I just got my crankshaft back from the machine shop. It's been balanced and polished. And with it I got back 4 tapered plugs (they look like aluminum). I am assuming these are the plugs for the sludge traps. But when I tried to put them in the holes, the plugs only go in about half way leaving almost a half inch sticking out. I'm not sure if I should tap it in as tight as possible and grind down the extra material. Someone please help!!!!!