Voltage at Coil

[itstom]

Hi,

From what I can tell from past discussions and the wiring diagram for my '38 Special, there is no ballast resistor or resistor wire in the ignition circuit.  Is this correct?  What would be considered an acceptable voltage to see at the coil with the car running.

 

Thanks,

Tom

[DonMicheletti]

You should see full 6 volts at the coil, maybe a touch more depending on your voltmeter accuracy

[Bloo]

Correct, there is no resistor. I know of no normal looking cylindrical 6v coils that use a resistor, and I have looked.

 

The bigger problem might be finding a meter that can measure the voltage. The coil voltage (running or with points closed) ideally should be the same as the charging system voltage . It won't be. (try measuring at the battery or the "bat" terminal on the regulator).

 

If I saw more than half a volt less I would be looking for things to fix. I don't know what you can actually get away with. Maybe more. Probably more. I have not had a lot of luck measuring this lately. For best results get the loss as low as you possibly can.

 

Edited August 12, 2019 by Bloo (see edit history)

[itstom]

Thanks guys.

 

Tom

[Hubert_25-25]

Many coils these days are marked indicating no resistor needed.  That is the kind of coil I buy.  They can take full battery voltage.    Hugh

[DonMicheletti]

A possible source of voltage loss is the ignition switch. The contacts are small and can oxidize with time. Especially if there are added switched acessories.