Abstract: A cylinder head with improved intake ports and a process for manufacturing such a cylinder head are provided. The process includes providing a cast cylinder head having a cast intake duct with an intake port that opens to a combustion side of the cylinder head and machining a first portion of the intake port so that the first portion has a cylindrical wall that extends generally perpendicular from the opening by a predetermined depth. In an embodiment, the process also includes machining an angled portion of the cast intake port so that the angled portion has a wall that extends adjacently from the first portion at an angle relative thereto. A cylinder head manufactured using the inventive process is also disclosed.

Abstract: A unitary combustion deck for an internal combustion engine includes a main body portion having a cylinder-facing surface and a coolant-side facing surface. The combustion deck further includes a plurality of bolt bosses which are integrally cast as part of the coolant-side surface and each bolt boss defines a bolt-receiving aperture which extends through the main body portion and which is designed to receive a mounting bolt for securing the combustion deck to a cylinder block for sealing against the leakage of combustion gases. Further included as part of the combustion deck is a load distribution rib which is constructed and arranged to extend in a ring-like form around the at least one cylinder while integrally connecting with each bolt boss of the plurality of bolt bosses.

Abstract: A pushrod-operated-valve-in-head six cylinder engine has two intake valves per cylinder. Five of the seven air intake runners in the cylinder head are arranged so that at least one intake valve port of each cylinder adjacent to another cylinder shares an intake runner with an intake valve port of the adjacent cylinder. Each of the shared runners feeds one valve port of each of two adjacent cylinders. The firing order of the engine is such that intake strokes for the adjacent cylinders are separated in time. Therefore, only one of the sharing cylinders at a time is supplied with air by the shared runner. In addition, because each runner is supplying only one valve per cylinder, there are two runners feeding each cylinder. For each cylinder, one port is the tangential type, and the other is the helical type. In one embodiment, the valve port connections to the shared runners are arranged for variable swirl production, by pairing the same style intake ports on each runner e.g.