Harmonic damper wobble
Thread Starter
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
Harmonic damper wobble
I had a C6 come into my friend's shop that has a slight wobble to the balancer. Its brand new. It makes no vibration, no noise from the belt, and runs perfect. Its a fraction of a mm of a wobble. Barely detectable.
For reference, I looked at my 2005, it has the exact same wobble, no issues. I looked at my hummer (LS engine in there too) and it had a worse wobble although still barely detectable. My Hummer has silky smooth revs and is not modded in any way. There is no vibration in the driver's seat nor when I put my hand on top of the engine with someone revving it.
Did anyone else have this issue? I've read about dampers failing with the rubber separating from the metal but other than belt squeal, there isnt a vibration.
I've seen two C5's this week and both have that exact same wobble none had a vibration. Is it a GM normal?
5 cars with a wobble and no belt noise or vibration cant all have bad harmonic balancers.
Did anyone have this issue and did you have a vibration or belt noise?
For reference, I looked at my 2005, it has the exact same wobble, no issues. I looked at my hummer (LS engine in there too) and it had a worse wobble although still barely detectable. My Hummer has silky smooth revs and is not modded in any way. There is no vibration in the driver's seat nor when I put my hand on top of the engine with someone revving it.
Did anyone else have this issue? I've read about dampers failing with the rubber separating from the metal but other than belt squeal, there isnt a vibration.
I've seen two C5's this week and both have that exact same wobble none had a vibration. Is it a GM normal?
5 cars with a wobble and no belt noise or vibration cant all have bad harmonic balancers.
Did anyone have this issue and did you have a vibration or belt noise?
Le Mans Master
Joined: Dec 2004
Posts: 5,491
Likes: 806
From: West coast CA
My original one wobbled a little, then after a while it wobbled a lot, so I replaced it. The new one wobbles a little.
What would be helpful is an official run-out specification so we could stop using words like "a little" and "a lot."
Maybe you could put a test indicator on your collection of LS2s and we could start compiling a run-out database.
Drifting
Joined: Apr 2006
Posts: 1,276
Likes: 5
From: Ambler Pa.
I had a C6 come into my friend's shop that has a slight wobble to the balancer. Its brand new. It makes no vibration, no noise from the belt, and runs perfect. Its a fraction of a mm of a wobble. Barely detectable.
For reference, I looked at my 2005, it has the exact same wobble, no issues. I looked at my hummer (LS engine in there too) and it had a worse wobble although still barely detectable. My Hummer has silky smooth revs and is not modded in any way. There is no vibration in the driver's seat nor when I put my hand on top of the engine with someone revving it.
Did anyone else have this issue? I've read about dampers failing with the rubber separating from the metal but other than belt squeal, there isnt a vibration.
I've seen two C5's this week and both have that exact same wobble none had a vibration. Is it a GM normal?
5 cars with a wobble and no belt noise or vibration cant all have bad harmonic balancers.
Did anyone have this issue and did you have a vibration or belt noise?
For reference, I looked at my 2005, it has the exact same wobble, no issues. I looked at my hummer (LS engine in there too) and it had a worse wobble although still barely detectable. My Hummer has silky smooth revs and is not modded in any way. There is no vibration in the driver's seat nor when I put my hand on top of the engine with someone revving it.
Did anyone else have this issue? I've read about dampers failing with the rubber separating from the metal but other than belt squeal, there isnt a vibration.
I've seen two C5's this week and both have that exact same wobble none had a vibration. Is it a GM normal?
5 cars with a wobble and no belt noise or vibration cant all have bad harmonic balancers.
Did anyone have this issue and did you have a vibration or belt noise?
01 LS1 , no wobble, 98 LS1 ,no wobble. Seems to be more common in the later LS engines . Not sure what year it started to occur.
Melting Slicks
Joined: Mar 2011
Posts: 2,708
Likes: 83
From: Arkansas
I had an issue with my 2010 base coupe. Here's the GM TSB#2489214...........(from my service receipt).........after the third visit. I could not locate any info on the net related to the number.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
10 Most Common Corvette Problems of the Last 20 Years!
Joe Kucinski
5 MOST and 5 LEAST Popular Corvette Model Years in History!
Joe Kucinski
Thread Starter
Tech Contributor
Joined: Mar 2003
Posts: 12,094
Likes: 197
From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
I know UD pullies like a powerbond dont have the wobble but are they acting as a vibration dampener? The GM use of the two piece with rubber is to absorb vibration. A solid unit without rubber is just a weight. I know nothing of the science behind it but since I havent seen a car without the wobble, I am led to believe that its a byproduct of the design. I know they fail making noise but I was more concerned with bearing damage if they dont do their job of absorbing vibration. I can see an out of balance engine running a solid pulley having more issues.
One thing to keep in mind is that GM considers our engines to be balanced if they are +/-70grams which is rediculous. Unless I have an aftermarket forged motor that is properly balanced, I wont run a solid pulley. I think high rpm use would be best served with a $435 ATI superdamper as opposed to a 250 dollar solid piece.
Thanks everyone for posting. Manners and pooling the experience base is what makes this forum the best around.
Le Mans Master
Joined: Jun 2009
Posts: 6,528
Likes: 752
From: South Dakota
I put a Powerbond on mine, but not the underdrive one. I used the standard size. It is not a solid piece. It has an "rubber" section to help absorb torsional vibration just like the OEM one.
Platinum Supporting Dealership
Joined: Sep 2007
Posts: 4,206
Likes: 28
From: Houston Tx
Very common problem we replace 3 or 4 dampners each month c5 and c6 ls3 dosnt seem to be as bad as ls1 or ls2
__________________
YOUR CORVETTE SUPERSTORE SINCE 1988
CORVETTE WORLD HOUSTON
281-821-1222
http://corvetteworldhouston.com/
YOUR CORVETTE SUPERSTORE SINCE 1988
CORVETTE WORLD HOUSTON
281-821-1222
http://corvetteworldhouston.com/
Intermediate
Joined: Feb 2014
Posts: 48
Likes: 1
Instructor
Joined: Apr 2013
Posts: 114
Likes: 4
From: Lititz Pa
I had this problem too
I replaced the balancer with a SLP 05-06 C6 HARMONIC BALANCER/UNDERDRIVE PULLEY Part No. SLP-100225. Cleaned faces carefully and ended up with .001" runout.
Got mine from http://www.lethalperformance.com/.....cost $211
Got mine from http://www.lethalperformance.com/.....cost $211
Intermediate
Joined: Feb 2014
Posts: 48
Likes: 1
I replaced the balancer with a SLP 05-06 C6 HARMONIC BALANCER/UNDERDRIVE PULLEY Part No. SLP-100225. Cleaned faces carefully and ended up with .001" runout.
Got mine from http://www.lethalperformance.com/.....cost $211
Got mine from http://www.lethalperformance.com/.....cost $211
Drifting
Joined: May 2012
Posts: 1,618
Likes: 105
From: Southport North Carolina
Intermediate
Joined: Feb 2014
Posts: 48
Likes: 1
