[Tuesday]

Hi. Well this is my first post and you are probably going to hate me because it's about a BMW I6. But it is a general crankshaft question and you guys are smart so you can probably help anyway.

Crank main and rod bearings are sold (on this site anyways) in sets with all the same size bearings. Do they machine the journals on the bearings all the same, or is it possible that one journal may need one size, and one needs another? Also why do they even sell different sizes (ie oversize) bearings, why don't they just make all cranks of the same engine the same?

If you have any more info that you think I'd like to know about crankshafts, bearings and/or rods I'd love to know.

Thanks!