Distributor Cap: Description and Operation

Distributor Cap And Rotor:

CAP

The molded plastic distributor cap has a central connection for voltage "in" from the ignition coil and connections around its perimeter for voltage "out" to the spark plugs. As it turns, the rotor connects the coil terminal to each spark plug connection in sequence (firing order). The cap is constructed so that integral towers at each connection securely retain the high tension wires and accept rubber boots to exclude dirt and moisture.

ROTOR

The rotor, mounted on top of the distributor shaft, is the link between the distributor cap ignition coil terminal (voltage "in") and each spark plug (voltage "out") terminal. From the coil high tension lead, voltage is directed to the rotor through a spring-loaded solid carbon brush inside the distributor cap. As the rotor tip passes each distributor cap spark plug terminal in turn (firing order), voltage jumps an air gap to the terminal and is directed to the plugs via a high tension lead.