Quote Originally Posted by alanTDM
As the shims wear then the gap gets narrower so infact it tightens up which in extreme cases if left to long you end up with burnt valves cause they are not sealing properly.
I keep thinking about this statement since I read it last night and I'm struggling to understand it. If the shims sit on top of buckets which sit on top of the valves and are directly under the cam shaft as they would be in any OHC engine... then as they wear the gap between the cam and the shim is going to get wider/bigger.

What am I missing?

Thanks,