1985 Alternator Help
Thread Starter
Racer
Joined: Jul 2009
Posts: 454
Likes: 0
From: None None
1985 Alternator Help
Hi, I have a 1985 L98 and just before I put it into storage I noticed that the battery volts were dropping to about 11 at idle. If I gave it gas the volts would rise but then fall again as soon as I let off the throttle. Im assuming that this is an alternator problem as my headlights have been flickering a bit lately as well as the dash. Also, the battery is brand new (that got replaced diagnosing a bad starter which is a whole other story). So basically what Im asking is do others agree that this is a bad alternator? Also, what should I get for a replacement. Is there anything special or will a PepBoys or Autozone deal work just as well.
Thanks for the advice
Thanks for the advice
Le Mans Master
Joined: May 1999
Posts: 6,514
Likes: 1,301
From: Windermere FL
Let me suggest that if you do get a replacement, consider PowerMaster alternators. I went through MANY alternators from Pep Boys and the other national parts stores. They never lasted very long. Even though some had a lifetime warranty, it get's old replacing them for your whole life! PowerMaster really hold up.
Racer
Joined: Apr 2006
Posts: 327
Likes: 0
From: edgerton WI
If you don't have the tools to test it , most of the stores do. I suggest getting one with a lifetime warranty. I had to change one every year and a half on my 84 before I got a good one from Auto Zone. 4th time was the charm for that one.
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
If your alternator has normal idle rpm and no unusually high electrical loads, then your alternator definitely is defective. Normal idle with normal electrical load, you should measure 14.7 volts at the alternator output terminal, alternator cold and this drops to 13.7 volts when the alternator gets to its normal operating temperature.
Also, a battery with 11 volts is a badly discharged battery and should be charged up overnight or longer with a battery charger.
Also, a battery with 11 volts is a badly discharged battery and should be charged up overnight or longer with a battery charger.
Safety Car
Joined: Nov 2009
Posts: 3,973
Likes: 341
From: Adelaide South Australia
Howdy Bucs34, I had the alternator go in a similiar way on my 85, it ended up being the rectifier inside, I took it to the auto electrician, had it rebuilt with a new rectifier and new bearings, got the housing chromed while it was apart, its run flawlessly since then.
The original Delco Remy's will run great with a bit of a freshen up !
The original Delco Remy's will run great with a bit of a freshen up !
Thread Starter
Racer
Joined: Jul 2009
Posts: 454
Likes: 0
From: None None
Thanks for the input so far! Based on what Ive read my car either has a 108 or 120 amp alternator. Im wondering if replacing it with a 140 amp powermaster (or an equivilent) from summit would damage anything?
Thread Starter
Racer
Joined: Jul 2009
Posts: 454
Likes: 0
From: None None
Heres a link to the powermaster for reference.
http://www.summitracing.com/parts/PWM-47294/?rtype=10
http://www.summitracing.com/parts/PWM-47294/?rtype=10
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Race Director
Joined: Jun 1999
Posts: 14,924
Likes: 9
From: Merritt Ils Fl
I am wondering why you need 140 amps unless you are hauling a very big audio system. I agree with blackoz, take it to a local auto electrical shop and have it rebuilt. Should cost about half the price of one from a retailer. If you are reasonably good with tools your alternator is very simple to rebuild. Takes about two beers time to off-rebuild-on. Kits are available from multiple sources.
