A camshaft is a rotating object that has oblong lobes protruding from it. The shape and position of these lobes determine the timing and lift of the valves in an engine. Cam lobe shapes are designed to open and close the valves at specific times during each cycle of the engine, and they also determine how much lift is given to the valve.
The term cam lope refers to the distinctive sound that is made when an engine with a camshaft is running. This sound is caused by the way in which the lobes on the camshaft open and close the valves in the engine. When a lobe opens a valve, it allows air and fuel to enter into the cylinder. As the lobe continues to rotate, it closes off the valve so that compression can occur within the cylinder. When this compression happens, it creates a characteristic loping sound.