case through bolts take 2
 

Hi Everyone: I tried adding my question to an existing through bolt thread. That didn't work, so I am trying again. Engine is a 3.0 from 1979 sc.
I'm at the case joining stage, reading the bible and gathering info from the forum and can't find a clear answer. The through bolt holes on my right side case are chamfered (except for the two under the oil cooler). The left side case bolt holes are not chamfered. I think the chamfering helps the viton seals sit better. But why are both sides not chamfered? I read that the nut end of the through bolt with threads doesn't need the chamfering as the seals can sort of wiggle into the bolt threads. If that is the case (sorry about that), then this suggests that the through bolt acorn nut ends should be on the left-side of the case. Wayne's book suggests this (p134), but then Figure 3-28 on the same page shows acorn nuts on the right side of the case!
Questions:
1. Is it standard practice to chamfer the left case through bolt holes?
2. How about the two bolt holes under the oil cooler?
3. Which side of the case for the acorn nuts (wouldn't matter if all chamfered)?
4. Any lube on the viton seals?

Thanks for any help, David

I added chamfers to the half that was missing them. All holes that get a sealing oring now have a chamfer.

Yes they are supposed to help the outing sealing because there is a room for them to properly deform.

Can’t explain why. It is what it is.

Every factory build I ever opened had acorn nuts on the 1.2.3 side
I use oil on all torqued threads, grease the O rings and washers
Keep the washer from spinning Under the acorn nut while torquing the through bolts
Bruce

Thanks
 

Thanks for the replies. Will follow all advice....d

Do not RTV the case o-rings as suggested in Wayne’s book. Henry at Supertec uses Dow 55 to lube the Viton o-rings and says it has a swelling effect on the viton material to further help with sealing. It’s not easy to find- call him if you can’t find it on your own.