C2 ballast resistor

[Tom Merkel]

What is the function of the ballast resistor, on engine compartment (firewall)?

Tom

[John H.]

Re: C2 ballast resistor

Tom -

It reduces the voltage to the coil in the normal "run" mode to 7-8 volts in order to extend the life of the points. The coil only sees full 12 volts during cranking, when it's fed from the "R" terminal of the starter solenoid; that's why there are two wires at the coil (+) terminal - one is from the resistor, and the other is from the starter solenoid.

[John H.]

Re: C2 ballast resistor - Addendum

The separate ceramic-encased wirewound resistor was used through '67; after that, through 1974, the ignition feed wire to the coil was a special woven cloth-covered resistance wire that provided the same function. HEI came in 1975, with a full-time 12-volt feed to the HEI distributor.