Rotary engines (also known as Wankel engines and Wankel rotary engines) are quite different from piston or "reciprocating" engines. One of the distinguishing features is that they don't need valves to ...

Here's the process of making this rotary valve engine with a different intake and an exhaust system. It wasn't easy to start ...

Last month's "How It Works" story gave you the basics of the four-stroke cycle, describing the motion of the intake and exhaust valves in relation to the piston moving up and down in the cylinder.