I recently purchased an 80 amp upgrade kit for my original 42 amp series 10SI 1970 alternator. Kit included new brushes/springs, voltage regulator, stator, and diode trio.

Installed everything, put it on the car, and had no voltage output at the lug. Installed a delco replacement alternator on the car and had plenty of juice. OK, so the problem lies within the original upgraded alternator.

Took that 80 amp upgraded alternator to Autozone where they tested it on their machine which indicated bad diodes. So, I searched their GM database and found another application having 80 amp diodes ('79 caddy). Installed the new diodes right there while at Autozone, put it back on their machine and, sunnova-beach, bad diode indication AGAIN.

Here are my questions:

1) I reused the original rectifier bridge from the 42 amp original guts in the new 80 amp guts. I understand after reading the factory service manual that the rectifier also has diodes in it. Could this rectifier be my problem? Should I upgrade it to one that is rated for the 80 amp alternator?

2) New stator checks out ok. Could the rotor be bad?

3) I'm 99% certain I have all the insulating washers in the correct locations, but if I don't could that be my problem?

Somebody point me in the right direction. There aren't that many parts to troubleshoot, just thought someone could save me some time.

Thanks in advance.

 

3) I'm 99% certain I have all the insulating washers in the correct locations, but if I don't could that be my problem?


I would double check this. I had no output on my alternator and it turned out that I had one of the insulators in the wrong place. Also make sure that they are not cracked or broken.

 

ttt