A Camshaft is a shaft in the engine, which has a series of cams for operating the valve mechanisms. The camshaft is driven through gears by the crankshaft and mounts overhead on top of the cylinder head.
- Some engines use a combination of timing chain and timing belt to drive the camshafts.
- When the camshaft is driven by a timing chain, the crankshaft and camshaft rotate in the same direction.
- With gear, the camshaft rotates in the opposite direction. Most camshafts have a cam for each valve in the engine.
Composition of a Camshaft
- In addition, the camshaft has another cam to operate the fuel pump.
- It also has the gear to drive the ignition distributor and the oil pump.
- The camshaft sprocket or gear is twice as large as the crankshaft sprocket. It gives a 1:2 gear ratio, which means the camshaft turns half the speed of the crankshaft in a four-stroke cycle engine.
- Thus, every two crankshaft revolutions give one camshaft revolution and one cycle of valve action.