valve clearance

[blackstack]

On page 142 of the Operating Instructions book, in the explanation of finding TDC it uses the term"....valves must overlap" What does this mean???

Thanks

[pinzinator]

Both valves are open at the same time, this happens at TDC of the exhaust stroke.

[blackstack]

Thanks!!

[David Dunn]

Both valves are open at the same time, this happens at TDC of the exhaust stroke.

Actually, when they're closed.
The top of the compression stroke .
TDC is the basic reference for setting ignition timing on the compression stroke..... for instance, if you hear 6 degrees before top dead center (BTDC) , the timing is set to ignite the spark 6 degree before the compression cycle is complete (TDC).
.

[blackstack]

From page 142 of Operating manual...(paraphrasing)To set valves of #1 cylinder crank engine till both valves of #4 are open etc.....is my understanding of statement correct?

[David Dunn]

From page 142 of Operating manual...(paraphrasing)To set valves of #1 cylinder crank engine till both valves of #4 are open etc.....is my understanding of statement correct?

With your last statement, then Pinzinator's statement is correct.
When both vlaves of #4 are in a open position when #1 are closed, and ready for adjustment.