JWT expends a lot of effort on properly engineering any product it makes. Before they set out to make a true set of competition cams (hence, the C-series name) that were a step above their already proven street cams (S-series), JWT set out to design a valvespring that controlled float at any expected RPM for the SR20DE and was reliable enough for daily-driven street use. While this sounds rather simple, it is an amazingly complex process that required a lot of thought. First and foremost, JWT wanted to ensure that their valvespring would not encounter its natural frequency at any expected engine speed. Natural frequency occurs in a valvespring when the forces of acceleration during compression and decompression happen rapidly enough (due to RPM) to cause the spring to resonate. If you have a cam with a lot of area under the curve (a more square shaped lobe), you will encounter a valvespring's natural frequency at a lower RPM. A lobe with less area under the curve (a more rounded lobe) will encounter its natural frequency at a higher RPM.

When a spring reaches its natural frequency, it no longer controls the valve in a predictable manner, and the steel reacts in much the same way as when you strike a tuning fork. Natural frequency is not the only consideration when designing a valvespring, as a spring with a higher natural frequency puts more stress on the metal from which it is made. JWT addressed this in a number of ways. First, because a valvespring is only as good as the metal from which it is made, their valvesprings are manufactured by an OEM spring supplier that ensures the highest quality wire and rigorous quality control. Second, JWT spec'd springs with an ovate cross section (also known as multiple arc) to allow for a spring that has a high natural frequency, yet can be expected to have a long service life. An ovate cross section spring is superior to a round spring because it spreads its stress focal points to the just below the surface of the inside diameter of the spring – vice at the surface of just the inside diameter. Having the focal point of stress below the material's surface makes the spring less susceptible to failure due to surface imperfections introduced during the manufacturing process. JWT is the only company to offer an ovate valve spring for the SR20, and felt that the added cost in manufacturing was well worth the added reliability and performance of the design. In the end, JWT ended up with a spring that had a high enough natural frequency, was firm enough to control valve float, yet was not overkill to reduce valvetrain friction and wear from contact stress.

Worn guides can also contribute to valve breakage. The guides support and center the valves as they open and close. A worn guide will allow the valve to wobble slightly as it opens, which cause it to drift off-center with respect to the seat. This can cause the head of the valve to flex slightly each time it closes (much like a valve with a nonconcentric seat). After so many cycles, the metal fatigues and the head of the valve breaks off from the stem.