Distributor Advance Unit: Description and Operation

Centrifugal Advance:

Within the distributor there are two governor weights and two governor weight springs. These weights and springs are attached to the distributor shaft. A rotor shaft is also attached to the distributor shaft.

As the distributor rotates, centrifugal force pulls the governor weights against the tension of the springs. As the weights spread apart, locating pins on the weights rotate the rotor shaft causing the ignition timing to be advanced. The amount of centrifugal advance is determined directly by the engine RPM (distributor rotating speed).