The ignition system is divided into 2 circuits: high and low voltage.
Low voltage circuit (sometimes also called primary) consists of a battery, a wire leading to the ignition switch, a wire leading from the ignition switch to the primary winding of the coil, and a wire leading from the primary winding of the coil to the breaker contacts and the capacitor in the distributor.
The high voltage circuit consists of the secondary winding of the coil, the ignition wire leading from the center of the coil to the center of the distributor cap, the runner, the ignition wires leading to the plugs, and the spark plugs themselves.
The ignition system works as follows. Low voltage is converted into high voltage in the ignition coil by opening and closing the breaker contacts in the low voltage circuit. High voltage is supplied through "ember" in the center of the distributor cap to the slider on the cover, and whenever the slider is aligned with one of the four electrodes standing on the distributor cap and connected to the ignition wires, the opening and closing of the breaker contacts causes a build-up of high voltage, leading to a spark jumping between the slider and the corresponding electrode. The voltage is transmitted through the ignition wire to the spark plug, a spark jumps between the electrodes, leading to ignition of the mixture, after which the current goes to "mass".
In order for the mixture to ignite at the right time in relation to engine speed and load, the ignition timing is automatically adjusted.
The ignition timing is controlled by mechanical and vacuum regulators. Mechanical (centrifugal) the regulator consists of two weights, which, due to centrifugal force, diverge as the rotation speed of the distributor shaft increases and rotate the cam relative to the distributor shaft, thereby accelerating the spark. The weights are held by two springs, and the correct mechanical adjustment of the ignition timing depends on the tension of the springs.
The vacuum regulator consists of a membrane, one side of which is connected by a thin tube to the carburetor, and the other to a contact breaker plate. The vacuum in the intake manifold and carburetor, which varies with engine speed and throttle opening, causes a diaphragm to move, which moves the breaker plate accordingly, speeding up or slowing down the spark (see photo).
Photo 1.8. Connecting the distributor vacuum tube to the carburetor.
A resistor located on the low voltage wire leading to the coil keeps the coil voltage at 6 V during normal operation. This resistor is bypassed when the starter is turned on to compensate for the resulting drop in battery voltage.
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