911sc shudder on take off

floodbkt · 12-02-2002, 05:57 AM

does anyone know what would cause a slight shudder when taking off from a stop in first gear? 83 911sc!

thanks,

flood

Eric Mckenna · 12-02-2002, 06:02 AM

I would think it could be your Clutch need adjusting. but it could be a few things I am sure.. I hope someone else has some insight..

Cheers,
Eric

floodbkt · 12-02-2002, 06:04 AM

that is what i was thinking, but is shifts ok. if i let the clutch out faster it seems to help. it also seems to be more noticable when the car is cold.

thanks for any help.

sithot · 12-02-2002, 07:09 AM

Worn pressure plate/clutch face or glazing of either. How old is the clutch?
Leaking rear main seal can spray oil around on the face and create some issues as well. Since SC's are tight engines I would say is likely not an issue so don't get too worked up!

Also might want to check your CV's too. They would be more obvious but while your there have a look-see. One of the most overlooked maintainence items on a 911.

Good luck.

yelcab1 · 12-02-2002, 07:41 AM

I vote for uneven wear on your flywheel.

sithot · 12-02-2002, 07:46 AM

I'll buy some of that as well. If you get to that point, it's always a good idea to have it checked and resurfaced.

ebrownson · 12-02-2002, 08:10 AM

I have read on this BBS(I think it was JW) before that it could be three things:

1) uneven wear on the flywheel'
2) clutch cable rubbing or catching on the underbody' or
3) engine or transmission mounts.

I have the same thing and will probably check the clutch cable and replace mounts before I take it in for a flywheel grind.

Eric
83SC

john walker's workshop · 12-02-2002, 08:17 AM

replace the clutch assembly and surface the flywheel. 95+% of the time, that will fix it.

floodbkt · 12-02-2002, 08:39 PM

it seemed to happen very suddenly. fine and then noticable. wonder if this points to clutch cable????

don911 · don911's Garage

My clutch will shutter when it gets really hot. It works fine until I'm in stop and go traffic. I'm sure a clutch job is in my future.

kristian85 · kristian85's Garage

Quote:

Originally posted by floodbkt
does anyone know what would cause a slight shudder when taking off from a stop in first gear? 83 911sc!

thanks,

flood

Dunno, Flood, mebbe you're cold and should turn the heat up? Or are you speaking of the car?

Glasgow 911SC · Glasgow 911SC's Garage

Quote:

My clutch will shutter when it gets really hot. It works fine until I'm in stop and go traffic. I'm sure a clutch job is in my future.

Ditto

ron69912t · 12-03-2002, 05:44 AM

Oil on the clutch plate causes it to slip & grab! Rear oil seal probably the source.

Ron

tryan · 12-03-2002, 06:22 AM

the ansewer is d. all of the above

post last week..... shudder cured with cable adjustment.

tperala · 12-03-2002, 08:32 AM

floodbkt, my SC had similar symptoms. I replaced the clutch cable and it solved my problem. The cable housing had worn severely and was binding, causing the release to be, err, not smooth.

Good luck.

Tim

floodbkt · 12-04-2002, 05:37 AM

clutch cable seems likely. i took it out last night and it showed no symptoms at all. the clutch definitly has taken on a little bit of a strange feel, like there is some irregularity in the cable.

is it hard to replace?

tperala · 12-04-2002, 06:38 AM

floodbkt,

Replacing the cable is not too difficult, maybe a couple of hours if you don't run into any other problems. I did.

The cable itself is pretty straightforward. If I recall, the most frustrating part was reattaching the pin/trunion in the tunnel up near the pedal cluster.

My largest problem with the job was the PO had not kept the cable adjusted properly. As the clutch wore, the freeplay at the pedal went away, and the cable itself was under constant tension. This probably lead to the cable's premature failure.

What's worse is that the arm at the bottom of the clutch actuator shaft (I am making up these terms as I go along) was rusted to the actuator shaft. It should rotate slightly on that shaft. It was a bear to get off!

The good news is that the pedal became much easier to operate, takeoffs were smooth, and overall shifting seemed to improve.

Hopefully you won't run into this same problems I did. I think there is a tech article on replacing your clutch cable and adjusting it on Pelican's web site that will help.

Good luck.

Tim

tryan · 12-04-2002, 07:31 AM

i'll probably get hit for internet bunk, but here goes.

if you get your flywheel resurfaced, it is best to take the same amount off the pressure plate mounting surface on the flywheel.

it helps to maintain pressure at the wear limit of the friction disc.