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Strong clutch; where from?

911hillclimber

911hillclimber

PCGB Member
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I am on the look-out for a decent clutch for my Lola Porsche project.

It must have a sprung centre to the driven plate, fit the stock flywheel and be able to tolerate 5000rpm drop-the-clutch starts with a 500Kg car, 250 lbft and 12'' wide soft slicks...and fit a 3.2/915 drive train.

AP list a 'fast road' organic centre plate with a stock cover plate, so the F&Sach unit must be good?
I once had a real RSR alum cover plate with cerametalic 4 paddle/sprung centre. Bit snatchy, but strong.

Any ideas/supppliers?
Would a stock cast iron F&S road unit be ok??

Graham.
 
I've been using a "power clutch" from Crispin at Oak Tree Garage for the last 18mths +. Not as good as our old triple plate clutch, but has handled the power and weight OK, and it's an aluminium cover, so a bit more free revving than cast iron. Shouldn't be any problem in the Lola with half the weight of our old beast..................[8D]

Happy New Year!

JW
 
Happy New Year to you too!

Thanks for the info. I've found a Quartermaster single and twin plate sprung centre unit in Demon Tweeks, but not sure if it will fit the 911 flywheel.
400+ lbft capable!
 
Ahhh!
Super Clutch is Tony Tewson's outfit who were on my To Call list today.
Tony is a long standing hillclimber, so I'll be in safe hands. Will see what he has to say.
 
Interesting conversation with Tony at Superclutch dinner time.
Fitting a twin plate/solid centre plated cerametalic 7 1/2'' unit needs a fair bit of engineering to squeeze it all into the minute 915 bellhousing.
However, tony suggested a nice try-it-and-see solution for starters in the form of a stock (preferably aluminium) cover with a Helix organic sprung centre as the car is mid engined and light comparted to the 911 1000Kg and rear engine traction.

This will be the route to follow, and come Xmas it will be interesting to see how the Helix tolerates the hillclimb starts.
Can clutch covers be re-faced?

I also ended up designing a corporate T shirt...[8D]
 
The stock 2.4 to 3.2 clutch assy I know is good and strong after knocking hell out of my Bitza on the hills. But they are cast iron (which I think is best for the 'heavy' 911 car), but to get some low down improvement, the alloy cover will ease the inertia the engine has to overcome. I took about 3 Kg out of my Impreza;s flywheel and the difference was marked, and for gear changes too. God knows the 915 needs all the help it can get.

The car came with an alloy cover, well used, and the organic disc was well past the sell by date, well past. However, this combo will make the Lola easy to drive up a hill. It is also cheap. The twin plate 7.25'' clutches will be £1000 when finished, A Helix plate is about £150. I can almost buy all the slicks for the car for the difference.

Big issue will be the 12'' wide Avon hillclimb slicks, about as soft as natural rubber from the tree.
 
Gone around the houses on this one as ever with this car.

Superclutch were very helpful indeed, and suggested for a season to fit a good stock type clutch rather than a twin plate (which certainly is not a bolt-in option).

Spoke to Helix about an uprated organic/alum covered 225mm to be quoted a huge £620...
Spoke to design911 about their Sach uprated one @ £400, so better but still tight. A stock organic Sach is starting to appeal! (£250), but I think I will end up with the £400 Sach.

Nothing is simple?
 
It occurs to me that you will be running uncut wets on the back made with a very soft compound. Twin plate or even single plate with sintered friction surfaces mean that the clutch is either in or out with no slip - and that will create problems if you need to get off the line at a trillion revs and a clutch drop.
Francis Tuthill sold me a Sachs powerflow for the RS at less than £400 complete; loads of grip if you drop the clutch and it drives just like a shopping car.
It's an economical way to start?
 
Yep, that's the one. Seems a good way to see how things go.
The tyres on the Lola are very old, esp the front, but the cut slicks for 'wets' are unused odly.

For the 4 hills I expect to do this year to shake the car down I'll be trying them. I have fronts and rears. That will save £1200 on fresh tyres that will be duff by 2010.

The rear of the car is all painted black since the wife allowed a pass-out to the garage for the weekend, so got lots done.

I have a neat pile of tubes all ready for the nickel platers, and a very long shopping list for gaskets etc so I can finish off the underside of the engine. With a clutch and a repaint of the box it can go into the car for good (well, for 2009 anyway)

I love this stage of a project when all the hours start to come together.

