Allan Moffat's Cologne RS3100 - Australia's wildest V6 Capri
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Allan Moffat's Cologne RS3100 - Australia's wildest V6 Capri

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By MarkOastler - 08 March 2013
Allan Moffat’s RS 3100 Capri was the ultimate V6 Capri to compete in Australia. Despite having about half the engine capacity of the top V8 sports sedans, Moffat had numerous giant-killing wins in this remarkable car. (Image from: autopics.com.au)

Multiple Bathurst 1000 and ATCC winner Allan Moffat needs no introduction to Australian motor sport fans. And for a good chunk of his celebrated racing career, he clearly enjoyed an equally high profile within the Ford Motor Company on a global scale.

For it was only through his solid company connections that Moffat was able to get his hands on one of a mere handful of Mustang Boss 302 factory race cars when they were being built for the 1969 Trans-Am wars in the US and ship it back to Australia to race.

And in 1974 it was also through those channels - this time in Europe - that Moffat was able to secure one of the equally rare RS 3100 ‘Cologne’ Capri factory-built race cars fresh from battle with BMW in the 1974 European Touring Car Championship (ETCC).

Moffat was given direct access to the exotic Cosworth-powered racer straight after Ford had shut down its German-based competition department in Cologne at the end of the 1974 season, due to the global energy crisis that put the squeeze on many factory-backed racing programs.

He figured it would be just the right weapon to tackle Australia’s booming sports sedan category, which by 1975 was prompting race promoters in various states to offer big prize money and appearance fees to lure the best cars and drivers in the country.

Fortunately Moffat had ruled out radical modification of his ageing Trans-Am Mustang to keep pace with the latest sports sedans, preferring to gracefully retire such a rare jewel and tackle the top guns head on in 1975 with his new European weapon.

It was without doubt the wildest and most exotic Ford Capri V6 to race in Australia. The high-pitched scream from its quad-cam, fuel injected, 450 bhp, Cosworth V6 being revved close to 9000 rpm sent shivers down the spines of all those who witnessed the car being driven in anger.

Moffat raced the Cologne Capri during the 1975 and 1976 seasons, during which time it won numerous races against lighter and more powerful V8 competition and played a pivotal role in securing the inaugural Australian Sports Sedan Championship.

Factory development of the RS 3100 Cologne Capri by Ford and the lengths it was prepared to go to beating arch rival BMW in the 1974 ETCC is a nostalgic reminder that when the Ford Motor Company went racing in the 1960s and ‘70s - it went all out!

In full house Group 2 racing specification, the RS 3100 was a stunning machine from any angle. (Image from: Allan Moffat Racing)

 

Why Ford built the ultimate RS

The catalyst for creation of the RS 3100 was the 1973 ETCC, when BMW fended off a gallant season-long challenge by Ford’s less powerful RS 2600 Capris to win the prestigious title.

BMW had caught Ford by surprise that year by equipping its 3.5 litre CSL coupe with a huge boot-mounted inverted rear wing, made even more effective by a full-width scoop mounted along the rear edge of the roof to feed it clean air flow for maximum downforce. Not surprisingly, the big CSL coupe soon earned the nickname ‘Batmobile’!

Ford rightly figured that to overcome the CSL challenge in 1974, the Capri would firstly require more power. However, the RS 2600’s German 2.6 litre V6 engine, which had already been bored out to 2.9 litres capacity and was producing around 320 bhp, had reached the peak of its development.

By comparison, the capacity of BMW’s potent 3.0 litre in-line six had been increased to 3.5 litres under the FIA’s liberal Group 2 rules, providing a big power advantage over the Fords. The obvious answer was a switch to the larger capacity 3.1 litre British-built Essex V6 as used in UK-built Capris.

The CSL’s inverted rear wing also provided a considerable edge in traction and high speed stability so Ford had no choice but to join the aero wars with a large rear spoiler of its own. Wind tunnel and track testing of various designs proved how effective a large ducktail spoiler could be.

As a result, Ford committed to production of a ‘homologation special’ called the RS 3100 that would serve as the road-going production basis for its full-house Group 2 competition cars for the 1974 ETCC attack.

Built in a batch of 250 (the minimum number required for FIA homologation) the British-built RS 3100 came with front and rear spoilers and the 3091cc Essex V6. Use of this engine of course would allow the 1974 race car to increase its engine capacity to 3.5 litres to match the BMW.

