Case questions

[jhg41977]

Tonight with the help of a neighbor I finally sealed the case up. This is the first time I have done thisand I have a few questions.

When inserting the bolts into the case, they go in with no resistance and then resistance starts and the kind of 'click' into position. I assume this is the oring sliding into the hole. Is this normal and correct?

When setting the orings on the threaded end I used a sharpie marker cap with the tip cut off to size. I had to stretch the ring over the cap and then place the cap over the bolt and push the oring down. I could only push so far that the oring was just below the ridge of the bolt hole, ie the washer would still push the oring down further when the washer and nut were secured. Is this normal or did I shred the oring?

I sealed the case with Permatex anerobic gasket maker. Everything was torqued down properly, approximately within an hour of application to the case half. If I had to replace the orings due to shredding as mention above but have not started the engine or even finished assembly, can I remove one throughbolt at a time to replace the orings?

Thanks
Jim

[jhg41977]

Should have mentioned its a 3.6 993 motor and I used the green Viton seals.

Also, we hand tightened all of the case bolts then went back to torque them. When I torqued them down my neighbor said there was very little and a few times, no transferrence of rotation into the bolt.

[cmcfaul]

Correct procedure is to put the orings on. Goop some sillocone on both sides of the bolt, put the washer and nut nut on and torque to spec in a criss cross pattern as outlined in the books. No need to streach the oring over the nut (thats nuts ;-). Make sure you do not disturb the oil pump gaskets.

If it were me I would do it over again. Otherwise you could have a very leaky engine.

Chris

[jhg41977]

Here is what I did,
I applied the permatex in a even layer to all perimeter and throughbolt mating surfaces on one side of the case only. Then I installed all perimeter washers and nuts hand tight.

1) oiled the entire bolt lightly with motor oil
2) installed one washer
3) Placed sharpie cap over the threads and slid the oring over and onto the shaft placing it just at the beginning of the increase in diameter near the bolt head (on narrow portion of bolt)
4) installed bolt into the case, this is where there was resistance and then it sort of 'clicked' into place.
5) slid the sharpie cap over the threaded end again and slid the oring over the cap and slid the oring into the recess in the case using a blunt pick.
6) installed a washer
7) installed a nut
8) lightly hand tighten all through bolts
9) tightened all through bolts to 50 Nm in a criss corss/butterfly pattern
10) Tightened all perimeter bolts to 24Nm (I think that was the spec)

If I were to replace the orings at this point, would I have to split the case or can I remove and replace one at a time?

Is silicon recommended for all engines? The factory manual only says to oil lightly.

[KTL]

I think you did a fantastic job protecting the o-rings for installation. I would not do it over again, as they should seal fine.

The trick with the Sharpie cap is a nice homemade solution for protecting the o-rings from being cut by the fine threads on the thru-bolt. Nice job. You made your tool in like what, 30 sec? Stomski had to do some machining with his solution! http://www.stomskiracing.com/products.php?id=13 No offense intended to Stomski. Very nice guy who makes very nice mechanical solutions for our cars. Great supplier to the Porsche community.

The silicone mentioned should be silicone paste like Sil-Glyde, Dow Corning 111 or 112, Dow Corning 55, etc. All sorts of slick lubes you can use on the o-rings to avoid damaging them during installation and tightening. I hate silicone RTV in most applications.

You can go back and check thru-bolts one at a time no problem. I actually do this as part of my installation procedure to speed things up with sealing the case. I install the thru-bolts with no o-rings then I go back the next day and do each one one at a time with the o-ring installation. My feeling is it lets you work quicker on getting the case sealed and no time wasted fiddling with o-rings & silicone paste (I like Dow 112) while you're trying to beat the clock on the case sealant.

I bet if you did check the o-rings, you might find some that are damaged. But that doesn't mean they would have leaked. The case bores need to be chamfered a bit more for the fat Viton o-rings. So it's almost inevitable that some o-rings get damaged during install if they are a little too big and the bores haven't been massaged a bit.

What I wouldn't do is goop them up with silicone RTV. That just makes a mess to clean up later. If RTV is globbed in there, might as well leave out the o-ring altogether because the RTV is defeating the function of the o-ring.

[jhg41977]

Another question, the orings that go between the cylinder and the case fit very loose around the cylinder. There is a groove at the base of the cylinder which I assumed the oring should sit in. The orings supplied in the kit are way too big.

[jhg41977]

[jhg41977]

Im not stretching the oring here, just fitting it around the back of the piston to show how much larger it is.

[jhg41977]

Figured it out. The seals I was attempting to use appear to be for a different place or engine.