Coil primary feed, 1966

[PhilK]

I'm working on a 1966 Thunderbird with the 428 engine. I have replaced the points and condenser with the Pertronics system, including their coil. They recommend removing the resister from the primary feed. The feed runs from the ignition switch to the starter relay (solenoid), then to the coil. I have checked the voltage to ground at the relay and again at the coil connection. Both places read over 12 volts. My service manual states that with the resistance wire in place, it should read about 6.6 volts. Am I missing something? It does not look like either of these wires have been replaced, and I don't see a ballast resister anywhere else. Any suggestions will be appreciated.

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[64ZCODE]

Pertronix makes a primary circuit by pass relay which is well worth the $35 or so it costs. It is energized by the primary circuit when turning on the ignition, and it supplies full 12v to the distributor and the coil. Easy to install. Pic below:

 

[PhilK]

Pertronix makes a primary circuit by pass relay which is well worth the $35 or so it costs. It is energized by the primary circuit when turning on the ignition, and it supplies full 12v to the distributor and the coil. Easy to install. Pic below:

Thanks. I just ordered it from Amazon.

 

[projo198]

If Petronix recommend removing the resistor and you are already getting 12V at the coil does it still need to be fixed, or are you still wanting the 6.6V as the service manual states?

 

[64ZCODE]

You need the full 12 volts at the coil in order to generate a strong spark. Presumably you upgraded your coil when you installed the Pertronix, right?

The stock resistor wiring is designed to reduce the voltage to the coil after the engine starts, in order to reduce wear on the points. But, this setup results in a weak spark to the spark plugs. More voltage, better spark, better ignition.

By the way, did you install the Pertonix III? If so, it acts like a spark box, generating multiple sparks per power stroke. If not, you could add a spark box to do the same thing. Now you have stronger spark multiple times per power stroke, and you'll notice the difference in how smoothly the engine runs and available power.

 

[05Dave]

I'm working on a 1966 Thunderbird with the 428 engine. I have replaced the points and condenser with the Pertronics system, including their coil. They recommend removing the resister from the primary feed. The feed runs from the ignition switch to the starter relay (solenoid), then to the coil. I have checked the voltage to ground at the relay and again at the coil connection. Both places read over 12 volts. My service manual states that with the resistance wire in place, it should read about 6.6 volts. Am I missing something? It does not look like either of these wires have been replaced, and I don't see a ballast resister anywhere else. Any suggestions will be appreciated.

If you are measuring approx. 12 volts then the resistor has been removed. If the new system wants the full battery voltage you should be good to go.

 

[64ZCODE]

But, the advantage of the Pertronix relay is you know you have the full 12 volts getting to the coil. I would think that if you rely on the primary ignition wire from which the resistance wire has supposedly been removed, you might have 12 volts measured but nevertheless a dodgy half ass circuit that someone in the past wired up.