Beehive Springs
Simple tweaks to a venerable design can yield big dividends in performance, and beehive springs are a perfect example. Elementary physics is why they work so well. "The difference in the active mass of a beehive spring compared to that of a conventional dual spring for the same application is more than the difference between a steel and a titanium valve in the same application," explains Billy. "Beehive springs take more mass off the top of the spring, which is the area that moves the fastest and the longest distance. Beehives are also naturally progressive in rate, therefore each coil vibrates at a slightly different frequency. This keeps the spring from going into resonance like a conventional spring and results in more of a self-damping effect."
When To Go Custom
According to Billy, cam manufacturers have done most of the homework for you. He recommends off-the-shelf camshafts whenever the application has something available for it that was designed with a similar application in mind. "These cams have a great deal of testing and are going to be better all-around performers than a custom cam 99 percent of the time," he states. "If we could make a better cam for a typical 383ci small-block Chevy, a ZZ4 crate motor, a 5.7L LS1 with aftermarket heads, or even late-model dirt-track and Super Comp-style NHRA applications, you can bet we would already have that part tested, verified, and included in our next catalog. However, chances are, if you're building a turbocharged NASCAR-style SB2 Chevy for a Suburban that you want to take on a cruise or bracket race, we are going to need to grind something custom, since you're doing something very unique. Likewise, we do custom grinds on many land speed and 24-hour endurance racing camshafts." Talking to someone at a cam company you trust is the best way to figure out whether or not you need a custom cam.
Solid-Roller Reliability
"Originally, solid roller lifters were designed for high-rpm race use. The only source for oiling the needle bearings was from oil thrown up by the crank. That works great at speed, but not so well near idle. The same lifters that lasted for several seasons in bracket and circle-track race cars were failing more quickly just going to the local cruise night and back. The other factor was spring load. Most of the older roller cams were designed for use with high spring loads. This helps keep everything under control at high speed with an aggressive cam, but greatly increases the load at low speed. The solution was twofold. First, we totally redesigned all of our roller lifters, both street and race, so that any lifter we sell with an oil band has a small hole feeding oil down to the needles. At the same time, we greatly improved the steel used for the axle while providing stricter control of the needle sizes to better distribute the load. The second part of the solution was to develop new profiles and springs for street roller use. These new profiles work great in the 2,000-7,000 rpm band while requiring far less spring pressure than the older race profiles. Together, these changes make it so the only maintenance consideration in buying a street roller from Comp Cams is whether or not you want to have to set and check lash. I recommend going through and checking the valves along with your oil changes. If you run Poly-Locks, this is probably overkill. Once you know what the engine sounds like, you will most likely be able to distinguish the tick of loose lash."