Engine builder Chris Lafferty...
Engine builder Chris Lafferty switches out a set of springs for Endura-Tech valvesprings in a test engine.
Have you ever wondered what separates the good engine builders from the best engine builders? Well, I believe it is the ability to find every ounce of performance from every part that goes into a racing engine. With all the turnkey engine combinations out there, it's easy to open up a catalog and find something that works well for your application. Of course, everyone else can do that too, so what are you going to do to separate yourself from the pack?
Take the valvesprings, for example. A valvespring is a pretty straightforward engine part. It's just a piece of steel wire at a given diameter that is wound and ground. As simple as that sounds, you'd think there wouldn't be any room for improving a valvespring over what's already out there. After you spend all that money on your race engine, don't you think you should buy the cheapest valvespring you can find because there is no sense in throwing away good money? Let me come right out and say there is a difference.
Let's start out by understanding what makes a good valvespring. Good-quality steel from the steel manufacturers is the foundation of any spring. Now I know you're thinking this is obvious, but you'd be surprised by the amount of inconsistent materials out there. A valvespring company's ability to check the materials it is using in its products is essential for a good valvespring.
Until now, Endura-Tech valvesprings...
Until now, Endura-Tech valvesprings were found only in a handful of Winston Cup cars. Lafferty has begun experimenting with them in Saturday night classes to take advantage of the increased performance available. Photo by Jeff Sandt
As an engine builder, I am always looking for new hardware I can take advantage of to build more powerful or more dependable engines. You probably haven't heard of Endura-Tech because only a handful of winning Winston Cup teams are currently using the springs. In some respects, they'd like to keep it that way. So there you have it: You now know a legitimate Winston Cup secret.
The question you should be asking is, "How can these springs be so much better?" The manufacturer has to pay attention to each step in the process to make a better spring. It all begins at the steel mill where the manufacturers use some of the finest steel in the world to make racing valvesprings. The raw materials must be completely consistent and reduce inclusions (the impurities that cause spring failures) to an almost immeasurably low percentage. From there, the steel is "drawn," or formed, into its final diameter.
Although Endura-Tech won't get into specifics about how its springs are manufactured, we do know that after springs are wound, they go through an additional heat-treat process that's methodically executed in order to greatly increase the springs' durability. A final shot-peening process further increases the springs' strength.
As you might expect, the additional steps in the manufacturing process also mean additional cost. The big question is, does the improved performance of these new springs make them worth the extra money? My firsthand experience allows me to say that these springs are going to last and be reliable.
One of the keys to Endura-Tech's...
One of the keys to Endura-Tech's improved durability is the heat-treating and shot-peening processes that take place to increase the spring's strength after it is manufactured. This creates a visible difference on the exterior of the valvesprings (right). The Endura-Tech springs are smoother and have a unique, shiny gray finish.
To find out if these springs were indeed as good as I had heard, I did an intensive Spintron test designed to push these springs to their limits. A Spintron is a testing device used by all Winston Cup engine builders to test the characteristics of different valvetrain components.
For the test, I enlisted the help of engine builder Lloyd McCleary of T&L Engine Development, who has tons of experience testing valvetrain combinations on Spintron testbeds. For the test, McCleary and I chose a test cam with a pretty extreme lobe. The cam makes power, but it has so far been unusable for racing. In testing, it destroyed every spring it was tried with in less than 200 miles.
Before the test, McCleary and I figured that it would be incredible if Endura-Tech's springs could last 400 miles. To our surprise, the springs went 2,000 miles without any sign of fatigue. Also, while all springs normally go "out of control" (they begin to allow the valve to either bounce or float) beyond 9,600 rpm with our test cam, the Endura-Tech springs proved they can live for a prolonged period in an out-of-control state.
This is not to say these springs will never break. At some point, all springs will eventually fatigue and fail. I am simply saying that these springs have so far outperformed any other I have tested.
To help give you an idea of what I'm talking about, graphs from the Spintron test show that the Endura-Tech springs largely keep the valves under control until around 9,600 rpm, which is impressive in itself. Even more impressive is that these springs didn't fail during the test. This will make these springs winners for the Saturday night racer, just like they have been for the handful of Winston Cup teams that currently run Endura-Tech. These springs not only allow the use of more aggressive cam profiles to make power; but, considering the extended lifespan that's possible, they also become affordable.
A Spintron tests valvetrain...
A Spintron tests valvetrain components by spinning the crankshaft in a mocked-up engine with a powerful electric motor. This allows the operator to precisely measure every piece of the valvetrain at virtually any rpm.
Chris Lafferty owns Lafferty...
Chris Lafferty owns Lafferty Engine Creations, which builds and maintains race engines for every level, from Late Model to NASCAR's Busch Series. Lafferty (left) and Lloyd McCleary of T&L Engine Development perform yet another measured rpm run on the Spintron.
Here's a graph of the valve...
Here's a graph of the valve movement at 9,600 rpm with the Endura-Tech springs. The yellow line is the valve's motion at 4,000 rpm for comparison (more or less ideal). The black line is the valve's movement at 9,600, which is the point where the spring reached a significant out-of-control state. Valve float causes the black line to rise above the yellow on the front of the curve. Pushrod deflection is the cause of the black line going below the yellow on the back side. As you can see, there is minimal valve bounce. Lafferty and McCleary stress that they were testing only the springs' ability to live in an out-of-control state in this test (not oscillations or level of control). Amazingly, it survived for over 400 miles without significant degradation of pressures!