I'm replacing the rings on a '80's 4 cyl. (not M.B.) and thought I might as well replace the rod bearings while it was apart. Bad idea. When I tightened down the bolts on the last rod I was doing (#3), I couldn't turn the crank with a wrench on the pully bolt. When I loosen that rod it turns fine. Plastigage shows a clearance of .0015" while the other rods showed .002" to .003" which shouldn't make much of a differance. Specs are .0008" to .002" with maximum of .0031" I tried using an old bearing on the lower half with no change. Should I also put back the upper half as well? I could turn the engine over be hand before taking it apart.