Distributor Cap: Description and Operation

Distributor Cap And Rotor:

PURPOSE
Distribute high voltage secondary coil output to spark plugs in proper sequence (firing order).

LOCATION
Cap on top of distributor. Rotor inside on distributor shaft.

OPERATION
Sparking voltage travels through the coil wire to the center electrode and to the center of the distributor rotor. The distributor rotor turns with the shaft. As it rotates, the electrode at its tip passes close to the spark plug terminals. The distributor cap, rotor and wires are arranged so that when the coil discharges, the tip of the rotor is pointed at the correct spark plug terminal.

CONSTRUCTION
The molded plastic distributor cap has a spring loaded carbon electrode at its center and electrodes positioned around its inside perimeter that connect to the spark plugs, one for each cylinder.