page_title: Piston
section_title: Racing Pistons
hierarchical_section_title: Piston / Piston engines / Internal combustion engines / Racing Pistons
caption_attribution_description: 1830s beam engine piston with rope seal, Coalbrookdale Museum of Iron
context_page_description: A piston is a component of reciprocating engines, reciprocating pumps, gas compressors, hydraulic cylinders and pneumatic cylinders, among other similar mechanisms. It is the moving component that is contained by a cylinder and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder. In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder.
context_section_description: In racing engines, piston strength and stiffness is typically much higher than that of a passenger car engine, while the weight is much less, to achieve the high engine RPM necessary in racing.
caption: Early (c. 1830) piston for a beam engine. The piston seal is made by turns of wrapped rope.
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