Mr Fufu

There's a capacitor in a metal bracket attached to the voltage regulator on my '67 small block car . This looks like in the photo below.

I somehow broke the black wire that connects the rcapacitor to the regulator, right where it goes into the capacitor, so I can't splice the wire to fix it.

My questions are:

1. What's the purpose of this capacitor? Has it something to do with reducing radio interference? My car has the stock AM/FM radio.
2. Is there any danger in running the car without this capacitor hooked up?
3. How do I fix the broken wire? Is there a way to reattach it to the capacitor?
4. Is this an easily found part at NAPA or similar? Or will I need to order one from a Corvette supplier?

Photo credit goes to Leif Anderson - I snipped this picture from one of his 2019 hposts!

Thanks,

Frankie the Fink

You can buy reproductions (not at NAPA), it won't be exactly like the original:

https://www.ecklerscorvette.com/corv...All%20Products

After 60 years its not doing anything anyway but it USED to serve for radio AM band noise suppression; there are 10,000 of these cars running around with non-functional capacitors that don't even know it - won't hurt a thing. You can take some clear epoxy and tack that lead back onto the capacitor just for looks. Some will tell you if the capacitor is shorted putting the lead back in any fashion can be a problem if its shorted. Trust me, capacitors almost never short, nearly always "open", if shorted, you'd know before now.

If it worries you, check the resistance from the lead to the case with an ohmmeter on a low scale before re-installing. It will read infinity....

dplotkin

I'm bored and cannot help myself from adding to Frank's good answer. Electric sparks, the blue kind you can see at spark plug electrodes or at the end of your finger when touching a metal object on a dry winter day create radio waves in the same frequency as the AM radio band of between say 560 to 1600 Khz. Mechanical contact voltage regulators, ignition points, generator commutators and their brushes as well as switches create sparks in normal operation. AM radio design through the 1960's was prior to technology that could discriminate between the radio waves caused by the sparks and the radio waves coming from the radio station. The capacitor traps this noise and drains it to ground before it gets in the RF section of the radio. Fewer of these capacitors were used in other cars but a Corvette with its plastic body required them everywhere to keep the AM band quiet. As Frank mentions the capacitors are of little value unless you rely on the use of the AM band of your original radio. Newer radios have built in filters to deal with RF interference.

Dan

Frankie the Fink

Folks also think the points in a “vibrating points” regulator are either connected or disconnected on some low duty cycle when they can actually “vibrate” 120 times a second.

Mr Fufu

Thanks Frankie and Dan!

Glad to hear the capacitor is (mostly) now ornamental. I'll glue the lead back on with epoxy and carry on!

Cheers,
Alex

Mr Fufu

I epoxied the broken wire on my radio suppression capacitor last night.

I rigged up an old apple slice to hold the wire in place while the glue set. Worked like a charm!