Pent-roof combustion chamber

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In engine design, the penta engine (or penta head) is an arrangement of the upper portion of the cylinder and valves that is common in engines using four valves per cylinder.[1] Among the advantages is a faster burn time of the air-fuel mix.[2]

It is similar in concept to the hemi engine, both in design and purpose, but a hemispherical cylinder head is limited to only two valves without the use of a more complex sub-rocker assembly.

The four-valve penta engine design was invented by Peugeot of France,[citation needed] to be first used in the 1911 Indianapolis 500 race.

The penta engine (also termed pentroof combustion chamber) is the most common design[citation needed] used today[when?] by many manufacturers for four-valve-per-cylinder engines producing relatively high horsepower for displacement, for both racing engines and engines for passenger cars.


  1. ^ Tim Gilles (1 January 2014). Automotive Engines. Cengage Learning. p. 15. ISBN 978-1-305-17665-2. Retrieved 10 December 2016. 
  2. ^ Tim Gilles (1 January 2014). Automotive Engines. Cengage Learning. p. 88. ISBN 978-1-305-17665-2. Retrieved 10 December 2016.