Hitachi Distributor

Hitachi Distributor:

Within the distributor there are two governor weights and four governor 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 four 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).