Abstract: An internal combustion engine is described having a crankshaft (14) and a camshaft, the ends of which project from a front end of the engine. A hydraulically operable variable valve actuation mechanism is mounted on the camshaft at the front end of the engine for driving the camshaft. A front cover (10) that overlies the end of the camshaft projecting from the front end of the engine, includes passages (40, 42) that are connected to supply oil under pressure from an engine driven pump (16) to the variable valve actuation mechanism.

Abstract: A variable phase coupling for connecting a crankshaft to a camshaft (12) comprises a drive member (20) for connection to the crankshaft having grooves (40) of a first pitch, a driven member (14) for connection to the engine camshaft (12) having helical grooves (26) of a different pitch facing towards the grooves (40) in the drive member (20), balls (28) engaged in the two helical grooves (26, 40) and serving to couple the drive and driven members for rotation with one another, an intermediate member (16) disposed between the drive and driven members for rotation with one another, an intermediate member (16) disposed between the drive and driven members in contact with the balls (28, 34), and means (56) for displacing the intermediate member (16) relative to the drive and driven members. The displacement of the intermediate member (16) serves to move the balls relative to the helical grooves in the drive and driven members so as to vary the phase between the drive and driven members.

Abstract: A method is described for manufacturing a multi-component camshaft assembly having an internal mechanism for enabling relative angular movement of individual cams of the assembly. In the invention, the cam surfaces are machined after the individual components of the camshaft assembly have been assembled to one another.