Impending clutch failure?

[db@944s.co.uk]

Hi Guys,

In your experience, what are the tell-tale signs that the clutch is about to expire?

I have no slipping, but the bite is high and there is a slight judder on take-off.

Thanks in advance,


Derek

 

[944cabby]

I had mine done around 90k or so and i had quite a bit of judder but mostly when slowing down changing down gears.

 

[timig]

I had much the same at 100k miles, lots of judder on take off (though most noticebaly when stuck in stop-start traffic).
You are in luck though, I noticed you are in Fife and can highly recommend a specialist to fix it, he did mine for me very reasonably. (no connection etc, just one of many happy customers).

 

[Indi9xx]

The clutch can fail in several ways.

Here are the symptoms and causes

1. Backlash when taking up drive or decellorating - Clutch centre decomposing (not a problem for turbos)

2. Slipping clutch - Worn out plate

3. Noisy clutch - worn out release bearing

4. Binding clutch (problems getting in 1st or reverse in particular) - Siezed spigot bearing or bad clutch hydraulics

5. Clutch pedal sticking down or slowly rising after use - Bad clutch hydraulics, often the flexi hose

6. Heavy clutch - worn out plate or in some cases a bad clutch fork

7. Juddering clutch - contaminated plate, scored flywheel or coverplate, or using an uprated clutch

Standard rubber centre clutches in normally aspirated models tend to degrade over 8 to 10 years and need to be replaced before the backlash gets to great, otherwise it can take its toll on the transmission.

All the best

Jon Mitchell

 

[sawood12]

I'm in a similar situation as you, noisy clutch bearing and very high biting point and a little bit of eveidence of slippage.

I'm looking to replace with a Cup clutch that i've noticed being discussed on Rennlist which I believe is a hybrid of a 944 turbo cluch with a 964 drive plate (or something like that). Can anyone advise where I can get one of these kits from?? I don't fancy the Spec clutch as reports of its snappy/juddery nature put me off. I belive one of the problems with the standard clutch is the small springs can break up.

 

[Indi9xx]

If its the genuine 944turbo cup clutch system, then I may be able to help with getting them.

Not sure about the using 964 plates etc... can you direct me to a thread on this subject? its just that the Americans have some funny ideas at times, such as throwning a pile of bits together, calling them something that implies they were as Porsche used them and then calling them plug and play as if they are a perfect fit.

However, the plate may have a 964 part number in a propper turbocup clutch kit, I dont think I have ever looked.

I would recommend the turbocup clutch over a specA, superfanglated or other aftermarket ones. The standard clutch, will cope with just about any amount of power you will get out of a 2.5 engine, and a propper turbo clutch I know is good for 550 BHP from experience as I know its the same part as used in the 924GTR-ex-Lemans car that we maintain. Which in qualifying trim produces 650BHP and in endurance settings produces 495bhp.

All the best

Jon Mitchell

 

[John Sims]

I'd go with Jon's recommendation.

I have a Stage II clutch and it is about as much fun as drizzling salt water in my eyes. My Independent Porsche Specialist was very impressed with the build quality but after fitting it ask me what I was going to do to the car to make it less drivable next time.

1K+ later it is still juddering and makes me look a complete during slow speed manoeuvres.

Assuming you don't want to spend all of your time doing tyre spinning burnouts (about the only way to pull away smoothly with an upgraded clutch) the only advantage of an upgraded clutch is in clamping force, so you don't get slippage during transient application of large dollops of power. There is no reason to question the capabilities of a new standard clutch in this respect.

Upgraded clutches tend to have more brutal take up and transfer more force more violently to the transmission - do you really want that agro?

 

[Fen]

ORIGINAL: John Sims

My Independent Porsche Specialist was very impressed with the build quality but after fitting it ask me what I was going to do to the car to make it less drivable next time.

I can suggest removing the power steering as the perfect complimentatry mod to the juddery Spec clutch. You think you look bad low speed maneuvering now...

