Abstract: An injection-type internal combustion engine with cylinders arranged in line, with two overhead camshafts, and four valves and a central pump nozzle for each cylinder, and with detachable rocker arms being provided on the cylinder head above the respective camshaft, for actuating the pump nozzles. With this arrangement, the cams for the rocker arms actuating the pump nozzles are operated from the two camshafts in turn, i.e., the first camshaft actuates the pump of one cylinder and the second camshaft actuates that of the adjacent cylinder, each rocker arm being mounted separately. This will facilitate assembly and disassembly of the pump nozzle including the corresponding actuating mechanism and valve gear.