since this comes up enough maybe this will help to explain it

Originally posted by Terry Haines @ FCO:
...it's double answer.IF you get lucky its 'non',that is if the engine dies with the cams 'in sync' your OK...BUT if an intake or exhaut cam gets out of sync the valves can hit each other.If after a new belt the engine has no compression ,odds on they have 'kissed' each other.It doesn't take much to bend the valves as they have very small dia stems........




- 95 Mystique LS - Zetec/5spd - 99 Contour SeVT Sport - Duratec/5spd Official NE-CEG Contour/Mustang Family