vibration / shuttering in first

My CMC VW based speedster shuttters rather violently in first when starting out from a stop. It doesn't happpen while driving or shifting. Just when letting out the clutch in first. I've varried the rate (with my foot) that I let the clutch out and the engine rpms, but it doesn't make much difference to the vibration. It rattles the doors and all the deck lids. In traffic it really gets to me. Once the car is rolling its fine.

Dave,
Things to check:
Tranny mounts. If worn, torn, or loose, that'll cause it.

Yoke that carries the tranny bell housing mounts. If those 2 big bolts that mount the yoke are loose, that'll cause it.

Bowden tube and clutch cable tube that is welded in the Pan.
If the bowden tube doesn't have the propper droop or bend in it, (especially if it goes straigh across) that's usually an indication that the clutch tube is broken from the pan.
the bowden tube without the droop, and or broken clutch cable tube in pan, that'll cause it.

If all those things look good. It may be time to pull the motor and check the pressure plate and clutch. If either of these is broken, especially the pressure plate, that'll cause it.

Good Luck.
Greg B

You might also check to see if the transmission main shaft seal is leaking oil onto the flywheel or clutch plate.....this will also have the same effect

I'll bet you a buck it is the bowdin tube. You can get the proper droop measurements from a VW manual. Its an easy fix.
ed

looks like I'm going to be up to my elbows in speedster this weekend. Thanks for the help. I'll post when I find something.

I'm with Ed! Boden tube for sure . . . or . . . all that other crap.

OK, now I'm undecided.

Nope! Boden tube it is, absolutely.

I've had same symptoms with oil on clutch disk from leaky main seal and also from burn marks (caused by racy starts and clutch slipping) on the pressure plate/flywheel. When I pulled clutch plate there were several quarter size blue marks on the pressure plate surface.

I'm a believer in the bowden tube. I'm going today to get a VW service manual, but here's what I found.
First, there was some droop in the tube, but I couldn't quite tell how muchas I had a hard time getting to the female end on the tube side. The male end nearest the clutch had no washers on it at all leading me to believe there is not enough droop in the bowden. I snaked my arm up in there and pulled a little down on it and it gave me some slack. becuase I could see the male end I assume the slack came from the female end on the tube. I think in the process I may have pulled the female end off the tube or partially off the tube. The test drive around the block gave me some clutch chatter, but not as much. It does chatter in reverse also.

I'm posting another topic that may be related about a whining noise in the clutch.