The small batch of RS 3100 road cars went on public sale in November 1973 with FIA homologation approved on January 1, 1974. Surprisingly perhaps, these rare homologation cars proved hard to sell. Evidence of that fact is that 50 of the 250 built were shipped to Australia as late as June 1974 where they were eventually sold through selected Ford dealers.

Exotic Cosworth-designed GAA-V6 featured four belt-driven camshafts, fuel injection and 450bhp from just 3.4 litres. (Image from: Ford Motor Company)

 

Cosworth to the rescue

Michael Kranefuss was the man in charge of Ford’s ETCC program. Given Ford’s long and successful association with Cosworth, in particular its 3.0 litre V8 DFV Formula One engine, he approached the Northhampton firm to design the new RS 3100 race engine. Initial discussions between Ford and Cosworth about this engine had started back in 1972.

The Group 2 rules required use of the manufacturer’s standard cylinder block, but a timely change that allowed use of alternative cylinder heads for 1974 left Cosworth with the task of designing new aluminium heads with dual overhead camshafts, four valves per cylinder and an initial power target of 400-plus bhp.

The Cosworth GAA-V6 was designed by Keith Duckworth and Mike Hall, featuring cast aluminium heads that could be used on either bank. The four overhead camshafts operating 24 tiny valves were belt driven by toothed pulleys at the front of the engine, with one spark plug per cylinder and Lucas mechanical fuel injection.

Cosworth needed to increase the cylinder bore size of the Essex block, but wayward casting tolerances meant that few of these mass produced blocks survived the machining process.

It settled on 3412cc as the safe limit. Cosworth also beefed up the bottom end with rugged four-bolt main bearing caps.

In-house dyno testing of the new 3.4 litre GAA-V6 began late in 1973 and it produced 420 bhp straight up, instantly meeting Ford’s 400 bhp plus target. With on-going development these engines reached 450 bhp at a spine-tingling 8750 rpm.

The RS2600’s five-speed ZF gearbox was carried over and matched with a rugged Borg & Beck triple-plate clutch in a feather-weight magnesium bell housing.

The RS 3100 Cologne Capris were built with a win-at-all-costs approach at Ford’s German competitions department in Cologne, under chief engineer Thomas Amerschlaeger. The exotic materials, quality of workmanship and attention to detail evident in the construction of these factory race cars was beyond belief.

The emphasis was on minimising weight, as the lightweight fiberglass doors, bonnets and boot lids used on the RS 2600 were no longer allowed and the new Essex V6 was slightly heavier than the German engine. This resulted in a 50 kg weight increase in the new cars, which would be offset somewhat by the more powerful 3.4 litre Cosworth engine.

They started with standard LHD steel body shells taken from the production line which were rumoured to have spent time in an acid bath to remove some excess metal before they arrived at the workshop.

Large aerodynamically shaped fiberglass wheel arch flares were installed at each corner to shroud huge wheels and tyres and lightweight laminated window glass was fitted throughout the cabin. The large front and rear spoilers, which under Group 2 rules had grown considerably from the road car versions on which they were based, were fitted front and rear.

The increased weight of the Essex V6 altered the car’s critical front to rear weight distribution, which Amerschlaeger’s team addressed by mounting the engine’s dry-sump lubrication oil tank and fuel injection pumps inside the boot area, where the battery and huge 120-litre long distance fuel tank also resided.

Oil cooling radiators for the gearbox and rear axle were also moved to the tail end and mounted directly behind the rear wheels, with oil circulation controlled by a pump driven directly by the tailshaft via a toothed belt and pulley arrangement. The engine oil cooling unit was mounted in the nose where it was fed fresh air through the grille.

This shot shows the large openings in front of the rear wheels to feed cooling air to the engine’s rear-mounted radiators. (Image from: autopics.com.au)

The engineers also experimented with a rear-mounted engine radiator but found that there wasn’t sufficient air flow available because of the effectiveness of the huge front spoiler in stopping air from flowing under the car. Amerschlaeger eventually opted for twin side-mounted engine radiators mounted just ahead of the rear wheels.

The standard dashboard pad and door trims had to be retained but the rest of the interior was stripped bare, leaving a full set of competition gauges, remote switch panels, massive roll cage, on-board fire extinguisher system plumbed to every corner of the car and lightweight Nomex covered driver’s seat.

To minimise weight, many suspension components were made from aluminium or magnesium.

Under Group 2, a touring car’s suspension had to keep its original ‘architecture’ so the RS 3100 was equipped with strengthened front suspension towers, Bilstein aluminium McPherson struts with gas-filled adjustable dampers, a wrist-thick anti-roll bar, magnesium hub carriers and solid aluminium replacing rubber in all suspension bushes.

