Hot Coil

[pbc]

Hello could someone please help me out i have a 41 ford i just rebuilt a 59ab it runs great i converted to 12 volts neg ground i am now running a gm altinator i have tried a coil with a internal resister and external resister coil with the ballast resister please excuse my spelling my wiring is simple wire on coil side of ignition to pos of coil and neg to points with new condenser i can not remember the part no. of the ballast resister but i am getting around 5 volts on one side and 10 on the other side why would the coil be getting hot this coil gets hot to a burn car runs great till it gets hot then dies it will start after it cools down thanks paul

[WestCoast]

you only need one resister either a coil that is internally resisted or a coil that is externally resisted, not both

[pbc]

yes i have tried both ways i have tried just the internal got hot then tried external with ballast resister and got hot when i run the the internal coil i am not using a ballast resister

[BUBBAS IGNITION]

You didnt mention what coil you were using. Many coils are made very cheap and often have incorrect resistances causing the heat build up you decribe.
What ignition distributor are you running??
I would suggest running the Bosch blue # 0012 , its a stand alone coil with 3 ohms resistance internal to the windings. No resistor is need, can be purchased from Amazon.com

[JM 35 Sedan]

As Bubbas (Jim) said, you didn't mention which distributor or coil you are using on your 59 engine in a '41. It's tough to try to help someone with a problem when only half of the important information is given.

[JonC]

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I just went through your issue, (12V neg ground and a 1 wire Alternator) Bubba explained it to me when I called frantic after I burn't up the first coil, and this is how mine works now: a 1.5 ohm internal resistor coil and a ballast resistor from a dodge car from the 70's wired to drop the voltage to the coil ( I used a dodge dart) now every thing works fine.

[Walt Dupont--Me.]

Originally Posted by BUBBAS IGNITION

You didnt mention what coil you were using. Many coils are made very cheap and often have incorrect resistances causing the heat build up you decribe.
What ignition distributor are you running??
I would suggest running the Bosch blue # 0012 , its a stand alone coil with 3 ohms resistance internal to the windings. No resistor is need, can be purchased from Amazon.com

Hey Bubba, I think that Bosch coil is no. 00012 not 0012 I had quite a job finding it on Amason. The price is right and don't need a resistor. Walt

[ford38v8]

Originally Posted by pbc

...Their is one more thing I am going to try the gauge of my wire I am using might be to much I will be changing it. ... thanks paul

Paul, A reduction in wire gauge can certainly reduce the voltage by offering increased resistance, but the resulting heat produced by such action can also reduce your car to a pile of ashes! I would start by determining the exact requirements of the coil you are using, then arive at that voltage by conventional means.

[pbc]

Alan I have tried internals and externals with a ballast resister . I have heated them all up to where they are no good as jonc mentioned I will find a 1.5 ohm coil . what I do not understand he is running a coil with a internal resister and a ballast resister?

[ford38v8]

Paul, You have a 12 volt system, do you have a 12 volt coil or a 6 volt coil? If a 6 volt, it only wants to see 3 to 4 volts maximum. As I said, I don't know much about electrics, but I heard that name Bubba mentioned, so I'd go with what he told JonC.

[pbc]

Alan i was told a 6 volt coil may work i had one it turned up missing . The advice i have been given will be a coil between 1.5 and 3 ohms. i will price them when i get it i will let you know how i did thank you for your help paul

[BUBBAS IGNITION]

Originally Posted by pbc

Alan I have tried internals and externals with a ballast resister . I have heated them all up to where they are no good as jonc mentioned I will find a 1.5 ohm coil . what I do not understand he is running a coil with a internal resister and a ballast resister?

The logic here is by splitting the resistance the wattage or heat is split. System still has the correct current flow but voltage is dropped in each unit.
The oems have done it that way for years.......

[G.M.]

Originally Posted by pbc

yes i have tried both ways i have tried just the internal got hot then tried external with ballast resister and got hot when i run the the internal coil i am not using a ballast resister

Why don't you send a stock coil to Skip and have him wind it for 12 volts
NEG ground. Install it using a late 50's large white resistor and your problem is gone "forever". I it falls other than leaving the ignition switch
on he will repair it at no charge. G.M.