Eran Sharon

Hi all,

at the risk of repeating a previous post (easy although I've searched some 150 "vibrat" posts...):

When in gear and engaging the clutch (car begins to move) I am experiencing a strong vibration until clutch is fully engaged.

1. the clutch assy is new
2. The torque tube has been rebuilt (thanks a bunch DAVE "Go Fast"!).
3. engine mounts are new
4. Transmission mounts look fine to the naked eye.
5. I am experiencing no clutch "drag" as listed in the forum.

the vibration is also noticeable on 2nd gear changes, though much less as the car is already moving.

Since I have seen this happen in in "lesser" 4 cylinder cars I thought this will disappear as clutch discs do take a few miles to lose any slight warping and "seat" neatly (let's face it, not all discs were created equal). Today, however this is not the case...

Can somebody help me ? anyone encountered such vibrations?

Thanks
Eran Sharon
1980 Euro 928S 5sp
"love every inch of it"

Porsche928Driver

I would drop the clutch and have the plates, discs and such looked at and rechecked/adjusted. I don't think that the assembly is quite on the mark.

Also, when you say you are experiencing "vibration", is it at low speeds? Example: Letting out the clutch until the the vehicle is creeping along at walking speed or idle speed.
Vibration happens at 10 or 15 MPH and faster?

What is the engine RPM when you feel vibration?

Eran Sharon

Thanks, Porsche928Driver,

The vibration disappears when the car starts 'creeping' along at walking speed/idle speed. It is only happening until I fully release the clutch pedal, engaging 1st gear. No vibration after that until engaging 2nd, where it again appears, though less apparent since the vehicle is already moving and there is probably less 'torque difference' on the clutch assembly.

I followed the installation procedure in the W.Shop manual, and checked for the symptoms listed on devek.net

If you have any further insight in light of this info, please reply, as I will probably not remove the assembly until later on this week (don't feel like working these days anyway, since yesterday's tragedy)

Thanks
Eran Sharon

WallyP

This is usually called clutch chatter, or judder, or shudder, and most mechanics will understand what you mean by those terms.

Some possible causes:
Oil on the disks - not likely in your case.
Hard spots or uneven surface on the flywheel surface.
One clutch disk is installed backwards.
The clutch disks are swapped.
Warped pressure plate.
Warped center plate.
Hard spots or uneven surface on the center plate.
Bad pilot bearing - it is a good idea to replace the pilot bearing every time that you replace the clutch. A failure can cause severe damage ($$$$).

Sounds as if a careful examination is next.

Eran Sharon

Thanks, Wally

I will follow the suggested path and post here if interesting evidence (not mentioned in your list) will surface.

Eran Sharon

SteveG

"Shudder" if that is what it is, likely due to imperfections or unevenly worn flywheel. The fly can be milled by competant shop, but I've not had good experience with it on non Pcar flywheels. Unless you are doing the labor, or you have good relationship with shop doing the flywheel, I would go with a new one.