at88mph

Welp, I've got my 01 coupe apart (have a rear main seal leak I'm replacing) and I'm about to remove the flywheel. I haven't done this before and have read different things searching the forum. Do I need to mark anything before removing it? (as it seems it will only go on one way anyway) Also, I'm planning on upgrading to the LS6 clutch so my question here is, do I need to have the clutch and pressure plate balanced with the flywheel or am I good to go once I have the stock flywheel resurfaced?

Thanks for any help!

ericdwong

There is a hole in the flywheel that bolts into the crank- you don't have to mark that, it's very obvious how that goes on. You should, mark the pressure plate and how it goes onto the flywheel. The pressure plate should be zero balanced but if you want to get it checked just to be sure now's your chance. You'll _probably_ be OK though since you're reusing your stock flywheel.

at88mph

Thanks!! however, I didn't mark the pressure plate when I took it off...I'll be getting a new Z06 clutch and pressure plate, but I'm guessing the new pressure plate will only bolt up one way as well?

SaberD

correct. the pressure plate also only goes on one way.

at88mph

Great!! Thanks for the info!!

Johnny wangwang

NO the pressure plate will not only bolt up one way. It can be rotated on the flywheel.

thbwlZ

A STOCK LS1/6 flywheel has two locating dowel pins clocked at 170° from each other. This allows a STOCK pressure plate to only mount in one orientation.

Aftermarket flywheels and pressure plates often have other designs.

So the answer is "it depends".

Replacing with stock kit or aftermarket.

thbwlZ

The flywheel bolts to the crankshaft via 6 bolt holes on an equally spaced bolt circle. This allows six possible mounting orientations.
There is a "7th" hole intended as an alignment hole, that lines up with a "7th" hole on the crankshaft hole pattern, but it is a visual alignment only. There is no pin or other physical means of locking those two alignment holes together. So there is no physical feature to ensure only one orientation. It is possible to mount the flywheel other than only one way (6 to be exact).
And yes, when assembled at the factory, the design intent is to have the two "7th" holes line up. But sometimes during the hot balance procedure, flywheels have been mounted in a different orientation when encountering a tricky balance requirement. That was supposedly rare, not the norm, but it DID happen.

But FWIW, every factory service manual instructs you to mark the flywheel's orientation to the crankshaft before removal. Sooooo there's that.

thbwlZ

Please hang on to your stock FW and PP until after you are done with the clutch swap and are HAPPY with NO VIBRATIONS.

Do not throw them away.

fmvette9

Is it OK to resurface the flywheel? Most people seem to replace.

thbwlZ

The service manual says not to resurface, but to replace.

Plenty of people have resurfaced without issues. It's not a dual mass flywheel, for instance.

With the relatively low cost of a new flywheel, I'd much prefer to replace with a new one.

at88mph

Yea, I've actually decided to go that route. I ordered the whole LS6 kit (clutch, pressure plate, flywheel) I'm ASSUMING that I can just bolt it right on up? No need to balance since it'll be brand new?

thbwlZ

Maybe, maybe not.

I'll try to keep this really short.
Manual corvettes, C5 to present, needed a finer overall engine balance than what the regular machining and assembly processes could attain.
SO
All LS engines for manual corvettes from 1997 to present are taken through a post assembly balance check. With the flywheel and pressure plate installed, the engine is run on natural gas for a short time in a "balance stand". Accelerometers identify imbalances and tell the operator where to install balance weights in the flywheel and/or front damper IF NEEDED.
The weights are effectively counter balancing effects from the engine, flywheel, and pressure plate all combined. So just swapping weights to a new flywheel is not "enough".
The only way to duplicate this factory balance, for sure, with no guessing and games of chance, is to have the balance checked on your factory setup. FW/PP together as a combo. Whatever that state of balance happens to be, make the new combo match it. That way you are "putting back on" the same thing you "took off", with respect to balance.

Plenty of people put in a new clutch/FW straight out of the box and have zero issues, no vibrations. Many people also put in a new clutch/FW straight out of the box and HAVE new vibrations. It's a pain in the A$$ to do it all over again just to chase vibrations. The choice is yours whether to take the gamble or not. Any competent machine/balancing shop should be able to do this for around $100 or less.

That is the only way to MATCH what you currently have.

However there is a chance it's not necessary. Vibrations suck. Just a matter of what you're willing to chance.

Good luck

at88mph

Thanks again for the reply This is actually my first clutch replacement I've attempted by myself. I don't have a problem taking it to the machine shop and paying to have the new setup compared/matched to the old setup, I just wasn't sure exactly the best course of action. That's why I was asking. Just wana do it right the first time

thbwlZ

I understand. You're asking the right questions.

Just be prepared, the shop will likely tell you it's not necessary. And it might not be, but there's no way to know for sure without checking the balance of stock unit first.

If the stock FW/PP subassembly is close to zero balanced, and the new subassembly is close as well, then that's good enough. The cost will only be for the checking. If the stock is noticeably unbalanced however, then the new should be unbalanced to match it. Then they'll charge you for that work.

HOWEVER, since you are replacing with a stock clutch/flywheel kit, your new flywheel will have the 12 equally spaced balance "receptacle" holes located around the perimeter. If you have weights in any of the holes of your stock FW, you can punch them out and possibly use them to unbalance the new assembly. That should make the job much easier, quicker, no machining. They won't necessarily just go back into the same hole locations of the new flywheel, but they might. The weights have protruding ridges on the sides that create a slight interference fit with the holes. You apply some blue Loctite and tap them in.

Most aftermarket flywheels DO NOT have these 12 holes.

Just be prepared for people not understanding why you're doing this.
But that doesn't matter, as long as the job comes out right.

at88mph

Exactly!!! Thanks so much again for all the info!!