The Ford Barn

russcc · 11-02-2021, 06:16 PM

Running a 1GA coil, converted to 12 volts by Skip. Skip recommends 3.8 to 4 volts at the + terminal on the coil. I have tried a number of resisters, and the closest I could get was 6 volts. I then wired two resistors in series and it dropped to 3 volts which is not enough. Anyone have a source for a resistor the will net 3.8 to 4 volts at the coil ? Thank you.

paul2748 · 11-02-2021, 07:43 PM

H ave you talked to Skip to see if has the correct resistor or where to get one?

Crankster · 11-02-2021, 10:56 PM

Just to be clear, is that with the engine running?

PeteVS · 11-03-2021, 02:36 AM

If you had three resistors, you could try putting two of them in parallel and then putting the third in series with the pair. (But, I'm pretty sure that a better recommendation will show up!)

Mart · 11-03-2021, 03:56 AM

Forgive me, but I need to say if the coil is converted to 12V it should need more than 4V. 4V sounds right for a 6V coil.
Mart.

Jack E/NJ · 11-03-2021, 06:31 AM

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Static voltage drop to coil is usually measured between resistor side of coil & ground, points closed.

russcc · 11-03-2021, 06:34 AM

Not running, but in a complete test circuit, + battery terminal to resistor, to + coil terminal, Neg. coil terminal to Neg. battery terminal. readings across + coil & neg coil.
When talking with Skip, he may have meant 3.5 to 4 volts for a 6 volt coil, when we were talking about the 12V coil he converted. Will check with him again. Good point Mart.

russcc · 11-03-2021, 11:22 AM

Skip says 3.5-4 volts for either a 6 volt or 12 volt system. Testing as Jack said, static voltage drop I am measuring between the + resistor side of the coil & ground with the circuit complete or closed as in points.

Glenn Thoreson · 11-04-2021, 08:43 PM

Have you tried a stock resistor for a '41 ? to '48 ? It's a small wire wound resistor that would drop 6 volts down to 3 point something. with 12 volts it may put you in the ballpark.
Early V8 parts vendors usually have them. I use '70s Chrysler electronic ignition resistors for several things. Double resistors in one. One side will drop 12 volts enough to run a 6 volt heater motor and the other side drops it down quite a lot. Have never put a meter to it, though.

11-02-2021, 06:16 PM	#1
russcc Senior Member Join Date: May 2010 Posts: 2,871	Resistor for 12V coil Running a 1GA coil, converted to 12 volts by Skip. Skip recommends 3.8 to 4 volts at the + terminal on the coil. I have tried a number of resisters, and the closest I could get was 6 volts. I then wired two resistors in series and it dropped to 3 volts which is not enough. Anyone have a source for a resistor the will net 3.8 to 4 volts at the coil ? Thank you.

11-02-2021, 07:43 PM	#2
paul2748 Senior Member Join Date: May 2010 Location: Midland Park, NJ Posts: 3,982	Re: Resistor for 12V coil H ave you talked to Skip to see if has the correct resistor or where to get one? __________________ 48 Ford Conv 56 Tbird 54 Ford Victoria

11-02-2021, 10:56 PM	#3
Crankster Senior Member Join Date: Oct 2017 Posts: 563	Resistor for 12V coil Just to be clear, is that with the engine running?

11-03-2021, 02:36 AM	#4
PeteVS Senior Member Join Date: May 2010 Location: FP, NJ Posts: 2,770	Re: Resistor for 12V coil If you had three resistors, you could try putting two of them in parallel and then putting the third in series with the pair. (But, I'm pretty sure that a better recommendation will show up!) __________________ Don't never get rid of nuthin!

11-03-2021, 03:56 AM	#5
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,754	Re: Resistor for 12V coil Forgive me, but I need to say if the coil is converted to 12V it should need more than 4V. 4V sounds right for a 6V coil. Mart.

11-03-2021, 06:31 AM	#6
Jack E/NJ Senior Member Join Date: May 2010 Posts: 2,173	Re: Resistor for 12V coil Sponsored Links (Register now to hide all advertisements) Static voltage drop to coil is usually measured between resistor side of coil & ground, points closed.

11-03-2021, 06:34 AM	#7
russcc Senior Member Join Date: May 2010 Posts: 2,871	Re: Resistor for 12V coil Not running, but in a complete test circuit, + battery terminal to resistor, to + coil terminal, Neg. coil terminal to Neg. battery terminal. readings across + coil & neg coil. When talking with Skip, he may have meant 3.5 to 4 volts for a 6 volt coil, when we were talking about the 12V coil he converted. Will check with him again. Good point Mart.

11-03-2021, 11:22 AM	#8
russcc Senior Member Join Date: May 2010 Posts: 2,871	Re: Resistor for 12V coil Skip says 3.5-4 volts for either a 6 volt or 12 volt system. Testing as Jack said, static voltage drop I am measuring between the + resistor side of the coil & ground with the circuit complete or closed as in points.

11-04-2021, 08:43 PM	#9
Glenn Thoreson Senior Member Join Date: May 2010 Posts: 203	Re: Resistor for 12V coil Have you tried a stock resistor for a '41 ? to '48 ? It's a small wire wound resistor that would drop 6 volts down to 3 point something. with 12 volts it may put you in the ballpark. Early V8 parts vendors usually have them. I use '70s Chrysler electronic ignition resistors for several things. Double resistors in one. One side will drop 12 volts enough to run a 6 volt heater motor and the other side drops it down quite a lot. Have never put a meter to it, though.