Track Day Clutch Failure

[Kett]

I can't think it would be the fluid because the brakes would have failed first...

It has be:
some problem with the master/slave cylinder
or
air bubbles in the system
or
an unidentified problem with the single-mass wheel conversion

 

[Lankan]

I can't think it would be the fluid because the brakes would have failed first...

an unidentified problem with the single-mass wheel conversion

The TTV has been brilliant so far, have had it for just under a year now, and no issues whatsoever, so certainly hope it is nothing to do with this conversion. Taipan has done circa 2,000 miles (on a trip to the continent), with some spirited driving on some Alpine passes, without issue.

Of course, this is the first time I took #002 on track......but the issue (or symptom) has been seen on more than one Vee with a standard dual-mass flywheel.

 

[k1ano]

Probably repeating some of the above ...

The slave cylinder is in the gearbox/bell housing so heat could cause boiling of the clutch fluid locally if it hasn't been regularly changed.
Shared fluid can impact the clutch if the fluid is low causing engagement problems requiring pumping of the clutch pedal to allow gear engagement.
As brakes wear the fluid level drops below the point at which the clutch circuit is fed causing clutch issues before brake issues as the brake feed is lower down.
Organic clutches can heat up and lose effectiveness when hot which is restored when they cool down.
It is easy to slip the clutch even inadvertently when driving in a spirited fashion.

Simple solutions to eliminate a worn clutch are ...

Simply replace and bleed clutch and ideally brake fluid and ensure levels are correct.

Martin

 

[Kett]

I can't think it would be the fluid because the brakes would have failed first...

an unidentified problem with the single-mass wheel conversion

The TTV has been brilliant so far, have had it for just under a year now, and no issues whatsoever, so certainly hope it is nothing to do with this conversion. Taipan has done circa 2,000 miles (on a trip to the continent), with some spirited driving on some Alpine passes, without issue.

Of course, this is the first time I took #002 on track......but the issue (or symptom) has been seen on more than one Vee with a standard dual-mass flywheel.

It's a desirable conversion - as are the trophy coils that you've had fitted.
: )

It's just a process of elimination. If you've learned of cases where this has occurred with the dual-mass flywheel - then you can rule that one out.

Replacing the fluid should resolve. Super dot 4 is what the Porsche techs used to advise (back in the day).

 

[Ben123]

I've got some useful experience here.

A year ago my car was standard. Phase 2 clutch and dual mass flywheel. I lost my clutch mid way through a "car limits" day. Came back when cooled down. Brake fluid was old - put it down to this. Bled just the clutch and problem went away.

At Goodwood my car had just come back from SG. Now has phase 1 clutch, TTV flywheel and brand spanking brake fluid. Lost clutch mid way through final session. Again came back when cool.

I believe it's an inherent design issue with heat build up around the slave cylinder I guess and the fluid just boils locally. Bleeding through until you get to non-boiled fluid puts you back to square 1.

I guess what we need to find is the best fluid in terms of heat-resistance vs longevity.

 

[Lankan]

I can't think it would be the fluid because the brakes would have failed first...

an unidentified problem with the single-mass wheel conversion

The TTV has been brilliant so far, have had it for just under a year now, and no issues whatsoever, so certainly hope it is nothing to do with this conversion. Taipan has done circa 2,000 miles (on a trip to the continent), with some spirited driving on some Alpine passes, without issue.

Of course, this is the first time I took #002 on track......but the issue (or symptom) has been seen on more than one Vee with a standard dual-mass flywheel.

It's a desirable conversion - as are the trophy coils that you've had fitted.
: )

It's just a process of elimination. If you've learned of cases where this has occurred with the dual-mass flywheel - then you can rule that one out.

Replacing the fluid should resolve. Super dot 4 is what the Porsche techs used to advise (back in the day).

