Inside The Crucial Role Of The Spintron In Valvetrain Evolution

One of the keys to success in any endeavor is knowledge—although knowledge is rarely free—and not always easy to obtain especially if you are looking for knowledge that others don’t have. The search for such knowledge led to the development of one of the biggest advancements in the science of valvetrain development: the Spintron, which was developed in the 1990s by Bob Fox, the owner of Trend Performance, and his team. Originally constructed to be able to develop advanced pushrods for small- and big-block Chevrolet engines being used in competition, today the Spintron is used by parts manufacturers and race teams across the globe to perform research and development—as well as validate the performance of—their valvetrain components while in use.

How Does It Work?

First, we should explain exactly what the Spintron is, and what it does. The Spintron system consists of two major components. The first element is a large AC motor unit that attaches to a complete engine via the crankshaft, and will spin the engine anywhere from 500 rpm all the way up to 20,000 rpm with incredibly precise control.

The second—and arguably the most critical part of—the Spintron is the laser camera used to track valve and pushrod motion and behavior. The Laser Valve Tracking System (LVTS) allows the detection and recording of things like valve bounce, valve lofting, spring harmonics, and pushrod deflection. The computer is able to display real-time graphs of what the valvetrain is doing, along with producing detailed reports based on RPM.

The Early Days

Prior to the development of the Spintron, valvetrain development involved a lot of guesswork. Granted, it was educated guessing, but guessing nonetheless. “Back in the late-1980s and early-‘90s, valvetrain parts were being made lighter and lighter to affect mass,” says Steve Rhodey of Trend Performance. However, with the advent of the Spintron, it was shown that lighter wasn’t always better.

“The pushrod was proven to work best while at its stiffest possible build. That meant larger diameters and thicker walls worked best,” Rhodey says. “Even though the pushrod weight more than doubled, the stiffer piece offered that much more stability and strength to the system.”

Back in the early ‘90s, you have to remember that new technology wasn’t simply accepted as “better” right out of the gate, especially when it went against the current theories and practices at the time. “It took a long time for the weight concern to get debunked, but eventually it all came to light and was accepted by the masses,” Rhodey says.

With such a revolutionary technology, the Spintron ran the risk of being ahead of its time, technologically speaking, but luckily, the only real hurdle it faced was the widespread acceptance of its information. “To my knowledge, the Spintron never ran into an issue where it discovered issues that were beyond the industry’s ability to remedy them,” says Rhodey. “Early testing showed improvement requirements that, fortunately, were readily available.”

Before the Spintron came along, these 7/16-inch diameter, .165-inch wall pushrods would have been considered “too heavy.” The Spintron had to not only validate data, but change the thinking of the time.

Perfecting Pushrods

As its original intent was to refine pushrod design, it’s no surprise that the Spintron has done that amazingly well. Through a combination of intense R&D and the use of the Spintron, Trend Performance has taken something as seemingly simple as a pushrod, and brought it into the 21st century.

“In all reality, the overall design and shape of the pushrod is near-perfect,” Rhodey says. “There is almost no comparison to a 20 year-old OE pushrod to our modern-day pushrod. Even the technology in our 5/16-inch diameter, .080-inch wall pushrod still smokes the competition, not to mention our one-piece forged-cup pushrods.”

However, Rhodey acknowledged that there is more than just a shape that needs to be considered when creating the perfect pushrod. “Design is important but how we make our pushrods is unlike any other company in the world” Rhodey says. “Design, plus material, plus heat treat recipe combine to equal the perfect pushrod.”

It’s not just the design of a pushrod that accounts for its improved performance, but also how it’s manufactured. Trend Performance’s advanced manufacturing processes account for a significant portion of their product’s advantages.

While not necessarily a direct result of Spintron testing, Trend’s manufacturing processes do affect the performance of the products they make. “Besides being able to turn around true one-piece, custom designs within 24 to 48 hours, even our entry level .080-inch wall pushrod has critical features, which separate our pushrod from a similar pushrod from our competitors,” says Rhodey.

