Benjam88

So I picked up a 97 Z28 with an M6 for $1k. The previous owner botched a clutch job and low and behold it chatters and vibrates. I'm gearing up to fix this problem and I have been looking into parts.

I have looked at the Zoom flywheel on Summit Racing and have heard a fair amount of good things about their products. My other option is an OEM replacement from GM Parts Direct. The parts number is 10125379. Anyone ever used one of these? Are they still a dual mass flywheel? Information on it is shockingly limited.

Now for a clutch. I am leaning towards using a Luk clutch kit from Rock Auto. Or the Zoom Clutch kit from Summit Racing.

The car is stock and going to stay that way for some time while I take care of a few mechanical issues. Any input would be appreciated!

ACE1252

You will need a stock flywheel as the LT1 is externally balanced(with the flywheel) from the factory. You can't use a neutral balanced flywheel.

When pulling the old flywheel, there will be holes around the flywheel that could have weights in them. They must be transferred to the new flywheel in exactly the same positions as the old one. They can be knocked out with a punch. Use something like loctite quickmetal or rough them up in the jaws of a vice to get them to interference fit in the holes.

The other issue that could be happening is that the clutch pressure plate may not be neutral balanced properly. I have run into this on several Autozone clutches. The way I fixed it was to put in a Valeo replacement clutch kit(new), but they don't make them anymore....which sucks.

Spec may make sure they are balanced properly I'm not sure. But I do not trust the major auto stores to have them balanced properly. I had to pull my trans several times trying to figure out what on earth was wrong with it as it was vibrating so badly @ 4500 rpms and up(especially felt in the shifter). Pulled three times rotating the plate in various positions, once for another "new" autozone kit, and yet another to put in the Valeo kit. Valeo kit worked first try.

This is on CamaroZ28.com, but there is a good thread there on clutch options...although some of the info may be out dated as some LT1 parts are being discontinued.
http://www.camaroz28.com/forums/driv...ptions-520404/

I detailed some of my above issues with pictures here....in that same thread.
http://www.camaroz28.com/forums/driv...8/#post5906458

Here is a direct link with my clutch balance issues, flywheel information, what the colored dots on the pressure plate means....pictures...the works.
http://www.camaroz28.com/forums/driv...-plate-663827/

hrcslam

I ran into the same thing when I bought my car. Previous owner installed a new clutch. Turns out, the bellhousing bolts from the to the engine and the bellhousing bolts to the transmission are different lengths. He had swapped them, this allowed the transmission to float off the engine. It caused some serious chatter (shook the whole car). I ended up chucking a driveshaft and cracking the bellhousing before I figured it out.

ACE1252

I'm surprised he even got that to work. It might be different on different years, but on my '96, I'm fairly certain the bolts are different thread pitches(bellhousing vs trans bolts).

Benjam88

Thanks for the info guys. Does anyone have any experience with the 10125379 flywheel from GM Parts Direct?

It's been a really buzz kill not getting to enjoy the full RPM range of my car. My brothers have some 5.0 Mustangs that need put in their place

ACE1252

10125379 is the correct GM part number for the 4th gen f-body stock LT1 flywheel(94-97). I verified the number in the parts manual and on the box from my the last flywheel I ordered sitting in my garage.

Badazz 97 TA

iTrader: (18)

I didn't order from gm directly but I did order a LUK replacement flywheel that was under the same part number on rock auto. Looks exactly like my stock one just at a much discounted price compared to a gm price.

hrcslam

Nope, same size and pitch. But the bolts to the transmission are longer with taller shoulders.

ACE1252

I was pretty sure I'm right on this one...so I pulled a trans and bellhousing bolt to check. They are different thread pitches. Right bolt is a trans bolt, left is bellhousing.

The bellhousing bolt is standard 3/8 -16 and the trans is metric M10x1.50. You can get the bellhousing bolt to thread into the trans hole, but about 1/8th inch from the head contacting the trans, it gets really tight. I'd say your lucky with him reversing them, that it didn't screw up the threads in the holes.

hrcslam

Yeah I did! I bought new bolts for each when I replaced the clutch and housing. No issues with the trans or block. That explains the gap I found!

In any case, some idiot can get them swapped and it will wreak havoc if they don't notice the gap.