Distributor: Description and Operation

Disassembled View Of Breakerless Type Distributor:

The Distributor, mounted on the front of the cylinder head, is an electrical distribution device. It provides high voltage current to the spark plugs, by directing the current to each terminal of the distributor cap as the rotor turns. From the distributor cap terminals, an ignition wire directs the current to each spark plug.

The magnetic pickup unit (Igniter) is located inside on the vacuum advance breaker plate. The reluctor (signal generator) is located on the driven shaft.


Mounted on the side of the upper body of the housing is a vacuum advance control unit. This unit is connected to the breaker plate and when operating, rotates the breaker plate, causing the igniter to move. This advances or retards the ignition timing as required.

Mounted on the side of the upper body of the housing is a vacuum advance control unit. This unit is connected to the breaker plate and when operating, rotates the breaker plate, causing the igniter to move. This advances or retards the ignition timing as required.


Located under the breaker plate on the main shaft is the centrifugal advance assembly. It consists of 2 governor weights mounted on the main shaft, held in place by springs and connected to the rotor shaft. The weights move according to engine RPM. As RPM increases, the weights overcome spring tension and move out towards the edge of the distributor housing. When this happens, the rotor shaft rotates ahead of the main shaft and advances ignition timing.