A double overhead camshaft engine having two camshafts rotatably supported by a cylinder head. This two camshafts are drivably connected through an idler gear with a crankshaft of the engine by means of drive chains. The idler gear is rotatably mounted on an idler gear installation bolt which is fixedly secured only to a front end section of the cylinder head in a so-called cantilever arrangement. A surrounding wall structure for the idler gear is formed integral with the front end section of the cylinder head and extends in the direction of axis of the idler gear over the idler gear to form a front end section. An opening is formed at the surrounding wall structrure front end section and located on an opposite side of the cylinder head front end section with respect to the idler gear. The opening is closed with a cover which is disposed spaced from the idler gear installation bolt, so that no connection is made to the idler gear and the installation bolt therefor.