Whoa that's a first. I thought for sure Ray was gonna try to buy this one too. ::)
We had a friends boat in here last year, he worked on it himself, with the cam 45* out....and running! Bent every intake pushrod. I replaced them and away he went, still running today....compression is fine. Unbelievable, 'member that one Ray?
I don't know....I'll see when I tear it down.
We had 2 known problems....water in the cylinders and no compression........cylinders that had a cup of oil in
them when we got the heads off.
but not the 40% leak down I saw with the valves closed
I don't feel that 40% leak down on a cold engine with marine tolerances is excessive. My 454 was at 60% leak down (cold) before rebuild, and the main reason for the rebuild was, I was tired of it pushing oil out the breathers.
Pat, and this is more a question than a statement, bro, and I am not really second guessing you, but this is a seasoned block and crank and I value your input and thought into everything. But think seriously through on this thought.
I don't know much about BBC engines, I'll conceed that all day long, but I'm going to assume the same applies from Mopar and Ford blocks as well in that they are all odd fire from the corners and sequential fire in the center. BBC firing order is 1-8-4-3-6-5-7-2 if I'm not mistaken. Same as Ford, a little different from Mopar, BUT, sequential firing on center cylinders is the same but where ALL the also-mentioned engines have MUCH larger main journals than a BBC has.
Anyway, my point is, is it NOT conceivable that this "bow" in the center main journals is normal and compensated for, since that is where the vast majority of crankshaft deflection is going to occur, given the constant pounding the center (really, the #3 gets the pounding and #4 worse than #2 because of harmonics) journals receive on a routine basis? A seasoned block is not a factory block, we can at least agree on that, but given the bulk of the devastational forces of a BBC on it's crankshaft and reciprocating assemblies lie in the center 4 cylinders, which we can also agree on, would it not make sense IF you can determine (and you will if you can measure it) the crank is also somewhat twisted from it's stock state to account for this naturally?
In a nutshell, unless your dealing with a NEW block and NEW crank, a little extra clearance in #2 main, more in #3, and at least the same in #4 if not more, makes perfect sense to me.
Ray