LT1-LT4 Modifications 1993-97 Gen II Small Block V8

harmonic balancer fell off

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Old 10-26-2007, 10:42 AM
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Default harmonic balancer fell off

Yesterday I was driving and my harmonic balancer fell off. Im going to by an underdrive pulley to replace it. The problem is that the threads got stripped out (which we re-tapped). And the key lock is now smooth on the crank. I dont have money to buy a new crank, What else can be done to fix the problem?
Old 10-26-2007, 11:10 AM
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You cannot use an underdrive pulley alone. You must have a balancer of some sort on there to dampen the crankshaft harmonics. Not real sure how to repair the crank without removal however.
Old 10-26-2007, 11:24 AM
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Damn, I can't find the link. Someone listed a Dampener/Underdrive that was $160. You should be able to get a new key to replace your botched one. As far as the stripped threads, I assume you tapped it back to the original size. I just can't see how it would fall off like it did, kind of crazy.
Old 10-26-2007, 12:15 PM
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Originally Posted by Formula350
Damn, I can't find the link. Someone listed a Dampener/Underdrive that was $160. You should be able to get a new key to replace your botched one. As far as the stripped threads, I assume you tapped it back to the original size. I just can't see how it would fall off like it did, kind of crazy.
ya im not sure either, ive put 13k miles on since ive bought it.
Old 10-26-2007, 12:20 PM
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Yeah I guess you could get a key for it but I would think you would have to at least remove the timing cover. Would you just weld it on? Wouldn't it throw the balance off? How about the original key? Wouldn't the engine be full of metal now?
Old 10-26-2007, 12:25 PM
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Is this on an LT1? Your balancer is held on by three bolts and unless you damaged the hub I don't see why you can't just tap the holes and put a new one on. LT1 crank isn't keyed, the hub is a press fit. I must be missing something.

Edit: The crank is keyed but it doesn't use one. You can buy one from Thunder Racing if you want to run a keyed hub.

Last edited by ulakovic22; 10-26-2007 at 02:54 PM.
Old 10-26-2007, 12:27 PM
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With the bolts in it, it should be fine but the key would just keep it from ever spinning the bolts off, if you do just go with just bolts, I would buy some good ARP bolts.
Old 10-26-2007, 12:32 PM
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I'm not balancer guru, but I can't imagine any balancer being pressed on for a bigger CID motor.
Old 10-26-2007, 12:58 PM
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I don't have a stock crank or balancer hub but best I remember it did have a single keyway on it.
Old 10-26-2007, 01:04 PM
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Like stated above the stock crank hub is not keyed, but the crank is. The hub is pressed onto the crank hub, and is held on by one bolt, which threads into the crank. The dampner (pulley) is bolted to the crank hub with 3 bolts.
Old 10-26-2007, 10:00 PM
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Originally Posted by SprayedLT1
Like stated above the stock crank hub is not keyed, but the crank is. The hub is pressed onto the crank hub, and is held on by one bolt, which threads into the crank. The dampner (pulley) is bolted to the crank hub with 3 bolts.
the one bolt from the crank hub is the one that came out, and stripped threads and the key lock.
Old 10-27-2007, 10:28 AM
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bump for the day
Old 10-27-2007, 11:09 AM
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People usually have the cranks keyed for a supercharger, not NA. You sould not have spun the balancer off unless maybe there was a problem before you bought it. This makes me wonder if the previous owner had a supercharger on it?
Old 10-29-2007, 09:23 PM
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I had this happen to me twice this year. The hub is indeed pressed on but i had it off 3 times on the same crank and it never fit the same again. Bought a new damper from a local auto parts store and got a used hub online for $25 and all it better ...
Old 10-29-2007, 10:39 PM
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Originally Posted by Blown93Z28
I had this happen to me twice this year. The hub is indeed pressed on but i had it off 3 times on the same crank and it never fit the same again. Bought a new damper from a local auto parts store and got a used hub online for $25 and all it better ...
thanks for the info, if it falls off again i know what to do
Old 10-29-2007, 10:41 PM
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I'm not sure of other brands but the Fluidampr 704101 and ATI 917268 dampers have the hub as part of the unit like a good old chevy motor should. I think GM designed the LT1 motors with a split damper/hub assembly so you would only need to unbolt the damper half to get to the distributor.
Old 10-30-2007, 09:05 AM
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Originally Posted by Paul Bell
I'm not sure of other brands but the Fluidampr 704101 and ATI 917268 dampers have the hub as part of the unit like a good old chevy motor should. I think GM designed the LT1 motors with a split damper/hub assembly so you would only need to unbolt the damper half to get to the distributor.
CORRECT!!


For what it's worth, I'm running with the Fluidampr.



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