Hotrod Lincoln I was under the impression that with oil pressure on a round and properly clearanced journal and bearing that it was harder for the journal to touch the bearing under a load. You know you see performance engines tore down where the bearings still look new !On the other hand you see 60 year old dippers where the babbitt rods look fine too. One of mine that was rung in 82 and didn't need shimming still runs fine and it has had some workouts getting out of the woods loaded to the gills. Wish I had another dipper to fix-up,my local crank turner is getting old need to use him before he dries-up on the vine,of course rods are expensive now !!