Clutch pressure plate weight - gearbox 901 -

Max911 · Post by **Max911** » Tue Mar 07, 2017 9:40 pm

Hello

Finally assemblying clutch kit (I ordered a sachs kit from rosepassion.com) I notice that new pressure plate is not made of aluminium and much heavier...

6kg versus my original(?) alu 3,5kg !!!!

An enormous difference.

Although I bought the "sachs racing pressure plate" From rosepassion.com I would obtain a 4,7kg... Not comparable with my original one.

What would tou suggest me to do?
Is anywhere available an original specs clutch pressure plate?

Thanks
Max

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Bruce M · Post by **Bruce M** » Tue Mar 07, 2017 10:57 pm

Swb 911"S"?
I vaguely recall reading on the forum they had a light weight clutch.

One of the "Mike"s will be along in a bit to explain.....

fetuhoe · Post by **fetuhoe** » Wed Mar 08, 2017 8:08 am

A 901 Gearbox has a 215mm diameter 'push' clutch and there are 2 x different versions - one for the Normal 911 and an uprated cover for a 911S.

These covers are both pressed steel with the S Version being heavier. I have never seen An aluminium Cover used on this style of transmission although I am sure that it may be possible to modify the system to use an aftermarket 'lug' clutch.

If you have an aluminium 215mm push clutch I would be very keen to see a photograph.

The '911' transmission fitted to the later cars was available with a 215mm push clutch on the 1969MY and 225mm pull clutch on the 1970 2.2 litre cars.

The later 225mm clutches use a 'pull' method of actuation and the cover is available in either Cast Iron or Aluminium.

The Aluminium style cover is not only lighter but typically has a greater clamp force.

The increased inertia of the Cast iron clutch will have an impact on the acceleration of the car in the lower gears and if you are accustomed to the lighter clutch you may be unhappy.

Lightweight_911 · Post by **Lightweight_911** » Wed Mar 08, 2017 8:14 am

Here are some comparison weights from my 904 build a few years ago:

Std ’65-’69 2.0 litre flywheel weighs 5.73/5.86 Kg (12.6/12.9 lbs)

906-style lightweight flywheel weighs 4.2 Kg (9.24 lbs)

Lightening has removed ~ 1.6 Kg (3.5 lbs)

901 & 914/6 all-steel clutch pressure plate weighs 4.3 Kg

’69 911S steel/alloy clutch pressure plate weighs 3.1 Kg

Clutch weight saving is 1.2 Kg

Total clutch & flywheel weight saving ~ 2.8 Kg

The big drawback with using a '69 S pressure plate is that you need to use the corresponding (thinner) '69 S clutch (driven) plate - which is very difficult to find.

You could use a '67/'68 S (copper-faced) alloy pressure plate as this uses a std thickness clutch (driven) plate.

However, all of these pressure plates are hard to find - & expensive!

fetuhoe · Post by **fetuhoe** » Wed Mar 08, 2017 10:08 am

Andy,

Do you have a photograph of the 69S Pressure Plate - I would also be interested in the copper faced alloy pressure plate.

When I last bought an S Clutch from Sachs it was a steel pressing.

Thanks

Chris

fetuhoe · Post by **fetuhoe** » Wed Mar 08, 2017 11:05 am

I just found a photograph of the 96S pressure plate - copper coloured - which if its is Aluminium must be a hard faced coating.

I bought a 69 S clutch from Sachs last year and it was all steel and heavier then a standard clutch.

Refacing a clutch plate to the relevant thickness shouldn't be an issue but the cover could be more difficult if they are not available.

If anyone has an old cover I would be interested to take a look.

Lightweight_911 · Post by **Lightweight_911** » Wed Mar 08, 2017 12:29 pm

Chris - the '69S pressure plate wasn't copper-plated - that was the earlier ('67S/'68S) version (an often repeated mistake - especially on Pelican).

Part number for the '67S/'68S pressure plate (which had a copper-coated mating surface) was:

901 116 003 01

This was used in conjunction with a standard thickness driven plate (901 116 014 00)

Here are some (poor quality pictures):

Part number for the '69S pressure plate (which had a steel-coated mating surface) was:

901 116 009 00

This was used in conjunction with a thinner ( 6.5mm-7.0mm) driven plate (901 116 017 01)

Here are some (poor quality pictures):

Both of these steel/alloy ('67/'68 & '69) lightweight pressure plates had a steel outer cover.

.

Lightweight_911 · Post by **Lightweight_911** » Wed Mar 08, 2017 12:32 pm

As far as I'm aware, neither version has been available for many years - ditto the thinner '69S driven plate.

Certainly for my 904 I had to source NOS parts.

Apparently the copper-faced '67/'68 version wasn't successful (as the copper proved too soft ?) &, I would imagine, most/all '67S/'68S models have long-since had theirs replaced with std steel items.

The '69S steel-faced version is, if you can find one, a lot more expensive (& as mentioned previously, very hard to find) so, again, many have probably been replaced with the non-S all-steel pressure plate & std thickness driven plate.

davep · Post by **davep** » Wed Mar 08, 2017 12:50 pm

Andy is correct, the copper faced pressure plates were problematic, thus only in use for a year or two. The 69S aluminum version was only the one year before the whole design changed. I have managed to keep one set with a spare disc for future needs. These parts are rare and expensive now, but do pop up occasionally. I don't know if the last one I saw sold or not.

TimB · Post by **TimB** » Wed Mar 08, 2017 1:42 pm

I thought 901.116.003.00 was the 'copper faced' for 67/68 911S and this was replaced by 901.116.003.01 ? (None 'S' swb being 901.116.001.00).

Lightweight_911 · Post by **Lightweight_911** » Wed Mar 08, 2017 2:33 pm

You may well be right Tim - I just copied those part nos from an old note I had on my computer - when searching for lightweight steel/alloy clutch parts for my 904 I used Sachs part nos from memory ...

I think I have some pictures of NOS parts I bought in their original packaging - will have a look later ...

Max911 · Post by **Max911** » Thu Mar 09, 2017 1:09 pm

Thank you so much GentleMen for all your competent consideration!!

Sorry I forgot to tell that my car is a 2,2 T my 1970 built in december 1969 and matching trasmission is a 5 gears magnesium case with 225mm clutch plate.

In the meanwhile I searched across all clutch provider (sachs, ap racing, luk, valeo) but the only "light aluminim pressure plate available" is the one from sachs with 4,7kg versus my original 3,5kg.

I'm trying to get anybody able to reman my plate in order to keep original weight and performance.

I try to attach pictures

Max

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Max911 · Post by **Max911** » Thu Mar 09, 2017 1:10 pm

New

Old

Sorry for not professional weight scale

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