degreeing a slant camshaft with no cam card

1930 said

You show this as exhaust valve opens 36 degrees BDC= Before Bottom dead center in the text but drawing indicates 36 degrees after botom dead center.

FSM shows it as 36 degrees BTC= Before top dead center

Why?

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My drawing shows that the exhaust valve opens before Bottom Dead Center (BBDC). It opens 36° before it gets to BDC then stays open to TDC, then another 12° after TDC.


I think that you are confusing Bottom Dead Center (BDC) with Before Bottom Dead Center (BBDC).

There is Before Bottom Dead Center (BBDC) and After Bottom Dead Center (ABDC).


TDC it shown at the top of the drawing.

BDC is shown at the bottom of the circle.