Coil Overheating
Thread Starter
Melting Slicks
Joined: Nov 2006
Posts: 2,618
Likes: 149
From: Anaheim California
Coil Overheating
I have been chasing a misfire when the engine is hot on my '61 283/315. I am running the original Pertronix I (10 years old) with the Pertronix coil.
When the car was at operating temperature 165* I touched the coil and it was very hot, almost fried my hand! I put an IR gun on the thermostat and the engine was 165* and the middle of the coil case was a whopping 195*. I swapped the stock coil in and it also heated up. The unit is hooked up correctly: red wire to 12V resister, black to
- coil. The ballast resister is also new.
As a comparison, I fired up my '65, same pertronix set up as above and the engine temp was 180* and coil was only 160*. You could touch the coil without frying you hand!
Could a defective Pertronix module be heating up my coils? I haven't replaced the module yet. Anyone have this problem?
When the car was at operating temperature 165* I touched the coil and it was very hot, almost fried my hand! I put an IR gun on the thermostat and the engine was 165* and the middle of the coil case was a whopping 195*. I swapped the stock coil in and it also heated up. The unit is hooked up correctly: red wire to 12V resister, black to
- coil. The ballast resister is also new.
As a comparison, I fired up my '65, same pertronix set up as above and the engine temp was 180* and coil was only 160*. You could touch the coil without frying you hand!
Could a defective Pertronix module be heating up my coils? I haven't replaced the module yet. Anyone have this problem?
Team Owner
Joined: Aug 2007
Posts: 58,061
Likes: 7,146
Army
Which side of the ballast resistor is the red wire hooked to ?
That determines if the resistor is in the circuit -- which is what you want with a Pertronix I with a stock (or high-resistance substitute) coil.
That determines if the resistor is in the circuit -- which is what you want with a Pertronix I with a stock (or high-resistance substitute) coil.
Thread Starter
Melting Slicks
Joined: Nov 2006
Posts: 2,618
Likes: 149
From: Anaheim California
Frank, I am hooked up to the 12V side of the resister and I am using the Pertronix coil. I have swapped out back to the original coil with no change.
Last edited by jtranger; Dec 28, 2011 at 12:31 PM. Reason: add
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
I have been chasing a misfire when the engine is hot on my '61 283/315. I am running the original Pertronix I (10 years old) with the Pertronix coil.
When the car was at operating temperature 165* I touched the coil and it was very hot, almost fried my hand! I put an IR gun on the thermostat and the engine was 165* and the middle of the coil case was a whopping 195*. I swapped the stock coil in and it also heated up. The unit is hooked up correctly: red wire to 12V resister, black to
- coil. The ballast resister is also new.
As a comparison, I fired up my '65, same pertronix set up as above and the engine temp was 180* and coil was only 160*. You could touch the coil without frying you hand!
Could a defective Pertronix module be heating up my coils? I haven't replaced the module yet. Anyone have this problem?
When the car was at operating temperature 165* I touched the coil and it was very hot, almost fried my hand! I put an IR gun on the thermostat and the engine was 165* and the middle of the coil case was a whopping 195*. I swapped the stock coil in and it also heated up. The unit is hooked up correctly: red wire to 12V resister, black to
- coil. The ballast resister is also new.
As a comparison, I fired up my '65, same pertronix set up as above and the engine temp was 180* and coil was only 160*. You could touch the coil without frying you hand!
Could a defective Pertronix module be heating up my coils? I haven't replaced the module yet. Anyone have this problem?
Safety Car
Joined: Mar 2001
Posts: 4,359
Likes: 116
From: AUSTIN Tx
Regards, John McGraw
Drifting
Joined: Jul 2009
Posts: 1,610
Likes: 11
From: Tampa, FL & Harleysville, PA
I use a 1/4" thick hard rubber insulator gasket between the coil bracket and the coil on my 61 fuelie (a bike cycle inner tube works well). Also base of coil shouldn’t touch anything leaving a nice size air gap. You will see a dramatic reduction in heat transfer afterwards.
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rustylugnuts
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Race Director
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From: CT
John - Pertronix, Mallory, Accel, MSD, all list higher output .06 ohm coils for electronic conversions. Stock can be used and will work, but for maximum spark the heavier duty coils are suggested.
Thread Starter
Melting Slicks
Joined: Nov 2006
Posts: 2,618
Likes: 149
From: Anaheim California
Thread Starter
Melting Slicks
Joined: Nov 2006
Posts: 2,618
Likes: 149
From: Anaheim California
This sounds like the problem! You should be hooked to the output of the resistor and not the input. It sounds like you have completely bypassed the resistor. This will make the current go through the roof, and eventually damage the coil. Move the wire to the low voltage side of the resistor, and hope that you have not already damaged them. The only time that the coil should see full battery voltage, is when in the cranking mode. That is why the wire comes up from the starter solenoid to the output side of the resistor.
Regards, John McGraw
Regards, John McGraw
Team Owner
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Army
John, Instructions call for Ignitor module (red wire) to get the full 12V to the input/ignition side of coil. The + coil side has a wire to the low voltage side to keep the coil from getting the full 12 volts.
Is the coil that's getting hot epoxy or oil filled ?
Last edited by Frankie the Fink; Dec 28, 2011 at 03:52 PM.
Safety Car
Joined: Mar 2001
Posts: 4,359
Likes: 116
From: AUSTIN Tx
Regards, John McGraw
Team Owner
Joined: Oct 2000
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From: Washington Michigan
http://www.lbfun.com/warehouse/tech_...tionBasics.pdf
Le Mans Master
Joined: Nov 2000
Posts: 7,246
Likes: 21
From: Going too fast over the hill. Iowa
A combination of resistor spark plug wires and resistor plugs can overload the coil.
A short in the engine harness from any 12 volt line to the pink wire from the starter solenoid to the coil will provide 12 volts to the coil all the time.
Last edited by magicv8; Dec 28, 2011 at 04:42 PM.
Le Mans Master
Joined: Nov 2000
Posts: 7,246
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From: Going too fast over the hill. Iowa
I bought the Flamethrower coil from Pertronix. It melted down in 2 months. I put an old GM coil back in. No problem for years and years.
Team Owner
Joined: Oct 2000
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From: Washington Michigan