Abstract: A crankshaft is rotatably supported by an engine block and rotatable about a crank axis. An eccentric shaft is rotatably supported within the engine and rotatable about an eccentric shaft axis, wherein the eccentric shaft axis is parallel to and distal from the crank axis. A speed change mechanism interlinks movement of the eccentric shaft and the crankshaft. The speed change mechanism selectively varies a ratio of a rotational speed of the eccentric shaft relative to a rotational speed of the crankshaft from 1:1 to one of: ?8:1, ?6:1, ?4:1, ?2:1, ?1:1, ?0.5:1, 0:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, and 8:1, thereby causing the eccentric shaft to rotate at a speed different from the crankshaft and varying a rotational position of the eccentric shaft relative to the crankshaft.

Abstract: A crankshaft is rotatably supported by an engine block and rotatable about a crank axis. An eccentric shaft is rotatably supported within the engine and rotatable about an eccentric shaft axis, wherein the eccentric shaft axis is parallel to and distal from the crank axis. A speed change mechanism interlinks movement of the eccentric shaft and the crankshaft. The speed change mechanism selectively varies a ratio of a rotational speed of the eccentric shaft relative to a rotational speed of the crankshaft from 1:1 to one of: ?8:1, ?6:1, 4:1 ?2:1, ?1:1, ?0.5:1, 0:1, 0.5:1, 1:1, 2:1, 4:1, 6:1, and 8:1, thereby causing the eccentric shaft to rotate at a speed different from the crankshaft and varying a rotational position of the eccentric shaft relative to the crankshaft.

Abstract: A cylinder head defines an inlet port having an exit. A valve seat insert defines a seat cut surface that is disposed adjacent to the exit of the inlet port. A cross section of the inlet port parallel to a centerline of the inlet port defines a long turn edge of the inlet port cross section. The long turn edge of the inlet port cross section defines a flow path trajectory of the inlet port. The seat cut surface and the flow path trajectory are substantially aligned to extend the flow path trajectory of the long turn edge of the inlet port cross section across the seat cut surface.