6.2 Crank size

[Bill Siver]

Hey everyone, I am new here and I am just rebuilding my 6.2. I was wondering if anyone could tell me the standard dia. of main and connecting rod journals.

When I took out the bearings, the mains were stamped
GM
A-200
0.013US
8 91
The rod bearings were stamped

GM
A-250
0.026US
1 0 91

Any help?

Thanks alot! I sure have a lot of reading to catch up on. ;)

Bill

[84 C2B2]

Hi Bill,

I just happen to have a handy manual in front of me. Your mains - The crank is supposed to be from 74.917 to 74.941 (mm) thick. Your bearings that state 0.013US are actually 0.0005" oversized to give a good clearance. you should see the #2 stamped near each main cap when looking at the bottom of the block. Your rod bearings - marked 0.026US are 0.001" oversize.

Really no worries but GM used different size tops and bottoms to get a perfect match. So, you might have a standard lower half and a 0.13US upper half. The only way to know for certain is to measure the crank bearing surfaces.

If the mains measure 74.917-74.925 use 0.026 bearings. If 74.925-74.933 use 0.013 and 74.933-74.941 use standard bearings. Bearings #5 is 0.005 smaller for each. Measurements are in MM.

Rods - came in standard or 0.001" oversize. Crankpin dia is 60.913-60.939 (mm) Oversize for 60.913-60.926 and standard for 60.926-60.939 (MM)

I believe mm to inches conversion is 25.4 mm to 1", 2.54 mm = .1", .254 = .010, .0254 = .001.

Jerry

[Bill Siver]

Thank you very much!

Bill