Abstract: The cam shaft carried in the cylinder head is driven by the crank shaft with a gear drive that is borne or supported partly in the crank housing and partly in a gear housing flangely attached to the crank housing. In order to compensate for the thermal induced increase in the distance of the cam shaft with respect to the crank shaft and to hold the torsional flank play at the gear teeth constant, the gear wheel engaging with the cam shaft gear wheel is arranged on a line extending approximately perpendicularly to the connection line between the cam shaft and the crank shaft.