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Lau Christophersen
Joined: 17 May 2013 Posts: 108 Location: Denmark/Copenhagen
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Posted: Sun Jan 31, 2016 7:45 am Post subject: 968 clutch on a 931 |
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Hi.
I am building some kind of a copy of "Raceboys" (Peep)s design of a 924 turbocharged but with a 931 as starting point.
The question is; can I make a 968 clutch fit in the 931 bellhousing? I do have both an S1 and S2 bellhousing.
The reason for that option is because i am aiming at 300+ hp and allready got a gearbox from a 951 S and the transaxel, torsionbar carrier etc. and now one of my friend have found a never used 968 clutch in the garage together with the flywheel and pressure plate.
So it was tempting to try to make the 968 clutch fit in the 931 bellhousing and on the crankshaft or maybe try to find a 968 bellhousing if that in any way will fit the engine block.
I hope someone here maybe have tried this or maybe have an opinion about the idea, because i have never touched a 968 with a wrench... |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Sun Jan 31, 2016 11:11 am Post subject: |
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Hmmm....it's an interesting idea...
Of course, the clutch, pressure plate, and flywheel all have to work as a unit. If you can get the 968 flywheel to bolt to the 931 crank, then you would be golden.
From what limited knowledge I have of the 2.5L and onward setups, the flywheel surface dimensions are different from the earliest 2.5L onward, meaning that the pressure plate engages at a different depth relative to the setup on a 931. So I doubt it will be possible to just mix and match. I did some comparisons of the 944 setup hoping to find an easy path to upgrades using the late S2 931 flywheel, but the geometry was all wrong. So I don't think you would be able to use any of the 944/951/968 setups with a 931 flywheel.
The only way to know for sure is to have all three components from early 931, late 931, 944. 951, and 968, and then do comparisons to see if there's a combo that would work.
If you're main concern is slippage, however, probably just easier to go with 915 pressure plate which has double the clamping force of 931 pressure plate. This should put you squarely in the 300BHP range without any worries about slippage. _________________ erstwhile owner of just about every 924 variant ever made |
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morghen
Joined: 21 Jan 2005 Posts: 8879 Location: Romania
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Posted: Sun Jan 31, 2016 6:03 pm Post subject: |
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As far as i know the 968 has a dual mass flywheel design, meaning that the flywheel is really thick. Try to match the clutch with the S1 gear first but do know that the dual mass flywheel setup has clutch plates without springs...the springs are in the flywheel...so if you use a springless clutch on a non dual flywheel setup it will feel and change gears like a race car...thats not really ok for road use.
There are various shops in europe that can rebuild your existing clutch assy to whatever specs you need. I know a shop in Hungary who rebuilds pressure plates and clutch disks to your desired hp rating...and the cost is like 100-200eur if i remeber corectly. _________________ https://www.the924.com |
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jason c
Joined: 13 Jan 2014 Posts: 1018 Location: Nwi
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Posted: Mon Feb 01, 2016 12:57 am Post subject: |
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The 968 does have a duel mass flywheel.
The 968 flywheel (9 bolts) won't fit on the 924 crankshaft (6 bolts).
The 968 disk is a different design with a bigger diameter.
The 931 PP won't fit on the 968 flywheel.
The 968 PP won't fit on the 931 flywheel.
Why would you want to put a solid (no spring) disk on a street car or the heavy 968 flywheel assembly on the 2.0 anyway?
Sell the 968 parts & get the right 931 clutch. |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Mon Feb 01, 2016 2:10 am Post subject: |
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jason c wrote: | Why would you want to put a solid (no spring) disk on a street car or the heavy 968 flywheel assembly on the 2.0 anyway? |
Lau Christophersen wrote: | because i am aiming at 300+ hp and allready got a gearbox from a 951 S and the transaxel, torsionbar carrier etc. and now one of my friend have found a never used 968 clutch in the garage together with the flywheel and pressure plate. |
Buy the 915 xxx xxx 27 pressure plate; direct fit for 931 spring-centered disc, and plenty of clamping force. Bass GT was using this on his 400BHP monster with no reported issues, should be plenty for what you are planning, Lau. _________________ erstwhile owner of just about every 924 variant ever made |
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Lau Christophersen
Joined: 17 May 2013 Posts: 108 Location: Denmark/Copenhagen
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Posted: Mon Feb 01, 2016 3:44 am Post subject: |
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Thanks for the answers !
