Red Rocket

Replaced my Spec 3+ clutch and Camaro FW with a new Spec 3 + clutch and Spec lite weight steel FW.

The old set up lasted 4 years of bracket racing.

When I picked up the car today with the new set up, it had severe vibration/shutter when engaging. The pedal would shutter bad about an inch before hitting the floor.

Here is the question: Should the shop had the set up neutral balanced before installing. They claim it's already neutral balanced when It's bolted together by Spec. Told them it should be balanced prior to the install. The old set up with the Camaro FW was neutral balanced after shaving the FW.

The same shop did both installs. Any thoughts out there or is there something else I'm missing.

Had the same vibration issue years ago when a different shop did not neutral balance the set up.

1985 Corvette

This is something that never crossed my mind. I have the 3+ as well, though the flywheel was balanced with the rotating assembly. Hopefully I am good to go on the bolt on and go. Just spit balling here but did they zero out your housing upon reassembly?

Race Prepared

The Spec 3+ is an aggressive setup for the street & with the light weight flywheel, will surge at lower speeds.

cv67

Surprised they let it go out the door like that!

I always take the PP and FW in and have them balanced even if they say it is already.

Telll them time for a do over! Thats unacceptable imo.

mtwoolford

I installed the same set up in my 96; it was spot on; no vibration issues.

Is your lower end stock? anything with a one piece rear seal will NOT be neutral balanced unless it is aftermarket and even then most aftermarket cranks mimic the factory and need a counterweight.

Stock flywheels have a counterweight pad cast into the flywheel; SPEC bolts a removable counter weight to the inside of the outer rim. If removed, the flywheel then becomes "neutral balanced".

So, I'd start there and see if the presence, or lack thereof, of the removable counterweight matches your crank shaft.

With that said, check the crankshaft / flywheel for excessive fore and aft movement. If excessive, replace the rear main crankshaft bearing, it contains the thrust bearing surfaces that determine the end play on the crankshaft. I've see excessive crankshaft end play cause the exact symptoms you are experiencing.

Red Rocket

The old set up with the Spec 3+ clutch and Camaro LT1 steel FW worked great on the street and strip. It weighed very close to the new set up with the Spec lite weight steel flywheel.

A lot of guys on other forums have had similar vibration issues even though Spec claims the setup is balanced. It seems the pressure plate is off a lot of the time after sending to a machine shop.

Red Rocket

have worked with this shop for 15 + years. Told the owner it should be balanced no matter what Spec says.

captainkawasaki

I have the spec lighter steel flywheel with the stage 1 clutch kit. I sent it off to be balanced with the rest of the rotating assembly but it came back untouched. For the first 50-100 miles I had some clutch chatter but it cleared up and now engages and disengages smoothly.

dizwiz24

Red Rocket:

Yes, absolutely the shop should have neutral balanced the clutch pressure plate the flywheel (take the crankshaft counterbalance weight off when doing this) before installing.

I dont care if its my toyota corolla 5spd, I have this done as well.

I recently replaced a 'Valeo' stamped SPEC stage 3+ pressure plate/clutch assembly (bought in 2006) with a new SPEC stage 3+ pressure plate/clutch assembly (bought in 2012).

Jeremy? of SPEC insisted the parts were of the same quality. When I got back the balanced parts, I was amazed at how many holes / how big the holes were drilled on the SPEC pressure plate to balance it to the same flywheel I had used before.

The shop owner had said some 11 grams??? (if my memory serves me right) had to be removed to get it to balance. In contrast, the 'Valeo' stamped pressure plate that came with the SPEC stage 3+ I purchased in 2006 had very little weight removed..

I called up Jeremy at SPEC and he claimed my machine shop screwed something up.

I told the machine shop and they assured me they did the job correctly (which I do believe they did, because this is a one-man operation that many racers in the akron, ohio area have used before. Gabels machine shop is the name. Very good quality work. )

I wished they would have called me before they started drilling and that I could have sent it back in hopes of getting a pressure plate that required less balance work.

All this said: I installed it and it works great. No vibrations or anything like that.

However! I dont want to claim this is the issue you had.

I hope not, but if you do have to tear it back down. Consider adding a zfdoc 'thicker' counterbalance shim. I did this at the same time I did the clutch and all the rattle I used to have in the trans went away. My ZF is now cadillac smooth. Even with my aluminum fidanza flywheel!!

Red Rocket

your right on. The shop worked all night and said it needed to be balanced this morning.

dizwiz24

Please call up spec, ask to speak with jeremy and tell him about it.

Mention that he already knows about the new c4 spec pressure plates requiring lots of balance work Because i told him about it a year ago.