Valve gears for load-change valves of four-stroke internal combustion engines, in which the load-change valves are closed by spring force, engage a pivot lever moved by a cam for opening a load-change channel. The cam engages an intermediate element that it is additionally moved by the lifting curve of the cam during a different work cycle, and adjusts the pivot lever to open the load-change valve slightly during a different work cycle. The intermediate element is prismatically guided on an element that can pivot in the cylinder head and is adjustable in its position, and engages the cam and the pivot lever, so that the stroke movement of the cam for opening the load-change valve via the pivot lever can be adjusted.