I'm have a brand new LS7 clutch assembly and LS7 flywheel from Scoggin Dickey performance ready to bolt onto my LS6. I've read and found some people have balance issues with their clutches even new. I called the machine shop to see if they could help balance the flywheel/clutch assembly and they said they would need the entire engine to bolt the assembly onto to balance it which is a bit more work than I was wanting to deal with. Scoggin Dickey states that there is no balancing required...
So, what are your thoughts? Also How do I interpret the markings on the flywheel and pressure plate that it comes with?

- Steve

 

Oh boy....here we go again!!!
What year is your car??

 

IF you want it balanced you take the old assembly and the new and have them matched... has nothing to do with the engine.

 

it’s a 2002 Z06. Sorry for bringing up what is likely an old topic, I’ve done my google searching and come up confused… Chevy mechanics say just slap it on at the local dealer.

 

Mine has a SLIGHT vibration, but a vibration none-the-less because it wasn't match balanced. Before it was silky smooth. Have it match balanced. If you are replacing the flywheel you have to match it also.

 

Have the machine shop zero balance the entire clutch assembly. I also used the Scoggy Dickens LS7 kit (with billet aluminum flywheel) and it was 3 grams off. The machinist brought it as close as possible to zero balance and it is 100% fine. Your machine shop will also tell you there is no way to actually truly "match balance" two out of balance assemblies with out many hours of labor. This was my experience when I did my clutch last year.

 

I have read many stories about vibrations but never one where the new assembly was confirmed to be zero balanced. Lots where it was removed and taken to the machine shop with the new clutch to be matched balanced, but none of those commented on the balance of the assembly in the first place. My gut feeling is that most, if not all, of the replacement clutch "failures" are because the new assembly was not very close to being zero balanced like it was claimed to be by whoever was selling it. Case in point is CinciZ06's experience.

I would also agree that match balancing is not a simple task. Balancers spin the piece and then stop and tell you where the heavy (or light) side is. They are not capable of matching another out of balanced piece. So, it'd ,more or less be trial and error.

 

For what it's worth, my LS7 clutch was bolted in out of the box with no problems

 

Hi Steve,
Mine is a 2002 Z06 I bought new...
First time I changed the clutch using a zero balance assembly the engine was vibrating horribly above 2800rpm...
Fortunately I had kept the OEM Flywheel and after multiple exchanges with GM it was agreed that some engines from 2001 until mid 2002 were "assembly balanced" (costly process) and that there was two way to solve the issue after replacement:
-1) Match balanced the new flywheel to the OEM flywheel that came with the engine.
-2) take the engine apart and have the crankshaft zero balanced.

Below is the OEM Flywheel of my 2002 ZO6, one of the engine that was balanced using the flywheel...as you cam see, there are weights (tungsten I guess...) around the flywheel and holes.
Long story short, the 2002 ZO6 Flywheel in my engine in the picture below was out off balance by 37 grams...New flywheel was match balanced (meaning the new flywheel was offset of 37 grams exactly in the same location versus the central fixation bolts) and engine went back to normal, no more vibration.

 

No reason to be sorry. This is pretty important and it is very confusing.
Not sure which year the issue of match balancing might have changed. I studied for a few years knowing that eventually my high mileage car would need a new clutch. After all that time studying and calling around to find a shop that could/would match balance my clutch (and I never found one within a few hundred miles of my home) I checked the factory service manual for my 2004 Z06 and it stressed that you Do Not match balance the new clutch. WTF.
I'm in the process of changing my rear main seal right now and will be replacing my 205k mile clutch assembly. I'm going to be taking mine to a local machine shop and have them get mine as close as possible to zero balance, install it and hope for the best!!
Good luck and let us know how you end up.

 

Clutch balancing - imperative? - CorvetteForum - Chevrolet Corvette Forum Discussion

 

Steve:

I have a 2002 Z06 and just replaced my stock clutch with a (Monster Twin Disk). I was also concerned about the need to match balance the new flywheel pressure plate with the stock one. I decided to have the new flywheel pressure plate matched balanced to the stock assembly. It turned out my stock unit had balancing weights and was not zero balanced. The machine shop put the same imbalance in the new Monster unit. My car runs great with the new flywheel and pressure plate no vibrations at any RPM.
I decided to go this route as insurance against a balance problem. Although many have changed flywheels and pressure plates without issue and many shops reccomend this is not necessary. I thought the cost of fixing the vibration after the fact warranted the cost of match balancing as a precaution up front. It took a little less than two hours to match the new Monster flywheel and pressure plate to the imbalance in the stock unit. Cost me about $200. Turned out to be a big saving overall.

If you are having trouble finding a machine shop to do the work, my advise is to keep looking. I went to a local race engine builder who had all the latest milling and balance equipment. When I spoke to him about doing the work, he said he didn’t know that C5s required this but he was well experienced matching (balance or imbalance) in flywheel/pressure plates. He wrote out instructions he needed followed for the shop pulling the old unit out and putting new unit in.

The biggest problem was scheduling the transfer of the old unit to the machine shop and back in a timely manner as your car is stuck on a hoist waiting for the new clutch to come back. No doubt this counts as shop time and goes into the bill.

With regards to GM’s take on clutch balancing; I have a 2002 service manual which clearly documents balance issues for flywheel/clutch replacement. There has been a more recent GM technical bulletin on this issue. Document id 892762 (for Corvette (VIN Y)). This bulletin identifies 1997-2003 LS/1/LS2 engine balance instructions regarding weight transfers between flywheel assemblies. However, it does exempt new flywheel, pressure plate, and clutch from going through this process. I suspect that the balancing weights are no longer available as parts. Perhaps I’m being too cyncal.

Good luck on whatever direction you pick