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How can I tell what main bearing are in my block. I have the crank removed and the bearing are showing slight marks on them. The engine is a 1995 Gen 5 454. I believe the bearings are still the original. The only markings on them are
GM
A-100
9 90
Thanks
Robert
They are probably standard size. Although GM may still "select" bearings on the assembly line. If they look pretty good just clean them with scotchbrite and solvent and put them back in.
fiat, I thought that scotch brite wasnt good? I am just curious. I did that to a motor and it lost a rod :cry:
396
Losing a rod bearing probably can not be attributed to using scotchbrite to clean the bearings, unless you left material embedded in the bearing itself. Depending on how the bearings looked, it could have been a clearance issue, out of round, or debris in the crankshaft or oil passages in the block, among other possibilities.
Nothing wrong with cleaning a bearing by lightly scotchbriting it.
In the days of the Mark IV, Chevrolet used to use "select" bearings to correct the lousy (for lack of a better word) line boring they did on the block.
And sometimes to correct high tolerance cranks. These bearing had different numbers and some even had .0003 or numbers as such. These were factory only bearings, not available from a dealer and only from the factory. You throw in a set of standard main bearings and lose the fit the factory had. Stock motor no big deal. Motor that makes some power and it can be a big deal. Why so many BBC are line honed. But a lot of guys don't line hone right and it is worse than before the line hone. Main bearings are BBC weak points when hp comes to play.
That is why I said "if they look good, put them back in."
Not sure if GM still does select bearings on the later stuff. I never build those.