Yes that is one of them. The small chamfer on the case holes compliment the washer'a chamfer. They provide a good shaped feature for the orings to fit into.

As I found, one side was chamfered from the factory, the other wasn't. Go figure! They must have been in the process of converting over.

LHS Case through-bolt holes needed chamfers.

AND the RHS holes behind the oil cooler.

12.7-12.9mm OD of the chamfer. (.5" diameter)

http://forums.pelicanparts.com/uploa...1455502497.jpg

http://forums.pelicanparts.com/uploa...1455502695.jpg

If you look closely in the upper right hand corner of the second picture, you can see one of the through-bolt holes that came chamfered from the factory. I measured this chamfer, and machined to match using a chamfer bit and a hand drill to control the process. Go slow! Check often.

thanks for the info. a bit worried those bits could fall down and clog an oil passage in the through holes!?

You could have just loosened one at a time and retorqued. Why is there loctite 574 (hate that stuff) on the main webs? You don't need any sealer there.

It's supposed to glue the webs together and prevent shuffling. Not sure I see the need for it on a street engine and if I was building a race engine I'd just have it shuffle pinned or bushed around the through bolts. But it gets done a lot I guess, I just have a hard time seeing that stuff so close to the bearings and the through bolt holes. I guess it's suppose to dissolve in oil so no harm if it gets into the galley? I'd like to buy some and mix it with oil to see what happens.

Mag Cases NEED shuffle pins , Al is a nice option.
I so doubt anything you can pry apart at a later date will or would stop "shuffling " in use.

Yeah, I've questioned the need for it too (574 on webs), but used it anyways.

Per Henry Schmidt's instructions in a well-read thread on case sealing Loctite 574 is used on the webs and threebond 1184 on the perimeter. This is Henry's tried and true method for sealing up a case and some methods were debated in the thread but a consensus was never met (if that's even possible on the internet).

The webs are pressurized oil passages. They feed the piston squirters. So there is a potential to leak between the mated mains.

Wprater

Yes you do have to clean out all the little bits. But that is true of any used case covered in 30 years of dirt and grime. The little bits of al are easily cleaned out because they aren't embedded in the surface.

My 930, which was never opened up until now, shows no evidence of any sealer on the main webs. Plenty on the perimeter but that's it. I would think that if the web faces are far enough out of parallel to cause oil leakage between them then there are other major problems with the case? It's hard to argue against the success that Henry has had with his method though.

this is the same with mine, the LHS is chamfered, RHS is not. I might think about doing your trick.. if I can find a hand drill tomorrow :)

About the camfered holes for the through bolts in cases. I allso had that on mine. Long story short: my case halves was of not only different serial numbers, but one was from -83 and didn't have the camfered holes, the other was from -87 and had the camfered holes. So my gestimation is that Porsche incorporated this modification sometime between here. I allso camfered the holes on my case halve from -83.
Good luck with the rest of youre build.

Not a big deal to stress about. Just take it apart, clean, then redo. It's not as though you're at assembly step 26 and have to redo step 2. Good to have a check list as you assemble so you don't forget to install something, like piston rings.

Remember to confirm crank rotates smoothly while tightening the through bolts/nuts.

Sherwood