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.