Tumbler

Collapsed engines

In the engine spark-ignition , the tumblers are used to transmit the push of the pushrods towards the Soupape S (valves being above the Cylindre, the pushrods along the cylinders, and actuated by a side Camshaft, located to the bottom of the cylinders, near of the Vilebrequin). These engines are known as collapsed . They were very much used in Automobile of tourism until years 70-80 and in Motocyclette. They remain still used on the engines which have a mode of maximum rotation relatively low.

Engines with simple camshaft at the head

If one wishes a mode of rotation more raised, it is of use to just put the camshafts above the valves (Camshaft at the head), and, therefore there does not need more pushrods (less parts moving, plays, therefore less risk of Affolement of valves).

When the valves all are not aligned and that one wishes to use one camshaft at the head, one has the tumblers to transmit the push of the cams to the valves.

Engines with double camshaft at the head

Although the assembly with double camshaft at the head makes it possible to be freed from the tumblers, it sometimes happens to use small tumblers provided with an adjustable tangent intercalated between the cam and the tail of valve, primarily in order to make it possible to regulate the Jeu with the valves.

Engines without tumblers

Lastly, when the cams push the valves directly (case of the simple camshaft in an engine with aligned valves or of a Double camshaft at the head), there does not need more tumblers.

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