tunesport

I'm looking for a supplier who sells just the pressure plate alone. Anyone know of one? Only reason I'm doing this is because I have a freshly resurface flywheel and found a LUK friction disc cheap online which I already purchased. Id like to replace everything in there while its apart because I'm not dealing with this pita again.

Evil-Twin

Forget about it...... you have to buy a clutch disc, pressure plate, and flywheel as a unit which is zero balanced and then use the weight clocking from the original flywheel to repeat the factory engine balance, or you will wind up with engine vibration, and potential , rod and main bearing failure.

tunesport

So my best bet is to stick with the oe flywheel and pressure plate then and replace the friction disc only? The engine has also been replaced once so this has never been balanced together. But it ran without vibration before taking it back apart. Only reason it has to come apart is due to a bad slave

Ray 2000 C5 FRC

I agree with Evil Twin :agree: about the imbalance issue you might encounter after assembly. Also, consider on changing the pilot bearing while you are at this stage of disassembly. Some else to check, make sure the clutch disk will work with the pressure plate you are about to purchase! Some clutch disks need to be mated with their respective pressure plate.

SaberD

It doesn't matter if the flywheel and pressure plate didn't come together, and it doesn't matter if they came neutral balanced either. As long as the balance of the new assembly is matched to the balance of the original assembly, it is the exact same process. As long as you save your original assembly to match the balance to, you can mix and match any components you want as long as they fit together properly. Also, the clutch disk should ALWAYS be neutral balanced. If it's not, it's defective and should be returned to the supplier for a refund/replacement.

Good luck trying to find a pressure plate by itself though. Mostly all of them are sold as kits from retailers which includes disk, pp, and fw. Maybe try your local chevy dealer to see if they can get you one. Another idea would be to make a post in the for sale section to see if anyone can sell you one. Another option would be to buy the kit, and sell the parts you don't need because chances are someone else will be in a similar dilemma due to the fact that they are always sold as kits.

I went with an aluminum flywheel, and had to buy a kit to get the pressure plate I wanted. I still have the brand new unused flywheel sitting in the garage though... really need to get around to selling it. I have to say I do find it strange that you can buy flywheels by themselves all over the place, but you have to buy a kit to get the pp. I was quite annoyed to say the least because you pretty much always replace the pressure plate when replacing the clutch or flywheel.

Evil-Twin

All I can say is "WOW". The reason they sell a complete clutch, flywheel and pressure plate, is because the LSX is externally balanced using the total rotating assembly to balance the original individual engine. So to say that it doesn't matter if the new unit does not need to be neutral balanced is laughable... unless you pull the engine when doing the install and have the total engine rotating assemble balanced..
Each LSX engine has a critical clocking aspect, specific to each engine... Some motors have no weights and some have 2 to six weights , clocked at strategic points. if you do not have a zero balanced flywheel pressure plate, and clutch disc ( as a unit ) any out of balance of these components will throw the total clock balance off. if the original motor takes 4 weights at 2:00 , 4:00 , 7 :00 and 11:00 o'clock. adding any unbalanced components to the rotating mass will throw off the original clocking. Cause little to serious vibration and possible destruction of the connecting rod and main bearings. I hate it when people are so willing to offer bad advice and potentially cost members thousands of dollars, because their opinion is lacking factual technology. I use to argue with those who offer this bad information.. IM too old and sick to do that anymore.. there is a reason GM sells a
" clutch Kit " with a zero balanced flywheel, pressure plate and clutch disc as a complete assembly. its because of the factory external clocking.

SaberD

What you are saying is that if A=10 and B=10 then A is not equal to B. This violates the transitive property of equality. If you balance a rotating component to say 10 inch grams off balance at 12:00, it's 10 inch grams off balance at 12:00. End of story. It doesn't matter if it started out as 6 tons off balance at 3:00 or perfectly neutral balanced. A competent machine shop WILL match the off balance to the original pressure plate and flywheel assembly with the new assembly. This is an extremely simple principle, and you are overcomplicating it.

