Cast Away

There’s much more to casting high performance engine parts than simply pouring liquid metal into a mould – as Racecar discovered on a visit to Formula 1 supplier Grainger and Worrall

- Gemma Hatton

In a Formula 1 engine during the combustion process the instantaneous gas temperature reaches 2600degC, which is half as hot as the sun’s surface, and the gas pressure forces are equivalent to four elephants acting on each of the pistons. Within a blink of an eye an F1 engine completes 200 ignitions, with 43 trillion calculations over a race distance. And it only takes one combustion error in 37 million to cause a terminal failure.

With these figures in mind we can maybe start to appreciate the phenomenal challenge facing motorsport engine manufacturers. ‘The shift towards small capacity turbocharged engines that we’ve seen in F1 and, are starting to see in other championships, results in the engine stresses and temperatures reaching new levels,’ explains Phil Ward, director of performance products at Grainger and Worrall, which is a world leader in manufacturing structural engine castings. ‘The increase in temperature is more of a challenge than the increase in stress, because the aluminium alloys within the engine experience a dramatic drop off in strength once a threshold temperature has been exceeded. A material that is perfectly strong at 160 to 180degC will behave like toffee above 250degC, so the alloys we used in the V8 era, which was only three years ago, are now no longer strong enough.’