Clutch time redo

[kenthompson]

Well,

It turns out that the noise was the pilot bearing turning inside the crankshaft. The clutch was fine, the throwout bearing was fine.

I could have put a new pilot bearing in and been done two weeks ago.

Course, I had to put the Fidenza in.....

Now, the pressure plate that I bought (Valeo) was about .200" thinner than the original. I thought that was curious, but maybe it was right.

Then, when I went to put it back together, the transmission didn't want to go in. After MUCH consternation and cussing, I figured out the new throwout bearing had a plastic bushing inside that was preventing the transmission from homing. Put in the old throwout bearing, and away it went.

I read somewhere that the nose cose on the transmission is larger on the ZR1 Transmission than the regular C4.

Does this mean I've got a clutch for a regular C4?

[tpepmeie]

Yes, there is only one pressure plate available, and like you said it is thinner. Make sure you use shorter bolts, else it will not work. Ask me how I know.

Tom at Carolina Clutch assured me that all future kits from him would have the bolts included..

Todd

[Paul Workman]

Originally Posted by kenthompson

Well,

It turns out that the noise was the pilot bearing turning inside the crankshaft. The clutch was fine, the throwout bearing was fine.

I could have put a new pilot bearing in and been done two weeks ago.

Course, I had to put the Fidenza in.....

Now, the pressure plate that I bought (Valeo) was about .200" thinner than the original. I thought that was curious, but maybe it was right.

Then, when I went to put it back together, the transmission didn't want to go in. After MUCH consternation and cussing, I figured out the new throwout bearing had a plastic bushing inside that was preventing the transmission from homing. Put in the old throwout bearing, and away it went.

I read somewhere that the nose cose on the transmission is larger on the ZR1 Transmission than the regular C4.

Does this mean I've got a clutch for a regular C4?

I recently installed a new Valeo (OEM) clutch plate/disc bearings, and had to smile at some of your tribulations. BTDT.

The new throwout bearing has a nylon insert which slides over the spline closely, but with a (very thin) smear of grease on the spline, it will not be impeded by the insert, I found.

As for the nose of the input shaft being bigger on a Z: I doubt it is different, but easy enough to check it with a spare pilot bushing. (My Helms manual made no mention of a different size for the ZF, but you could ask Bill at BillB@zfdoc.com for expert knowledge.) After a couple hours of trying to get my @$#@@$%^&% ZF to "home" into the new clutch/pilot bearing, a member of the Corvette Forum suggested me having someone climb inside and push in the clutch while I pushed on the tranny.

So, I gathered my strength one more time, got myself braced as best I could, and told my wife to push in the clutch pedal. I gave a mighty shove, and the danged tranny slipped in slick as snot and actally banged up against the clutch housing! Apparently, the alignment of the disc was off just enough that the nose of the input shaft would not self center in the pilot bushing, in spite of using the plastic alignment tool provided with the transmission. Give that a try and see if that doesn't solve your reinstalling the ZF issues.

Be sure to reinstall the spacer plates; the one between the block and the clutch housing, and the one between the trans and the clutch housing, and be sure there is no corrosion buildup on the mating surfaces, or that the plates do not have any kinks or ripples along the mating surfaces. Otherwise, you'll be tearing it all out again to get it right, possibly after replacing the input bearing again...Just a thought!

HTH,

P.

[kenthompson]

Originally Posted by Paul Workman

The new throwout bearing has a nylon insert which slides over the spline closely, but with a (very thin) smear of grease on the spline, it will not be impeded by the insert, I found.

Be sure to reinstall the spacer plates; the one between the block and the clutch housing, and the one between the trans and the clutch housing, and be sure there is no corrosion buildup on the mating surfaces, or that the plates do not have any kinks or ripples along the mating surfaces. Otherwise, you'll be tearing it all out again to get it right, possibly after replacing the input bearing again...Just a thought!

My "new" throwout bearing had a plastic bushing that was 0.020" smaller than the nose of the transmission. Not the splines, but the surface the bearing rides on. I tried having my son push the clutch in, and had my foot against the rear of the transmission. No luck.

What spacers? None came out when I took it apart.

KT

[A26B]

Originally Posted by Paul Workman

Be sure to reinstall the spacer plates; the one between the block and the clutch housing, and the one between the trans and the clutch housing, and be sure there is no corrosion buildup on the mating surfaces, or that the plates do not have any kinks or ripples along the mating surfaces. Otherwise, you'll be tearing it all out again to get it right, possibly after replacing the input bearing again...Just a thought!

HTH,

P.

What spacer plates???? Only thing I've ever seen resembling a spacer plate was on a phase II engine and it had about a jillion countersink screws bolting it to the back of the block like a scattershield. Are you referring to the dust shield at the front lower part of the bellhousing, held on by 4, 10mm bolts?

[Paul Workman]

Originally Posted by kenthompson

My "new" throwout bearing had a plastic bushing that was 0.020" smaller than the nose of the transmission. Not the splines, but the surface the bearing rides on.

, Yes, the "nose" (I meant to say). some light lube on the spline helps a lot with the spline gliding thru the friction disc. Anywayz, something is not right, if the throwout bearing bushing is .02 smaller than the tranny nose, "fer sher". I bought my clutch "kit" from Mid America, and had no problems.

Originally Posted by kenthompson

What spacers? None came out when I took it apart.KT

More like thin aluminum gaskets; one between the the block and the clutch housing, and one between the housing and the transmission. There were several references to them and the importance of them being clean, etc to assure the clutch housing and transmission surfaces are perpendicular with the driveline axis. (The Helms manual refers to them in several places - with respect to the '95 LT1/LT5s). I know I had kinked one and ended up having to hammer it out for things to fit right.

P.

[Paul Workman]

Originally Posted by A26B

What spacer plates???? Only thing I've ever seen resembling a spacer plate was on a phase II engine and it had about a jillion countersink screws bolting it to the back of the block like a scattershield. Are you referring to the dust shield at the front lower part of the bellhousing, held on by 4, 10mm bolts?

More like shims or gaskets...(see post above).

P.

Those shims are only on the L98 & LT1 car.