When browsing new cars for purchase one might hear the word Camshaft and wonder what it might mean. Cams and their operation are often misunderstood in the automotive world and to consumers looking to understand cars when buying new or used cars. The duration, LCA, control valve timing, the effects of increased lift and the different valve timings often confuse people, leaving them frustrated when things don’t work right. Below is some clarification about the science of cams that helps explain precisely how cams work. In understanding the science of cams, you can then be more conscious about your cam selection, ensuring that you chose the right cams for every purpose.

Cams open and close the engine valves; if you don’t have the proper camshaft the intake and exhaust valves will not open and close the valves correctly, and significant engine power and efficiency will be lost. Camshaft valve timing piston to valve clearance and valve-spring pressure must be precise or significant power loss will result.

According to Mustangs and Ford magazine; when buying a cam the consumer should always buy a cam-kit which will normally come with the camshaft, the lifters, and valve-springs rated to match the camshaft. The installer should always review the camcard which will be included with the kit. The camcard will give adequate information on installation procedures and the cam specs, such as LCA, also referred to as lobe centerline angle (the way the lobes are cut), lift, and durations. The camcard will also give you information on how to degree the camshaft for the engine you are putting together. There are many different cam shafts that are on the market. The engine builder must know exactly what camshaft is going to benefit him/her most; for example, in oval track racing, the engine builder should know the length of the track, how much rpm the engine should be turning with the gears, tire size, and transmission. All of the latter mentioned necessities should be reviewed long before purchasing the cam.

The term duration refers to how long the valve stays open and how fast it closes. “Duration” is directly affected by the LCA and the LCA determines when the valves will open and close. The longer the valve stays open, the more air-fuel mixture is taken into the cylinder for better combustion. Further, the long the exhaust valve stays open, the more exhaust that escapes when the engine is running,