What's Causing This...
Thread Starter
Racer
Joined: Jun 2013
Posts: 278
Likes: 22
From: Concord NH
What's Causing This...
2003 Z06: So, a completely new engine, new clutch assembly (Kevlar) and an unexpected consequence... The clutch won't release at rpm's above about 5,000.
My question is not what do we need to replace, but why does this happen? Does the higher rpm cause an increase in load due to centrifugal force? It shifts normally up until then...
New master cylinder, fluids, pressure plate and clutch plate. Slave is fine as is the throw out bearing...
I'm just trying to understand the cause so that I can affect a fix.
I know that a lot of others have had similar results and have gone to an adjustable Master Cylinder (like the one that Tick sells), but there problems were typically across a broad range of rpms...
If anyone can explain the science behind what is going on, I'd sure appreciate it!
Jeff
My question is not what do we need to replace, but why does this happen? Does the higher rpm cause an increase in load due to centrifugal force? It shifts normally up until then...
New master cylinder, fluids, pressure plate and clutch plate. Slave is fine as is the throw out bearing...
I'm just trying to understand the cause so that I can affect a fix.
I know that a lot of others have had similar results and have gone to an adjustable Master Cylinder (like the one that Tick sells), but there problems were typically across a broad range of rpms...
If anyone can explain the science behind what is going on, I'd sure appreciate it!
Jeff
Melting Slicks
Joined: Jul 2010
Posts: 2,503
Likes: 33
From: McGrady NC
St. Jude Donor '15-'16
In the old days, it was because the clutch springs were too weak or the throwout bearing was over-centering (pushing on too far at high RPM's so that centrifugal force was not letting it spring back and grip the disk). I think that the better slave cylinders, like Tick's, control the clutch better and deal with your problem.
Melting Slicks
Joined: Nov 2008
Posts: 2,938
Likes: 65
From: Rochester Hills MI
So you replaced all those things without replacing the throwout bearing/slave assembly? 
What makes you think it's fine?
FWIW, the tick slave is just an oem GM slave sold by tick. There are not upgraded throwout bearing/slaves available to my knowledge.
This link pretty much explains what you need to know about why it would stick at high RPMs. The clutch fluid gets hot at high rpms. Eventually the seal gets worn out, the cylinder doesn't have the same surface finish it used to. All these things result in the cylinder sticking just as any other type of hydraulic cylinder.
http://ls1tech.com/forums/manual-tra...-write-up.html
What makes you think it's fine?
FWIW, the tick slave is just an oem GM slave sold by tick. There are not upgraded throwout bearing/slaves available to my knowledge.
This link pretty much explains what you need to know about why it would stick at high RPMs. The clutch fluid gets hot at high rpms. Eventually the seal gets worn out, the cylinder doesn't have the same surface finish it used to. All these things result in the cylinder sticking just as any other type of hydraulic cylinder.
http://ls1tech.com/forums/manual-tra...-write-up.html
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
MAN,,,,,,,,,,,,,,, You left out a LOT of details on your clutch replacement. What CLUTCH SYSTEM parts were replaced????
Slave Cylinder?
Pilot Bearing?
Clutch Disk?
Pressure Plate?
Throw Out Bearing?
MASTER CYL??
Please add the information..
Was the slave cylinder properly shimmed when the clutch was installed??
Do you have a remote bleeder kit installed?
Bill
Slave Cylinder?
Pilot Bearing?
Clutch Disk?
Pressure Plate?
Throw Out Bearing?
MASTER CYL??
Please add the information..
Was the slave cylinder properly shimmed when the clutch was installed??
Do you have a remote bleeder kit installed?
Bill
Former Vendor
Joined: Jun 2008
Posts: 1,222
Likes: 7
From: Mount Airy NC
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Another good read here: http://tick-performance.com/images/tickshiftfaq.html
Outstanding read and great information.
You have to get something like that for the Slave Cylinder SHIM!
I added this to my HAVE TO HAVE POST list.
Bill Curlee
Former Vendor
Joined: Jun 2008
Posts: 1,222
Likes: 7
From: Mount Airy NC
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
Thanks Bill! It is on LS1tech, but here is a popular thread we started about slave cylinder shimming: http://ls1tech.com/forums/manual-tra...need-shim.html
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