Motorsport engines demand higher performance and that means the manufacture of very pure metals. It’s an area of intense competition and innovation, as Nigel Eames of MCT explains
One of the most gruelling automotive environments for metals is that found in a motorsport engine, where reliability and performance are pushed to their limits. This has an impact, not only on the types of metal used but also how those parts are made.
Nigel Eames, Manufacturing Manager at MCT, one of the world’s leading motorsport engineering organisations, notes that the environment in which a metal operates plays a key role in deciding how that material is selected and machined in the first place. And as the project manager behind engines that powered the Group C Jaguar, Volvo touring car and Nissan IRL programmes, he should know.
“Numerous different metals pass through machine shops on their way to motorsport grids across the world. Yet the three that we see the most of, particularly in terms of work for NASCAR and other North American series, are titanium, aluminum and steel.
“There are now some extremely pure steels in the marketplace developed initially for aerospace use, which are double or even triple vacuum re-smelted, removing a large percentage of the impurities from the metal. The purer aerospace-derived steels offer greatly improved fatigue life. And because the steel is so pure, it offers similar fatigue properties to forged components manufactured from a standard steel, with a quicker turnaround – one of the reasons why it is used in the wider automotive industry for prototype pre-production parts.
“Steel is utilised for the crankshafts, con rods, camshafts and valvetrain, as well as many other smaller components on a typical NASCAR engine. Generally, a purer, aerospace steel is used and is machined in much the same way as normal steel. The main problem with utilising purer steels is not the machining of it but the difficulty of its initial procurement as a raw material. Indeed, it is extremely expensive and the clever part of working with aerospace steels is to minimise waste.
“If one uses conventional steel, the grain structure will not be as good but with the vacuum-smelted steels – one gets similar benefits to a forged component without having to incur the costs and extensive lead times of forge tooling. All of this means that one can manufacture more quickly, which is so vital in the motorsport environment.
“As a material for engine components, steel is rough machined from its basic state, then heat-treated. Depending on the component, there is often a requirement to finish the component in a hardened state, which brings with it benefits of reduced distortion and better finish. Using conventional machining technology, we machine materials up to 45 Rockwell C, maintaining accuracies of around plus or minus ten microns. If finer finishes or greater accuracy are required, additional grinding operations are utilised. In addition, when machining hardened steel, it is vital that the correct cutting tools are utilised, as well as optimising tooling and cutting methods, to maximise efficiencies.
“The fascinating issue of motorsport metals is the way that the picture evolves constantly and we continue to work on the development of these materials. Metal matrix composites (MMC), for example, utilise powder technology and are used greatly across the higher echelons of motorsport. In F1, new regulations have banned the use of MMCs for pistons but the technology is still being exploited elsewhere. Indeed, we are currently developing motorsport pistons made from these materials, within those arenas that allow it.
“A lot of the research and development work that goes into materials is aimed at optimising material properties, which perhaps makes it ironic that one of the metals with the most apt properties for motorsport pistons – and a material that is still utilised in aircraft frames for this reason is 2618, an aluminium alloy developed for use with the Merlin engine of the Spitfire! However, although the basic material is the same, the heat treatment processes continue to evolve.
“Like so many areas of the automotive industry, the use of metals in the world of motorsport manufacture – and their treatment in the machining and manufacturing elements of the process – is an area of constant development, where competition pushes us down new avenues. As these process improvements work their way across to road car design and development, another benefit of the motorsport discipline is there for all to see.”