Hi again,
so can I get any N18 crankshaft and install in my good block? Are there any codes to match?
I would keep my pistons and use the new used crankshaft with its rods. Then I will check what main bearings I need.
thanks

 

I would check real OEM dot com and make sure the part number of your crankshaft matches the used one you are attempting to purchase. Then I would take the crank along with the block, pistons etc and have them inspected by a qualified machine shop to make sure all the parts are within specification. Engine assembly is easy, it's the machine work and ensuring the crankshaft journals have the proper surface finish that build long-term reliability.

Also, don't worry about BMW's TIS main bearing color codes; I installed a set of King bearings in my rebuilt N12, and after three oil samples, oil analysis shows a very healthy engine. You'll want .002 - .0025 clearance on the mains.