balancing clutch assembly
I'm having trouble with the concept of balancing the clutch, flywheel, and pressure plate as a unit. I can understand the flywheel and pressure plate because they remain in the same orientation continually. On the other hand, the disc does not stay in the same position or orientation relative to the flywheel and PP, so if the disc is out of balance and you have the assembly balanced as a unit, that would be a potential mess, wouldn't it?.
So, the manufacturers will go to the effort to nuetral balance a clutch disc, but not the flywheel and PP? Or is it that the QC on aftermarket stuff just isn't very good?
Just asking, because I believe the manufacturers will say their parts are balanced. And if they screw up the balance of the flywheel and PP, what's to say they haven't screwed up the clutch disc?
It almost looks like the moral of the story is that when you buy aftermarket parts, you need to have the balance issues checked by a local shop. I don't even know if I have a shop in my local area that has the equipment to do that, or what it would cost if I did.
I do believe it's accurate that the balance should be checked because my Fidanza and SPEC setup had a slight vibration that wasn't there with the OEM parts.
Just asking, because I believe the manufacturers will say their parts are balanced. And if they screw up the balance of the flywheel and PP, what's to say they haven't screwed up the clutch disc?
It almost looks like the moral of the story is that when you buy aftermarket parts, you need to have the balance issues checked by a local shop. I don't even know if I have a shop in my local area that has the equipment to do that, or what it would cost if I did.
I do believe it's accurate that the balance should be checked because my Fidanza and SPEC setup had a slight vibration that wasn't there with the OEM parts.
Last edited by kenp; Jan 30, 2006 at 07:41 PM.
Personally when it comes to new parts, I think "this is cheap insurance" is the equivilent of volcano insurance in florida.
I just got a brand new Spec clutch and the paperwork only mentions balancing the assembly when used with a USED/RESURFACED flywheel.
For $500, the clutch damn well better be balanced when I buy it. Same thing goes with my brand new flywheel. I understand what people are saying about the variance between the two 'could' add up. However if the variance is that great between the two then BOTH items should be produced with tighter tolerances. Zero Balance is zero balance. It is absolutely absurd that you should buy a brand NEW part and need to take it somewhere to fix it before using it.
Whats next, buy a car from the dealership and taking it right to the machine shop to have the engine torn down and balanced before you drive it? I mean, if the individual parts are produced with such rough tolerances..the whole thing should vibrate like a pogo stick right?
I just got a brand new Spec clutch and the paperwork only mentions balancing the assembly when used with a USED/RESURFACED flywheel.
For $500, the clutch damn well better be balanced when I buy it. Same thing goes with my brand new flywheel. I understand what people are saying about the variance between the two 'could' add up. However if the variance is that great between the two then BOTH items should be produced with tighter tolerances. Zero Balance is zero balance. It is absolutely absurd that you should buy a brand NEW part and need to take it somewhere to fix it before using it.
Whats next, buy a car from the dealership and taking it right to the machine shop to have the engine torn down and balanced before you drive it? I mean, if the individual parts are produced with such rough tolerances..the whole thing should vibrate like a pogo stick right?
Last edited by MawneeC5; Feb 13, 2007 at 04:08 PM.
Staging Lane
Joined: Oct 2006
Posts: 72
Likes: 0
From: Hobbs, NM
I just did a clutch swap in my 01 Vette. The original clutch didn't like my head/cam swap and started to slip. I put in a LS7 setup along with all new hydraulics from a 04 Z06, pilot bearing, the drill mod, and a remote bleeder from steve d.
To change the clutch out in a Vette is a major PITA as the rearend, the trans, the rear subframe with running gear, exhaust, and the torque tube has to come out. I only wanted to do this once.
I had read where some of the Vette guys that changed out clutches had picked up a vibration after installing a new clutch setup. Most suggested to do a match balance of the old pp/fw assembly to the new one.
Before I took my original pp loose from the flywheel, I took a center punch and marked the pp and fw so I could line them back up in the same position that they came from the factory after I took them off.
I went to the machine shop and we spun the old pp/fw assembly and it showed that it was off by 15 grams and we marked where it was heavy. We then put the LS7 pp/fw on the balancer and it checked out 6 grams off but it was heavy in a different place on the flywheel. We then just unbolted the pp and turned it until it went back on the dowels on the flywheel in a different position. We spun it again and it showed 17 grams off but it was off 17 grams where the original one was off 15 grams. So I was within 2 grams of where the original pp/flywheel weighted in at. The machinist took a dollar bill out of his billfold and tossed it on the digital scale he had and the dollar weighted 1 gram. Not very much. He said he would call that good with the 2 grams. I did not have a vibration with the old clutch and did not want one with the new setup.
I finished the installed this past Saturday and no vibration and the clutch works great. I read on this forum where GM does a final balance on the Vettes with the pp/flywheel assembly. So if GM added weight to the pressure plate which they do with rivets to the outside of the pp, and you installed a zero balanced assembly, then you stand a good chance of picking up a vibration. From what I understand from this forum is that they do not do this final balance on the fbodies.
I would still suggest that you have your new assembly balanced to match your old one. It made alot of difference in my new assembly just unbolting the pp and turning it one notch on the flywheel. Changing these things out is to much work to have to do over and it very aggrevating if it has to be done. I am glad mine worked out liked planned.
Just thought I would pass along what my experience was.
To change the clutch out in a Vette is a major PITA as the rearend, the trans, the rear subframe with running gear, exhaust, and the torque tube has to come out. I only wanted to do this once.
I had read where some of the Vette guys that changed out clutches had picked up a vibration after installing a new clutch setup. Most suggested to do a match balance of the old pp/fw assembly to the new one.
Before I took my original pp loose from the flywheel, I took a center punch and marked the pp and fw so I could line them back up in the same position that they came from the factory after I took them off.
I went to the machine shop and we spun the old pp/fw assembly and it showed that it was off by 15 grams and we marked where it was heavy. We then put the LS7 pp/fw on the balancer and it checked out 6 grams off but it was heavy in a different place on the flywheel. We then just unbolted the pp and turned it until it went back on the dowels on the flywheel in a different position. We spun it again and it showed 17 grams off but it was off 17 grams where the original one was off 15 grams. So I was within 2 grams of where the original pp/flywheel weighted in at. The machinist took a dollar bill out of his billfold and tossed it on the digital scale he had and the dollar weighted 1 gram. Not very much. He said he would call that good with the 2 grams. I did not have a vibration with the old clutch and did not want one with the new setup.
I finished the installed this past Saturday and no vibration and the clutch works great. I read on this forum where GM does a final balance on the Vettes with the pp/flywheel assembly. So if GM added weight to the pressure plate which they do with rivets to the outside of the pp, and you installed a zero balanced assembly, then you stand a good chance of picking up a vibration. From what I understand from this forum is that they do not do this final balance on the fbodies.
I would still suggest that you have your new assembly balanced to match your old one. It made alot of difference in my new assembly just unbolting the pp and turning it one notch on the flywheel. Changing these things out is to much work to have to do over and it very aggrevating if it has to be done. I am glad mine worked out liked planned.
Just thought I would pass along what my experience was.
