Well I finally got my 68 back on the road with an entirely new stereo, Covan's dash, and Autometer guages. Also a lot of electrical system rework and upgrading including headlight relays and a CS-130 alternator.

Anyways I have figured out a couple of startup gremlins, have not blown any fuses, and everything seems to be working as expected to a point...

The problem is that I occasionally see momentary voltage drops significant enough to cause the radio to reset (power up again). These can also be associated with all of the electrical guages going wacky as well. The drops seem to correlate with road vibrations: hit a bump and see an electrical bounce. Run down the botts dots and watch the needles keep bouncing around.

After one of these bounces the system voltage seems to be lower as well. At startup when cold I see about 14.2 volts at the fusepanel battery post. When warm this drops to the 13.8 range and after a dropout it stays around 13.3 and may gradually return to the 13.8 range or maybe even 14.1 idling at the next stoplight.

It seems to be worse when warm or with an electrical load like the headlights.

The alternator tested fine on the machine at Autozone, but I don't know if I either trust or believe the test.

I have not been able to get a twitch by wiggling any wires or tapping anything.

My buddy keeps talking short, but I have a hard time fitting that into the problem not blowing any fuses. After all the alternator should put out over 100A and I have a 60A maxi-fuse in the main fusepanel feed path. I also keep thinking that the alternator should respond to a demand increase like that very fast, no? At least fast enough to not see a voltage guage needle move let alone bounce?

I keep thinking an open but am running out of places that could be opening up. All of the connections in these circuits have been soldered along with crimping. One that I do wonder about is the alternator ground with painted brackets (albeit scraped up by installation)...

Anyone seen this type of thing before or otherwise have suggestions?

Thanks,
Steve

Have you made sure the ground is securely attached, and both battery connections are tight? I know this is pretty academic, but I have seen time and time again the ground was/is loose or a loose connection at the battery or starter.

You may want to spend $20.00 and grap another CS alternator at the pick-a-part junkyard. Doesn't need to be as high as the one you have. Just needed for test purposes.
Get that tested and install that one for awhile. See if the problem disappers.

maybe it is just a cracked cable or some , i read you soldered some parts , it's possible if you bonded the wiring by tape ore by krimping , it's bonded to hard and the cable might get to stiff and so reacts on shocks!

Hmmm, no fuses blown yet.....I have to go with pops on the ground or cables. All belts tight?

Actually the diagnosis of this problem has moved to a back burner for a while... bigger fish turned up in the form of a cylinder with **no** compression. So once I get the new motor built and installed, then I will get back to figuring out this one.

One idea I am puzzling over is the CS-130 wiring. Right now I have the resistor hooked up to the indicator light terminal (forget off the top of my head which letter that is). Ran across an alternative wiring setup on the web showing direct 12v into the other terminal. I am considering trying that setup.

First I think I will unwire the alternator and go run down the Botts Dots and see how it behaves. If no voltage drop, then at least I have it isolated to the alternator or attached wiring. If there is still a voltage drop than I better find a padded cell to beat my head against 8O