The 2019 Insurance Classic Motor Show : Car of the Month - Roy Williams and his Ford Sierra RS500 Cosworth The 2019 Insurance Classic Motor Show : Car of the Month - Roy Williams and his Ford Sierra RS500 Cosworth
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Car of the Month - Roy Williams and his Ford Sierra RS500 Cosworth

‘I’ve always been a fan of the Ford “Twin Cam” family, and I’ve owned Lotus Cortina Mk.1 and Mk. IIs; the Sierra RS500 Cosworth is very much a car in that tradition’. On 10th January 1989 Roy Williams acquired a 1987-vintage “Diamond White” example of one of the greatest sporting saloons of its era. In the words of Andrew Frankel, ‘in the British Touring Car Championship (BTCC), the Cosworth RS500 won 40 races on the trot, a number unapproached by any other car before or since’.

Ford -Sierra -RS500-Cosworth parked outside house side on

The original high-performance Sierra was, of course, the XR4i, which was launched in 1983 to the delight of ambitious sales reps and anyone who liked to create a stir when arriving at the Harvester Inn. Ford considered it to be the eventual heir to the Capri Injection (although the older model remained in production for another three years) and 1985 saw the introduction of the XR4x4.

In March of that year, the Geneva Motor Show paid host to the RS Cosworth, with production commencing in the summer of 1986. Keen motorists eagerly noted the 1,993cc DOHC engine and the specification that included a Borg-Warner T5 gearbox. – and  Mr. William Woollard described the latest “Fast Ford” as ‘pure magic’.

And in July 1987, Ford announced the RS500, a Sierra developed by Ford Motorsport of Europe to further maintain the Cosworth’s profile. Roy points out that homologation regulations of the day meant that race cars could be modified if the company manufactured a limited run of road-going vehicles.

The RS500s were made at the Tickford works at a rate of 15 units per day, and all came in RHD form. They were sold only via Ford’s 90 Rallye Sport specialist dealerships, and the majority sported black paintwork with only 52 in “Moonstone Blue” and 56 in white.

As compared with the Sierra Cosworth, the extensive list of changes ranged from a modified inlet manifold to a Garnett T31 turbocharger with an enhanced intercooler and induction system. The oil pump was uprated while the block itself was strengthened. As Roy observes, the RS500 could be recognised by several exterior details including a coachline and additional spoiler on the tailgate.

Ford -Sierra -RS500-Cosworth parked outside with rear end showing and spoiler visible

The specification included a Ford/Teves-developed anti-lock braking system and – but of course – Recaro front seats (‘they are very comfortable’). A further reason for building the RS500 was that it would also serve to attract yet more customers to their friendly local (and non-Rallye Sport) Ford dealer.

In reality, the gulf between the 1.6L driven by Roger the Rep and £19, 950 worth of Sierra with a Weber-Marielli multi-point fuel injection system was akin to several Grand Canyons. But that would not prevent them dreaming of eventually taking the wheel of a car capable of 154 mph with 0-60 in 6.1 seconds.

Ford -Sierra -RS500-Cosworth on ramp with exhaust system visible

When Autocar tested the RS500 in August 1987, they very accurately described the performance as ‘storming’. It is an opinion with which Roy would concur, and wherever he goes in his Cosworth ‘it does tend to cause a stir’.

One reason is the Sierra’s appearance, for this is a car that laughs in the face of subtlety, but also because it was the childhood dream of so many Britons of a certain age to one day own an RS500. Mr. Williams has also occasionally encountered ‘people who say, “I remember those – they had the V6 engine”, and you just know they have confused my car with an XR4i!’.

Ford -Sierra -RS500-Cosworth -4

Over the past three decades, Roy has modified the suspension – ‘it improved the handling and the geometry’. Some ten or twelve years ago he also decided to ‘refresh the engine, but I ended up completely stripping it down!’.

Perhaps the best tribute he can pay to this Sierra of Sierras is that ‘it lived up to all my expectations – and more!’. Nor is the RS500 the only Cosworth in the Williams fleet, for ‘tucked away in a garage is a Sierra Sapphire’ – but that, as they say, is another story…

Ford -Sierra -RS500-Cosworth in garage

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WITH THANKS TO: Roy Williams



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