Patent ID: 8813706

Claim:
An internal combustion engine comprising: an engine housing having a head side and an opposite crank side, and defining a lifter bore extending longitudinally between the head side and the crank side, and a slot in communication with the lifter bore; a camshaft rotatably mounted to the engine housing and including an engine cam; a valve lifter assembly positioned within the lifter bore and including a valve lifter defining a longitudinal axis, a lifter roller in contact with the engine cam, for reciprocating the valve lifter within the lifter bore, and a key pin coupled to the valve lifter; the valve lifter having a planar peripheral face, and defining a transverse bore extending radially inward from the planar peripheral face, and the key pin having a shank held fast within the transverse bore, and an outwardly projecting head having a first and a second longitudinal edge, and a contoured outer surface; and the contoured outer surface having a plateau, and a first and a second slope descending from the plateau to the first and the second longitudinal edge, respectively, and the contoured outer surface being positioned within the slot such that the first and second slopes respectively contact the engine housing at a first and a second rotational orientation of the valve lifter, to limit misalignment thereof, and wherein the valve lifter is positioned at the first rotational orientation and the first slope contacts the engine housing in a line pattern of contact.