Abstract: A valve control system for an engine having a camshaft with first and second cam profiles, the valve control system comprising a rocker arm assembly including a first rocker arm having a first cam follower in engagement with the first cam profile, and a second rocker arm having a second cam follower in engagement with the second cam profile. The first rocker arm includes a latch member biased toward a latched condition by a fluid pressure in a chamber, and the first rocker arm defines a fluid passage having a first end in open fluid communication with the pressure source, and a second end in open fluid communication with the pressure chamber. An alignment feature cooperates with the latch member to ensure proper alignment with a latch surface.

Abstract: A cylinder head (10) for an internal combustion engine has hydroformed port liners (18) positioned within selected ports, either exhaust and/or intake ports (14, 16). The hydroformed port liner (18) includes an air gap (24) for an insulation layer within the selected port (14, 16) between an outer surface (19) of the hydroformed port liner (18) and the wall of the port (14, 16). A cylinder head (12) with a predetermined port configuration has selected ports (14, 16) cast with protrusions (22). The selected ports (14,16) have a larger diameter than a standard size port diameter for that cylinder head to provide a predetermined port configuration by a preset amount based on the thickness of the hydroformed port liner (18) and a desired air gap (22). Protrusions (22) in the wall of the selected ports (14, 16) or on the insert sleeves (17) facilitate formation of the air gap during the hydroforming process.