I pose this question based on my experience. I have now owned two B series
engines with around 70,000 miles on them. They both had low oil pressure.
Upon dissassembly, both had all of the babbit worn away from their rod
bearing exposing the underlying copper layer. On the B, replacing the rod
bearing fixed the oil pressure problems and, based on what I have found, I
fully expect the same results with my A.
Replacing the rod bearings is not that tough. Maybe we should start
thinking about them as 50,000 mile items and just replacing them as a
matter of course. Expecially when you consider the havoc raised at the top
end of the engine with low oil pressure and the cost of an MGA crankshaft
Just a thought.