Noting the word “near” in the “near-perfect” comment, there is still room for improvement, and Trend is still heavily involved in pushrod R&D. “Pushrod development is at its peak, but we aren’t about to be caught on our heels,” says Rhodey. “We are still playing on Spintron to validate different materials and shapes.”

“The taper aspect of a pushrod is inherently dependent on fitment,” says Rhodey. With Trend’s ability to custom-grind tapers into the pushrod, it allows for the largest OD and wall-thickness to be used without contacting critical components.

Market Demands

While some might think that with so many of today’s modern production engines utilizing overhead camshafts, the pushrod is headed the way of the dodo bird. However, walking through the pits at any drag race, from a weekend test and tune to an NHRA national event, or really, any motorsport utilizing V8 engines, you’ll notice a large majority of the powerplants utilize pushrods.

“We make one million pushrods a year,” says Rhodey. “A large portion of those Trend pushrods are for the LS platform. We private label for all of the serious LS specialty brands in the world, and that engine platform keeps us going 100 mph in our manufacturing of the one piece pushrod.”

While the LS and LT engines are a huge slice of the pie when it comes to pushrods, there are still plenty of other platforms still pushing the envelope on new pushrod design. “We have seen a huge push to the 1/2-inch diameter, .200-inch wall Trend pushrod. It is starting to become a hot mover, next to the LS-style pushrods,” Rhodey says. “We sell 1/2-inch pushrods to people for a wide variety of applications: LS, BBC, SBC, Pro Stock, Pro Mod, and Marine applications. You name it, people are getting creative and are putting the big pushrods in it. Enough so, that we keep several different 1/2-inch diameter pushrod designs on the shelf.”

Unique to Trend is the one-piece forged cup pushrod design (in the middle). “We started doing this on the Duramax and Cummins pushrods about 2 years ago. The problem was that the maximum cup OD was significantly larger than the pushrod OD. We got creative with an in-house-engineered tube/forge operation that gives us the material consistently to machine the radius into. It’s a proprietary operation that has never been done before.” Rhodey explained.

The Future of the Spintron

While pushrods have benefited immensely from the Spintron’s contribution to the R&D landscape, so has the entire valvetrain. By being able to test a complete, as-used-in-competition engine with laser analysis of the valvetrain behavior, teams have started looking at the system as a whole, as opposed to just focusing on individual parts.

“People are still tuning around valvetrain-related problems. The most critical use the Spintron has today is aligning the valvetrain combination,” says Rhodey. “Once the cam, springs, rockers, retainers, locks and pushrod combination gets figured out, the rest is history. Everything in the engine just gets happy.”

In addition to becoming more widespread both in scope and overall use, the team at Trend Performance are putting as much effort into keeping the Spintron on the cutting edge of today’s needs, as they do into their products.

Looking at the entirety of valvetrain performance, Trend decided to address the pushrod and rocker adjuster interface by designing a line of rocker adjusters. “Since we already master every aspect of a pushrod we decided to perfect the adjuster,” Rhodey said. “What we came up with is the end-all-be-all tool steel, nitrided adjuster with proprietary shaping which allows the mating surfaces to interact in the best possible manner; smoothing out the operation and minimizing friction to keep everything happy.”

“The Spintron is undergoing a technological face-lift as we speak. We are currently running the 2003 version of the software. Now, don’t get me wrong; it still works very well, but we’re trying to revamp the Spintron and bring it current,” Rhodey says. “Not to say too much, but there is a high probability of a custom software option coming out in the next release.”

Pushrods may currently be at their technological peak thanks to the Spintron, but we are also seeing its widespread use in a wide variety of valvetrain applications. From product manufacturer research and development, to individual race-team durability and performance testing of their specific valvetrain combinations – not to mention the uses we aren’t privy to behind-the-scenes – the Spintron is still at the forefront of analyzing and improving the performance of something as deceptively simple as an engine’s poppet valves.

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About the author

Greg Acosta

Greg has spent over a decade in automotive publishing as Senior Editor of Race Pages magazine. In his free time, he is a firearms instructor and volunteer in the police armory.
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