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AD1948Ford · 05-08-2021, 08:51 AM

I have been reading the various threads on this issue and after checking my system, I am still having the same issue with my coil overheating.

I have a 1948 ford tudor sedan with the original flathead but converted over to 12 volts negative ground. When cold, the car starts up perfect and runs like a charm. After driving around for 30-45 minutes, I pulled up to a friends house and turn the car off. about 10 minutes later, I got back in to leave, car started up fine and then about 2 minutes down the round, it started to miss and died.

I could get the car to turn over but could not get it to start. I had this issue before so i had a spare coil in the car. I took the old coil off, installed the new coil and boom, car started right up.

What could be causing this issue? The coil is a 12v internally resisted coil. when the car is running at idle, the coil has 12.4 volts going to it. At higher RPM, it is showing 14.4 volts going to it. Is this causing the overheating issue? Do I need to run a ballast resistor with it even though it states its internally resisted?

Any help would be appreciated.

05-08-2021, 08:51 AM	#1
AD1948Ford Senior Member Join Date: Dec 2015 Location: Houston, Texas Posts: 110	1948 Ford 12 volt coil issues I have been reading the various threads on this issue and after checking my system, I am still having the same issue with my coil overheating. I have a 1948 ford tudor sedan with the original flathead but converted over to 12 volts negative ground. When cold, the car starts up perfect and runs like a charm. After driving around for 30-45 minutes, I pulled up to a friends house and turn the car off. about 10 minutes later, I got back in to leave, car started up fine and then about 2 minutes down the round, it started to miss and died. I could get the car to turn over but could not get it to start. I had this issue before so i had a spare coil in the car. I took the old coil off, installed the new coil and boom, car started right up. What could be causing this issue? The coil is a 12v internally resisted coil. when the car is running at idle, the coil has 12.4 volts going to it. At higher RPM, it is showing 14.4 volts going to it. Is this causing the overheating issue? Do I need to run a ballast resistor with it even though it states its internally resisted? Any help would be appreciated.