mating 915 to 3.2 - a few questions

[cubby911T]

As I prepare to install my clutch and then mate the 915 tranny from my '77 to my new 3.2 engine I've got a few questions:

1. I bought a new pilot bearing which bolts onto the 3.2. There seems to be some "felt" like material on the inside of the new pilot bearing. At first I thought it was grease, but it isn't. Is that supposed to stay on there? And what about grease? Do I need to pack this thing like a wheel bearing?

2. Where else should I be putting grease (and/or NOT putting grease) before I bolt everything together? Tranny splines? Guide tube?

3. Some of you may remember my adventure with the broken engine-to-transmission stud (the long one that goes thru the starter). I have a new stud on the way and I'm wondering about using locktite when installing it. I think I have read to use a drop of red locktite, but just wanted to confirm this.

4. How much torque should be applied to the 4 bolts/studs that hold the engine and transmission together?


Thanks guys!

[Rot 911]

That felt piece is just packaging to keep the bearings clean. Remove it and use some good quality wheel bearing grease on the bearings. Don't pack it full like a wheel bearing. Just a thin coat.

I wouldn't use red loctite on that stud. Use some blue if you are worried about it backing out.

[Peter Zimmermann]

Originally Posted by cubby911T

As I prepare to install my clutch and then mate the 915 tranny from my '77 to my new 3.2 engine I've got a few questions:

1. I bought a new pilot bearing which bolts onto the 3.2. There seems to be some "felt" like material on the inside of the new pilot bearing. At first I thought it was grease, but it isn't. Is that supposed to stay on there? And what about grease? Do I need to pack this thing like a wheel bearing?

2. Where else should I be putting grease (and/or NOT putting grease) before I bolt everything together? Tranny splines? Guide tube? Thanks guys!

1. The felt ring stays inside the bearing housing! It's designed to prevent dirt from entering the needle bearing. You will notice that your new bearing was probably shipped dry, and you will need to work a thin layer of grease into the bearing. I like amber grease made for disc brake wheel bearings (it's higher temp rated), and you can also put a very thin film of the same grease on the tip of the mainshaft where it will contact the bearing.

2. The TOB guide tube definitely needs a light coating of the same grease, and I also like to put a tiny bit on each tip of the release fork. The splines are a tough one, if you get a touch too much grease on them it can get thrown out and on to the clutch disc - not good! Put a touch of grease on them, but use a fingertip to work it down into the grooves, don't just leave the grease on the outer tips of the splines.

FYI: An excellent grease to use is available from Porsche under the part number 000 043 024 00; it comes in a tube and is Optimoly High Pressure Amber grease.

[cubby911T]

Ah, thanks for the explanation, Pete. Makes sense about the felt. Sounds like "less is more" in the grease department, so I'll go easy on it.

Any comments on the locktite or torque questions?

[Rot 911]

I guess you can go either way with the felt on the inside of the bearing. I always removed it, half the pilot bearings I see don't even have the felt. My concern with the felt is that it is not a bearing surface and would shortly tear into pieces.

[Peter Zimmermann]

Originally Posted by cubby911T

Any comments on the locktite or torque questions?

I think that a couple drops of "Blue" would be better than red.

Regarding torque, I've always done those by feel, tight is tight. A general rule of thumb for 10mm hardware is 32-35 lb/ft (although there are many special 10mm fasteners on a 911 that the torque spec is all over the board on), but there is a torque spec listed of 29 lb/ft for the 10mm nuts that hold the rear, center engine mount "pylon" (aka console) to the crankcase. I guess about 32 lb/ft would be appropriate, but no more than 35 lb/ft.

[marlinaness]

what happens if I forgot to lube the TOB guide tube? Do I need to separate and lube?
thanks