Join Date: Apr 2012
Location: Cairns, Australia.
Perhaps you should consider "stop drilling" the crack first.
This is a common technique whereby a tiny hole is drilled at the furthest end of a crack, the idea being to stop it spreading further. I've never used JB Weld but I'm aware of the type of repair and agree that it could go for ever if you do a good job. If it was mine that's what I'd do and and then, being acutely conscious of the weakness there, would maybe use sealant or locktite or thread tape or a combination of all three whenever I changed the oil in future and then tighten it enough to seat nicely and no more. Perhaps lockwire the bolt if you are worried about it coming loose.
A few random thoughts.