John Veninger

I've been fighting a clutch issue on my 80 EuroS track car.
The clutch, slave cyl, clutch master cyl. and hose are all new. I have about 1200 miles and 3 track days on the setup.
I've bleed the system 5 times. Pressure bleed, pump bleed, removed the slave and manual bleed.
I've also readjusted the dual clutch.
Here is the problem. When the car is cold (first started) the clutch works, but the clutch will engage when the pedal is released only about an inch off the floor. Once everything heats up I sometimes get a grind into first at a stand still and difficult shifting into 2nd on the track.
My thought is a bad slave or clutch MC (so much for new parts).
Can someone look at their slave cyl. through the access hole and mark the rod to measure the "throw" for me?

John..

I'd hate to break this news to you, but it sounds like you might need syncros. Checking the slave throw is the first place to start though. I don't remember the numbers, but I have them at home in my manual. In my case, the 2nd gear syncro was shot...it sometimes shifted fine, and other times....grind!

Proper center disk adjustment of the dual disk clutch is essential for any life on the clutch and the syncros! Most Porsche shops didn't even know how to adjust them, so the life of the syncros was greatly shortened. Plus the early cars had syncro problems. The syncros on the early cars are of Porsche design, they switched to a standard unit later.

A good way to see if your center disk is properly adjusted is to put the car in neutral give it a little gas. If the clutch is "dragging", which it sounds like your's is, when you put it back into gear (try reverse), you'll get the buzzsaw sound. This is a good indication that one of the disks is dragging.

I was hoping it was my slave cylinder as well, but it turned out my syncros were on the way out. Porsche did away with the twin disk setup on the later cars.....85 and up I think.

If you think they are dragging and you are not getting and grind in between gears, try to properly adjust the clutch center disk. There are three adjustment points on the disk and ultimately what you want is for both disks to become "free" at the same time, when the pressure plate is pulled back by the system. The best way is with trial and error.....


Remove the lower housing with the slave in tact.

You can then use a socket to hold the throw arm out on the clutch assembly. Put the socket underneath the throw arm (where the slave acts) and the housing.

Check the relative location of the disks (i.e. free space) between the flywheel and the pressure plate.

You can then use varying sizes of sockets and washers (or coins) to slowly close the pressure plate back onto the package. I would do this at least 5 times while you rotate the assembly and adjust the three points on the center disk.

What you want to see is the two disks become free from their respective friction surfaces as soon as the pressure is relaesed.

This is best done by feel with a small pick tool to slide the disks ever so slightly back and forth on the splined shaft.

I have heard going by the dimensions given in the factorty manual can yield poor results.

You adjust the stops on the center disk (3 of them) with a screwdriver.


Good Luck

John..

Sorry....missed you line on readjusting the center disk. If the slave doesn't solve it, your syncros are probably due. I'll check my manual tonight to see the dims on the throw.

John Veninger

Thanks for the response and help John.
I'm pretty sure it's not the synchros.
Want to know why <img src="graemlins/a_smil17.gif" border="0" alt="[blabla]" />
I expanded the syncro ring on third gear at Lime Rock in March. The car now has an 89 5 speed with the new style syncros.
I'm pretty sure the issue is in the clutch system based on the engagement of the drive train with only a small release of the clutch pedal.

John.

John,

The throw on the slave should be 17.5 mm or about 11/16"

Sounds like you have gone through all of the other stuff.

Good Luck.

Steve Cattaneo

John,
It sounds like a clutch release problem, if the clutch is adjusted properly. The new slave or master could be defective. Check the pedal push rod travel. The clutch could be worn; the wear limit is reach when the front edge of the clutch lever has reached the end of the inspection hole.

Contaminated, over heated fluid can cause a release problem. Make sure the lines are not touching the exhaust. For added protection wrap them with a heat shield.
<img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

John Veninger

John,
Thanks for the measurement. I just came back from Watkins Glen yesterday night.
Wonderful two day at the track except for the heate wave!
Clutch acted up a bit, but not as bad as before.
I'll be playing with it this weekend.
Steve,
The clutch is new, but I will take your suggestion and wrap it from any additional heat.
Thanks again