit Breaker—Mounted

It requires 25 amperes to start the circuit breaker vibrating, but once vibrating a current of three to five amperes will cause it to continue to operate.

In case the circuit breaker vibrates repeatedly, do not attempt to increase the tension of the spring, as the vibration is an indication of a ground in the system. Remove the ground and the vibration will stop.

The ammeter on the right side of the combination switch is to indicate the current that is going to or coming from the storage battery with the exception of the cranking current. When the engine is not running and current is being used for lights, the ammeter shows the amount of current being used and the ammeter hand points to the discharge side, as the current is being discharged from the battery.

When the engine is running above generating speeds and no current is being used for lights or horn, the ammeter will show charge. This is the amount of current that is being charged into the battery. If current is being used for lights, ignition and horn, in excess of the amount that is being generated, the ammeter will show a discharge as the excess current must be discharged from the battery, but at all ordinary speeds the ammeter will read charge.

The ignition coil is mounted on top of the motor generator as shown in [Fig. 94] and is what is generally known as the ignition transformer coil. In addition to being a plain transformer coil it has incorporated in it a condenser (which is necessary for all high tension ignition systems) and has included on the front end an ignition resistance unit.

The coil proper consists of a round core of a number of small iron wires. Wound around this and insulated from it is the primary winding. The circuit and arrangement of the different parts are shown in [Fig. 97]. The primary current is supplied through the combination switch through the primary winding and resistance through the coil, to the distributor contacts. This is very plainly shown in [Fig. 98]. It is the interrupting of this primary current by the timer contacts together with the action of the condenser which causes a rapid demagnetization of the iron core of the coil that induces the high tension current in the secondary winding. This secondary winding consists of several thousand turns of very fine copper wire, the different layers of which are well insulated from each other and from the primary winding. One end of the secondary winding is grounded and the other end terminates at the high tension terminal about midway on top of the coil. It is from this terminal that the high tension current is conducted to the distributor where it is distributed to the proper cylinders by the rotor shown in [Fig. 98].

Connects
To Switch		High Tension Wire
To Center Of Distributor		Connects To
Distributor
Primary
Winding		 Resistance
Unit
Secondary
Winding		 Iron Core
Condenser
Coil Bracket Must Be Grounded

Fig. 97. Delco Ignition Coil

The distributor and timer, together with the ignition coil, spark plugs, and wiring, constitute the ignition system.

The proper ignition of an internal combustion engine consists of igniting the mixture in each cylinder at such a time that it will be completely burned at the time the piston reaches dead center on the compression stroke. A definite period of time is required from the time the spark occurs at the spark plug until the mixture is completely expanded. It is therefore apparent, that, as the speed of the engine increases, the time the spark occurs must be advanced with respect to the crank shaft, and it is for this reason that the Delco ignition systems are fitted with an automatic spark control.

CIRCUIT BREAKER
AMMETER
COWL LIGHT
RESISTANCE UNITSWITCH
BRUSH SWITCHES
OPERATED BY
STARTING PEDAL		 CONDENSER
IGNITION COIL TONNEAU
LIGHT		HEAD
LIGHTS
SERIES FIELD ROTOR FOR DISTRIBUTING
HIGH TENSION CURRENT
MOTORGENERATOR TAIL LIGHT
STORAGE
BATTERY		 SHUNT
FIELD		TO SPARK PLUGS
DISTRIBUTOR		ADVANCE
TUNGSTEN
TIMING
CONTACTS		 AUX
LIGHT
HORN BUTTON
IN WHEEL

Fig. 98. Delco Wiring Diagram—Buick Cars

The quality of the mixture and the amount of compression are also factors in the time required for the burning to be complete. Thus a rich mixture burns quicker than a lean one. For this reason the engine will stand more advance with a half open throttle than with a wide open throttle, and in order to secure the proper timing of the ignition due to these variations and to retard the spark for starting, idling and carburetor adjusting, the Delco distributor also has a manual control.

Rotor Button
Rotor
Breaker Cam
Timing Adjustment
Automatic Weights

Advance Lever

Fig. 99. Delco Ignition Distributor

The automatic feature of this distributor is shown in [Figs. 99] and [100]. With the spark lever set at the running position on the steering wheel (which is nearly all the way down on the quadrant), the automatic feature gives the proper spark for all speeds excepting a wide open throttle at low speeds, at which time the spark lever should be slightly retarded. When the ignition is too far advanced it causes loss of power and a knocking sound within the engine. With too late a spark there is a loss of power which is usually not noticed except by an experienced driver or one very familiar with the car and heating of the engine and excessive consumption of fuel is the result.

The timer contacts shown at D and C ([Fig. 100]) are two of the most important points of an automobile. Very little attention will keep these in perfect condition. These are tungsten metal, which is extremely hard and requires a very high temperature to melt. Under normal conditions they wear or burn very slightly and will very seldom require attention; but in the event of abnormal voltage, such as would be obtained by running with the battery removed, or with the ignition resistance unit shorted out, or with a defective condenser, these contacts burn very rapidly and in a short time will cause serious ignition trouble. The car should never be operated with the battery removed.

