After driving ~3.5 hours today in my '69 GS 400, I heard a hissing sound from underhood - turns out the Optima red top was getting a little bulgy and making the noise. A read of other posts indicates probable overcharging, which implicates the voltage regulator as the culprit. Now here's my question - the VR is mounted on the firewall, about 2 inches square, maybe, as I see it. It's to the left (looking at the car from the front back) of a smaller metal box, the purpose of which I have not yet determined. However, to what I surmise is the VR is also attached a (rusted) capacitor (or at least a one-wire metal cylinder). What's up with that? None of the replacement VRs I've seen include such an item. Any help, as usual, greatly appreciated. John
Without getting into the technical electrical engineering principles, capacitors were used to extend the life of mechanical points used in voltage regulators at that time and to suppress the noise that opening of the mechanical contacts would induce into the radio's audio. In essence it tends to dampen the electrical arc pulled across the gap when the points open. Less arc means the points surface does not erode as much plus you have less induced electromagnetic signal at freqencies that can be heard in the radio. New regulators do not use mechanical points. They use transitors to do the switching electrically. Therefore the need for the external capacitors was eliminated.
Thanks! So can I pitch it if I install a new one? Also, what's the little metal box to the right of the VR?
No-- I looked through many, many cars to find the correct date coded Delco covers and then refinished them. You still see them for sale in the sealed Delco containers on Ebay. At one time there was a guy in Florida that stocked oid electrical parts like this.
From Ames Pontiac for $20.00 there:https://secure.amesperf.com/qilan/Detail_Web?part_num=M241&order_number=2757478&web_access=Y
