The Ford Barn

signsup · 03-08-2025, 06:26 PM

Obviousely need to clean up the Bubba coil set up. Converted to 12v. The beer can has got to go and a coil bracket obtained. I've got some WWII Ford jeep coil brackets and I'd be shocked if they were not correct for this car, and a nice script F for good measure.

But this resistor or relay that is in one of the mounting holes does not look OE. Might be added for the 12v conversion. Leave? Remove? Mount somewhere else? Only one wire connected to it so perhaps the bracket is the ground? Appreciate any thoughts.

pbsdaddy · 03-08-2025, 07:10 PM

Yes, it looks like a ballast resister. However, since it isn't actually bin use, in your present configuration, I would remove it.

JayChicago · 03-08-2025, 07:42 PM

Agree with daddy.
Yes, it's a ballast resistor. Resistors don't have a ground, they should not go to ground. They just have two terminals, for current in and current out.
This one has one terminal with no wire, so it is nonfunctional. Since it isn't doing anything, you could just remove it. (Maybe it was left from before the 12volt conversion)

petehoovie · 03-08-2025, 07:44 PM

Quote:

Originally Posted by signsup

Obviousely need to clean up the Bubba coil set up. Converted to 12v. The beer can has got to go and a coil bracket obtained. I've got some WWII Ford jeep coil brackets and I'd be shocked if they were not correct for this car, and a nice script F for good measure.

But this resistor or relay that is in one of the mounting holes does not look OE. Might be added for the 12v conversion. Leave? Remove? Mount somewhere else? Only one wire connected to it so perhaps the bracket is the ground? Appreciate any thoughts.

rotorwrench · 03-10-2025, 12:26 PM

A 1.5 Ohm primary winding type coil will need a ballast in the input power wire if on 12-volts. The ballast resistor should be at least 1 to 1.5 Ohm. If you have a 3 Ohm primary winding type coil, no ballast is necessary on 12-volts. The 1.5 Ohm coil was designed to work with 6-volts with no ballast.

tubman · 03-10-2025, 12:44 PM

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I've generally seen ballast resistors mounted on the firewall or sometimes on the inner fender. If I had to guess, I'd say that that installation is not factory and more prone to vibration since it is mounted on the engine. Since it's already disconnected, I'd remove it and start from scratch. The first thing to do is "ohm out" the coil and see if a resistor is even needed.

See the previous post or calculate the total resistance needed through the coil circuit to yield 4 amps through the points using Ohm's Law.

03-08-2025, 07:10 PM	#2
pbsdaddy Member Join Date: Dec 2023 Location: From Pittsburgh, now call Delaware home Posts: 72	Re: Is this coil ballast resistor? And, if so, is this how itm ounts? Yes, it looks like a ballast resister. However, since it isn't actually bin use, in your present configuration, I would remove it.

03-08-2025, 07:42 PM	#3
JayChicago Senior Member Join Date: Jan 2019 Location: Chicago Posts: 927	Re: Is this coil ballast resistor? And, if so, is this how itm ounts? Agree with daddy. Yes, it's a ballast resistor. Resistors don't have a ground, they should not go to ground. They just have two terminals, for current in and current out. This one has one terminal with no wire, so it is nonfunctional. Since it isn't doing anything, you could just remove it. (Maybe it was left from before the 12volt conversion)

03-10-2025, 12:26 PM	#5
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 17,411	Re: Is this coil ballast resistor? And, if so, is this how itm ounts? A 1.5 Ohm primary winding type coil will need a ballast in the input power wire if on 12-volts. The ballast resistor should be at least 1 to 1.5 Ohm. If you have a 3 Ohm primary winding type coil, no ballast is necessary on 12-volts. The 1.5 Ohm coil was designed to work with 6-volts with no ballast.

03-10-2025, 12:44 PM	#6
tubman Senior Member Join Date: Dec 2013 Location: Minnesota, Florida Keys Posts: 11,639	Re: Is this coil ballast resistor? And, if so, is this how itm ounts? Sponsored Links (Register now to hide all advertisements) I've generally seen ballast resistors mounted on the firewall or sometimes on the inner fender. If I had to guess, I'd say that that installation is not factory and more prone to vibration since it is mounted on the engine. Since it's already disconnected, I'd remove it and start from scratch. The first thing to do is "ohm out" the coil and see if a resistor is even needed. See the previous post or calculate the total resistance needed through the coil circuit to yield 4 amps through the points using Ohm's Law.