I’m finishing up an old build. Its a b18a1 and I lost crankshaft gear some were at the shop. this is what the timing belt raps around. I found a gear on line local that’s off a b20z. will it work?
Looking at the parts lists, it looks like the OBD1 B18A/B18B had the same gear type and interchangeable oil pumps.
But in 96 with OBDII when they moved to an oil pump that had the crank (CKF) sensor in it, they moved to a slightly different gear design (same one the B20Z uses). But all of these engines use the same timing belt.
So, will it have the correct # of teeth and probably work fine? Yes. Is the timing belt going to line up perfectly in the Y-Z plane? Maybe.
I have no idea how that CKF sensor works in OBD2 engines, but I suspect it uses the inner cog on the later gears which is why that part (the part you are looking for) is different.
Hopefully that is enough info for you to decide if you want to use that B20Z one or just find a used B18A one. I will say that lots of engine builders list “Type R oil pump” as part of a build, but don’t mention having to replace that ~$60 gear, so things will probably line up just fine. Just check for possible rubbing on the T-belt cover.