The weights don't even matter unless you use a stock flywheel and want to transfer the weights to the new flywheel. Even this is a bit of a hack way to do it, because there is no guarantee that the new pressure plate is going to match the balance of the original pressure plate exactly. You could just as easily take a new stock flywheel to a machine shop and have them match the balance by removing weight from the new flywheel instead of transferring the weights with much more accurate results. Go check you harmonics and vibrations text book from engineering school, because I know you should have taken that class because you are an engineer.

I took my flywheel and pressure plate assembly to Dynotech engineering here in Troy, Michigan to have them match balance it to the original assembly. They actually built the technology that GM uses to externally balance these engines on the production line, and they know about this process better than anyone. They whole heartedly agreed with me that I was doing everything correctly, and I used a separate pp and fw because I went with an aluminum flywheel. If you have any questions, you should give them a call.

toddk

Gentlemen, I hear both of you saying that a balance-matched assembly is a requirement to avoid vibration issues and bearing failure upon reassembly. No "net change" in assembly balance is the goal, accomplished by:

• buy a new pre-zero-balanced clutch kit, transfer weights from old flywheel
• a mix with used parts, plus match-balancing by a machine shop
• some guys do both, to get a precise balance on new parts

I get the impression the OP is taking the piece-parts approach for a low budget clutch job. The takeaway is that one of the required costs when buying mismatched components is to pay $50+ for a machine shop to have the used parts match-balanced. Buying a new clutch kit costs more and the components have a longer service life than used/resurfaced, versus cheaper parts but added machine shop expense. Skipping the balancing step risks serious engine damage or vibrations as has been stated.

If the OP re-uses the existing PP and flywheel, there is nothing to match-balance against. You are simply R&R'ing your drivetrain. Hopefully the resurfaced flywheel measured greater than discard thickness.

A $500 replacement clutch should last 12+ years like my OEM one has, so for $42/year I would opt for the longer service life. Used parts just mean dropping the drivetrain again sooner, for saving a few hundred bucks now. I expect to keep my car thru the next clutch change.

Todd

thbwlZ

Replicating the GM factory hot balance is a moot point. OP says the original engine has "been replaced". So what does this mean? Was the original engine replaced with a new built longblock from some performance shop? Was the engine replaced with a new crate engine from GM or someone else? If so, was this crate engine supplied with a corresponding FW/PP clutch assembly? I doubt it.
Answers to these questions will tell you the best route to take when replacing the clutch with respect to balance operations.
However, if the current setup is smooth, and you are keeping the engine currently in use, then MATCHING the balance of the clutch assembly that is currently in use will give you the same smooth operation (with respect to balance conditions only). I hope no one can dispute that. And it doesn't matter how you replicate the balance. There are an infinite number of ways to match an existing state of balance. As Saber said, it doesn't matter what you start with as long as what you finish with MATCHES what you are replacing. I hope no one can argue with that either.
Glad to see this discussion, as always.

lionelhutz

LOL, even a new "zero balanced" clutch assembly is not perfectly balanced. So, buying a replacement clutch assembly and just transferring the weights is not a guarantee for success. More than one person here has proven this approach can fail with some drivetrain vibration as the result.

When just replacing the clutch, match balancing the new assembly to the original is the only way to know it will work for sure without vibrations. When you do this, it doesn't matter if the assembly came as a "balanced" kit because you are getting it balanced anyways.

Otherwise, if your engine has been worked on/replaced/rebuilt and it's no longer original from the damper to the clutch then just get the clutch assembly zero balanced. The LS engine is internally balanced well enough it won't have any issue with a zero balanced clutch. The weights are to fine-tune the balance to eliminate some drivetrain vibrations at certain engine rpm's caused by the C5 drivetrain configuration. If you have lost the ability to match the original factory setup then the engine will remain perfectly healthy going with a zero balanced clutch.

Also very important if you don't want to take it apart again - measure the slave distance and shim the slave if necessary. Tick has a good explanation of how to do this on their site.