Do all GM alternators interchange?
Thread Starter
Pro
Joined: May 1999
Posts: 521
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From: Garland Texas
Do all GM alternators interchange?
I need to know if the mounting holes are the same distance apart
on all GM
alternators.I have a 63 amp on my 68 and it should be a 37 amp.My
problem is the belt tension slot does not line up with a p/s bracket I
am installing.
on all GM
alternators.I have a 63 amp on my 68 and it should be a 37 amp.My
problem is the belt tension slot does not line up with a p/s bracket I
am installing.
Team Owner
Joined: May 2001
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
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St. Jude Donor '06-'10, '13
Re: Do all GM alternators interchange? (Tahos)
I know that most generic GM cars used the 10SI alternator.
But my 1980 uses the 15 SI which is a much bigger alternator.
Don't know about the early C3's
But my 1980 uses the 15 SI which is a much bigger alternator.
Don't know about the early C3's
Le Mans Master
Joined: Sep 2000
Posts: 5,635
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From: Orlando Floriduh
Re: Do all GM alternators interchange? (Tahos)
No. Not all GM alternators are alike. Corvettes have smaller crankshaft pulley's so the alternators turn slower... A Chevy alternator may look the same and most rebuilders list them the same. In use they work fine at engine speeds above 1100-1200 but do not put out enough at low speed with everythig on. At idle with the A/C on and wipers and lights on, there is a good chance that the "generic" alternators may not keep up with demands.
Instructor
Joined: Jul 2001
Posts: 168
Likes: 4
From: central Washington state
Re: Do all GM alternators interchange? (Tahos)
Tahos;
Sounds to me as if your problem may lie with the bracket rather than the alternator. To the best of my knowledge, there is no difference in the spacing of the mounting holes between a 37 and a 63 amp alternator case, as long as they're fairly close to the same vintage. I also know from personal experience that small block bracketry is (or certainly can be) a miasma. Is it possible that the power steering bracket might be mispositioned? It's an easy thing to do. Ask me how I know!
Sounds to me as if your problem may lie with the bracket rather than the alternator. To the best of my knowledge, there is no difference in the spacing of the mounting holes between a 37 and a 63 amp alternator case, as long as they're fairly close to the same vintage. I also know from personal experience that small block bracketry is (or certainly can be) a miasma. Is it possible that the power steering bracket might be mispositioned? It's an easy thing to do. Ask me how I know!
