BB Standard,
 

So guys I have Fuji gravel bike, In internet I found that it has PIIS BB86 shell, and Oval Consepts 520 cranks. I want to change the bb but I cannot find what I need. And is it possible to convert press fit to threaded? thanks!

Wheels Mfg - BB86/92 Bottom Brackets


COMPLETE BOTTOM BRACKETS FROM REAL WORLD CYCLING

It is not. "Threaded" usually refers to something like a 68mm English BB, and your frame is 86mm wide, so there won't be any -18mm conversion. You have to stick with wide format 24mm or 30mm diameter spindle cranks like Shimano Hollowtech and SRAM GXP or BB386EVO. BB30, ISIS or square taper BBs are too narrow for your frame.

What are you wanting to convert too? BB86 is pretty much standard Shimano 24mm. Are you wanting to replace the crank, if so, to what?

Bb86.5 can't be converted to a threaded bb, but can use most of the cranks that a threaded bb can use with the appropriate bb. I couldn't find details about the bb needed for that oval crank, but if both bearings have a 24mm inner diameter, it'll probably work with a Shimano press fit bb. If it has a 24mm driveside ID and a 22mm non drive side ID it'll probably work with a Sram press fit gxp BB.

Sure way would be to contact Fuji.