I got in a discussion at work today about checking push rod valves. A co-worker who I believe is very competent tells me I have been doing it wrong my entire life. I make sure the valve is closed by rotating the engine to the half way point of where the valve closed and where it begins to open. Valve should be on opposite side of cam lobe. He says it has to be TDC on the compression stroke. I say the manual will say TDC to make sure the valve is closed not because it actually has to be there. I can't see any difference but I have been wrong before. I have always adjusted my way and never any issues. Am I doing it wrong?