924Board.org

[3d914]

Been getting my son's 924S running and hit a snag with the clutch. Already replaced the slave, master cyls, and rubber hose between. Checked clark's page and measured the travel. It measure 17.5-18mm. Haynes says min is 15mm, so I should be good.
Looking in the inspection port with the pedal depressed, the arm gos all the way forward and just touches the bell housing. I have adjusted the pedal rod as needed with very little free play.

With clutch in (not running) it will shift no problem between gears.
With clutch in (engine running) get a little grinding and have to push the pedal to floor.
With clutch in (engine running) in first gear, and press on break, idle drops and engine dies. Hear a pronounced brushing sound (not metal grinding).

Recently installed the engine, used clutch disk (in spec), and splines had only minor wear. Fork didn't appear bent, but don't have specs to verify any measurements.

OK did the 5th gear, one wheel on the ground, clutch in test and there is definitely a clanky/grinding noise when the rear wheel is rotated - so there is must be interference at the disk. Decided to disassemble.

OK finally got the tranny out & everything off. Fortunately, there were no surprises during disassembly and no spare parts fell out.

Here's some pics of the parts.
Flywheel:


New plate (forgot I bought new instead of the used):


Existing pressure plate:


Existing Release lever:



Existing Release bearing:


Visual inspection doesn't indicate any severe failures as far as I can see. If you zoom in on the disc plate springs at 3:00 & 9:00 o-clock you'll notice they were hitting on the flywheel bolts. I did have it installed correctly as that is the flywheel side. The disk surface doesn't look like its been touched at all. I would expect to see some marring. Perhaps I got an incorrect disk.
If I set it against the flywheel it certainly hits the heads of the flywheel bolts before the disk touches the mating surface.

The pressure plate spring arms don't appear to have excessive wear. The bearing spins freely with no axial play while spinning. However, there is 3mm of axial play between the bearing and the spring arms.

The release lever doesn't appear to be bent - but without some dimensions to check or pictures of a new one to compare with there is no way to tell. The tips of the arms do have about .5mm wear from interference with the bearing.

Are there other signs I'm missing? Anyone have specs on parts that I can verify their condition?

Still not clear about what's not working and why.

TIA,
_________________
Gerard
74-914 2.0L Ravenna Green
87-924S 2.5L Alpine White

[gohim]

What does the "tube" look like? Did you use a new one? They wear out.

The clutch forks are known for bending (and breaking sometimes). For some reason, yours doesn't look quite right to me. You might want to find a store/Porsche Dealer with one in stock that you can compare yours with.

Are you sure you have the throwout bearing assembled to the pressure plate correctly (right number of shims/spacers in the right locations)?

[3d914]

Done some more research, and found that I did buy my the clutch disk new/used from the guy I bought the engine from. Was intended for a 944 NA, so it should work. I'm checking with him to see if he has any more details.

I also recall that I used the flywheel on the used engine with my other parts. Its possible this flywheel was at the end of its life. I checked the offset distance from the base to the top of the mating surface with the disk and measured 5.5mm. However, the heads of the flywheel mounting bolts sit 8.5mm above the same base. That doesn't even make sense.

I also measured the flywheel side of the clutch disk and the center shaft is flush with the mating disk surface. On the back side the disk/spring assy extends over 17mm from the back face of the disk surface.

I checked the OD of the bearing tube and its 33.5mm, while the ID of the bearing is at 34mm - so no issues there.
_________________
Gerard
74-914 2.0L Ravenna Green
87-924S 2.5L Alpine White

[ole billy]

Check the disc again. 944 and 942S have a spacer between the disc material and the hub to raise the center away from the flywheel bolts. Check your PM for more information.