Both valves will be closed for the firing stroke. So, the cam lobes should be pointing more or less up and not pressing any valves down.

360 degrees opposite would be before TDC on the exhaust stroke, and you'd see the cam lobe pushing down on the exhaust valve.

Hope this helps.

-dan

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1976 w115 300D 4-speed conversion!!
1985 w123 300TD 4-speed conversion!!

Non-Mercedes old stuff:
1941 Buick Special (Straight 8!)
1946 Luscombe 8a
1947 Willys CJ2a
1950 Chevrolet 4400 dump truck
1954 Chevrolet 3600 3/4 ton
1954 Cessna 195B
1955 John Deere model 40
1991 Ford Taurus SHO
2013 Jetta SportWagen TDI 6-speed (I sold out...