Clutch Shudder
Addict
Rennlist Member
Rennlist Member
Joined: Jul 2003
Posts: 2,577
Likes: 52
From: Atlanta
I have done the bone-head clutch scorch in the 964. Clutch worked fine before I did that, and it is still great 4 years later.
Pro
Joined: Jan 2005
Posts: 701
Likes: 6
From: St. Albert, Alberta, Canada
i'm wondering if the clutch judder i experience is a result of using the normal looking disc that Vertex sells rather than the old rubber centered style (of the 89 C4). It certainly does grip.
Also, when drag racing a 90's corvette on the freeway on ramp - only up to the legal speed limit of course - tonight I noticed "clutch smell" coming from the dash vents (the heat was on because it was only about 8 degrees out so it was getting the "fresh air" from the engine bay instead of up front). Is clutch smell normal for a new clutch when it's used hard (borderline abuse
)
Also, when drag racing a 90's corvette on the freeway on ramp - only up to the legal speed limit of course - tonight I noticed "clutch smell" coming from the dash vents (the heat was on because it was only about 8 degrees out so it was getting the "fresh air" from the engine bay instead of up front). Is clutch smell normal for a new clutch when it's used hard (borderline abuse
)
Advanced
Joined: Oct 2006
Posts: 98
Likes: 0
From: Kent/Surrey UK
Agree with altarchsa
I had the same symptoms. Required a clutch and flywheel change to sort out. The clutch was on the limits and misaligned with the flywheel causing hotspots, which is the cause of the judder. It's an expensive fix but the car is transforme after it is done.
I had the same symptoms. Required a clutch and flywheel change to sort out. The clutch was on the limits and misaligned with the flywheel causing hotspots, which is the cause of the judder. It's an expensive fix but the car is transforme after it is done.
Instructor
Joined: Jul 2005
Posts: 197
Likes: 0
From: London, England
I had exactly the same symptoms two years ago, which was gradually gettinh worse. I had the clutch replaced and the shuddering disappeared completely. So I would go along with the idea of spinning & slipping the clutch to see if you can burn any contamination off, and if not then dig into that wallet and have the clutch replaced. 
Three Wheelin'
Joined: Jul 2007
Posts: 1,307
Likes: 0
From: Helotes, TX
I think you can smell a burned clutch no matter how tight the car is sealed up. I've cooked the surface on a couple of them and they never seemed to operate as smoothly thereafter, including juddering, because of the glaze that spinning it hard puts on the surface of the disk. If you remove the clutch, you can restore it by wire brushing the glaze off the faces. A cup type wire brush on a drill works best I think.
UPDATE:
I installed the new flywheel and "almost new" clutch kit from OK Foreign this weekend.
WOW!!!!!!!! Clutch is sooo smooth now. It grabs low on the pedal and there's absolutely no judder. Pedal pressure is asbout half what it used to be, but that improvement may be due to some R&R I did on the release fork shaft while I had it out.
I found that the metal bushings on the shaft had worn through on one side. I "manufactured" a repair to the bushing instead of ordering new parts. Since it was the last opportunity I would have to finish the job before the Maverick AutoX Time Trials this weekend, I didn't want to wait for parts. Hope I don't regret this patch later.
Frankvan, you mentioned that you used the more standard looking clutch instead of the rubber center clutch like in the '89s. You don't say if you have an '89, but that's what I have and the advice I was given by several parts houses was that you can't use the later model clutch. The '89 is a one year only design and the shaft and clutch diameter are different.
I found this out after I had directed Zim's to send the later model clutch, thinking that's what I had. It is definitely a different setup and the new later model clutch is still sitting in the box.
Please keep us posted on what you find.
UPDATE:
I installed the new flywheel and "almost new" clutch kit from OK Foreign this weekend.
WOW!!!!!!!! Clutch is sooo smooth now. It grabs low on the pedal and there's absolutely no judder. Pedal pressure is asbout half what it used to be, but that improvement may be due to some R&R I did on the release fork shaft while I had it out.I found that the metal bushings on the shaft had worn through on one side. I "manufactured" a repair to the bushing instead of ordering new parts. Since it was the last opportunity I would have to finish the job before the Maverick AutoX Time Trials this weekend, I didn't want to wait for parts. Hope I don't regret this patch later.
Frankvan, you mentioned that you used the more standard looking clutch instead of the rubber center clutch like in the '89s. You don't say if you have an '89, but that's what I have and the advice I was given by several parts houses was that you can't use the later model clutch. The '89 is a one year only design and the shaft and clutch diameter are different.
I found this out after I had directed Zim's to send the later model clutch, thinking that's what I had. It is definitely a different setup and the new later model clutch is still sitting in the box.
Please keep us posted on what you find.
