Show full size 924Board.org
Discussion Forum of 924.org
 
 FAQFAQ   SearchSearch   MemberlistMemberlist   UsergroupsUsergroups   RegisterRegister 
 ProfileProfile   Log in to check your private messagesLog in to check your private messages   Log inLog in 
 Technical FAQ924 FAQ (Technical)   Technical924 Technical Section   Jump to 924.org924.org   Jump to PCA 924 Registry924 Registry

Clutch, clutch, clutch
Goto page 1, 2  Next
 
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions
View previous topic :: View next topic  
Author Message
bass gt  



Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!

PostPosted: Wed Apr 04, 2007 5:17 am    Post subject: Clutch, clutch, clutch Reply with quote

Gents,

Hoping to tap into some of the collective wisdom here. I have a strange query you may be able to help me with.
OK, my car is a Series 2 931, and had the stock clutch assembly fitted, except the new friction plate i fitted last year.
I then purchased a 911 Sachs sport clutch pressure plate, as would you believe it, it wont fit.
The problem is this. The stock pressure plate is a lot deeper than the 911 type, with the friction disc protruding beyond the mounting face. Now when i offer up the 911 pressure plate, the friction disc is inside the assembly, by about 3-4mm. So when i fit this to my flywheel, there is a 15-18mm gap between the two friction surfaces. Obviously WAY too big.
Now, i have a load of old bits floating about, and guess what, the deeper pressure plate fits the clutch disc with the big rubber doughnut mounted spline. When this is offered up, hey presto, all the faces mate up.
So, am i right in assuming that the S1 and S2 flywheels are different in terms of their friction disc mating surface height??
And do i ned an S1 flywheel to make this work. Or, can i use a Fidanza 924 NA flywheel, as i am now longer using the ring tone as my ignition trigger?
Sorry for the long post, but any insight or info anybody has would be of great help.
Best Regards,

Steve
Back to top
View user's profile Send private message
-nick  



Joined: 16 Nov 2002
Posts: 2699
Location: Cambridge, MA

PostPosted: Wed Apr 04, 2007 6:37 am    Post subject: Reply with quote

Hey Steve,
Is the friction surface of your flywheel on the same plane as the surface where the pressure plate mounts against? I think that may be the trouble. The flywheel should be flat across the friction and mounting surface (where the bolt holes are), and have a little lip around the outside that the entire plate fits within.

I'm not sure what the story is with the rubber-center disk. As long as the thickness of the friction material is the same, a rubber or spring center disk would fit identically.

We need pics

For reference, here are the 931 S1 parts -



_________________
1980 931S
15psi boost, MS-II, EDIS, 951 IC, custom intake, Ford 5.0L throttle body, Forge BOV, WB o2, G31 w/LSD, 964 wheels, 968 rear sway, Bilsteins, 200# Welt. springs. A laptop, and a partridge in a pear tree.
1991 964 C4 Cabriolet
Back to top
View user's profile Send private message Send e-mail Visit poster's website
bass gt  



Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!

PostPosted: Wed Apr 04, 2007 6:41 am    Post subject: Reply with quote

Nick,

No, my flywheel is deeply dished!! The PP sits down into the flywheel, as does he frictions plate. Once i get home, I'll upload the pics and post them up
Steve
Back to top
View user's profile Send private message
bass gt  



Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!

PostPosted: Wed Apr 04, 2007 9:32 am    Post subject: Reply with quote

Guy's,





You can clearly see how dished the flywheel is. It has had a tiny skim, about a couple of thou, to clean it up, but thats it, thats how it came from the car. And as for the 2 PP's, the silver is the 911 unit, and the old is the one from my car.
Oh, and check out the crank and rods

Steve
Back to top
View user's profile Send private message
-nick  



Joined: 16 Nov 2002
Posts: 2699
Location: Cambridge, MA

PostPosted: Wed Apr 04, 2007 9:57 am    Post subject: Reply with quote

Need bigger pics - my eyes aren't that good!
* edit, ok I see the pics now!

It looks like there is a huge difference between the friction surface on the flywheel and the mounting surface for the pressure plate. Mine is flat, and 911 flywheels are also flat between the two surfaces. Yours doesn't look stock by any means to me! What does it weigh in at?

Also, where did you get the pressure plate you had before that worked with it? You were right, the friction surface on it protrudes by a lot! That doesn't look like any of the stock 931 plates that I've seen.

Everything I have has the same part numbers listed for S1 and S2 clutch packs. This is a real head-scratcher!
_________________
1980 931S
15psi boost, MS-II, EDIS, 951 IC, custom intake, Ford 5.0L throttle body, Forge BOV, WB o2, G31 w/LSD, 964 wheels, 968 rear sway, Bilsteins, 200# Welt. springs. A laptop, and a partridge in a pear tree.
1991 964 C4 Cabriolet
Back to top
View user's profile Send private message Send e-mail Visit poster's website
bass gt  



Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!

PostPosted: Wed Apr 04, 2007 11:41 am    Post subject: Reply with quote

Nick,

Weird Eh?? Well that flywheel weighs very little, however, that is offset by the weight of the iron PP!! But that is going to be lightened as well.
Just checked my other engine, and guess what, it has a flywheel much like yours. Weighed that and the 911 PP and there is a total weight saving of 7kg(15.5lb) over the stock items.
I think i will try the stock looking items in this engine, and the ali flywheel/PP in my other. Might be interesting to see how the spool ups compare, given they will share the same head and turbo.
I have somebody over here looking a their S2 clutch this week, to see if this is how the UK/ROW S2 clutches are.Very strange that Porsche would fit different flywheels todifferent markets. However, with the US cars running less boost, and generally being detuned a little from the factory, maybe this is part of the deal.
I'll keep you posted if anything turns up.

