Bad alternator? [Archive] - Chevelle Tech

: Bad alternator?


bistledink
Feb 6th, 00, 7:56 PM
Well I just replaced my alternator, and I noticed a few differences in my '70. First off, the "generator" light is no longer on when the key is turned to accessories, and for some reason my battery is dead, which leads me to believe the culprit must be the alternator. It's brand-spankin new, so I must be the one at fault. My question is this: What can you guys tell me about this "Alternator Death" I've heard about, and please don't tell me that I screwed myself and I need yet another alternator.

72chevelle350TH350
Feb 6th, 00, 8:15 PM
All that comes to mind is this:

Does the ALT have an internal regulator?
Is the stock "black box" regulator still in use?

Any curious wire mismatches when you hooked it up?

A "search" may help matters....

------------------
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rick
Feb 6th, 00, 9:01 PM
bd
Why did you change alternators? Was the battery dead B4 you changed it? Did anything NOT match up when you were doing the install? Its not much work to remove the alternator and take it to be checked where you bought it. Also year may be helpful.
rick

bistledink
Feb 6th, 00, 9:37 PM
72chev,

The alt is an external regulator (The guys at autozone said my year would have an external), and as far as I know, the regulator is stock. There was, however, a wire mix up: After i had set the alt in and tightened the belt etc, i was reconnecting the neg battery terminal, and i got a big spark show, so I switched the only two wires there were and voila, no more sparks.

rick,

i took the old alt and had it tested, it was FUBAR. The battery was not dead when I changed it. The only thing that didn't match up was the connector on the back. They gave me a replacement one that would fit it.

Bret
Feb 6th, 00, 10:32 PM
Is this a 70 or 72 your posts shows 2 different years. it sounds like you have the wrong alt. If you look through the case in the rear of alt. int, regulated alt have a heat sink on the diod trio.the heat sink has fins for cooling int. parts. ext. regulated do not. I ran into this on a 72 chevelle, this seams to be the break between int. or ext regulated. the alt must look exact. not just terminals and plugs but look at back inside case for heat sink. If you have to change anything plugs etc. there is something wrong. most likely wrong part.By the way you should change regulator at same time.

Coppertop
Feb 7th, 00, 8:33 AM
If you have a voltmeter, you can check the alternator yourself.

Start the car, and while the engine is running, place the positive lead of the voltmeter to the positive terminal on the battery and the negative lead to the negative terminal on the battery. You should get a reading of about 14 volts.

bistledink
Feb 7th, 00, 9:33 AM
Bret,
When I said 72chev on my second post, I was just answering 72chevelle350th350's question. Mine is a '70. I compared the 2 alts at autozone, and everything was exact except for the plug on the back. Mine was too wide so they gave me a replacement one to install. I guess the next thing to do is test this alt and go buy another regulator.