This IS a good thread, near and dear to me since I have replaced many C5 clutch assy's for customers and have never been 100% clear on this issue.

My understanding: any OE balast weights on stock flywheel was to 0 bal PP/FW assy at factory, not necessarily to 0 bal the motor rotating assy. IF this is the case, then it would stand to reason that simply making sure the new clutch assy is neutral should prevent any vibe issues.

My experience: I've replaced ~ a dozen C5 clutches. I've never transferred weights from old flywheel to new. I usually have the new PP/FW checked for 0 bal, and in each case they were good. Also, I've had several old clutch assy's referenced for balance to find they were at/near 0. I do not recall if these had balast on the flywheel or not. Anyway, I've not had a single clutch balance issue until very recently, possibly. A customer brought me a LUK clutch assy. It had the markings and cuts of a spun-balanced assy. I installed it, then drove it, seemed fine. However, since customer has had the car, he believes there is a vibration at specific RPM. While his vibration could also be his exhaust system moved and touching heat shields (TPIS header floating collector connection always been a problem with Xpipe sliding/moving/leaking), it might be possible the LUK is not balanced.

I will be watching this thread closely to see if anyone uncovers a clear definition of what needs done regarding the matter. Yah, anyone have Dave Hill's phone number?!?!

Robert/ Gen 3 Motorsports

 

I just installed a ZO6 clutch kit in my 2001 C5 coupe. I got the kit Gene at Fred Bean and was told it was balanced from the factory. I did transfer the weights, but have not had enough break-in time to really lean on it. I thought I felt a vibration at 2200rpms, but I am not sure. I should be able to got out later today and try higher rpms.

IF we decide that the weights are not to be transferred, could you remove the flywheel inspection cover and punch out the weights????

 

I'm pretty sure we've determined that weights on the flywheel are for balancing the entire rotating assembly because of how it mentions that their location in reference to the crank matters.

 

Very funny and very true!!

 

Are we 100% sure about this?

If these weight are for the entire rotating assembly (engine and clutch together) you should be able to put that clutch assembly on a balancer and find it off - I would guess. The only way you would get a true 0 balance would be to spin it in conjunction with engine.

If your flywheel has weights and you find it to be 0 balanced that leads me to believe that the weights are there for the clutch assembly not the engine and clutch together.

Could it be that there are 3 scenarios

1. Engine 0 balanced internally w/ a 0 balanced clutch assembly which needs no weights. Basically each is 0 balanced on it own and needs nothing

2. Engine out of balance internally w/ a 0 balanced clutch assembly which would HAVE weights to 0 out the combo of engine and clutch. Basically the clutch is a natural 0 balance but needs weights to compensate for engine being off

3. Engine out of balance internally w/ a unbalanced clutch assembly which would have weights to compensate for both units being out. Basically both engine and cluch are out of balance and weights are added to compensate for both factors

Does this make any sense what so ever??

 

I'm going with the "three fingered European inspired monkey balance" here... tests prove that it adds 14.6 horsepower and 13.9 lb/ft of torque.

 

I've made a post on www.corvettemechanic.com. Hopefuly C4C5specialist will chime it.

Again the damn repair manual contradicts itself.

I'm going to have my stock stuff spun. I have two balance weights in the stock flywheel. If it runs true, then that means the weights are there to balance that clutch assembly.

All the big tuners have said the weights in the flywheel are to balance the clutch itself. We'll see.

Also, these car's aren't lexus' so some vibration in the stick is normal. I went out and flogged my parents' stock '99 vert mn6 to compare, and drove my buddies '03 Z06, and another friends '00 FRC (stock too). They all have some vibration, but I'm not sure what's normal in my car.

When I picked it up the tech informed me that there was a minor vibration now, so I got into the car looking for one. It was indeed there, and has subsided over time (or I'm used to it). Everyone who drives my car says there's nothing wrong.

That still doesn't help my sliping brand new LUK... make sure you check the adjustment of the Pressure Plate! Mine isn't clamping right, and per Mark at MSI, a select few can come from the factory not fully adjusted... my clutch is easier to push in than stock and it shouldn't be.

 

Removing the cover below the flywheel is all that was done to remove the weights from my flywheel. So the answer to your question is yes.

 

SWEET!!!

That is wanted I wanted to hear....

Thanks,


NOW back to the discussion, do I need to remove the weights?

 

Hmmm.... tight fit.

Here are some pics of my clutch install from this weekend, Thanks Ed!

In the Top pic one you can see where my two weights are on the old flywheel, under the pressure plate. I am sure I could punch out the weight on the left (A), the one to the right (B) will take a skinny punch and a little luck....

NOW, if we can just get a correct answer as to transfer the weights or not..

Top



Bottom

 

Thats a good idea to be able to pop out weights out of the OE flywheel with it still on the car... I wasnt so lucky... My last two replacement assemblies were (2 brand new) McLeod Aluminum flywheels with a single disc then Double Disc clutch.

VR

 

SideStep are you having vibration problems w/ the new assembly now? Also you'll have to make srue you have the assembly in the same orientation when installing the new weights. Good luck.

 

I am absolutely sure we correctly referrenced the postion of the old flywheel and installed the new based this. Then we moved the weights over to the new flywheel in the same orientation as the old one. We also referenced the new pressure plate to the new flywheel before taking them apart out of the packaging and installed them back together correctly again....

Am I having vibration problems??? I don't know. How would I know??? I have a slight pulse in the shifter right at 2200-2300 rpms that I do not think was there before. Not below that rpm and not after that rpm, all the way up to 6800 rpms. I have to assume there would be varying levels of imbalance??? Yes, No??? OR is the imbalance thing going to be so bad it shakes the entire car???

 

Same thing here.... when we're talking imbalance are we talking a mild vibration in the sifter or something that shakes the whole car. If we're talking shaking the whole car... as one member put it "my drive shaft feels like it's going to snap on high RPM downshifts", then I don't have any of that. I do however have a mild vibe in the shifter... upon driving a few other C5's I'm finding that they all have it too, and the vibe may be planted in my head by the mechanic telling me there was a mild vibe and me getting in the car on the lookout.

 

What features on the flywheel and crankshaft do you use to reference the two of them. Is there an extra hole in both that should be lined up?

 

Yes the flywheel has 7 holes... 6 are for bolts and evenly spaced, the 7th is a "sight" hole to line up w/ a hole on your crank.

 

Hmmm, I guess I didn't really know what I was looking for when I took mine out. I thought they would be weights you could see on the back surface of the FW or something. If they are plugs pressed into the holes around the FW I could have very well missed them.

I guess I lucked out, no vibration, but I can no longer definitively give the statement that I had no weights.

 

Yes...

Notice the one offset hole that does not have a hole oppostite of it,


Same with the flywheel...

 

This what the weights looks like....

In the flywheel


and out...

 

Robert,
JB bought a z06 clutch from the dealer...while it is a luk clutch it is the OEM z06 unit not the 'aftermarket' luk gold unit.

Had to chime in. I am watching this one too since I am planning a new clutch very soon!