Steve
Back to top
View user's profile Send private message
Rasta Monsta  



Joined: 12 Jul 2006
Posts: 11378
Location: PacNW

PostPosted: Wed Apr 04, 2007 12:51 pm    Post subject: Reply with quote

Pressure plate? What pressure plate??


_________________
Toofah King Bad

  • Red (1987 924S) - Pro44/Spec944
Back to top
View user's profile Send private message Visit poster's website
Smoothie  



Joined: 01 Jan 2003
Posts: 8030
Location: DE (the one near MD, PA, NJ)

PostPosted: Wed Apr 04, 2007 3:34 pm    Post subject: Reply with quote

Yes, nice looking workbench.

I got a look at the "E_924_85_KATALOG" .pdf (Euro PET .pdf).
It does show a couple more pressure plates than the USA PET.
They are
931.116.001.02 for M31.01/02, M31.03/04 -also used on US cars. -and only with the spring damped clutch plate 931.116.011.04

915.116.001.27 for '81 M31.50 -only with the spring damped clutch plate 931.116.011.04

931.116.001.03 for '81-up M31.03 -only with the rubber damped clutch plate 944.116.012.08


Maybe see if you can find that 915.116.001.27 number on the unusual pp.
_________________
"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox
Back to top
View user's profile Send private message Visit poster's website
Smoothie  



Joined: 01 Jan 2003
Posts: 8030
Location: DE (the one near MD, PA, NJ)

PostPosted: Wed Apr 04, 2007 3:48 pm    Post subject: Reply with quote

For flywheels... they show 931.102.206.01 for use with engine types M31.50/03

engine types from the tech specs booklet -
M31.01 is Euro 79-80 931 ....... clutch contact force = 7200-7900N
M31.02 is US/Can 79-80 931 .. clutch contact force = 7200-7900N
M31.03 is Euro 81-84 931 ....... clutch contact force = 7200-7900N
M31.04 is US/Can 81-82 931 .. clutch contact force = 7200-7900N
M31.50 is "924 Carrera GT" .... clutch contact force = 7800-8500N

The guess from this is that you have some Carrera GT clutch parts.
_________________
"..it's made in Germany. You know the Germans always make good stuff."


'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox
Back to top
View user's profile Send private message Visit poster's website
ic932  



Joined: 11 Feb 2005
Posts: 1104
Location: UK

PostPosted: Thu Apr 05, 2007 10:04 am    Post subject: Reply with quote

[img]http://i115.photobucket.com/albums/n281/daverea/daverea3251.jpg?t=1175727282[/img] [/img]http://i115.photobucket.com/albums/n281/daverea/daverea3252.jpg?t=1175727178[img][/url]
Back to top
View user's profile Send private message Send e-mail
ic932  



Joined: 11 Feb 2005
Posts: 1104
Location: UK

PostPosted: Thu Apr 05, 2007 10:10 am    Post subject: Reply with quote


Back to top
View user's profile Send private message Send e-mail
ic932  



Joined: 11 Feb 2005
Posts: 1104
Location: UK

PostPosted: Thu Apr 05, 2007 10:15 am    Post subject: Reply with quote

finally, with the help of my wife lol, some pics of the two different style 931 flywheels (both S2's).
Back to top
View user's profile Send private message Send e-mail
bass gt  



Joined: 02 Dec 2004
Posts: 971
Location: Johannesburg for now!!

PostPosted: Thu Apr 05, 2007 10:21 am    Post subject: Reply with quote

Interesting!!!
Mine is the same as the dished type. I'm guessing these are used for the rubber friction discs, which were introduced later on.
Is there a weight difference between the 2???

Steve
Back to top
View user's profile Send private message
ic932  



Joined: 11 Feb 2005
Posts: 1104
Location: UK

PostPosted: Thu Apr 05, 2007 11:39 pm    Post subject: Reply with quote

according to my digital bathroom scales they both weigh in at 4.9kg. so its safe to say they weigh the same if not precisely 4.9kg.

i used my rubber centred plate/pressure plate on a 944 engine so i cant do a weight comparrison with the spring centred plate/pressure plate.

BTW, flywheel for use with rubber centre plate .... 931 102 206 01.
flywheel for use with spring centre plate .... 931 102 206 03.
Back to top
View user's profile Send private message Send e-mail
-nick  



Joined: 16 Nov 2002
Posts: 2699
Location: Cambridge, MA

PostPosted: Fri Apr 06, 2007 6:15 am    Post subject: Reply with quote

Wild. I didn't know that any 931's came with a rubber centered clutch.
_________________
1980 931S
15psi boost, MS-II, EDIS, 951 IC, custom intake, Ford 5.0L throttle body, Forge BOV, WB o2, G31 w/LSD, 964 wheels, 968 rear sway, Bilsteins, 200# Welt. springs. A laptop, and a partridge in a pear tree.
1991 964 C4 Cabriolet
Back to top
View user's profile Send private message Send e-mail Visit poster's website
Display posts from previous:   
Post new topic   Reply to topic    924Board.org Forum Index -> General Discussions All times are GMT + 11 Hours
Goto page 1, 2  Next
Page 1 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum


Powered by phpBB © 2001, 2005 phpBB Group