ivai

Isn't the release bearing the same as the throw out bearing?

hot-J

Nope........

caster951

Yes, the release bearing is the same as the throwout bearing....................the other bearing is the pilot bearing.

ivai

Right. I replaced the pilot bearing and the throwout bearing.

Everything that's hanging onto the back of the crank is new except for the clutch fork..

New clutch fork pin
New clutch fork bearings
New clutch/pp/flywheel
New pilot and throwout bearings

My next step is going to be taking the clutch assembly apart again.. Hopefully I'll get to that this weekend.

hot-J

I always thought the pilot bearing was the throw out??? Sorry for the misinformation. Its gotta be the fork....

mtnman82

Hmmmmm, I've got a Fidenza flywheel with the 930 disk/KEP I combo about to go on ... so I'm very interested in this. I believe there are at least a few using this combo sucessfully - I've searched/read a bunch and started a couple threads of my own.

I actually got everything off without disconnecting the slave cylinder - just to avoid the bleeding hassle, and in case something goes awry I'm hoping I can discount air in the system.

I sent my fork/pin off to Marcus Blazack to have him work his magic on it. I'm thinking I should have bought a new pin too now .....

hot-J

You'll still need to bleed the slave.........

ivai

Does anyone ever have to use shims on the throw-out bearing? My friend who's got an n/a just told me that he had to use two shims on his throwout bearing when he did his clutch..

Thanks,
Jeff

TRP951

I used as many shims as I could fit in the throwout bearing so it would be tight

ivai

"In the throwout bearing"

How exactly do these work? Are they just a ring that goes between the two fingers on the clutch fork and the release bearing?

Anyone have a picture?

ivai

So, I took apart the clutch today. I did some measuring of things. My conclusion is in the last two paragraphs if you want to skip all the numbers and mumbo-jumbo.

First of all, I confirmed that I have 0.008" of crank walk, half of the wear limit (0.015"). Also, with the bellhousing on, the distance between the bellhousing and the clutch fork is ~13mm (spec for new clutch is 18mm, wear limit is 34mm).

I measured the depth of the flywheel/clutch disc/pressure plate assembly when it is bolted together. I measured between the surface of the flywheel which touches the crank, and the back of the release bearing. I was really just measuring for differences in the deptch. A smaller depth would mean that the clutch fork would be further from the bell housing, i.e. smaller depth is better.

I have my stock flywheel, stock pressure plate, and a used clutch disc (maybe a 930 disc, it has 6 big springs). The used clutch disc is 7mm thick whereas my new 930 disc is 10mm thick. On the engine the used disc came from, the distance between the clutch fork and the bellhousing was ~24mm.

Basically, the thinner (used) clutch caused the overall assembly to be 5mm thinner, which would give me ~10mm difference at the clutch fork, which agrees with the difference of 13mm vs. 24mm at the clutch fork.

I did try changing out the Fidanza with a stock flywheel, that made the assembly 1.5mm thinner (3mm at the clutch fork), and the stock pressure plate made it .5mm thicker (1mm at the clutch fork).

If I were to put the stock flywheel on the car, I'd only get 3mm back at the clutch fork, which would put me at 16mm (2mm less than what I want to be at), but that might be enough to work. Also, my clutch fork is slightly worn where it touches the release bearing.. ~.75mm (not sure if its supposed to be grooved or not), so this would put me around 17.5 mm at the clutch fork/bell housing distance.. and the .008" of crank walk might put me right at 18mm.

Anyways, what I get out of all this is that the thicker 930 disc works, but with a lesser margin for error.. If my thrust bearing was new, and my clutch fork was new, it might work with the fidanza flywheel.. And it would almost definitely work with the stock flywheel (considering that several people on here do it successfully).

I need to consider either going with a stock clutch disc (if its thin enough), using the stock flywheel, figure out how to put extra material (weld) onto the clutch fork fingers, or put a shim on the release bearing, or some combination of these.

TRP951

try contacting markus blazek I think he welds up the clutch forks for strength and might be able to put more material on yours

KuHL 951

I've seen the fork contact surfaces worn down well past spec on my 83 and bought a new one. Having it built back up by welding is a good fix. I'm about to install a new Cup/930 with a resurfaced OE FW and will certainly refer to your measurements. Last time I used every shim in the kit on the TO bearing. Good investigative work, I love it!

ivai

Tim, where/how can I get a hold of Markus?

My clutch kit didn't come with any shims for the throwout bearing.. I also called Jason @ Paragon Products and he said he hadn't heard of using shims for the throwout bearing before. Can you provide some insight on these shims Steve? Are they just rings that go on the surface of the T/O bearing that the clutch fork contacts?

Thanks.

KuHL 951

Both clutches I've done were on NA's and they definitely needed shims. Is the 951 TO bearing shim free? I really don't know but it doesn't seem that it would be given all the PP fingers are separate and are not perfectly aligned. Maybe yours is a setup for your particular PP. Was there much play in the TO bearing when installed on the torqued down PP? There shouldn't be any fore/aft play at all, just a little lateral play for lining up the splines. The clutch fork doesn't contact the shims, just the flange on the TO.

Here's a few pics in an old thread with an assembly order.

https://rennlist.com/forums/showthre...+bearing+shims