Since no coolant is getting in the
oil it doesn't sound like a crack. Coolant is a lot thinner then even hot
oil and would migrate through a crack when a hot engine is shut down.
The problem surfaced after the
oil pump was swapped to a high pressure unit. Since the 30psi boost in pressure caused the problem this points to gasket sealing to me.
As I stated in the previous thread, I'd go after the cause of the problem. Namely trimming the bypass spring to get the oil pressure back down where it's intended to be and verifying the heads are at the proper torque. (100ft/lbs seems awfull high, 65-75ft/lbs seems to be the level that comes to mind)
I actually prefer to bolt and unbolt heads in stages as stated to keep stresses as even as possible. 10~15lb increments is about right. This is even more critical with aluminum heads. Teflon sealant on head bolt threads is a must unless you know for sure they're blind holes.
If it turns out to be a crack there's only two things to do, weld it or replace the part. No way I'd trust Loctite for what's essentialy metal fatige. If you have a 40yr old casing with cracks forming it's usefull life is done and deserves to be put out to pasture.
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