Hot Coil, Anyone? 53 Ford F100, 6volt Pos Ground - recently replaced the coil, and it's getting very hot - just sitting with the ignition key turned on (engine not running).
I had a shorted primary wire (touching the distributor body) and was getting no spark, but found, and isolated the wire connection. In the process, I replaced the coil, with a 6V coil (marked on the top) from local Autozone. I started the truck up, but it died pretty quickly (timing/distributor need adjusting), and I left the ignition switch on for about an hour, and then touched the coil, and found that it was really hot (too hot to hold).
Do you think that the coil got shorted/ruined while the primary wire was shorted? I had tried to start the truck quite a few times with it like that, and the engine would turn over, but no spark, before I found the problem.
New 6v Battery, Positive Ground, new condensor, clean distributor cap - looks good. New wiring. *seems* to be in order... No voltage at coil terminal when ignition is off (as expected), and 6v when turned on (seems normal).

Thanks!

 

The coil normally only gets current flow intermittently as the points open and close. If the points were closed (which they probably were) or a wire in the distributor was grounded, the coil got continuous current for that hour. It is not rated for continuous current. That's why it got hot. That's normal. It is probably Ok unless you lost continunity between the + & - terminals.

 

As far as having no spark, maybe you burned up the points with leaving the key on for an hour. I have heard of people having this happen if the points are in the slightly open position and the electricity arcs. Maybe you can file and reset them or maybe new points are needed. They're cheap, so if you try a new set and that does not fix it, then you have a spare set to leave in the glove compartment for that day when you will be needing them. Jag

 

Hey, thanks for the "pointers". It turned out to be the primary wire grounding out on the inside of the distributor. There is an insulator on the outside, but nothing on the inside. It LOOKS like there may have been some kind of paper gasket inside, but it's 90% history... anyway, I found that I had continuity between the "+" on the coil and the distributor housing, and tracked it to there, and made a rubber insulator from a small piece of aquarium hose, and that seemed to do it! I got the extra set of points - good advice! RS, you are right, the coil WILL get hot with the key on like that also - Thanks for the help!

 

Early primary wires are braided and don't have a neoprene outer coat. First insulated primary wire: C1VY-12216-A = 1961.

 

Thanks Numberdummy. I wound up using a 10 gauge insulated wire from the coil to the distributor, and also, inside the distributor. Seems to be working ok. I might go ahead and buy the coil to distributor wire, in hopes of keeping it as original as possible. Thanks for the help!