The position of the camshaft depends on the design of the engine. It can be in the engine block close to the crankshaft - this is a called a pushrod or overhead valve system. Or there can be one or two camshafts mounted in the cylinder head.
But in both designs it does much the same job - driving the valves and the distributor, and sometimes the fuel pump, and the oil pump.
The camshaft is made of hardenable iron alloy or steel, and it can be cast or machined.
The cam lobes are ground to the proper shape and position in relation to one another.
Accuracy is crucial. If the cam is not exactly the required shape, or if it becomes worn, there can be impacts, fast valve wear, or noisy operation.
The bearing surfaces on the camshaft are ground smooth, and the distributor drive gear is machined into the shaft.
The cam lobes are then flame or induction hardened.
The camshaft has a cam for each valve. In some cases, there is an additional cam known as an eccentric, to operate the fuel pump.
A gear on the camshaft drives the ignition distributor, and, often, an oil pump.
