Putnam's Automobile Handbook: The Care and Management of the Modern Motor-Car

by H. Clifford Brokaw; Charles A. Starr

Everyone knows better than to crank the engine with the switch off, yet recently we saw an average motorist waste twenty minutes this way. The ignition switch was set in the center of the lighting switch handle. Therefore the absolute position of the ignition switch key varied according to what lights were on—hence the error; yet this motorist looked all over his engine before he discovered his trouble. Probably being absent-minded had something to do with it; he had just left his office for the day and was on his way home, which demonstrates that the thoughtless or preoccupied man is much more likely to make unrightful assumptions than the alert man.

Recently an old automobile mechanic was riding on an interurban car when the latter was held up by a motor car stalled across the tracks. There was a big crowd around the machine trying frantically to push it out of the way. For some reason the rear wheels were locked. No amount of effort would budge the car and it was too large to lift and carry.

The mechanic got off and watched the proceedings. He found that the gear lever was stuck in low gear, and inquiry as to whether the trouble was due to jammed gears or some other serious defect could not be answered by the owner or any of his helpers. He began to wonder where the trouble was while the others struggled, but being old in the game, the thought flashed across his mind: “Take nothing for granted.” Therefore the first question to determine was whether the whole difficulty might not be solved by pushing out the clutch. This seemed too easy—too good to be true. He hesitated to suggest it, but the more he thought about it the more he became convinced, and finally he mustered up enough courage to slip behind the wheel and command the resting crowd to push. The car glided off, to the astonishment of everyone. It developed that the owner of the car had become excited when he stalled the engine on the crossing with the lever stuck in low. In his feverish haste he tried to push the car off instead of shoving out his clutch and starting the motor, and as the crowd collected they accepted the locked condition of the rear wheels as something which could not be remedied.

A motorist of ten years’ experience bought a used car. He took delivery of it late one rainy afternoon. The former owner told him the car was complete, the only thing missing being the key to the tool box, which he promised to mail him early the next day. The motorist got a couple of friends and started for a ride. Finally they stopped for dinner. When they came out the owner put his foot on the starter pedal, but it stuck. He pulled up the floor boards but could not reach the mechanism. The only way was to crawl under the car and this was out of the question because of the mud. They looked for the crank under the rear-seat cushion and under the front-seat cushion, but could not find it. Quite naturally they concluded it must be in the locked tool box or else the former owner had neglected to include this very important item. They tried to locate a car of the same make in some neighboring garages without success. They jacked the car up and tried to crank it by turning a rear wheel, but the compression was too great, so they tossed the jack into the tonneau and started in search of someone who would tow the car to start it. Eventually they got the engine going. When they reached the garage the owner slipped his hand into the tonneau and he pulled out—not the jack—but the crank!

The worst is to come. The next morning a mechanic who had been in the business long enough to know better than to make unwarranted assumptions was called in. He pressed down the pedal without success, then for no logical reason but simply because automobiles were second nature to him he pulled up and the pedal came. Then he pushed and the starter worked. The owner was nonplussed. Later he admitted that he had thought of pulling up on the pedal but assumed it would do no good.

A few years ago, when expanding clutches were more popular, a motorist found one day that his clutch was slipping. He had a vague idea that there must be some means for adjusting the clutch to cure this trouble, but he looked in vain for a nut or a screw or a bolt which might do the trick. True, there was a small screw in the fly-wheel rim, set almost flush with the edge of the rim and locked by a tiny spring wire which rested in the milled slot in the screw. But he limped to a garage on low gear and held consultation with the entire force. They examined the car carefully and decided there was no way to adjust the clutch. They suggested a new lining or strips of metal under the old lining to swell it out so that it would grip. The former was out of the question because of the time it would take, so the latter was tried. The makeshift worked all right for a few miles, and then the clutch slipped more than ever. In desperation he called the agent up on the long distance, and was informed that his troubles would be over if he would give that innocent-looking screw a couple of turns. It sounded like black magic, but he went back and tried it, and his troubles ended.

An owner who was very particular about having his car in the best of condition found that the compression in the first cylinder was weak although the valves had just been ground. He removed the exhaust valve and found it in perfect condition. Then he took out the intake valve, although he felt foolish while doing it. It was in excellent shape but, just to be on the safe side and because he did not know what else to do, he ground it anyhow. The trouble was no better. Neither did the difficulty seem to be due to too small a clearance between valve stems and push rods, because the clearance was the prescribed amount on both intake and exhaust valves. He concluded that it must be the rings. Either they were gummed or broken. Flooding the cylinder with kerosene did not improve the condition, so a pint of very heavy oil was put in with the idea that this would temporarily stop any leaks between cylinder and piston, but the compression was no better. Several times during the hunt he was tempted to increase the clearance between valve stems and push rods, not for any sensible reason, because the clearance was correct, but simply in desperation. It seemed about the only thing left to do—it was the only thing he had not tried. But his “common sense” said no, so he took his car to the service station. The first thing they did was to increase the clearance on the intake valve, and the trouble was cured. The reason for doing this was that there was a high spot on the back of the intake cam which would open the valve a slight amount on the compression stroke. The clearance was increased to a point where the high spot had no effect.

One day a motorist had serious magneto trouble. The engine missed and finally stopped. It was necessary to take the magneto to an expert to have it repaired. The very day the magneto was replaced the car started missing again and it looked as if the work had not been properly done. Finally the engine refused to go further. A passing farm wagon was hailed and the car brought home—seven miles. The magneto was returned to the shop, but nothing wrong was found. Yet when it was replaced the car still refused to run. A telephone talk with the nearest agent, forty miles away, showed that the trouble might be in the carburetor and a search showed that it was—the low speed jet was clogged. To prove the truth of this suspicion the engine was primed and ran perfectly except at low speed. When the car first stalled, it occurred to the owner that it might be a good idea to prime the engine, but he dismissed the thought because he was so certain the trouble was in the magneto, and without a better reason than it was too much work to prime the engine because there were no priming cups.

A similar trouble in that it was of a dual nature was experienced with a car which had just had the valves ground and the carbon removed. After the work was done the engine could not be started. Investigation showed there was no spark. No short-circuits could be found in the wiring. The breaker points were examined and after filing and adjusting them the engine started on the first turn. Fortunately the man who did this job knew how to proceed—he made no guesses or assumptions. In this he was different from the owner whose experience was related elsewhere.

The last two instances show something it is very important for everyone to realize, although this is a diversion, namely, that repair men are often blamed for tampering with cars without cause. The preceding incident was pure coincidence. The breaker points gave out entirely when the engine was shut off prior to grinding the valves.