“Natural Frequency” – Differences between camshafts that require springs — and those that do not.

There is always power to be had with a camshaft swap in all vehicles on the road today, but since the inception of the old “3/4 race cam” of many years ago — cam manufacturers inch ever closer to making more power with less lift and duration with in recent years. So, what is the difference between a no spring required “NSR” cam, and a spring required cam?

No spring required (NSR) cams are a designed to consider the strength of the stock valvetrain components and their designed limit from the factory. NSR cams are often smaller in lift and duration to keep the valvetrain components stable but can either change overlap (such as a 2V or 3V Modular) or slightly increase lift and duration for more power. NSR cams can lead to decreased valve spring and valvetrain life along with valve float occurring at lesser RPM’s in tired high mileage applications or heavily raced vehicles. Also keep in mind, when increasing boost with a no spring required cam in a forced induction application boost pressure is pushing against the valve when closed on the seat as well making the valve springs job that much harder from more lift and duration.

Spring Required cams obviously require a valve spring change to keep all parts in the valve train stable. These cams allow for more lift and duration than an NSR cam could dream of, with the strict intention of making more power. Often stock valve springs are unable to survive or even compress as far spring required cams are designed to do. There is more labor involved installing new valve springs, and added cost, but valvetrain safety and stability is retained under all situations which is crucial in heavily raced applications..

We at JDM adhere to a safe and simple policy: With every performance camshaft install when seeking more power, install a set of upgraded valve springs at the time of the cam install regardless of spring requirements for peace of mind. Every custom camshaft kit JDM Engineering sells includes at a minimum an appropriate spring set to be installed at the time of cam install. With this method of upgrading, you shouldn’t have to worry about valve float, or valvetrain parts failures under the toughest of conditions for many years to come, unless finding new ways to push your combination past the limit is your goal.   Being cheap with engine internals never pans out in the end, so why not get your car built right the first time and never worry about it again.