New clutch: slipping

I'm having problems with my clutch slipping. I was wondering if someone would help by offering some insight.
I had my engine rebuilt 3K miles ago. During the process I also had a Kevlar clutch installed. The rebuilder said they resurfaced the flywheel as part of this process. I checked (and double checked) that the clutch is adjusted properly. It catches 1/2 way from the floor and seems fine.

1. How bad would the flywheel seal need to be leaking to cause the clutch to slip ?
(It seems to be "sweating oil" when i installed the engine, but i have yet to find a drip of oil on the garage floor.)

2. In the process of troubleshooting this problem, i adjusted the clutch so that it is 100% engauged when my foot is off the peddle (when under the car i can move the exposed cable side to side about 3/4 of an inch). There is very little tension on the cable when engauged
Should i have some tennsion on the cable ?

3. If the flywheel was not resurfaced, and a new clutch was installed. Is it most likely going to slip ? Will it get better over time...or worse ?

4. Do Kevlar clutches have a "break in" period since they wear slower ?

5. If i have oil on my clutch, is there a way to clean it without removing the engine ? (this assumes that the oil has was deposited by something other then a leaking flywheel seal)

Thanks,
Jim

I've explained in recent threads a part of the clutch cable adjustment that seems to be poorly explained in the Haynes manual. It involves taking the cable off the arm under the tranny, and using a big screwdriver to 'snap' the arm back to full return. This means the horseshoe spring will be pushing it to full return. This give the pedal a 'snap' feel at the top which pushes it to full return. If the horseshoe spring is not pusing the arm back, it may be pusing it forward and allowing pressure on the release bearing causing the slipping. Just a guess, but I believe this 'full return' thing may be important. Check recent threads.

------------------
'83 SC

Double check the adjustment; could be an easy fix!

But, I suspect that the fly wheel was resurfaced, cut down a mm or so, and the pressure plate mounting surface was not cut down a corresponding amount. If this was the case then there is not enough preload on the disk to hold it. i.e. The delta from the pressure plate mounting surface to the flywheel contact surface should be 22.5 mm +/- about .5 mm, the pressure plate will protrude about 17mm into this 22.5 leaving about 6mm for the 11 mm thick uncompressed kevlar disk, thus about 4-5 mm of preload. If they cut the fly wheel down 1-2 mm and did not cut down the pressure plate mounting surface the delta goes up to 24-25 mm resulting in only 3-4mm of preload which would not hold the disk very well.

If they installed the pressure plate with new bolts and used ones that were longer than stock; the bolts will bottom out in the holes in the flywheel before seating the pressure plate fully; so the clutch disk will not have enough preload and will slip!

Hopefully the problem is neither of these as the trany will have to come out if it is

Kevlar clutch's tends to be grabby and make a little noise during break-in; not slip!

hmmm...my gut tells me that the situation you explained is more likely to be my problem then an adjustment.
To my understanding, the only way it could be adjustment related is if the clutch engaugment arm had too much tension on it when it was disengauged... this is not the case.
Now, how do I confirm this ???
(I guess this means removing the engine again :-( )

Thanks -
Jim

I feel your pain!

My rebuilt engene came with the to long pressure plate bolts. I removed and reinstalled the engine five times before I figured it out.

You should be able to get it right on the first try anyway

I just got off the phone with the rebuilder...based on his comments I would assume you have a 2.2L ?? He said that on the 3.0L the flywheel surface area was completly flat, so this was not an issue.
He felt that my best approach to determining the source of the problem was to use Brake cleaner on the disk to eliminate the "oil leak" as a possibility. He reccomended using brake cleaner...the only problem is getting it in there (my second attempt at a smiley) I'm going to give this a try...if things get better...then i know the problem is a leak before tearing my engine out.
I put the engine and trans in this car by myself (just me and a floor jack) I'd like to make this the last time for a while (third attempt)

Thanks for your help...if you have any info on dropping "just" the engine and if you feel this would be less or more work for a solo effort...please pass it on. I'm tempted to just drop the engine...but i keep thinking about having to slide the clutch fork back over the throwout bearing with the trans still in the car. Seems like this could be more work then handling the engine and trans as one unit. Your thoughts ??
Thanks JIm

I recommend removing the tranny with the engine, but that's just my preference.

I do suggest you look carefully at the adjustment, even though it may very well not solve your problem. It could solve it, even if you have 'slack' in the cable.

You see, you can take the cable COMPLETELY OFF the car, and still have pressure pulling on that clutch release bearing. You see, the horseshoe spring helps pull the release bearing, along wiht the cable action. Even wiht 5the cable gone, the spring could still be trying to partially 'engage' the clutch.

Again, I have explained this twice, in some detail, in recent threads, or you can e-mail me. The trick is to force the arm under the tranny backwards (in the direction in which it RETURNS) until it 'snaps' under the pressure of the horseshoe spring pushing it the OTHER way (full return). done properly, this ensures that the horseshoe spring pushes the pedal, and linkage mechanisms, TO FULL RETURN. Then, when you push on the pedal, the horseshoe spring turns around and pushes the other way to help in engaging the clutch.

Again, I do not really believe this is your problem but unless you do this adjustment procedure, your next step is probably to remove the motor. Worth a try, I think.

Thanx to those of you who have tolerated my verbose rantings on this one subject.

------------------
'83 SC

If a flywheel needs resurfacing it will have black burn marks on it and will cause juddering as well as slipping eventually if not resurfaced hpefully they did what they said

did you install the clutch/pressure plate? did you use new bolts and torque them to 30ft lbs? I was going to reuse my bolts but one snaepped while torqing, so I replaced them all , the clutch install article here stated incorrectly to toque the bolts to 15Ft lbs the book says 30.

Well, it's 11:53PM...for argument i just got through checking the clutch adjustment again. The horseshoe spring is loaded and doing it's job. The tension spring is on the clutch engaugment arm and it not pulling too hard as to lift the clutch and cause slippage. The cable is taught...but not too taught where the clutch is partially disengauging. I confirm the clutch is adjusted correctly.

I tried the break cleaner trick...and it did help. It was difficult to spray in much through the bell housing drip hole...but i managed to get some in.

It looks as though the clutch has oil on it...which means old Jimmy is going to be dropping his engine again.

------------------------------------------

Thanks for the insight on the engine drop...I always take the trans out w/engine but i thought i might be missing a trick. I remember my VW years of just dropping the motor...the engine bay was "roomy" compared to a 911 I could just imagine trying to get it back in by myself.