I’m just about to start reassembling my ’53 235 powerglide engine. The block was bored 0.030” over and the crank is now 0.010” under on the mains and rods, the block and main caps were not line bored.

The machine shop told me to start with 0.004” shims under all of the main bearing caps. Then use plastigage and adjust the shims until I get between 0.003” and 0.001” clearance in all of the main bearings. I understand putting the plastigage in, tightening the bearing cap bolts to the torque specs, then taking it back apart to read the width that the plastigage has been squeezed to.

My questions are

Do I do all 4 mains at the same time?
Do I make sure all surfaces; both sides of the bearing inserts, the crank journals and the bearing caps are all wiped clean of oil
Where do I place the plastigage? Directly across under the center of the cap at12 o’clock, or maybe two strips at 10 and 2 o’clock

One thing that really has me confused. I bought a shim kit at the local NAPA in the kit there was 1 pair of shims for each bearing cap, but each of the 4 pairs was a different thickness from 0.0065” to 0.0085”.

I took shims out when I disassembled the engine. These were about 0.004” to 0.005”. I cleaned and saved them and marked each for where it came from, maybe I should start with these.

Since I have not done this since high school in the early 60’s I sure could use some advice from someone who has more recent experience

Thanks

Kip

1941 Chevy Master 3/4-Ton
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