One of the better tips was not mentioned above. People have a tendency to overtighten the VC. The bottom surface of the VC has metal nibs on it. Once these touch down on the head, the rubber gasket is compressed the way the factory wants it. Further tightening from that point on is stripping the threads in the head. It's a very low torque and you'll "feel" when the nibs touch down. Stop. Best tip I know of....