Engine Bearing Clearance

[BillK]

Chad,

I just threw 2 complete sets of .001" lower half Big Block Rod bearings away on Friday for the same reason. I figure if Clevite tells you to run them that way, there must be a reason. The engineering side of me says that the thicker bearing will conform to the diameter of the crankshaft better and will result in a larger bearing area as compared to the thinner one.

[Chad E532]

Thanks guys, that is what my gut was telling me, so I ordered up a couple sets of bearings to mix and match the correct way.
Chad

[Greg Reimer 7376]

Years ago, when I was a line guy at a Chevy dealer, the front main saddle on 350 blocks would move as the block seasoned on new cars and trucks. An attempt could be made to bring them somewhat into line by juggling over and undersize bearing inserts as long as the block stabilized. In extreme cases, the front main spun.This ruined the block, the crank and sometimes tossed the #1 rod as well. In an attempt to cut costs and be cheap, the thinwall castings weren't very stable, then were machined, then the casting moved and the critical dimensions went out of spec. That was a factory warranty fix to juggle bearing shells to move the hole back into place. Sort of an indictment on quality in the mid 70's.