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30 Closed Cab PU · 07-01-2019, 03:27 PM

I assume the 1st 2 that measure 1.5 ohms were specifically for Model As. You could also ohm each of the 1.5 ohm coils terminals to the high voltage output. Should measure 7k-15k ohms. Not sure what teh reading would be for a 12 v coil

I am unclear on your email. The coils that measure 1.5 ohms require the 1.5 ohm external resistor when used on 12 volts. Otherwise they are running twice their desired current and will heat up.

The 12 v coil should measure about 3 ohms and does not need the resistor.

Then, do not ask why, can not supply a reasonable answer - but would try a different condenser.

07-01-2019, 03:27 PM	#2
30 Closed Cab PU Senior Member Join Date: Aug 2018 Posts: 2,332	Re: Cause of hot ignition coil? I assume the 1st 2 that measure 1.5 ohms were specifically for Model As. You could also ohm each of the 1.5 ohm coils terminals to the high voltage output. Should measure 7k-15k ohms. Not sure what teh reading would be for a 12 v coil I am unclear on your email. The coils that measure 1.5 ohms require the 1.5 ohm external resistor when used on 12 volts. Otherwise they are running twice their desired current and will heat up. The 12 v coil should measure about 3 ohms and does not need the resistor. Then, do not ask why, can not supply a reasonable answer - but would try a different condenser.