Oil passing the intake valve guides can easily be detected because upon inspection, the underside of the intake valves will show a carbon formation. Sloppy exhaust guide clearance causes misalignment and bad seating, resulting in fast valve seat wear. Sticking Valves - Are caused by carbon, misalignment and excessive wear and heavily leaded or heavy gum content in the gasoline. Tappet Clearance - Adjust tappet clearance according to specifications. Correct clearance contributes to quite engine operating and long valve seat wear.
Insufficient clearance causes the valve to ride open, resulting in lost compression and burning.
Too much clearance retards timing and shortens valve life above seat preventing maximum intake and exhaust. Check tappet guide clearance. Sloppy fit permits tappet to strike valve stem off-center, causing side thrust on valve stem with excessive wear and bad seating. Timing - Adjust ignition timing with accuracy. Incorrect timing will cancel all benefit of precision reconditioning.