Earl: On most any "modern" car, when saying you are "adjusting valves" what you are really doing is adjusting the valve lash, this is the function of the rocker arms, however. But when you are adjusting valves, one assumes you have a "solid lifter" in reference to a pushrod engine, or on a o'head cam engine that you don't have hydraulic or automatic valve adjustment. On the engine in question, the 102/103 MB engine, the rockers do have hydraulic adjustment, or hydraulic compensators as MB calls them. They don't need adjustment after being properly installed, but what is being discussed is the initial set up of the clearance of the compensators.......Gilly