Volvo (and others) used to sell the gear set and needed parts as a kit, so they'd likely tell you to use the kit.

But the small metal crank gears never seemed to wear out -- only the fiber gear, which would break away from the hub or snap a few teeth.

If I were doing a B20 today, I'd find a replacement fiber gear (from somebody like NAPA or similar). But even better would be to find an old 164 with a B30 and grab the all-steel gear set, and here you MUST use the matched set. (The pitch is different from the fiber to the equivilant steel gear, so you must use the B30 smaller gear, too.)

Examine the brass "squirter" nozzle to be sure it's clear and aimed.

Examine the brass thrust plate (which holds the cam in position) to be sure it not worn or cracked.

Be sure that you keep the steel spacer ring on the camshaft -- otherwise the fiber gear will cinch down tight on the brass thrust plate and the cam and engine will be locked up solid.

1-7/16" socket for the cam nut (I bought mine at Sears), you'll probably need the 3/4" to 1/2" adapter.

--
Don Foster (near Cape Cod, MA)