HELP..URGENT...just installed SLP lightweight Flywheel / SPEC II clutch...problems>>

[Jay 95 T/A M6]

OK...I need advice...I just finished getting my SLP lightweight Billet Flywheel and Star Spec II clutch installed. Install went great, however first drive leaves me baffled. Clutch feels great (pedal effort, engagement etc..) but the whole car has picked up some resonance between 1500-2000 rpm. It seems to happen in any gear, only at part throttle...if I bring the rpm's up slow, no rattling...if give it a little more gas...it rattles everything (noise seems to come from the front of the car..tranny/motor)...if I give it even more gas...it doesn't rattle.

IS this a Harmonic balance issue...???? do I need a fluidamper or something to restore the proper operation of the motor?

PLEASE help??? I'm lost.

Jason.

[Joe 1320]

An engine's bottom end is usually balanced as a whole with the crank balancer and the flywheel included. When you change the weight of the flywheel, you change the dampening characteristics. In this case of an LT-1, the balancer is not a balancer per se, it is a damper. The fluidamper is a great piece, but that may not be the cure yet. Are you absolutely sure all the other parts are up to snuff including mounts? The engine might be shaking a little more and causing interferance contact either within a mount or exhaust rattle, etc.... The damper may help, but look for the souce of the rattle.

[Jay 95 T/A M6]

I'm pretty sure everything was done up tight...>>

I worked side by side with my mechanic while the whole job was done...specifically made sure nothing was rubbing etc. The noise is really dependant on throttle position...especially when "lugging" the engine around say 1500-1800rpm in 5th gear..that's the worst. just a nasty sound. Even put new fluid in the tranny today. Everything went together smoothly, no forcing of parts etc. If it starts to rattle...and I give it full throttle, the noise goes away. When sitting at a stop in nuetral, I rev it up to the same RPM that the rattling occurs, there seems to be a bit of roughness in the powerband. As I say this was not present earlier this morning.

I checked all heat sheilds etc before the car was let down off the hoist. That was the last thing I did.

Any other ideas?

[Jay 95 T/A M6]

UPDATE...still baffled...>>

OK..I've been under the car for the last couple hours, everything seems to be tight etc...no loose sheilds..etc. However, I still have this noise under light acceleration. It almost seems as if it is going away a little bit, but I'm still not satisfied. I wish I could describe it better, but a slight change in throttle is all it takes to make it vibrate/rattle. anything over 2000prm and there is no sound. If I run it up to 5000rpm under almost full throttle, it feels as if vibrations come and go during different RPM ranges. Anyways...the noise only comes when lugging around town 1500-1800rpm. 1500 rpm in fifth, roll on the gas, and the vibration starts..you can feel it through the shifter, seats, dash etc. Definitely audible..then it goes away once speed picks up. Is there a procedure for aligning the bellhousing/tranny to the motor? Everything seemed to be done with dowel pins, so I figure it can only go on one way.

I apologize for the lengthy thread, but I'm doing my best to give the details. This will drive me crazy eventually.

any other SPEC / SLP flywheel installee's out there, I'd love to hear from you. As I say, no problem existed before this install today.

Jason.

[BillWS6Formula]

Flywheel?

Possibly a balance problem with the new flywheel? I have a SPEC stage III with steel flywheel and in the instructions that came with it, it said it maybe be necessary to transfer balance weights from the old flywheel to the new one.

Just brainfarting...I've had no probs with mine so far.

[Jay 95 T/A M6]

..after calling Spec and SLP..>>

they suggested I run Synthetic fluid...and possible remove the driveshaft and rotate by 180 degrees. Any other Ideas???

[4THGEN Z]

Does it do it in neutral...if so I would say its a balancing issue with the flywheel it cannot be a driveshaft issue since its dependent on engine speed not wheel speed.......In my A4 I installed a B&M torque converter when my rebuilt tranny went in and when I picked it up I instantly felt a vibration at about 1100 rpm in any gear/neutral/park, whatever...and only at that rpm...I reinstalled the stock TC and went smooth as silk.....so I suggest looking at this flywheel as Bill mentioned....

[Jay 95 T/A M6]

No vibrations when in nuetral...

No, there does not seem to be any noticable vibrations when in nuetral. I just had the driveshaft rotated 180 degress, and the noise seems to have been reduced substaintially...this was the recommendation from SLP techline. I did notice when rotating the rear u-joint, that it was possible to shift the joint slightly from side to side during install. Maybe about 1/32 - 1/16" is this normal, or do I need a new U-Joint? It does seem to be a little tight. i've tried to order one, however the dealer is telling me there are about 4 different joints for my year.??? SO...my question is...what is the correct part number for the rear U-Joint for a 95 with the Alum. driveshaft?

Thanks again for everyones input...it is greatly appreciated.

Jason.