It is important to have 'achievment' points on a long haul job like this.

I think over the next 2 months it will move a long way forwards.(it needs to)

[8D]
 
Be careful with the sachs power clutch,they say its ment for fast road and no racing at all.
I destroyed 2 power clutches,1 at loton. on the 3 rd run,NO come back what so ever.Sachs do a motorsport ali cover,this on its own was over 400.But it takes the greif and most circuit racers use it.Funny enough it says race clutch on the box,looks very similar apart from stronger spring and thicker tourque pins.
I know from past talks with jw ,that he uses a powerclutch and finds it ok.,but it is a little slow off the line!!!![;)]
I dont think you will have much problem with the little 908 sorry lola,looking good.
I have been using a tilton tripple plate for about 5 year now,very good.The whole package of fly wheel,cover and plates etc weight half the weight of a factory lwt fly wheel alone!It is expensive.
Also smart racing do a nice kit,of which some parts look like tilton.
What clutches do ultima cars run as they use a shortened 915 box etc
 
That is very interesting Paul, and thanks for the reply.

As you know the Lola is 550Kg and a 'JW' 911 is about 850Kg. I don't want to carry the cost of a twin or thripple clutch (and all the engineering) because of the time it all takes, so I'm even tempted to fit an uprated plate and a stock cast iron cover, but those slicks will be very reluctant to spin with only 230 bhp ish.

The clutch is to get me going for about 4 events in 2009 assuming I try to be on track for June/July.

Do we think a stock Sash will tolerate some shake-down runs?
 
[:D] With that fan behind me it will be blown out or force blown!

Tony at Superclutch thought it worth putting a 'cheapo' clutch in and see what it is like at the end of the season.
If all is well:
1
It is a good clutch so carry on[8D]
2
I'm not trying hard enough....[&:]

Still tempted to use an iron Sach for £250. with the ponderous 915 gearchange why worry about the flywheel/cover mass realy?
When Terry had the engine it had an RSR type alum cover Sach with organic plate, but both are well cream-crackered.[8|]
 
Still tempted to use an iron Sach for £250. with the ponderous 915 gearchange why worry about the flywheel/cover mass realy?
When Terry had the engine it had an RSR type alum cover Sach with organic plate, but both are well cream-crackered.[8|]
Click to expand...

I think you'll find that the cast iron one will be too heavy - I would still go for the alloy cover. We noticed quite a difference (for the worse!) when we changed from our triple plate clutch to the alloy one.
You won't have any trouble spinning up the rears - I run 10" rears on the 911, and with 900kg ish and enough traction to pull sub 2sec starts there's no problem.........[8D]
I agree that it's not for now, but a triple plate clutch while expensive, is excellent value for money. We fitted ours in the previous car [8|] in 1985, transferred it to this car in 1986, and it lasted until 2008, 20 odd events a year, and a lot double driven[8D]. Wish I could find another one...........

Cheers!

JW
 
To ease the $$$ and the time side, I had toyed with the thought of building a twin plate special from Superclutch on a flywheel with all the bits so to transfer it over later (next year).
Tony says there is very little space in the 915 bell housing (very true) and the driven plates are all solid discs. Will the 915 tolerate such a clutch? Seems it will Jonathan from your experience (it was a 915 and not a Turbo box?)
 
Seems it will Jonathan from your experience (it was a 915 and not a Turbo box?)
Click to expand...

It has been several 915 gearboxes..................[8|]
We have broken most things inside and outside, including spitting the diff right out through the side on the Start line at Loton[:mad:]
The 3.2 915 that we currently have seems a much stronger unit.

Cheers!

JW
 
I was the start line Marshal when you did that at
Loton! Bloody hard start iirc.
Took a look at the alum clutch out of the transmission this afternoon. The pressure plate is crazed with fine cracks, is not flat and has 'hollows' in the surface...otherwise it looks good!
It is Soooooooo light though, so that does it. A Sash sports clutch with organic plate and say a little prayer on the start line.

I guess the previous gearboxes were mag alloy cases Jonathan?

Lots os bits arrived this week. The Smart Racing stuff is on (and looks sexy), the headers are all wrapped, and look neat, the fan is all back on and looks cool.

Best order the clutch pdq!
 
It's in there somewhere........[:-]

72721F6B02324225A29012A9D568B75F.jpg
 
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