1957. Hot coil

[valhalla 4771]

Project car has sat a few months. I’m in the process of rewiring everything. Just put in the battery to get it running. Went to check engine compartment wiring before cranking the starter and found the coil was hot to the touch. Not warm….hot. I don’t recall this before I started deconstruction. Is this normal and if not what would cause it?

This page contains affiliate links for which I may be compensated. As an eBay Partner, and Amazon Associate I may be compensated if you make a purchase at no cost to you.

 

[JRH]

Project car has sat a few months. I’m in the process of rewiring everything. Just put in the battery to get it running. Went to check engine compartment wiring before cranking the starter and found the coil was hot to the touch. Not warm….hot. I don’t recall this before I started deconstruction. Is this normal and if not what would cause it?

I put a coil reducer from NAPA 13.00 a mechanic buddy of mine that told me 12 volts makes the coil too hot and eventually will burn out. This reduces the voltage to about 9v. Easy to do just splice it to the wire from the ignition to the coil.

 

[JRH]

I put a coil reducer from NAPA 13.00 a mechanic buddy of mine that told me 12 volts makes the coil too hot and eventually will burn out. This reduces the voltage to about 9v. Easy to do just splice it to the wire from the ignition to the coil.

P.S. I have a 55 converted to 12v

 

[Ward 57]

Isn't that the purpose of the coil resistor at least on the 57's and also reduce the voltage at the points so they don't burn.

 

[JRH]

Isn't that the purpose of the coil resistor at least on the 57's and also reduce the voltage at the points so they don't burn.

Maybe your resistor went south? I don't know what the ohm's are suppose to be sorry cant help there. Also I went with the Pertronics electronic IGN and a new coil.

 

[doug7740]

Since you have a 1957 Thunderbird it has a 12 volt system. There should be a 1.2 to 2.0 ohms resistor installed before the ignition coil. The purpose is to reduce the voltage to the coil after the car is started.

https://www.classictbird.com/Coil-R...h-FoMoCo-Logo-12-Volt-Cars/productinfo/12250/

doug7740
1955 Thunderbird Blue

 

[Calistoga T-Bird]

I've also installed Pertronics electronic IGN and coil, can't say enough about the positive effects (engine temp, idle, fuel mileage ). If you do go with Pertronics you should eliminate the Ignition Ballast Resistor.

 

[CSPIDY]

I've also installed Pertronics electronic IGN and coil, can't say enough about the positive effects (engine temp, idle, fuel mileage ). If you do go with Pertronics you should eliminate the Ignition Ballast Resistor.

Some pertronics units still use a resistor and the original resistor will work.
Perhaps your using a Pertronics II

 

[CSPIDY]

There shouldn’t be power at the coil with the ignition off
Recheck the wires to the coil and starter relay

 

[jack-in-sac]

Ford continued using 6 volt coils through the sixties. The 12 volt wiring initially had a ceramic ballast resitor and later an inline reducer With Pertronix you bypass the ballast resistor and use a true 12 volt coil

 

[rponfick]

Maybe your resistor went south? I don't know what the ohm's are suppose to be sorry cant help there. Also I went with the Pertronics electronic IGN and a new coil.

It was my understanding you did not use the resister with the Petronix ignition module????

 

[CSPIDY]

It was my understanding you did not use the resister with the Petronix ignition module????

As stated earlier, it depends on which pertronics unit you are using
Read the instructions to be sure.

 

[cscolastico]

I've also installed Pertronics electronic IGN and coil, can't say enough about the positive effects (engine temp, idle, fuel mileage ). If you do go with Pertronics you should eliminate the Ignition Ballast Resistor.

My 57 came with a pertonix II, with the resister by passed, but I left it on for looks.

 

[Calistoga T-Bird]

Per Pertronix: Pertronix I, if your ignition presently uses a ballast resistor, do not remove it.

I installed Pertronix II on my '57 and eliminated the resistor.

 

[DiIanni]

I have a 55 T-bird with a 6 volt system. Is it a good idea to convert the standards point system to a Petronix ignition system?

 

[Calistoga T-Bird]

Pertronix can and do work on both 6 & 12 volt systems. I'd suggest calling the Pertonix customer service & technical support to be sure they have one that works for your specific application. 909-599-5955

​