The basic timing is set up with the #1 lobes facing up and the crank at TDC.
Next, there is a hole in each of the cam flanges. The hole is on the rear of the flange that the gear bolts to. The hole is to line up with the valve cover mating surface when the chain is installed at TDC.
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 11 YRS