What are pistons and what do they do?
A piston is essentially the top part of a giant press that’s used to compress fuel and air inside your engine. It sits within the cylinder bore and performs a vital action on each of an engine’s four strokes.
On the induction stroke, it moves down from TDC (topdead centre) causing a depression in the cylinder that draws in the air/fuel mixture through the inlet valve. On the compression stroke, with all valves closed, the piston travels back up the cylinder and compresses the air/fuel mixture ready for ignition and combustion. When the mixture ignites,
