With a B18b block and a B16 head, turbo, what pistons should I be using? I keep hearing about nippon? Any suggestions? And bore? Should I go bigger like 82 or 84mm?

 

the answer to that question largely depends on what crank and rods you'll be using.
bore size, well, bigger is always better, but you can only go so big before sleeving is a requirement

 

I want to keep the stock rods and crank, don't want a ton of power. Also going to get crank machined as I have zero oil pressure after warm up. Any ideas where to get thicker bearings to compensate for the machining?

 

on pistons, go to the smallest diameter that you can. If it does'nt need to be bored, deglaze, and leave it. Overboring has almost zero power gains on those little things, and makes the cylinder weaker. Oil presssure has more to do with worn oil pumps, and out of spec clearance issues. Something is worn/loose. If the crank is in spec, get it polished, and leave it. If it is ground .010" under, then you are going to need .010" under bearings. Or 5mm under. Whatever measurment they use. You get the idea. Always polish the crank! Always polish the crank! Most people don't know, or do this, but ALWAYS POLISH THE CRANK!

 

don't go 81.... go 81.5mm this will true out the bore AND tapper that all high mileage block will have not to mention your p2w clearances will be true and rings will wear properly.

I would run thicker oil before special bearings if oil pressure is your concern.