The camshaft profile refers to the shape of the individual lobes. The camshaft pattern refers how the profile of the intake and exhaust lobes compare to each other.
Symmetrical Lobe Profile
A symmetrical lobe has identical opening and closing ramps. Each half of the lobe is a mirror image of the other. This design opens and closes the valves at exactly the same rate.
Asymmetrical Lobe Profile
An asymmetrical lobe has different opening and closing ramps. It is usually designed with a steep opening ramp and a gradual closing ramp. This design opens the valve quickly. Then, slowly, gently sets it down.
Single Pattern Camshaft
A single pattern camshaft has intake and exhaust lobes with exactly the same profile. This is a simple design, usually found on older engines.
Dual Pattern Camshaft
A dual pattern camshaft has different profiles on the intake and exhaust lobes. This is a more complex design found on newer engines.
The lobe profiles can be optimized to account for specific conditions. For example, an engine with a free-flowing intake might have some exhaust restriction. It will need more Lift and Duration on the exhaust side to empty the combustion chamber. (The table below shows an example.)
| Camshaft Pattern | Intake | Exhaust | ||
| Lift | Duration | Lift | Duration | |
| Single Pattern | 0.443 in. | 214° | 0.443 in. | 214° |
| Dual Pattern | 0.475 in. | 208° | 0.500 in. | 218° |