Laurence Gibbs

I replaced my clutch pressure plate and friction plate . The old 4 puck friction plate was well and truly done.
I decided to go for a street set up to make the car slightly more manageable around pit lane. So went for a 996 GT3 clubsport friction plate and pressure plate. I believe these "should" be compatible with the Cup flywheel?
Since fitting this set up i have had trouble engaging gears. Gears can be selected easily when the engine is off but are difficult to impossible to select with the engine running . Some very small amount of drag is evident.
At first i thought it must be air in the lines or slave, so bled the system. This gave some useful improvement but the issue is still there. I then took the car to the track for a shakedown . The more laps I did the better it got but it was never right. It also seemed the hotter the car got the worse the shift got. To the point that i was back to almost impossible to engage by the end of the day.
When testing the car the next day when cold the shift improved and i could get gears again. At standstill in my garage.
Any ideas as to whats going on?

996FLT6

Maybe the linkage to shifter box needs adjustment and check to see the connector to the tranny is out of alignment. Mike

hms08

Sounds like you aren't getting enough travel to release the clutch properly. Check the clutch fork pivot shaft bearings. It's very easy to dislodge the needle rollers when inserting the pivot shaft. Was the clutch plate an OE part, if the plate is too thick then it will drag and not fully release.

Laurence Gibbs

Thanks for the replies. Plate thickness is a distinct possibility. In fact been mentioned to me by a good race shop friend. So that's two votes for the same thing. Would make sense given the symptoms. It's not a Porsche stamped plate but is OE manufacturer. Might have to bite the bullet and drop the box again. I have had the slave off and felt the movement of the fork. It feels ok , in so far as you can check the free movement. Not definitive I know.

fstockcarrera

My 2cents. Use a sachs oem cup pressure plate and a Kennedy disk 4 or 6 puck, as a good compromise .

Dan Jacobs

Check to make sure the clutch pedal stop if it has one has been removed
With the engine off and the car in gear with the clutch depressed you should be able
to turn the tires easily by hand ( car lifted ) If you can't you are going to damage the trans

32krazy!

does the clutch you replaced and the clutch you installed use the same pilot tube?

Laurence Gibbs

To the best of my limited knowledge all Cup and Clubsport (LWF) 996 GT3 use the same guide tube (a 944 part number) and throw out bearing and guide fork . The two significant differences AFAIK between street LWF set ups and the Cup parts are: the flywheel , which is is lighter and has a narrower contact area (not sure if the same for Clubsport) and the friction plate which is a 4 puk non sprung disc in the Cup. The Clubsport has a sprung full circle lining.
I am happy for someone to point out why the sprung disc wont work with the Cup flywheel. At present I cant see a reason other than plate thickness which when worn down wouldn't be an issue. The differences between the "standard LWF " and The cup LWF appear to be only what i have mentioned?

wolfgang1

did you ever figure out what happened here? I have a similar situation with a street 997.1gt3 where I had a 4.0rs clutch and lwf kit installed. Any updates are appreciated!

Laurence Gibbs

No simply not got round to looking at it. Though today i spent half hour checking that the clutch is not dragging. I noted that if the clutch is fully depressed to the stop , there is no drag and the clutch is as far as i can tell fully disengaged. Wheel movement with the car in 1st gear and clutch pedal all the way down. is free. About 8mm-10mm up from the stop and the clutch is in and biting. Not sure if there should be more free play than that or not? Anyone ?

Viperbob1

Check sprung hub part sticking out should be pointed towards flywheel If pointed towards Pressure plate, bad stuff happens.

Glen

was going to say clutch disk installed backwards but perhaps it's pressure plate backwards...can't remember but know I've done it....lol

Laurence Gibbs

Now i'm not definitely ruling it out ! But i was aware of it before i fitted it and i'd like to think i put it in the right way round . I'm reasonably sure i studied the picture in the Tech doc before i fitted it just to be sure too. But that's not to say the disk didn't get inadvertently swapped round somehow ? I am also thinking it would have felt wrong when fitting it , if doing it that way.. Never say never though lol
I am going to double check the shift cables, though they only came off at the tranny end , so have been altered in anyway. Then i will try one more bleed through and also put a camera into the bellhousing , just in case something is obvious. If none of that works i'll pull the box and take a closer look.
Thanks for the replies guys.

Viperbob1

The Street sprung hub disc made by Sachs also fits BMWs. For a number of years they MARKED on clutch "FLYWHEEL SIDE" on the wrong side for Porsches but correct for BMWs. It was easy for those not familiar to install wrong way. Lot of pissed off people back then...

Laurence Gibbs

Ok a further update. Pulled the gearbox to check the plate installation. It was correct. Nothing obviously amiss with the clutch friction or pressure plate, no needle rollers missing on the fork and the fork looks ok too. Lot of work to find nothing obviously wrong. I can confirm that newer clutch plates from Sachs are marked CORRECTLY now. So you can't get it wrong. Wish i had remembered that before i pulled the box and clutch ! My current thoughts are to go with either a Kennedy plate or go back to original style 4 puck . It doesn't solve or answer the question of why it's doing what it's doing though.
Before I pulled the box I checked the clutch actuation at the pedal The the clutch starts to lock up from about 8 - 10mm from the pedal stop. This seems very low to me ? Below that point the wheels turn freely with no drag. I also checked the shift cables, they're fine.
The new disc is about 8.6 mm thick uncompressed . The old solid disc thickness I can't recall but i think it was about 7.4mm . I do remember it was at the 0.3 wear limit on the rivets. Does anyone know what a new one is thickness wise? I have also noticed that there are more than one solid 4 puck disc listed for GT3 does anyone know the difference between them , as the only spec info i can find makes them sound identical other than weight? One last question how thick is too thick for the clutch friction plate? I know a few people have suggested this but i have no info on correct thickness?