It was just a thought, i have not looked any closer at the 968 parts yet because they are still at my friends garage. So i just wanted to get some answers from someone who was more clever on this theme than i am - and i got my answer, i will find a 915 pressure plate or get the 931 clutch upgraded.
There willl be a thread with pictures and info later, just have to finish some exams next week, then i will have some time to spend on the car again. Thanks for your help! |
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Lau Christophersen
Joined: 17 May 2013 Posts: 108 Location: Denmark/Copenhagen
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Posted: Wed Feb 03, 2016 8:22 am Post subject: |
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Hi again.
I have found the pressure plate for the 915; 915.116.001.27
Does it fit the S1 or the S2 bellhousing/disk/flywheel? or both the S1 and S2?
Dan do you have some info on this? |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Wed Feb 03, 2016 8:29 am Post subject: |
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This will fit both S1 and S2 flywheels EXCEPT for the late 82 flywheels that were setup for rubber-damped clutch disc. Do you know what flywheel you have? _________________ erstwhile owner of just about every 924 variant ever made |
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Kenodog
Joined: 25 Jun 2003 Posts: 2651 Location: Vancouver,B.C.
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Posted: Wed Feb 03, 2016 8:50 am Post subject: |
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This is what you want :
Leigh _________________ 1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140 |
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Lau Christophersen
Joined: 17 May 2013 Posts: 108 Location: Denmark/Copenhagen
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Posted: Wed Feb 03, 2016 9:39 am Post subject: |
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ideola wrote: | This will fit both S1 and S2 flywheels EXCEPT for the late 82 flywheels that were setup for rubber-damped clutch disc. Do you know what flywheel you have? |
I have a S1, so if it fits on that there is no problem
For the S2 I have, I dont know the year but i can not remember any rubber in the clutch disc so maybe 81?
Thank you! |
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Lau Christophersen
Joined: 17 May 2013 Posts: 108 Location: Denmark/Copenhagen
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Posted: Wed Feb 03, 2016 9:47 am Post subject: |
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Kenodog wrote: | This is what you want :
Leigh |
I think it is the right one yes
But maybe the shipping costs to Denmark will kill the deal? what are you asking for the plate?
Is it one you have found in one of the dead 931 of yours? or? any mileage? |
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Kenodog
Joined: 25 Jun 2003 Posts: 2651 Location: Vancouver,B.C.
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Posted: Wed Feb 03, 2016 1:39 pm Post subject: |
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Lau,
That was for display purposes only. Sorry, it is not for sale.
Leigh _________________ 1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140 |
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Lau Christophersen
Joined: 17 May 2013 Posts: 108 Location: Denmark/Copenhagen
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Posted: Wed Feb 03, 2016 11:11 pm Post subject: |
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Ahh.... sorry my misunderstanding. |
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ideola
Joined: 01 Oct 2004 Posts: 15548 Location: Spring Lake MI
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Posted: Thu Feb 04, 2016 1:33 am Post subject: |
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Leigh is teasing you. The 3032 015 399 pressure plate is all alu. If you can find one, get it. As far as I've been able to find, they are only available in a "915 power pak", sold as a complete kit with a bunch of bits for the 911 that won't work on the 931; but the 915 pressure plate and spring centered clutch disk that come in that pack WILL work for the S1 and the pre-82 S2 931.
The 915.116.001.27 is cast iron. There is a hybrid cast iron / alu version (915.116.001.16) but they are NLA and very difficult to find on the used market. The 3032 015 399 is an all alu version so it saves significant weight over both of the 915 part numbers. Expect to pay 911 prices if you're able to find one on the used market. For reference, Pelican sells a power clutch pak for the 911 with this pressure plate in it for about $850. You can use the pressure plate and clutch disk from that pak, but you will need to get the 931 throw-out bearing or reuse your old one. _________________ erstwhile owner of just about every 924 variant ever made |
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Kenodog
Joined: 25 Jun 2003 Posts: 2651 Location: Vancouver,B.C.
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Posted: Thu Feb 04, 2016 1:55 am Post subject: |
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I just got that beautiful piece from another 'Board member in a trade. Got a quick question Dan, is the ring gear on that compatible with an S2 or do I need to swap it for the 931 ring gear ?
Also, I may have found someone with some of these in his 'race junk' bin. Am contacting him now to see about prices.
Leigh _________________ 1979 Euro 931, Olive
1981 931, Sabine
1991 Ford Ranger XLT 4x4, Ricky
1996 Ford E-350 ex-FedEx Van
2014 Mazda CX-5 (Kinderwagon)
2019 KTM 790 Adventure
2024 KLX300
2024 KLX140 |
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