3 AUTOMATIC
WEIGHTS

DISTRIBUTOR
CONTACT BREAKER
CAM

Fig. 100. Delco Ignition Contact Breaker and Timer

It is a very easy matter to check the resistance unit by observing its heating when the ignition button is out and the contacts in the distributor are closed. If it is shorted out it will not heat up, and will cause missing at low speeds.

A defective condenser such as will cause contact trouble will cause serious missing of the ignition. Therefore, any of these troubles are comparatively easy to locate and should be immediately remedied.

These contacts should be so adjusted that when the fiber block B is on top of one of the lobes of the cam, the contacts are opened the thickness of the gauge on the distributor wrench. Adjust contacts by turning contact screw C, and lock nut N. The contacts should be dressed with fine emery cloth so that they meet squarely across the entire face.

The rotor distributes the high tension current from the center of the distributor to the proper cylinder. Care must be taken to see that the distributor head is properly located, otherwise the rotor brush will not be in contact with the terminal at the time the spark occurs.

The distributor head and rotor should be lubricated as described under the heading “[Lubrication].” The amount of ignition current required for different speeds is described under the heading “[Motoring the Generator].”

CHAPTER XXVI
STORAGE BATTERY
Construction, Operation and Care

The modern storage battery does not produce or generate electrical force. It was designed to carry an extra supply of current in storage to operate lighting and starting systems, and in most cases the current required for ignition is drawn from this supply.

Terminal Post
Cell Retainer Case
Cell Jar
Negative Plate
Separator
Positive Plate

Fig. 101. Storage Battery, Sectional View

A storage battery is also called an accumulator, as it accumulates and retains a charge of electrical current for future use.

[Fig. 101] illustrates a storage battery with a section of the cell retainer case removed to show the location of the cells, their respective order, terminal posts and connections. A section of the cell jar, has also been removed to show the core, which consists of a set of positive and negative plates. The positive plates are inserted between the negative plates and are held in this position through their respective connections to the positive and negative terminal posts. The cell retainer-jars are made of zinc or rubber, and contain an acid and water solution called electrolyte into which the core is entirely immersed.

The Positive and Negative Plates.—The plates are held from direct contact with each other by a wood or rubber separator. These plates are formed with small sectional compartments called grids, into which a lead compound in paste form is pressed. The positive plates are made of lead oxide (zinc), and are dark gray in color, while the negative plates are made of pure lead, and are light gray in color.

Cells.—The cells are connected up in series, that is, the positive terminal post of one cell is connected to the negative terminal post of the next cell, forming a direct path through the cell arrangement. Each cell will retain a two-volt pressure until fully discharged. The voltage of a battery is determined by adding the number of two-volt cells that it contains.

Amperage.—The standard type of storage battery shown in [Fig. 102] is composed of three two-volt cells which form a six-volt unit of sixty ampere hours, which means that a fully charged battery will deliver one ampere per hour for sixty hours. This, also, is about the rate of amperage consumed by the modern battery ignition system.

Electrolyte Solution.—The electrolyte solution is composed of a mixture of one part of sulphuric acid added to four to six parts of water. This solution is poured into the cell through the filler cap, until the plates are covered from one-fourth to one-half inch in depth as shown in [Fig. 102].

Care should always be exercised to keep the air vent in the filler cap free from grease and dirt in order that the gases formed through evaporation may escape.

Battery Charging.—The cells are charged by passing a direct current through them, which causes a chemical action to take place as the current flows in, changing the nature of the positive and negative plates, thereby retaining a current force equal to the difference of the changed nature of the plates. The battery is entirely discharged when the plates become alike in nature.

Unscrew
this Cap
Fill up to
this Point
SOLUTION Don’t fill
above
this Point
PLATE

Fig. 102. Storage Battery, Sectional View

Storage Battery Care and Maintenance.—Regularly once every week during the summer, and every two weeks during the winter, add water to each of the three cells of the battery, until the tops of the plates are covered. Use water only; never add acid of any kind. Water for battery purposes should be distilled fresh rain or melted ice, and must be free from alkali, iron, or other impurities. The battery should be kept clean and free from dirt. Use only clean non-metallic vessels for handling and storing water for battery purposes.

The state of charge of a battery is indicated by the specific gravity or density of the solution. [Fig. 103] shows a hydrometer syringe used for taking specific gravity readings. The filler or vent plug in the top of the cell is removed and the rubber tube of the hydrometer syringe inserted into the cell so that the end of the tube is below the solution. Then squeeze the rubber bulb slowly, drawing the solution into the acid chamber until the hydrometer floats.

Fig. 103. Hydrometer Syringe

The reading on the graduator stem at the point where it emerges from the solution is the specific gravity or density of the solution.

