Abstract: A pair of adjacent valves (intake or exhaust) are operated by a single cam lobe on an engine camshaft via a bucket tappet, the arrangement being such that both the bucket tappet and the valves are rotatable during engine operation to reduce wear thereof. Preferably, a hydraulic lash adjuster is operatively associated with the bucket tappet and with a thrust member engaging the free stem ends of the valves.

Abstract: Each cylinder of an engine is provided with a pair of intake valves and a pair of exhaust valves arranged opposite each other in a V-like pattern and are driven by an overhead camshaft having an associate intake cam lobe for the intake valves and separate exhaust cam lobes on opposite sides of the intake cam lobe. A single direct acting bucket-type tappet journaled in the engine cylinder head is acted on by the intake cam lobe to control opening and closing movement of the pair of intake valves. Each exhaust valve is actuated by an associate intake cam lobe via a valve train that includes a tappet, push rod and a rocker arm, with an integral hydraulic lash adjuster, pivotably supported on a common rocker shaft.