 

[sawood12]

OK, you've sold me, it's just that i've heard that with the standard clutch the small damper springs can break up causing premature replacement and the cup clutch has less of these springs and they are more substantial solving this problem. I wasn't necessarily looking to upgrade due to doubts of the standard clutch's ability to transmit my 237 / soon to be 270ish BHP. Standard clutch it is then!!

 

[John Sims]

ORIGINAL: sawood12

.... my 237 / soon to be 270ish BHP....

I wouldn't put money on it []

 

[PRJ]

The 20th May Dyno Day will indeed be very interesting given a current forum 'discussion' item []

 

[Yoda]

Hi

I am occasionally getting a bit of 4 + 5 listed above.

4. Binding clutch (problems getting in 1st or reverse in particular) - Siezed spigot bearing or bad clutch hydraulics

5. Clutch pedal sticking down or slowly rising after use - Bad clutch hydraulics, often the flexi hose

What are the remedial actions as I don't think the clutch itself is worn or damaged. Replacing the master and / or slave cylinder has been suggested but open to other thoughts or experience. I have a 964 although I guess the clutch issues are common.

Many thanks

 

[sawood12]

ORIGINAL: John Sims

ORIGINAL: sawood12

.... my 237 / soon to be 270ish BHP....

I wouldn't put money on it []

I can see a small wager coming on!!

 

[eastendr]

I agree with Jon. The standard clutch seems perfectly adequate.

I even went back to a standard clutch in the RS500 when the group 'a' one went chocolate a lot sooner than the original item.

At the end of the day, I think it's more down to the style of driving than absolute power through the flywheel.

Rick.

 

[Hilux]

924GTR-ex-Lemans car that we maintain. Which in qualifying trim produces 650BHP

[8D] any piccies/details, how the h*ll do you get 650 bhp, what engine?

Re clutches, isnt the best/sensible upgrade a std one to a turbo one, or am I talking dogs danglies............[&:]

 

[Indi9xx]

Factory 924Carrera GTR Le-mans, very rare endurance race car.

650 BHP in qualifying trim is through massive ammounts of boost (over 35Psi)... The engine is a billet prototype of the 944 blocks, complete with balance shafts.. the heads were custom made and look a little like a S or S2 head with a more angular cam cover.

Big intercooler... I have some pictures somewhere, or just search in google for "Porsche GTR" and then click on images, you should find some there.. The ones with the big box arches are the propper le-mans cars... the ones with subtle arches were just GTR's.

It runs a rare form of Bosch mechanical injection, which works more like diesel injection (super high pressure).

All the best

Jon Mitchell

 

[Big Dave]

Jons quote....
"I have a Stage II clutch and it is about as much fun as drizzling salt water in my eyes. My Independent Porsche Specialist was very impressed with the build quality but after fitting it ask me what I was going to do to the car to make it less drivable next time.

1K+ later it is still juddering and makes me look a complete during slow speed manoeuvres"....
---------- ------------- ------------- --------
To be honest ... I dont realy want to say ,, I told you so.!!!!!!!!!!!!!!
If you check back through the "clutch" posts regarding Spec clutches..

 

[John Sims]

ORIGINAL: Big Dave UK
... I dont realy want to say ,, I told you so.!!!!!!!!!!!!!!
If you check back through the "clutch" posts regarding Spec clutches..

Don't worry Dave I'm a big boy and am willing to stand by my mistakes. [] Beaky does rev quite nicely now (for what it's worth). I'm not sufficiently cheesed off with the upgraded clutch to want to change it, but wouldn't want anyone else to do what I did without appreciating the drawbacks.

 

[Diver944]

ORIGINAL: Indi9xx

Factory 924Carrera GTR Le-mans, very rare endurance race car.

You REALLY need to get that along to your open day when you move premises [8D] I'd always wondered where the Le Mans 924s were and have been hoping for years to see them at the Le Mans Classic events when they become eligible

Anyway back on topic. If a Turbo Cup clutch is good enough for a Le Mans car and is still easily driveable on the street then thats the sort of clutch I want in my car []