The last thing we will discuss is the difference between intake centerline and lobe separation angle. These two terms are often confused. Even though they have very similar names, they are very different and control different events in the engine. Lobe separation angle is simply what it says. It is the number of degrees separating the peak lift point of the exhaust lobe and the peak point of the intake lobe. This is sometimes referred to as the "lobe center" of the cam, but we prefer to call it the lobe separation angle. This can only be changed when the cam is ground. It makes no difference how you degree the cam in the engine, the lobe separation angle is ground into the cam. The intake centerline, on the other hand, is the position of the centerline, or peak lift point, of the intake lobe in relation to top dead center of the piston. This can be changed by "degreeing" the cam into the engine. Figure 1 shows a normal 270 degree cam. It has a lobe separation of 110°. We show it installed in the engine 4° advanced, or at 106° intake centerline. The light gray curves show the same camshaft installed an additional four degrees advanced, or at 102 degrees intake centerline. You can see how much earlier overlap is taking place and how the intake valve is open a great deal before the piston starts down. This is usually considered as a way to increase bottom end power, but as you can see there is much of the charge pushed out the exhaust, making a less efficient engine. There is a recommended intake centerline installation point on each cam card, and it is important to install the cam at this point. As far as the mechanics of cam degreeing, Competition Cams has produced a simple, comprehensive video (part #190) that will take you step by step through the process.

On these pages we have discussed theory, but the video will show you how to actually get the job done. Competition Cams has put a great deal of effort into the design and engineering of their camshafts. All of these points were considered in each and every cam listed in their catalog What they intend to do here is show that camshaft design is not some "black art" but, rather, a series of decisions and compromises based on the exact application of the cam. Only many years of experience can say whether a certain combination of lobes will work, so you should trust the judgment of those who have engineered these combinations. If you have any other questions, the Competition Cams Technical Staff can be reached at 1-800-999-0853 and will be glad to answer them for you.