I've been using a single mass camaro flywheel and centerforce dual friction clutch for quite some time with my 350ci stock bottom end. From day one it always rattled in neutral without engaging clutch(normal) and I also got some gear rattle in gear at about 2200-2900 rpms(not normal).
Last time at the strip I broke a halfshaft on the launch and from then decided to build a stroker motor. The motor was balanced internally and the same was done with the flywheel. Well, I have a bad vibration that is rpm related whether the clutch is engaged or not. If I lightly rest my foot on the clutch pedal and rev the engine I can feel the vibration being transmitted. Same goes for the shifter, the higher the revs the worse it gets.
I have heard that some people have experienced vibration problems when using a centerforce clutch cause of the weights, true I don't know. I don't mind replacing the clutch and possibly the flywheel, but I don't want to throw money at it without a good plan.
I know all the variables are not the same as before, but if the balancing was done correctly I shouldn't have a problem. My only fear is that maybe at the dragstrip when I launched and snapped the halfshaft the driveline locked and maybe bent the input shaft or something in the tranny? Is there any way to check this without disassembling the tranny?
I need to get this resolved so I can enjoy my car again.:sad:

Plese help!
Bob

 

As long as all of the Centerforce weights were in place during installation, and none of them have come loose, then there is nothing inherrent in the Centerforce to be concerned with, they use a Valeo (factory issue) pressure plate that they add the weights to. There is a small vent/inspection opening on the driver's side of the bellhousing just above where the clutch slave cylinder mounts. If you can get one of those high tech probes with a viewing screen, you should be able to inspect the Centerforce without removing the whole trans. I've never heard of a ZF gearbox "bending" the main shaft - but who knows, you could be the first. Really, I think a mistake was made during balancing, and that is your vibration source. Here is something you can try if you are running the factory harmonic dampener with no machined keyway: rotate it 90 degrees and then see how it runs, if vibration is still present rotate another 90 degrees...and so forth. I can't remember where I saw it, but the factory issued instructions like the preceding for a possible engine vibration remedy on the LT1.

Thomas

 

Unfortunately, it sounds like you had a problem that the machine shop caused. Something did not get balanced properly. I would try green rockets idea first, since it is a free possibility. Next I would inspect the clutch.

As for the slight vibration that you mentioned before you did the motor, I know of a few single mass cars that had the same problem. Some of them do and some don't. There was no rhyme or reason as to how or when the ZF vibrates or rattles. I even know of one that doesn't make any more noise that stock and he has a camaro single mass in there.

 

Well, the funny thing is that the flywheel came out and was sent to the machine shop to have the balance rechecked!
Regarding the dampener, if rotating 90 degrees does not change anything what does that indicate? I'm assuming that if it does help then that would indicate the flywheel is definetely out of whack, correct?

Thanks

 

Yes

 

Take the tranny and clutch off just leaving the fly wheel, support the engine and start it up. If you have vibration there then you have a problem with the balancing in the engine. If not it will be one of the other options.

 

ask them how the flywheel imbalance/balance was checked. if they didn't bolt it to your crank when checking the balance, i'm extremely skeptical that it was balanced properly.

also, you said the assembly was internally balanced. this means the flywheel would have no imbalance whatsoever. if it's a stock flywheel, does it have balance weights on it?

 

I am a little confused.
Are you saying that you had the motor rebuilt and from day 1 on the new motor it has been out of balance?

Could be 2 things.

1. They balanced it wrong.
2. There should be a reference point on the pressure plate to line it up on the flywheel. if this is not matched up, it will be out of balance. Unless they did something to make it all balanced no matter what, which I highly doubt.

How bad is the vibration?
I built my motor up, balanced and blue printed everything, the dual mass flywheel failed after start up, I got a single mass FW and had it balanced to the old one (did not pull the engine) and it vibrated so bad at 4000 rpm in nuetral that the stuff on the roof of the car walked across it. I had to pull my recently installed motor to take it down to be completly rebalanced to the new FW.




[Modified by bill mcdonald, 8:42 AM 3/26/2002]

 

After the motor was built that's when I noticed the vibration, during the test drive. I had the tranny dropped and sent the flywheel and pressure plate to be checked. I don't know what the procedure was except that it checked out fine.

The flywheel is a camaro piece and in stock form it does have/require balance weights. All I need is the flywheel to be zero balanced, how hard can that be? It basically will just be free wheeling, since the motor is already balanced internally.

 

YES!


What do you mean with your 2nd statement? With a zero balanced flywheel it shouldn't matter in what position the pressure plate is bolted on, right?
The vibration is bad enough that I don't want to go WOT:( Even on the highway in 5th or 6th gear at 2000 rpms it can be felt.


[Modified by bill mcdonald, 8:42 AM 3/26/2002][/QUOTE]