The insert that comes with the Pertronix states that if you have a ballast resistor installed to leave it installed. I installed a Pertronix yesterday and the truck was very hard to start and ran like crap. Fiddled around with the advance and strained my eyes trying to see the timing marks on the flywheel but these old eyes couldn't "call the ball" or find the triangle. Today I put the points back in, re-gapped them and the engine starts right up and runs like a top. Perhaps I ordered the wrong Pertronix electronic ignition. Anyway, that's a whole another story.
I've posted this before but this is one of the best links I have found on
Ingnition Systems and has some very good information on this topic.
Ballast Resistor (or resistor wire)
The coil is designed to operate on 9 volts. Battery voltage (12 volts) is reduced to
9 volts by the Ballast Resistor. When the ignition switch is in the "run" position, the coil is powered through the Ballast Resistor feeding it 9 volts; but when the ignition switch is turned to "start", the Ballast Resistor gets by-passed. This feeds full battery voltage to the coil for better starting. The starter motor is drawing battery voltage down to about 10 volts at this time.
The sole purpose of the condenser is to protect the points, and keep them from burning out prematurely.
Don
