Nothing to adjust I'm afraid. The hydro valve lift adjusters are there to take care of the adjustment issue. Knocking valves is usually caused by:
Worn valve rockers, or
Worn hydro valve adjusters
Any one of, any combination of, or all three causes will cause knocking.
The valves are "adjustable", you select different sizes of shim pucks based on valve stem height which changes due to wear. Mercedes makes a tool for reading whether the shim is too big or too small. However if they are really making a racket instead of the "ticking" then maybe a valve job should be done first.
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