Alternator Bearing Failure
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,204
Likes: 4
From: Midland Georgia
St. Jude Donor '06
Alternator Bearing Failure
A few weeks ago I had a bearing failure on my Alternator. It was a Paladium from Advanced Auto Parts. I returned it and got a store credit. I then took the original alternator to a local rebuilder whom I have used before. A week later and one trip to the drag strip and another failure... Basically the pulley collapsed back onto the body of the alternator. Wondering why two failures in the last two weeks in the same manner... Engine is modified but maybe 380-400 hp at the crank.
The engine has a new pulley, tensioner, Newer Turn One power steering pump, new serpentine belt. So everything is fresh but still problematic...
The car is a 94 LT1...
The engine has a new pulley, tensioner, Newer Turn One power steering pump, new serpentine belt. So everything is fresh but still problematic...
The car is a 94 LT1...
Last edited by jakers; Mar 25, 2008 at 07:51 PM.
Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
been there done that, the l98 design alternator is very rpm sensitive. what pully size you use needs to be set to the operating range of the motor. a stock auto car gently driven works great on the 1.9" pully, higher rpms need underdrive pullys to slow the damn thing down. this of course means you will have crappy charging at idle. the best thing i could come up with is to use a pully out of an underdrive set and buy a 200amp alternator. i still have good charging at idle and don't kill it with 6500-6700rpm shifts. BTW what rpm are you turning at shift?
Thread Starter
Melting Slicks
Joined: Feb 2005
Posts: 3,204
Likes: 4
From: Midland Georgia
St. Jude Donor '06
been there done that, the l98 design alternator is very rpm sensitive. what pully size you use needs to be set to the operating range of the motor. a stock auto car gently driven works great on the 1.9" pully, higher rpms need underdrive pullys to slow the damn thing down. this of course means you will have crappy charging at idle. the best thing i could come up with is to use a pully out of an underdrive set and buy a 200amp alternator. i still have good charging at idle and don't kill it with 6500-6700rpm shifts. BTW what rpm are you turning at shift?
Factory rev limiter is still in place at 5800 rpms.
Race Director
Joined: Jan 2008
Posts: 16,028
Likes: 170
From: oregon
with that rpm you should be fine with the stock pully. some of the re-mans are just plain crappy. In another post a fourm member pointed out that not everyone winds motors up. it was a very good point that reminds me to ask that question before i suggest anything. for the most part you want to use the smallest wheel you can without destroying the alternator. since you still have the factory rev limiter i would try a delco if you pony up or i remember finding a guy on ebay who rebuilt these with higher end bearings and parts. the other thing i was wondering is if you have any vibrations or play or if your belt is in allignment. what you described happening is honestly a first and this is comming from a guy who has liquidated at least 10 alternators before he figure out what worked. gotta love those lifetime replacements. i wonder what is putting so much pressure on it? the 92+ is even a better design than the 91 and earlier unit.
Last edited by racebum; Mar 25, 2008 at 08:29 PM.
Race Director
Joined: Sep 2003
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From: Database Error Indiana
A week after I got the Miniram, I Killed 2 lifetime alternators (rebuilt) from Advanced within 1 hour. First one was a bearing, 2nd exploded the little fan. Got a NEW one from the Zone and its been going strong since July.
Melting Slicks
Joined: Sep 2003
Posts: 2,270
Likes: 118
From: N. Babylon NY
I run an under driven pulley on my alt. (and crank) with no problems with charging. Car is also tracked a few times a year and each session is (approx) 20 minutes.
Car is a 1992 (stock) the pulleys are ASP.
Steve
Car is a 1992 (stock) the pulleys are ASP.
Steve
