Harmonic Balancer
Thread Starter
Pro
Joined: Jan 2014
Posts: 731
Likes: 156
From: New Albany Indiana
Harmonic Balancer
We all know the problems with LS3 harmonic balancer problems some Corvette owners have experienced. Has anyone with one of the hand built, dry dump engines suffered a harmonic balancer failure?...😎
Drifting
Joined: Feb 2012
Posts: 1,428
Likes: 113
From: Brick NJ
I can't answer your question, but hand built engines or not it's not the build quality failing it's the part itself, so i don't see why it would make any difference in any harmonic balance failures other than the luck of the draw meaning which balancer your car gets because not all of them go bad.
Last edited by RoadkingC6; May 5, 2017 at 08:13 AM.
Safety Car
Joined: Aug 2006
Posts: 4,147
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From: Port St. Lucie West Florida
Race Director
Joined: Dec 2002
Posts: 10,467
Likes: 1,149
From: Wayne Township WI
Highly doubt it but I could've missed 'em.
FWIW I've wondered the same question over the years since I've skin in the game. That and reading repeated LS2/3 HB headache stories.
No clue except guessing LS7's HB's somehow different from the other LS series.
What say you pro wrenches?
Drifting
Joined: Feb 2012
Posts: 1,428
Likes: 113
From: Brick NJ
The balancers for dry sump and non drysump, big block and small block Chevy's are all different part numbers, i'm sure they are all made by the same manufacturer, but it seems as though the balancers failing are only the LS2 and the LS3 balancers.
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Drifting
Joined: Sep 2014
Posts: 1,924
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From: Atlanta - - - - - Save the manuals
On my son's C5, the outer part of the balance spun into the engine block. So it can be a big deal if it fails. If yours is wobbling I'd keep my eye on it.
Team Owner
Joined: Dec 2003
Posts: 57,408
Likes: 164
From: queensbury ny
That issue has been around for years and GM refused to warranty it for quite some time.There was,eventually, some kind of fix with a diamond bolt or whatever it is that get put in there that was supposed to correct the issue. I've owned 5 c6's from 1-05 - 2-08's-2-13 GS's...as well as a 14 and never had the issue myself.If you use the search function on top there,there is all kinds of info and you possibly may find out if anybody with the hand built had the issue.My 2 GS's were with the hand built and were fine as long as I owned them...
Thread Starter
Pro
Joined: Jan 2014
Posts: 731
Likes: 156
From: New Albany Indiana
Need info...
Does anyone have experience with the failure mechanism of these Harmonic Balancers. From what I can tell most of the failures relate to the outer pulley ring seperates from the rubber ring that binds it to the hub. Other failures relate to the Balancer hub that fits on the crankshaft, coming loose on the shaft. I think this would involve the large bolt holding the Balancer to the crank either backing out or failing and breaking. Any experience, descriptions of these failures would be appreciated, photos would be awesome. Thanks...
Le Mans Master
Joined: May 2016
Posts: 7,175
Likes: 1,546
From: Florida
Does anyone have experience with the failure mechanism of these Harmonic Balancers. From what I can tell most of the failures relate to the outer pulley ring seperates from the rubber ring that binds it to the hub. Other failures relate to the Balancer hub that fits on the crankshaft, coming loose on the shaft. I think this would involve the large bolt holding the Balancer to the crank either backing out or failing and breaking. Any experience, descriptions of these failures would be appreciated, photos would be awesome. Thanks...
Most of the failures involve the outer pulley first wobbling on the inner hub because the rubber center band fails. Many catch it in the wobble stage and replace, some ignore it and some of those completely separated causing the outer pulley to either spin off forward, or mostly spin off toward the motor usually destroying the timing cover. Some have actually been told a little wobble is OK...NOT! HBs should spin true especially on a high hp/torque motor.
On the bolt issue, I haven't heard of any snapping, but spinning loose and leaving the crankshaft is pretty well documented.
The HB is an interference fit on the crankshaft, no key. For an NA motor, this usually doesn't present much of an issue, but supercharged mods can cause the HB to slip/spin and possibly loosen the bolt. The recommendation on an FIed engine is to pin the HB to the crankshaft.
When I did my FI, I pinned both the bolt AND the HB, so in this configuration, neither the bolt nor the HB is at risk.
Melting Slicks
Joined: Dec 2013
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From: Bridgewater New Jersey
Le Mans Master
Joined: May 2016
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From: Florida
Le Mans Master
Joined: Feb 2014
Posts: 5,463
Likes: 1,138
From: Chino CA
Look down at your balancer from the passenger side of the engine bay with the car running. If it is wobbling, you have a potential problem.
Drifting
Joined: Oct 2010
Posts: 1,513
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From: Rocheport Missouri
