View Poll Results: Is the Vibration caused by the Weights or the Warp
The vibration is from the weights.
1
33.33%
The vibration is due to the flywheel being warped.
2
66.67%
Voters: 3. You may not vote on this poll
Flywheel weights or warp?
Thread Starter
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
Flywheel weights or warp?
Hey guys, I recently replaced the motor in my car with an LQ4 and upon starting it up it is vibrating pretty badly at around 3k and just vibrates faster the more i go up. Im trying to determine if its caused by a minor warp to the flywheel or because of the weights that are still there from my original motor. The stuff I know...
1. There was no vibrations at any time when I had my original LS1 in the car to the point I took it out.
2. The warp on the flywheel was very slight.
3. The weights meant to balance my LS1 are still on the flywheel that I just put on the LQ4 that is now in my car.
Just trying to feel for the answer here, Im thinking I may try to knock the weights out and go from there but again Im not sure 100% Interested in knowing what you guys think, thanks.
1. There was no vibrations at any time when I had my original LS1 in the car to the point I took it out.
2. The warp on the flywheel was very slight.
3. The weights meant to balance my LS1 are still on the flywheel that I just put on the LQ4 that is now in my car.
Just trying to feel for the answer here, Im thinking I may try to knock the weights out and go from there but again Im not sure 100% Interested in knowing what you guys think, thanks.
Race Director
Joined: Dec 2004
Posts: 13,760
Likes: 75
From: Haymarket VA
I think warp would be more apparent at engagement than steady cruising Eyeball the harmonic balancer for wobble. If that's good, sounds like the flywheel is the culprit. Another source of vibration is a bent propshaft.
Was the new engine used or rebuilt? Zero balanced?
Was the new engine used or rebuilt? Zero balanced?
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Number the 12 balance holes in the flywheel. Mark down what holes have the weights. Remove ALL the weights and check by revving the engine to your 3000 rpm point. My bet is you no longer need the weights if the engine was built with balanced parts. If it is engine imbalance, the shifter is the best thing to use to evaluate the vibration by resting your hand on it while running up to the 3000 rpm test point.
Thread Starter
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
The engine is used but its rebuilt and balanced, originally from a 2002 Chevy 2500. There's no wobble on the balancer. The vibration occurs both when the clutch is engaged and disengaged as you rev up the motor, Im almost certain its the flywheel, just not certain if I can knock the weights out and fix the problem or if its somthing requiring a new flywheel.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
The engine is used but its rebuilt and balanced, originally from a 2002 Chevy 2500. There's no wobble on the balancer. The vibration occurs both when the clutch is engaged and disengaged as you rev up the motor, Im almost certain its the flywheel, just not certain if I can knock the weights out and fix the problem or if its somthing requiring a new flywheel.
Thread Starter
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
Yes, What I meant was that I hope knocking them out will be enough and it wont still vibrate from the warp. From what youve said though it seems to be the fix to my problem, if I have it on a lift do you think I could knock em out by taking the starter off and hitting em backwards? Trying to avoid droping the entire driveline again.
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
Yes, What I meant was that I hope knocking them out will be enough and it wont still vibrate from the warp. From what youve said though it seems to be the fix to my problem, if I have it on a lift do you think I could knock em out by taking the starter off and hitting em backwards? Trying to avoid droping the entire driveline again.
Tech Contributor
Joined: Jan 2007
Posts: 19,413
Likes: 1,144
From: Dyer, IN
I don't know Eric....by the OP's own admission, the flywheel was warped before install, which is a deal breaker right there. I think the only way to know for sure, is to pull the flywheel and clutch, and have the flywheel inspected(resurfaced as required), and the whole assembly balanced checked.
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Tech Contributor
Joined: Oct 1999
Posts: 41,037
Likes: 9,801
From: Charlotte, NC (formerly Endicott, NY)
I don't know Eric....by the OP's own admission, the flywheel was warped before install, which is a deal breaker right there. I think the only way to know for sure, is to pull the flywheel and clutch, and have the flywheel inspected(resurfaced as required), and the whole assembly balanced checked.
Bill
Tech Contributor
Joined: Jan 2007
Posts: 19,413
Likes: 1,144
From: Dyer, IN
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
I don't know Eric....by the OP's own admission, the flywheel was warped before install, which is a deal breaker right there. I think the only way to know for sure, is to pull the flywheel and clutch, and have the flywheel inspected(resurfaced as required), and the whole assembly balanced checked.
Thread Starter
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
Ok, shoulda said that the flywheel was warped slightly and then resurfaced. Shouldnt be warped now but I thought there may still be a chance. Anyhow, was able to sneak some time in at the shop and knocked em out since it was quick. Seems to be be fixed, didnt go for a long drive since its gotta be put together but it wasnt vibrating like it had before at a standstill, went all the way to 6k. Hopefully this is it 
Thread Starter
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
Yup, my friend just got the car back together and it still vibrates some, not terrible like before, but still noticable. The flywheel must have been too warped and the resurface must not have been enough.
Tech Contributor
Joined: Jan 2007
Posts: 19,413
Likes: 1,144
From: Dyer, IN
The shop that resurfaced the flywheel should have caught this, and brought it to your attention. The whole assembly(including clutch) needs to be checked.
Thread Starter
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
Tech Contributor
Joined: May 2008
Posts: 2,843
Likes: 16
From: Howell Michigan
St. Jude Donor '09-'10-'11
If it were mine I would attempted an in car balance before taking everything apart. You removed the weights, how many and if you did as I suggested and numbered the holes, what was the number relation to the weights removed?
Thread Starter
Racer
Joined: Feb 2011
Posts: 478
Likes: 0
From: San Antonio TX
How was it determined that the flywheel is warped? Was it measured, and if so, what is the run-out?
If it were mine I would attempted an in car balance before taking everything apart. You removed the weights, how many and if you did as I suggested and numbered the holes, what was the number relation to the weights removed?
If it were mine I would attempted an in car balance before taking everything apart. You removed the weights, how many and if you did as I suggested and numbered the holes, what was the number relation to the weights removed?
As far as the weights I started the numbers on the first one, there were weights on 1,2, and a small one on 3 (going clockwise), then no weights at all on the rest.
I assumed you used a machine to balance everything and it couldnt be done accurately in car, if it can that would be amazing. lol
Last edited by Speedaemonc4; Dec 8, 2011 at 11:24 AM. Reason: more to add
Drifting
Joined: Apr 2011
Posts: 1,454
Likes: 6
From: Pittsburgh PA
The Youtube vid on this page convinced me to replace rather than resurface my flywheel. Mine had some really nasty hot spots. Metal had actually transfered from the flywheel to the disc.
http://www.perfectionclutch.com/flywheels.html
GM specifies replacement BTW. When I priced an OE LS1 clutch my parts guy said the PP and flywheel were sold together. The only thing available separate was the disc.
http://www.perfectionclutch.com/flywheels.html
GM specifies replacement BTW. When I priced an OE LS1 clutch my parts guy said the PP and flywheel were sold together. The only thing available separate was the disc.