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Hi everyone, My alternator on my 72 Cutlass Supreme went last night so while searching the web for a new one the is so many choices I don't know what to get. Should I up the amps? Any suggestions?
Hi Eric I don’t know how many amps it is. Its been in the car for over 15 years. My car is stock with a 350 with air. The only upgrade is a 200 r4 trans. I would like to do a headlight upgrade in the future.
ALL 1972 Oldsmobiles (including 442s and Toros) came from the factory with an external regulator. If it's stock, that's what you have. Non-A/C cars usually got 37 amp alternators, A/C cars got 55 or 63 amp depending on the other options. Be aware that 1972 cars may have come with the goofball 10DN alternators that actually used the SI style case and the flat two wire plug that makes them look like an internal regulator. Be sure you know what you have before ordering a new one.
Just out of curiosity, how do you know the problem is the alternator and not something else?
I put a tester on it when I got home. This is with the car running. I hope it's an alternator.
That's a battery tester. Where did you connect it? Even if the alternator put out nothing, that tester would read 12V or more on just the battery. If the battery is not charging, it could be a bad battery, it could be a bad alternator, it could be a bad voltage regulator, it could be bad cables, it could be a slipping belt, or it could be corroded connections. You MIGHT want to try more detailed troubleshooting before potentially wasting time and money on replacing the alternator.
I connected to the battery cables with the engine running. The battery is fairly new 2 months. The wire that connects to the battery post on the alternator is a little greenish. Is there a thread on the steps that I should take to diagnose the problem? Thanks again.
Is there a box on the firewall that looks like this?
Take it, the alternator, and the battery and get them tested before your start spending money. The wire/s that have green ends need to be replaced or cut back to where there is no corrosion if possible.
The 1102844 alt dated 8D6 is for a 1978 diesel truck. In 79 that number was used on Olds and Pontiacs. It is a 10SI internal, but like Joe said show a pic of the plug or the part of the alternator that the plug goes in. If it was rebuilt it may have been rebuilt with the transition rear case making it a 10 DN using an external regulator.
This is the money shot. You have one of the oddball "transition" alternators that have the 10DN external regulator guts in a 10SI internal regulator case.
Ok, I’m going to buy a new one so which one do I get? Is it a one wire? Will this fit? (Alternator, Performance, Silver Bullet, High Amp, GM 10si Case Style, 12 V, 100 Amps, Natural, V-Belt,). I looked at all the big part store websites and I can’t find any with external regulator in the description.
Last edited by Townie; June 16th, 2018 at 05:03 AM.
Reason: Description
Mine is this one, which is now discontinued. Performance tag said 51 amps at idle and 82 amps at cruise. Very happy with it's performance. https://www.summitracing.com/parts/SUM-812102
I see they now offer this with the same 80 amp rating. https://www.summitracing.com/int/par...2112/overview/
They probably made the change, which matches your current alternator that uses the common 10si chrome case, a very poor choice for 100+ amp alternators. The only chrome 10si alternator that lasted more than a couple of years for me was a 100 amp alternator that put out 70 or 80 amps, like this one. Why the aftermarket didn't use the 12si case and fan is beyond me, it was designed for higher amp output.
Last edited by olds 307 and 403; June 16th, 2018 at 06:21 AM.
Have you done the troubleshooting recommended above, or are you just going to throw money at a replacement alternator and hope that is your trouble?
I had the battery load tested but I’m buying a new alternator, cables and regulator. It sounds like grinding metal when I spin the alternator. I need to know what alternator to purchase.
Have you looked for a local rebuild shop in your area? I know they are few and far theses days but they are still out there. They usually are less expensive and can test or give you advice on what issues you have.
Also get the new solid state external regulator. Transfer the OEM cover over to the solid state reg so it looks OEM. And clean ALL of your grounds ALL.
Thanks for all the help and advice. I ended up getting a Power master chrome alternator 25% off at P Boys today and it sounds great. No more regulator on the firewall and it’s charging at a little over 14 volts at idle ant just under in gear with everything on. What a difference. I see a new harness in my future.
June 15th, 2018, 08:18 AM
