My engine case has both the oil pressure relief valve and the oil control valve. My relief valve (piston) is not the groved type (referred to in one manual as the 1500S valve) which it's supposed to have according to both my Muir and Hanes manuals...but neither explains why?
I assume there's a good reason that it should be the groved valve...but does anyone know?
Am I flirting with the engine tear down work bench by retaining the non groved relief valve until my next oil change?...or is my concern irrational paranoia?
