The Four-Stroke Cycle of an Engine What really makes a car go? There are many parts to an engine that are visible, like an alternator, starter, hoses, wires and a bunch of other things. But what is in the inside and how does it work? The process is really just a mixture of parts, moving in sync in a distinct pattern called the four-stoke cycle. To understand the components of a four-stroke engine better, a little background information may be needed. "In a gasoline engine, exhaust and intake manifolds (tunnels) and valve ports(inlets or outlets) are needed to supply air and fuel on the intake (first down) stroke of the cylinders, and to expel burned gases on the exhaust