Electronic Ignition Conversion
Thread Starter
Intermediate
Joined: Feb 2025
Posts: 45
Likes: 4
From: Pittsburgh, PA
Electronic Ignition Conversion
I have a 1972 Base Coupe. I am having an issue where the car stops running while driving, and I believe it is the coil getting too hot. I originally thought it might be vapor lock, so I insulated the fuel line. I don't think that was the problem. The last time it happened, the wire to the coil was smoking hot (literally smoking), and the coil was very hot. After about 15 min, the car started back up.
I want to convert the system to electronic (Pertrtonix). They have many products, so I am not sure what I should use (I am going to call them). My thought is a stock looking distributor and Flamethrower coil, and changing the spark plugs and wires while I am at it (they are probably at least 20 yrs old with about 15-20k miles on them).
As I look at the coil, there are four wires connected to the two terminals. On one side, a black wire that I assume to be the ground. On the other, there are three wires, two black and one red. One of the black wires was the "smoking" wire. The red wire was spliced in, and the splice was disconnected. What are the extra two wires for? Is this factory? If one of them is getting too hot, is it the wrong gauge?
I want to convert the system to electronic (Pertrtonix). They have many products, so I am not sure what I should use (I am going to call them). My thought is a stock looking distributor and Flamethrower coil, and changing the spark plugs and wires while I am at it (they are probably at least 20 yrs old with about 15-20k miles on them).
As I look at the coil, there are four wires connected to the two terminals. On one side, a black wire that I assume to be the ground. On the other, there are three wires, two black and one red. One of the black wires was the "smoking" wire. The red wire was spliced in, and the splice was disconnected. What are the extra two wires for? Is this factory? If one of them is getting too hot, is it the wrong gauge?
Tech Contributor
Joined: Jun 2004
Posts: 20,905
Likes: 962
From: I tend to be leery of any guy who doesn't own a chainsaw or a handgun.
I have a 1972 Base Coupe. I am having an issue where the car stops running while driving, and I believe it is the coil getting too hot. I originally thought it might be vapor lock, so I insulated the fuel line. I don't think that was the problem. The last time it happened, the wire to the coil was smoking hot (literally smoking), and the coil was very hot. After about 15 min, the car started back up.
I want to convert the system to electronic (Pertrtonix). They have many products, so I am not sure what I should use (I am going to call them). My thought is a stock looking distributor and Flamethrower coil, and changing the spark plugs and wires while I am at it (they are probably at least 20 yrs old with about 15-20k miles on them).
As I look at the coil, there are four wires connected to the two terminals. On one side, a black wire that I assume to be the ground. On the other, there are three wires, two black and one red. One of the black wires was the "smoking" wire. The red wire was spliced in, and the splice was disconnected. What are the extra two wires for? Is this factory? If one of them is getting too hot, is it the wrong gauge?
I want to convert the system to electronic (Pertrtonix). They have many products, so I am not sure what I should use (I am going to call them). My thought is a stock looking distributor and Flamethrower coil, and changing the spark plugs and wires while I am at it (they are probably at least 20 yrs old with about 15-20k miles on them).
As I look at the coil, there are four wires connected to the two terminals. On one side, a black wire that I assume to be the ground. On the other, there are three wires, two black and one red. One of the black wires was the "smoking" wire. The red wire was spliced in, and the splice was disconnected. What are the extra two wires for? Is this factory? If one of them is getting too hot, is it the wrong gauge?
I would disconnect the three wires off the coil C+ terminal and see if and when they are electrically hot. One of the wires (from the starter solenoid) should be hot only when the engine is being cranked, another wire should be hot (and current limited by internal resistance) when the key is on (and cranking IIRC). The third wire you have is a mystery. If it's hot all the time, or hot with the key on (but no resistance) that additional wire will try to cook your coil.
Let us know what you find there.
Race Director
Joined: May 2006
Posts: 18,729
Likes: 2,579
What you are describing on the coil is not factory.
Have you removed the distributor cap to see if someone has previously converted to an electronic module?
The coil has a negative and positive terminal.
The negative terminal has a single wire going to the points in the distributor.
The positive terminal has a double wire with a single U shaped connector. There also maybe a radio noise suppression capacitor on the coil.
Have you removed the distributor cap to see if someone has previously converted to an electronic module?
The coil has a negative and positive terminal.
The negative terminal has a single wire going to the points in the distributor.
The positive terminal has a double wire with a single U shaped connector. There also maybe a radio noise suppression capacitor on the coil.