Indeed Kett, as with the Coils, I am keen to find the root cause, and resolve it with a solution that will eliminate, or minimise, the issue. As such, I certainly hope the TTV is not the root cause for losing the clutch pedal, which from the feedback received so far, does not appear to be the case.

The first I heard of this issue was to the job on the day (with new brakes, brake hoses, fluids and tyres), and also specifically instructed Scott to flush the pipework on the clutch side. New Phase 1 clutch kit and Slave Cylinder (along with TTV flywheel and Quaife ATB diff) were only installed in October 2013 (at 26K miles - now at 28K miles).

Use of ATE (Super) Blue is very common amongst Porsche circles, which certainly was widely used back in the day 10 years ago, which is when I was last out on track.

 

[Lankan]

I've got some useful experience here.

A year ago my car was standard. Phase 2 clutch and dual mass flywheel. I lost my clutch mid way through a "car limits" day. Came back when cooled down. Brake fluid was old - put it down to this. Bled just the clutch and problem went away.

At Goodwood my car had just come back from SG. Now has phase 1 clutch, TTV flywheel and brand spanking brake fluid. Lost clutch mid way through final session. Again came back when cool.

I believe it's an inherent design issue with heat build up around the slave cylinder I guess and the fluid just boils locally. Bleeding through until you get to non-boiled fluid puts you back to square 1.

I guess what we need to find is the best fluid in terms of heat-resistance vs longevity.

Ben, I am glad someone else experienced the same thing I did, and under exactly the same conditions and with the same variables in play!

So going on from what you state above, as well as what Simon, Brett and Martin have said, heat build up localised to the clutch (slave cylinder) area appears to be the culprit. Eastlmark recommended the use of Castrol SRF, which is a full on race spec fluid (see one of my posts above).

Anybody used Castrol SRF in their Vee?

 

[Ali]

Nope, but it's rated to the same boiling point as the fluid I'm currently running in the Vee. (Millers 300) 590F Dry. So I can't see that a change to SRF would make a difference tbh!...Ho hum!

 

[Lankan]

Nope, but it's rated to the same boiling point as the fluid I'm currently running in the Vee. (Millers 300) 590F Dry. So I can't see that a change to SRF would make a difference tbh!...Ho hum!

....but you didn't have complete failure, right? So does it not mean that a more performance/race oriented fluid will hold up better, which may well be the way forward.

Castrol SRF has been proven to last a full race season with a couple of bleeds during the season.

Thoughts?

 

[Ali]

Nope, but it's rated to the same boiling point as the fluid I'm currently running in the Vee. (Millers 300) 590F Dry. So I can't see that a change to SRF would make a difference tbh!...Ho hum!

....but you didn't have complete failure, right? So does it not mean that a more performance/race oriented fluid will hold up better, which may well be the way forward.

Castrol SRF has been proven to last a full race season with a couple of bleeds during the season.

Thoughts?

In my last session I did. Pedal to the floor. First session, no issues at all.

For sure it would be better than OEM.

 

[Eastlmark]

Nope, but it's rated to the same boiling point as the fluid I'm currently running in the Vee. (Millers 300) 590F Dry. So I can't see that a change to SRF would make a difference tbh!...Ho hum!

....but you didn't have complete failure, right? So does it not mean that a more performance/race oriented fluid will hold up better, which may well be the way forward.

Castrol SRF has been proven to last a full race season with a couple of bleeds during the season.

Thoughts?

Not in the vee but in the Spider, all other fluids would boil (brakes only as it had a cable clutch). Once switched to SRF I never had an issue again. Mindbogglingly expensive, so much so that you wince every time you bled the brakes at the amount you discard.... however I found the brakes did not need routine bleeding at all during a race season so made up for it. It is however a motorsport fluid and not dot rated and will need replacing yearly.
Have seen plenty of ph1 and 11 vees trackdaying over the years using normal fluid without issues though so, as you suggest, although the fluid may cure the fault, it is probably not the cause.

 

[Ali]

Will give it a try! Cheap fix if it works!