Location: Lexington, KY
Posts: 218
My VIN: 16655
After a good bit of looking elsewhere in trying to diagnose my issue with the car running like crap (enough so that I was convinced its cat was clogged...), I think I may have found the problem...
CIMG0161.jpg
Unless I'm really out of it, a) the spring in the middle is supposed to be straight and b) there's supposed to be a contact 'button' on top of the spring...
Location: Leonardtown, MD
Posts: 9,004
My VIN: 03572
That is definitely going to cause some problems. That carbon button is probably coating the inside of the cap.
Location: North GA
Posts: 6,176
Club(s): (SEDOC) (DCUK)
After the initial shock, I bet you were 'grinnin like a jackass chewing on a saw briar'.
Location: South Texas
Posts: 849
.
Congratulations, you found one of your problems!
Supposed to look like this:
Originally Posted by Ashyukun
Location: Lexington, KY
Posts: 218
My VIN: 16655
Yeah, I couldn't find any sign of it. However, at least I now have a much better lead on what the problem is (though I don't know WHY it happened, which is worrisome...). I'd rather it be something simple that I can easily fix (even if it does essentially mean ordering a new cap) than something more nebulous, like an issue in the wiring...
Location: Leonardtown, MD
Posts: 9,004
My VIN: 03572
Are you running a stock coil?
Location: North GA
Posts: 6,176
Club(s): (SEDOC) (DCUK)
The most common cause of this is simply wear, followed by a coil or plug wire not seated (on either end), excessive plug gap(s), or break in plug wire core(s) -- If you add or increase a gap, you increase the resistance and therefore the voltage. Significantly increasing the voltage through the carbon button overheats it and causes it to break down and/or melt.
Location: Lexington, KY
Posts: 218
My VIN: 16655
I'm running a HEI coil with a modified resistor pack to put more power to the coil and increased plug gaps, which is somewhat standard for the carbureted D's like mine. I guess I'll just have to keep a close eye on the distributor cap, and maybe lower the gap on the plugs slightly...
Location: North GA
Posts: 6,176
Club(s): (SEDOC) (DCUK)
Before disturbing anything further, I'd check to make sure the coil and plug wires were seated and then pull and measure their resistance (I've found several bad out of the box) and if I didn't find anything, I'd do exactly what you said.
IF the wider gap is a main culprit:
Some low resistance wires might help a little (but can cause radio interference).
Bill once mentioned that he found a rotor button with a lower resistance (or ?maybe no resistor at all like other cars?)...that might help a lot!
I assume caps and rotors with higher ratings are unavailable for our cars.
...Dang domino effect!
Posts: 443
I had this happen to me before I was running HEI. Brand new cap, button disintegrated not long after installation. It was probably just a bad cap. If you see any other signs of damage I'd be wary but I wouldn't start replacing your ignition system yet.
Aka Adam S, aka Adam Wright
1981 DMC-12 #3416, mothballed in preparation for motor swap
2006 Volvo S60R
Reply With Quote
Dave M vin 03572
