Another new one on me...

J

JayJay

Well-known member
It seems that as time goes by, the amount of new stuff that I realize I don't know outpaces the new stuff that I learn. Here is an example.

This coil wire came off my '31 Town Sedan, the same one that I have complained about here regarding the omissions/shortcuts/kludges and just plain WRONG things I've found. I knew all along that this had a non-standard (e.g., braided copper center conductor) coil wire, but as long as it worked, it wasn't high on my priority list to replace. Well, today I was futzing around with the terminal box, and when I pulled the coil wire out of the bottom of the coil, this is what I found. Coil end is very swollen, and the swelling tapers down to about halfway down the wire until the insulation jacket remains intact. No signs of external burn. Seems pretty clear to me that it got internally hot - really hot! - sometime in the last year (I believe I had it off last summer when I put the new engine in). I don't know why this particular wire was there, perhaps since the previous owner had a CB and an AM radio in the car this was an attempt at RF suppression? Anyone ever seen this? (The swollen end is the coil end).

The car runs fine, even when I put this wire back in to move the car into the garage.

thanks.
 

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The "modern" coil wires, that are designed to suppress radio interference, have a resistor core made up of paper and carbon. They do wear out. The current is not enough to heat the core, but if it develops gaps it could start sparking internally, which could heat it.
 
The electrons are leaking from the coil when your car is parked, replace the wire and go for a long drive Enjoy the ride ! If you mount the coil with the high tension up maybe the electrons won’t leak out ;-)
 
The wire says 5mm metallic conductor which broadcasts your ignition throughout the neighborhood. Never seen one swell like that, something wrong. Replace it.
 
Good enough, all, thanks for the input. Never a question that I was going to replace it. I had a square body Chevy pickup long ago that had bad coil/plug wires, they jumped a spark from the wire to whatever part of the engine was closest. At night the engine compartment was like a lightning storm! I checked and could not see any signs of arcing from this wire. One of life’s little Model A mysteries, I guess.
 
if the electrons are truly leaking out- as big hammer says........


just cover it in duct tape.


problem solved!
 
So I went up to my local NAPA store and asked them to put together a 12" plug/coil wire for me. Custom spark plug wires, good auto parts store, used to be a standard service. The owner laughed at me, said that maybe 30 years ago? Anyhow, he found one in the Belden catalogue and got it in for me yesterday afternoon. I drove the car there to pick it up.

Funny thing, with the old gnarly wire in before I swapped it out in the parts house parking lot, every Tesla I passed stopped dead in its tracks. (That's a joke, son).

I have a full set of RF suppression coil wire, plug wire and newer style cap from Snyders that's supposed to get here today.
 
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