Thread Starter
Intermediate
Joined: Feb 2025
Posts: 45
Likes: 4
From: Pittsburgh, PA
Here is a pic. It does not really show much. The two wires that have blue collars were on a terminal that looks like the other one in the picture. The wires were bare for a few inches, so I cut them off and put new ends on them.
I will try the things suggested above. Thank you.
Race Director
Joined: May 2006
Posts: 18,729
Likes: 2,579
Here is a pic. It does not really show much. The two wires that have blue collars were on a terminal that looks like the other one in the picture. The wires were bare for a few inches, so I cut them off and put new ends on them.
I will try the things suggested above. Thank you.
One of the wires is obviously the radio suppression capacitor.
Thread Starter
Intermediate
Joined: Feb 2025
Posts: 45
Likes: 4
From: Pittsburgh, PA
I did have the shielding off, but I have not taken the cap off. I will do that the next time I get to the car (it is in storage nearby). Which wire would be the radio suppression capacitor? The second black one?
Race Director
Joined: May 2006
Posts: 18,729
Likes: 2,579
Do you see the cylindrical object screwed onto the coil clamp, that's the capacitor.
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Melting Slicks
Joined: Sep 2006
Posts: 2,814
Likes: 469
From: Wichita Kansas
I thought there was a wire to the coil that has like, a cloth covering? Anyway, I think when I put my Petronix II on, I did away with that wire (I think). Was it a resistance wire or something like that?
Thread Starter
Intermediate
Joined: Feb 2025
Posts: 45
Likes: 4
From: Pittsburgh, PA
As I read more about it, I believe I will be able to eliminate one of the wires. When you did your conversion, did you install a new distributor? If you did, which one? The billet ones are 1-1.5 in taller than stock, and I am curious if I can still put the shield back on it.
Tech Contributor
Joined: Aug 1999
Posts: 14,379
Likes: 6,390
From: At my Bar drinking and wrenching in Lafayette Colorado
I think that trying to fix your problem by installing an inferior aftermarket system is a really bad idea. Someone has obviously done a bunch of really bad work to your car. Identify the bad work, and set the system up correctly using correct parts properly hooked up. A good quality set of points in a properly tuned stock distributor will meet or beat the performance of any aftermarket setup in a street driven car. And it will be reliable.
:Lars
:Lars
Thread Starter
Intermediate
Joined: Feb 2025
Posts: 45
Likes: 4
From: Pittsburgh, PA
It appears that I just need a new coil with the stock points setup (after the above discussion and consulting with my local SBC guru). I am pretty sure the coil is overheating, and everything else is running well.
Question: will an MSD Blaster 1 or 2 work with a standard points setup? What is the difference between the two coils? What about a Pertronix Flamethrower I or II? Any other recommendations? I may go to an electronic ignition setup later down the road, but mostly I want to reliable coil that will work with my current setup. If I can use it later on an electronic setup, that is a bonus
Question: will an MSD Blaster 1 or 2 work with a standard points setup? What is the difference between the two coils? What about a Pertronix Flamethrower I or II? Any other recommendations? I may go to an electronic ignition setup later down the road, but mostly I want to reliable coil that will work with my current setup. If I can use it later on an electronic setup, that is a bonus
Race Director
Joined: May 2006
Posts: 18,729
Likes: 2,579
It appears that I just need a new coil with the stock points setup (after the above discussion and consulting with my local SBC guru). I am pretty sure the coil is overheating, and everything else is running well.
Question: will an MSD Blaster 1 or 2 work with a standard points setup? What is the difference between the two coils? What about a Pertronix Flamethrower I or II? Any other recommendations? I may go to an electronic ignition setup later down the road, but mostly I want to reliable coil that will work with my current setup. If I can use it later on an electronic setup, that is a bonus
Question: will an MSD Blaster 1 or 2 work with a standard points setup? What is the difference between the two coils? What about a Pertronix Flamethrower I or II? Any other recommendations? I may go to an electronic ignition setup later down the road, but mostly I want to reliable coil that will work with my current setup. If I can use it later on an electronic setup, that is a bonus
https://www.holley.com/products/igni...eet/parts/8203
Burning Brakes
Joined: Apr 2020
Posts: 789
Likes: 419
From: Western NY
I think that trying to fix your problem by installing an inferior aftermarket system is a really bad idea. Someone has obviously done a bunch of really bad work to your car. Identify the bad work, and set the system up correctly using correct parts properly hooked up. A good quality set of points in a properly tuned stock distributor will meet or beat the performance of any aftermarket setup in a street driven car. And it will be reliable.
:Lars
:Lars
Pat