Well, I replaced the alternator, and It's still not charging right. When the engine is cold, the alt works great. However, once it warms up it takes a nose dive towards no charge  ! This is the same way my previous alt behaved. I did a voltage check and the alt was not charging. I can't help to think there's something else causing this.

I've recently had the A/C controls, dash bulbs, switches etc fixed or replaced. My battery is an Ultima, all related contacts (battery, ground) are clean and tight. I also replaced the dash pad and added 2 new speakers. Am I looking to deep for a simple problem ? Can a crossed wire be causing my problem ?

It's not uncommon to get a bad alternator. Does yours have an internal regulator?

My suggestion is to test the alternator independent of the car. Autozone or an automotive electrical shop can strap it down and spin it up. You have to eliminate the alternator as the problem first.
Scott

It could be heat related inside the alternator, or outside the alternator in the wiring.  You may want to check the voltage to the alternator leads both when working, and when the voltage drops.  You may find a connection is losing contact when warm.

Thanks guys, I'll give it a try this weekend and let you know how I made out.

Another possibility is to check all the grounds for good contact. I'm reinstalling my BB in the 72, and have re terminated  all the ground lugs, as they looked questionable after 33 years.

I have also received 2 bad alternators in a row for a family ride, so its possible.

 

Good Luck

 

NJ BB Ken

 

It's done  The second alternator seems to have fixed the problem. I must admit the weather was cooler than expected, and may have an effect on the reading. I hope not !

Thanks guys