Modern engineering improving historic motorsport

Jon Lawson

Rising car values and the opportunity to take part in prestigious events is fuelling a boom in historic motorsport. Forward-thinking engineers are now helping to make those cars perform better than ever, as Nick Fleurot explains

Since the start of historic motorsport, the focus has been on the amateur racer but in recent years fixtures such as Goodwood Revival and Le Mans Classic have become must-attend events for car owners. As well as the prestige of taking part, success at such meetings adds to the provenance and value of the cars, leading to the sector investing in the latest technologies, materials and knowledge to succeed. That is now filtering down into club historic meetings where owners not only want to do well but also ensure that their car is reliable.

Today’s historic racers are faster than they ever were, even though now, in the main, they are driven by amateurs. A review by Motor Sport highlighted that today’s cars are around two to three seconds faster than when they were driven by the stars of the period. How is modern engineering contributing to these substantial gains?

A trip to CNC AWS Engineering in the Cotswolds provides a glimpse of the diversity of cars in historic racing. Alongside a Jaguar D Type and a 1980s F1 Fittipaldi, the workshop is packed with touring cars from the 1980s and 1990s. With 40-somethings now reminiscing of the battles between Sierras, BMWs and Rovers and having the income to re-enact those days, CNC AWS is busy applying new technology to not only keep the period cars on the track but also build ‘period correct’ recreations to satisfy demand.

Headed by Alan Strachan and son Andrew, the company draws on its own first-hand knowledge from working on the cars back in the day to restore and build ‘new’ Group Touring Cars. Strachan Sr worked for RS500 legend Rouse in the latter days of the Sierra domination. In the workshop are no less than five Ford Sierra RS500s, three of them ‘new’ cars.

“Access to new technology is keeping these cars alive,” says Alan. “We draw on the latest knowledge and materials to ensure reliability and performance gains within the strict rules. We also offer improvements in safety. For example, being able to machine new wheels, suspension parts and brake components in-house, that resemble period parts but draw on today’s more consistent materials to perform better and last longer.”

Strachan highlights a new brake calliper he has machined in-house using the 5-axis CNC machine that works flat-out producing parts for his own builds as well as for other race preparation specialists. “The original tooling is not available, and the rules won’t allow the use of modern callipers that don’t look as they did in the period. We can reverse engineer obsolete parts to keep a car racing and looking as it did. We use CAD, 3D printing and CNC machining to make a highly accurate part. It looks correct, has better tolerance for sealing and we know its history.”

Material gain in historic motorsport

That application of new materials is a common theme. At Tolman Motorsport in Warwickshire, whose projects span both current and historic cars, the business has become known for its attention to detail. Over the past decade it has become a specialist in what is often thought to be a temperamental engine, the Coventry Climax. Manufactured post-war, with origins in a fire pump engine, the Climax was the power source for the Lotus Elite sports cars. Founder Christopher Tolman’s mantra is “non-invasive improvement” and the company has developed a wide range of improvements for the Elite as well as single seaters and road and rally cars to make them more reliable, offer better performance and deliver an overall better driving experience.

“For years, it was just accepted that they were fragile or had nuances such as regularly leaking oil,” says Tolman. “Our background in contemporary motorsport led us to think that our knowledge could be applied to a far wider range of cars. We could see that engineering a correct solution now would result in a better long-term solution for the customer.”

According to Tolman, some gains were simple improvements such as developing brackets with a radius, like on the dynamo fixing for the Lotus Elite. “We got them to line up properly, eradicated the pre-load with new materials also playing a part; we now use clear zinc plating for corrosion resistance so it looks good and will not corrode.”

As an experienced engine builder, Tolman will also look to materials to extract performance without compromising on reliability. “Today’s gasket material, which is a huge step up from the period tin is one example, and another is that we use rolled threads on engine fasteners. This not only changes the mechanical properties of the material by work-hardening it, resulting in increased wear and fatigue resistance, but this also delivers enhanced shear and tensile strength as well as a smoother thread for assembly. As engineers we’ve learned so much in the past 50 years with more experience of thermal expansion, heat management, coatings and other materials. An engineering-led approach can make the difference between a car running smoothly all weekend or being packed up on the trailer early with a disappointed customer.”

Both engineers agree that machining improvements have resulted in significant advancements, leading to both creating in-house machine shops. “Minimising clearances of parts, such as in the drivetrain, can make a huge difference,” adds Strachan. “Eliminating leaks that could lead to a failure is a good example and engine-wise, the closer tolerances we can now achieve enable the motors to run harder and yield more power.”

For Strachan, additive manufacturing offers a solution for obsolete parts that are no longer easy to produce. “For certain trim or body parts we would have spent hours trawling eBay for parts that we only needed to comply with the rules such as internal trim parts or brackets that don’t add any performance. It also saves cost – an original front bumper for an RS500 could be thousands of pounds. The ability to make one using rapid tooling or AM means original parts can be saved for road cars and replica components can be used on the race cars where they are more likely to get damaged.”

With historic motorsport showing no sign of slowing down, both on- and off-track, both businesses agree that the sector has a bright future and for every generation there is sure to be a race car that can benefit from improvements that today’s and tomorrow’s engineering offers.

Recent Issues