Then, they are cooled and machined. Each piston goes through successive sculpting stages and, in some cases, the skirt gets an antifriction coating. This procedure ensures smoother operation of both the piston and cylinder wall. Friction will be negligible and, as a result, the engine will run at higher revs. Remember that the number one enemy of any engine is friction: it can generate intense heat that will destroy the piston.


Pistons are made of three parts: the head or top, which is in direct contact with the heat and pressure, the grooved section where the piston rings are fitted (right above the piston pin which connects to the tie rod), and finally the skirt, which guides the piston inside the cylinder wall during its stroke.

A piston can take many shapes, from dome to flat. It all depends on the shape of the combustion chamber in the cylinder head, which can either be hemispheric or two-way type. This holds significant importance, depending on the angle and number of valves as well as the location of the spark plugs. Gas combustion must reach optimum capacity for the engine to perform.

End of part one on pistons



Photo Credit : Henri Lebarbé