I did it with the heads themselves off because I put them on new heads to go on my engine, not the ones on it. So I can't truly answer all the questions. Mercedes may have special tool, I'm just sayin I don't see how you could do it. But when I did take my cams off (twice now), I zip-tied the sprocket to the chain so that it would not lose its position. Of course, I didnt rotate the engine when I did this, so I can't talk much but you'd have to move the cable tie on the sprocket as you rotated the engine.

I'd like to know from someoen who did this job with the heads on if they did it with the cams on or not, too. I really don't see how one could get the clearance in there needed to take the rocker arm out!