Hot coil

[Bill pilot99]

Has anyone had a coil bolw up ? I left the ign on for a hour with the engine

off, came back home to find oil under the ole B4B.

The coil blew up and parts of it were burning.

I had changed over to 12 volts and changed the coil, a couple of weeks before, used a coil off a slant six it was 12 volt.

Put another coil on and left the ign on for a while and it got hot. Starts and runs fine.

[Don Coatney]

Guess I must ask why you left the ignition on? Normally when the ignition is left on the points fry. Your points must have fused and taken the coil out too. When an electrical connection is left energised with no place to go something must give. Your coil was what "gave". You are lucky there was no fire and you still have a truck.

Did you install a ballast resistor to cut the coil voltage back to 6 volts?

[Bill pilot99]

No I used a 12 volt coil, the books say the pionts and all are fine with 12 volts, they may be wrong.

[greg g]

Most 12 volt system incorporate a resister in the wire feeding the coil. Some have provisions (like the ford 4 post solenoid) to provide 12 volts for starting, but then go to a resisted circuit when the key is released to the run position.

Think you got lucky and only fired the coil not the garage truck and house. Take Don;s advice and change the points also. If the coil over heated, the points wer closed with the ign on and they are probably toast also. A coli will be warm during engien on operations, due to the resistance of the many winding of fine wire within. The oil in the coil is for cooling. Usually the first sign of a coil going bad is it is over warm to the touch and or dripping oil. You should be able to comfortably hold on to a good coil while the engine is running.

[Bill pilot99]

Thanks for the info, going to get a resistor !

[Bill pilot99]

If you want a cool coil, put a $4 resistor in front of it !

Thanks to all on the Chat and Forum !

Coil is cool and truck runs fine .

Love this forum !

[Merle Coggins]

Cool (no pun intended)

Glad it worked out for you.

[norrism1]

Bill, The old 225 slant 6 used a 2 wire resistor block for the coil in the early models. Might be what you need. Won't hurt to check the specs to find out.