Arrangement for the operation of valves of internal combustion engine

An arrangement for operating intake and exhaust valves of an internal combustion engine having a cylinderhead with overhead valves and an overhead camshaft rotatably supported so as to extend longitudinally on said cylinderhead, said arrangement comprising at least one valve actuating lever and one coupling lever pivotally supported in side by side relationship on a lever support shaft extending parallel to said cam shaft, said coupling lever being in engagement with said camshaft along an engagement line for actuation of said coupling lever by a cam of said camshaft, said coupling lever and said valve actuating lever having guide bores with axes disposed at the same distance from the axis of said lever support shaft so that they can be brought into axial alignment, a coupling bolt disposed in said guide bores, actuating means for selectively moving said coupling bolt into and out of a coupling lever and valve actuating lever coupling position, a hydraulic valve clearance compensating element disposed in a bore formed at the end of said valve actuating lever, said lever support shaft having an axis of rotation and said guide bores having a center axis spaced from said axis of rotation of said lever support shaft by a distance which is greater than the distance between said guide bore center axis and the center axis of said valve clearance compensating element, wherein, in a coupled state of said coupling and valve actuating levers, the axis of rotation of said support lever shaft, the center axis of said guide bores, and the engagement line of said cam define in a plane transverse to the longitudinal axis of said cylinderhead approximately an isosceles triangle whose sides of equal length are formed by the distance between said engagement line and said axis of rotation of said lever support shaft and by the distance between the engagement line of said cam and said center axis, said camshaft being disposed between said intake and exhaust valves and at least partially above said valve actuating and coupling levers.