Just to see if my understanding is correct- on a motor destined for high rpm application and or a service life of a quarter million miles (to the Moon), First guarantee the mains were in line via line bore or hone. Assuming the crank needed to be turned, insert a set of .010 (or the next oversize) bearings, and measure ID of the bearing installed in the saddles. Subtract the clearance from that (say 2.2377 bearing ID, .0019 clearance), that main should be turned to 2.2358. repeat for all mains, then do the same for all rods, same deal. Resize, install oversize bearing, measure bearing ID and subtract the clearance from measured bearing ID to get journal OD.
I'm ignoring the fact that the mains bearing bores do need to be bored/honed to the correct diameter
If I had the correct (decent) instruments (ID bore micrometer, 2-3” outside micrometer- I’m not opposed to getting quality instruments and doing this myself), the correct feel (I believe you can change the measured dimension by how you turn the spindle on the micrometer, finger grip force and torque you apply- something I would like to learn), and equally important- a crank grinder who believes the number I give him and actually grinds the journal to specified diameter rather than ‘grind ‘er .010 under’. Unfortunately, I don’t have that guy in the town I live in. He may be here- I just don’t know who he is.
Thanks all for the input. I think, in this case, I’ll live with the additional clearance (I won’t know if it’s excessive until I run the engine.)
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