COMP Cams Titanium Super 7 Valve Locksretainers. It is critically important to make sure valve locks match the valve size. There should always be a small gap between the two halves of the lock when they are properly positioned on the valve stem. If the two halves fit together without a gap, they are too large. If the locks fit tight to the stem and leave a gap between the middle of the lock and the OD of the stem, the locks are too small. Most people believe that the tang inside a valve