930 clutch disc

[Thom]

Are there several variations in the 930 clutch disc?

I have just completed a flywheel + torque tube swap and replaced the clutch disc while in there. On the left is the disc that came off, barely used but some springs have got loose. It's got 70k miles. New one on the right went in and was sold to me as a 930 disc as well, but is it really?

I have not driven the car yet, it's still on the lift with some other work needed.

[Darwin]

I never used it, but when I was building my car I originally planned to use a 930 disc. It was a factory one with 930 PN and it had 6 springs like your old one. I wonder if there are different PNs?

Are they dimensionally the same? (Obviously your old one would be thinner on friction material).

[Thom]

Old one is 9.64 mm thick, new one 10.19 mm.
How thick is the 6 spring 930 disc supposed to be when new?

[Tom]

Thom, I think that is "a" 930 disk, but not the one you really want. I could be wrong, but that looks like the rubber-centered 930 disc shown below -- Sachs 1849003782

https://www.pelicanparts.com/More_Info/ ... &DID=25651

I think the "930 disk" that people use on the 951 is Porsche Part # 930 110 014 02, the Sachs version of which is shown here:

https://www.pelicanparts.com/More_Info/ ... &DID=11623

I am a big fan of the 944 Turbo "cup" disc with KEP1 PP, but know many have use the non-rubber 930 disc with success. The extra thickness of the 930 disk has created disengagement issues on some motors, but that's probably only an issue on old motors with worn-out thrust bearings and too much back and forth play in the crank.

[Darwin]

Thom, unfortunately the disc I had is long gone now so I can’t get a comparable measurement for you.

Thom, I think that is "a" 930 disk, but not the one you really want. I could be wrong, but that looks like the rubber-centered 930 disc shown below -- Sachs 1849003782

https://www.pelicanparts.com/More_Info/ ... &DID=25651

I think the "930 disk" that people use on the 951 is Porsche Part # 930 110 014 02, the Sachs version of which is shown here:

https://www.pelicanparts.com/More_Info/ ... &DID=11623

I am a big fan of the 944 Turbo "cup" disc with KEP1 PP, but know many have use the non-rubber 930 disc with success. The extra thickness of the 930 disk has created disengagement issues on some motors, but that's probably only an issue on old motors with worn-out thrust bearings and too much back and forth play in the crank.

Tom, I believe the issues people ran into was when they paired the 930 disc with the KEP2 PP. I couldn’t disengage the clutch fully, which is why I moved away from the set up and went with a disc relined from Southbend, and a factory PP, reworked by them as well.

[Tom]

Thom, unfortunately the disc I had is long gone now so I can’t get a comparable measurement for you.

Thom, I think that is "a" 930 disk, but not the one you really want. I could be wrong, but that looks like the rubber-centered 930 disc shown below -- Sachs 1849003782

https://www.pelicanparts.com/More_Info/ ... &DID=25651

I think the "930 disk" that people use on the 951 is Porsche Part # 930 110 014 02, the Sachs version of which is shown here:

https://www.pelicanparts.com/More_Info/ ... &DID=11623

I am a big fan of the 944 Turbo "cup" disc with KEP1 PP, but know many have use the non-rubber 930 disc with success. The extra thickness of the 930 disk has created disengagement issues on some motors, but that's probably only an issue on old motors with worn-out thrust bearings and too much back and forth play in the crank.

Tom, I believe the issues people ran into was when they paired the 930 disc with the KEP2 PP. I couldn’t disengage the clutch fully, which is why I moved away from the set up and went with a disc relined from Southbend, and a factory PP, reworked by them as well.

Yeah, any reduction in 'throw' can create an issue I suppose. I remember at least on guy who attributed his disengagement issue to axial play, but if the KEP2 has less throw then that makes sense too. I know lots of people run the KEP1 and 930 clutch without problems. The KEP1 holds so much power, the KEP2 is probably overkill for 99.9% of the cars out there, with tons of stress on the fork and firewall. I had a Southbend clutch at one point -- they relined a 951 clutch with their feramic material, and they changed the fulcrum point on the sachs pp to give it more clamping force. It was a "good" set up, but --for me-- the KEP1/cup combo is better because it holds tons of power and engages like a factory car without excessive pedal pressure. My bone stock 85 Carrera had a stiffer pedal for example... The southbend system started smooth, but developed a slight shudder off the line once it was broken in.

[Thom]

I never had any issue with the KEP 2 PP and the 930 disc. I will drive the car tomorrow and see if there is any difference, but it disengaged as we checked before fitting back the gearbox.
There is no rubber in the new clutch disc, which I believe is the replacement for the original rubber center disc which is NLA.

[Tom]

Odd are you'll be just fine. But are you positive about that disc not having rubber though? It has the same sachs part number on it as the pelican one, which is described as rubber-centered -- one side looks just like yours and the other shows the rubber hub.... Or did Sachs change the part but keep the same number?

Curious if you reinforced the fork or firewall for the KEP2? Also curious how stiff the pedal is... ?

[Thom]

Here is the engine side of the new disc, placed in the PP. I could not spot any rubber in there. The square-ish part is in steel.

I reinforced the firewall with a home-made steel sheet. The pedal was stiff when new but OK-stiff now.

Now I know that PET is not always correct but if you look at the 930 section you will see that early 930s had the 6 spring disc and later ones had apparently a rubber centered disc just like 944s. Now that these rubber centered discs are obsolete and the designs have been updated to spring centered discs, perhaps the rubber mention has remained in several nomenclatures?

[Thom]

I had to remove the dead travel on the clutch pedal otherwise releasing the clutch was difficult, but the car drives again. It's nice not to hear anymore the rattling from the worn out bearings of the original torque tube, which at ~246k miles was getting on a bit.
Gone also is the sometimes binary engagement of the clutch which I think was due to some rattling springs in the old clutch disc. A bit frustrating having to replace the old disc when the lining shows so little wear.

I will have to remake the stiffening bracket on the firewall around the clutch master cylinder as the current one that I made 13 years ago is beginning to crack. It never ends with these cars, does it?