bt and Boat1. He said all the old bearings were marked .010" under, not .001". Apperantly at one time the crank was ground .010" under size on the rods and mains which is typical. He was using standard size bearings at first so he had an additional .010" clearance. Therefore had low pressure as the oil flushed out the excess clearance. Now he has changed to the correct .010" undersize bearings and oil pressure has returned to normal due to now having .010" less clearance than he had with the standard bearings.

He's lucky he didn't spin one.

My bad. Everything I said about checking the clearances and end play still applies.

Totally agree with your routine for checking clearances before final assembly. I do believe though that a large percentage of people just take it for granite that everything is right and the machine shop couldn't make a mistake so they just put everything together with out checking. You could even get a bearing that was packaged wrong and not catch it. Definitely worth the time to check clearances closely before final assembly. I always check end play but don't remember ever having a problem there.

ditto. I was thinking .001. Its suprising it had any OP with .010 clearance all around.