A camshaft – an essential part of every car’s engine. But what exactly is it, and what exactly does it do? Here are some basic facts:
The camshaft is located at the top of your car’s engine.
Along the lengths of the camshaft are lobes (known as cams), which push on the rocker arms as it rotates. These in turn push on the valves, which open and close.
It essentially times the opening and closing of valves in a car’s engine at regular intervals. These valves control the flow of fuel and air throughout the engine, and so a camshaft is essential to the smooth running of your car.
The rotation of the camshaft is controlled by the rotation of the crankshaft, which is at the bottom of the engine. A timing belt stretches between them, so that the two move together.
Some cars have just the one camshaft (known as single overhead cam, or SOHC engines). Many cars have double headed cams (known as double overhead cam, or DOHC engines) as they have two sets of valves to let more air and fuel into, and out of, the engine. The timing belt drives the first one, and a short chain drives the second.
If a camshaft is broken, it goes without saying that it will need replacing immediately. But one common problem is wearing out a single lobe. This can cause a popping and backfiring of your engine. The best way to identify this is simply to remove the cam cover and check the cam’s lift directly, or if you are still unsure request your mechanic checks for a worn lobe.