[Fig. 103] shows an enlarged section of the hydrometer floating so that the reading of the graduated scale is 1.280 at the point where it emerges from the solution. This is the specific gravity or density of the solution.

After testing, the solution must be returned to the cell from which it was taken.

Never take specific gravity readings immediately after adding water to the cells.

The specific gravity readings are expressed in “points,” thus the difference between 1.275 and 1.300 is 25 points.

When all the cells are in good condition the specific gravity will be approximately the same in all cells and the difference should not be greater than 25 to 30 points.

With a fully charged battery the specific gravity of the solution will be from 1.280 to 1.300.

Specific gravity readings above 1.200 indicates that the battery is more than half charged.

Specific gravity readings below 1.200, but above 1.150 indicates battery less than half charged.

Gravity below 1.150 indicates battery discharged or run down.

Should the gravity fall below 1.150 the gas motor should be given a long run with all lights turned off, to restore the battery.

This condition may result from leaving a car standing for prolonged periods with all lights in use and insufficient running of the gas motor in between these periods to replace the current taken to supply the lights.

When the specific gravity shows the battery to be half discharged, the lights should be used sparingly until the gravity rises to approximately 1.275.

If the specific gravity in one cell is much lower than that of the others, and if successive readings show the difference to be increasing, this indicates that the cell is not in good order.

If one cell regularly requires more water than the others (continually lowering the specific gravity), a leaky jar is indicated. Leaky jars should be replaced immediately.

If there is no leak and the specific gravity falls 50 to 75 points below that of the other cells in the battery, an internal short circuit is indicated and should be remedied.

Battery to Remain Idle.—Where a battery is to remain out of active service for a long period, it may be kept in good condition by giving it a freshening charge at least once a month, by running the gas motor idle.

When a battery has been out of service for some time it should be given a thorough charge before it is placed in service again.

If the gas motor cannot be run to give a freshening charge, the battery should be taken from the car and placed at a garage, which makes a business of charging storage batteries. It can be charged at least once a month. This charge should be 4 and 3⁄4 to 5 amperes for twenty-four hours.

Battery Freezing.—In order to avoid freezing, a battery should be kept in a fully charged condition, as a fully charged battery will not freeze except at extreme temperatures. As a battery discharges the specific gravity of the solution decreases, and the specific gravity of a fully discharged battery will be approximately 1.120. Batteries of this low gravity will freeze at 20° F. above zero, whereas, the density of the solution in a battery approximately three-quarters charged will be 1.260, and a solution of this density will not freeze until 60° F. below zero.

See [Accumulator]. Chapter 14, Electrical Dictionary—Function and Chemical Action.

CHAPTER XXVII
SPARK PLUGS AND CARE

Some definite knowledge of spark plug construction quality, and care, will be found very useful to the average motorist in purchasing new plugs, and keeping those in present use, in good condition. A good plug properly constructed should outlast the life of the motor. When purchasing new plugs, first examine the old plug and get one of the same length. This is very important as spark plugs are made in as many different lengths as required by high and low compression motors. High compression motors have a small low walled combustion chamber, while low compression motors usually have a spacious high wall chamber and require a longer plug, whereas if the long plug is used in the high compression motor it may be put out of commission by the ascending piston. Next determine the size of the plug and the gauge of the thread. The majority of motors use the 3⁄4 inch plug, with the S. A. E. thread, while a few still use the A. L. A. M. thread which is much finer gauged. Another point to be remembered is that it is an unwise expenditure to purchase cheap plugs because the intense heat and pressure that they are subjected to and required to stand, demands that they be made of the highest quality of material and workmanship.

Fig. 104. Spark Plug

[Fig. 104] shows the sectional construction of a spark plug costing from one dollar to one dollar and fifty cents. No. 1, the terminal, is designed to fit all connections. No. 2 nut which holds electroids firmly in place. No. 3 represents round edged shoulders which prevent the plug from short circuiting on the outside. No. 4 is a heavy electroid which will not break or burn. No. 5 is an extra heavy insulator which insures a good spark in case the outer porcelain insulator becomes broken or cracked. No. 6 is a bushing which holds the insulator firmly in place from the top. No. 7 is a high compression washer which allows for upward expansion and makes an even seat for the bushing which holds the insulator in position. No. 8 is a massive porcelain insulator designed to withstand a high temperature without cracking. No. 9 is a copper asbestos washer that allows for the downward expansion of the insulator. No. 10 is the shell casting which holds and protects the insulator. No. 11 are rounded corners which will allow the plug to be screwed down flush without coming into contact with the curved walls of the cup containers. No. 12 is a high compression washer which prevents all leakage. No. 13 shows elastic cement which strengthens the lower construction of the insulator and prevents the compression from escaping through the center of the insulator. No. 14 is a hardened polished steel tipped electroid. No. 15 is a bent polished steel electroid dipped on each side of the spark in order to prevent oil from running down from the shell casting and closing the spark gap. No. 16 represents an extended center electroid which prevents any oil that may have lodged on it from stopping at the spark gap.