One of the big problems when it comes to race or high-performance engines using solid flat tappet lifters is the high spring pressures and super aggressive lobes available today can make it difficult to make a cam live through the difficult break-in process. One solution is to go with super expensive lifters made from tool steel and cams with exotic coatings on them, but most of us simply can’t afford all that. But there may be a better–and more affordable–way.
I’m working on a new engine build for a magazine, and as part of the build I had the opportunity to use a solid flat tappet cam from Comp Cams that utilizes what Comp calls a “Lobe Locker” core. As you can see from the photo, it uses extra material to tie the lobes on either side of each journal into one large hunk. The effect is to significantly shorten the sections of cam that are on the smaller diameter base circle, which should stiffen up the cam considerably.
With a standard cam, spring pressures can cause quite a bit of twist along the length of the camshaft as the engine is operating at speed. That’s why NASCAR Cup teams and racers in the top drag racing classes have gone to the much larger 55 mm cam cores. The extra beef helps stiffen the cam. Since you can’t easily use a larger diameter cam in a standard block, the Lobe Locker design is a good alternative. The added stiffness not only helps improve valve timing, but Comp’s engineers say that it should help prevent the edge of the flat tappet lifter from digging into the side of the lobe–which will destroy the valvetrain in a hurry. Cam flex allows bad things to happen, and the more flex you can get rid of, the better off you will be.
I’m excited to see how this cam works both on the dyno and the racetrack and will let you know more when the engine is complete and running.