Ask any engine builder what the most important requirement of a race engine is and he's likely to say it's for an engine to last. Of course horsepower and other factors of an engine are vital as well, but if an engine doesn't last, what's the point?
In the early years, much of the testing of engine parts was more or less trial and error, and often the car that finished first was the car with the engine that didn't blow up.
Frequent engine failure motivated engine builders to come up with solutions to prevent such lethal incidents, and for years they have searched for ways to make engines survive the very high-rpm demands of the racing environment. Much of the research has happened in the dyno room and on the track during testing time.
As racing and technology have advanced, engine failure has been dramatically reduced, due in large part to the high-tech innovation of parts and methods by manufacturers and engine builders alike.
One of the most innovative tools that has come on the engine building scene is a device that many refer to as a spin fixture.
The so-called spin fixture found its beginning with a man named Bob Fox. For nine years, Fox has been at the helm of Trend Products in Warren, Michigan, where the main function of the company was the production of pushrods.
As his pushrod business grew, it became clear that in order to stay on the cutting edge of manufacturing, Fox needed to know more than anyone else about the dynamics of pushrods. "I needed to know definitively what a pushrod meant to an engine and what I could do to make it better," Fox says. "In order to do that I needed to do some testing. And in order to test, I needed to come up with some kind of a fixture that allowed me to see what happens to a pushrod when it's in operation. In the beginning, I had no thought of looking at anything else in the valvetrain, because I was a pushrod man."
That thought process gave rise to the idea of an electric fixture that could turn valvetrain components at a high rpm rate to simulate close-to-real operating conditions. In addition to turning the valvetrain, it was imperative to see what was taking place in regard to the pushrod actions.
With that as a design baseline, Fox set out to build a machine that would satisfy the goals of turning the valvetrain at sustained high rpm and showing the dynamics of that movement. After a great deal of engineering and consultation with many people in the industry, a machine began to take shape. As the project came to realization, this so-called spin-fixture machine was appropriately named Spintron.
Once the machine was developed, a surprising thing happened. Engine builders (especially in the Winston Cup ranks) immediately saw the value of the machine for much more than the investigation of pushrod dynamics. As a matter of fact, this was a time when engine builders became something of a consultant group to Trend Products. Through the engineering of Bob Fox and the needs of the engine-building community, the Spintron has become a must-have tool for many engine builders.
From conception to reality, the Spintron has come full circle, and today it is available to engine builders with a variety of options. In simple but accurate terms, the Spintron is an electrically driven, computer-controlled device that allows the unique opportunity to graphically see inside an engine when it's running at a full range of rpm values. From an informational standpoint, it supplies both visual and diagrammatic opportunities to understand what goes on inside an engine. It gives the user the opportunity to identify, document, and record vital characteristics of the valvetrain precisely.
These graphs show a valve...
These graphs show a valve event that is referred to as loft. Notice the line where the valve trace line rises above the baseline. When the valvetrain becomes uncoupled during the opening event, it's referred to as loft.
This is the kind of minute...
This is the kind of minute detail the Spintron reveals to engine builders. Armed with data such as this, engine builders are able to see if the system is tuned, and if not, it gives direction to making changes that can correct potential reliability problems.