Likewise the Capri’s live rear axle and leaf spring design had to be retained, but Ford got very creative in its rule interpretation. It complied by fitting leaf springs, but they were made from lightweight composite materials and had no springing function at all.

This was performed instead by big coil springs and adjustable gas-filled Bilstein shocks. Ford’s homologation paperwork stated that these coils were simply ‘additional springs’ and the FIA duly agreed!

The rear axle was located fore and aft by upper and lower trailing arms and laterally via a Watts linkage that also allowed adjustment of the car’s rear roll centre.

The brakes were huge with four wheel discs permitted under Group 2, even though the road car had rear drums. The ventilated front rotors measured 12 inches (305mm) in diameter and more more than 1.0-inch thick, clamped by powerful servo-assisted calipers.

The front brakes were also fitted with an automatic water cooling system connected to a large tank in the cockpit which could spray a fine mist onto the disc rotors to cool them down each time the brake pedal was pushed. The rear discs were slightly smaller 10.5 inch diameter units.

The racing wheels and tyres were enormous given the size and weight of the car, capable of generating such huge cornering forces that the works Capris were often seen in the ETCC cornering with their two inside wheels clear off the deck.

German BBS composite rims (magnesium centres with aluminium rims) were secured by a single central locking nut and fitted with tailor-made Dunlop tyres that measured a staggering 16 inches (405mm) wide at the rear and 12 inches (305mm) on the front.

With top shelf drivers the calibre of Niki Lauda, Jochen Mass, Toine Hezemans and Dieter Glemser on the team, Ford was ready for all-out war.

Moffat had his work cut out in the 3.4 litre Capri against far more powerful 6.0 litre V8 competitors. Here he’s battling Bob Jane’s Monaro (leading), Jim Richards’ Mustang and Pete Geoghegan’s Monaro at Melbourne’s Calder Park in 1975. (Image from: autopics.com.au)

 

The 1974 ETCC

Unfortunately, the timing could not have been worse for what promised to be the battle of all battles for the ETCC crown between Ford’s new RS 3100 Capris and BMW’s mighty CSL ‘Batmobiles’.

The world’s worsening energy crisis, which had been triggered by the Arab-Israel war, forced car companies to quickly change priorities in their marketing and product development strategies. Motor racing programs were hit particularly hard during this time, including Australia where Ford withdrew its factory support in January 1974.

Sadly BMW also began to scale down its racing activities during the ETCC which left easy wins to the new Capris at several rounds. Even so, despite these outright victories and the vast sums of money spent designing, building and developing the new RS 3100s, it was the German Zakspeed-prepared RS 1600 Ford Escorts which ended up winning the manufacturer’s title for Ford due to a points system that was heavily weighted in favour of smaller capacity cars.

The last time an RS 3100 Cologne Capri competed in full works guise was when Jochen Mass and Toine Hezemans were sent to Kyalami in South Africa to compete in a gruelling non-championship 9-Hour endurance race as part of the Springbok series that featured many sports cars. The Capri was fast and faultless again, winning the touring car class and finishing an outstanding fifth outright.

The same car - chassis number GA ECPY19999 – would not return to Germany after the race, though, as it was destined for a very different life in Australia.

Moffat chasing Bryan Thomson’s wild V8-powered Type III Volkswagen coupe and Bob Jane’s 350 Monaro on debut at Sandown Park in early 1975. Moffat won when Jane and Thomson spun. (Image from: autopics.com.au)

 

The Moffat era

In late February 1975, GA ECPY19999 arrived at Allan Moffat Racing in Melbourne after being shipped directly from its last race as a works car in South Africa.

Although the stunning European thoroughbred won first time out at Sandown it soon became apparent that the Capri, which was built for long distance racing on high speed European tracks, was going to be doing it hard against lighter and more powerful V8 competition on Australia’s tighter tracks in short sprint races.

Its V6 engine just couldn’t match the explosive power and torque outputs of rival V8s. And it was restricted to the local maximum wheel width of 10 inches, which was a substantial drop in traction given the car was designed to race on massive 16-inch wide rears and 12-inch fronts in Europe.

It was also comparatively heavy given its touring car racing origins, competing against increasingly sophisticated purpose-built local designs that featured mid-mounted V8 engines, space-frame chassis, Formula 5000 suspension and featherweight composite body panels.

Moffat had his sights set on winning the inaugural Australian Sports Sedan Championship (ASSC) in 1976, so when it became clear he would need V8 power to do it he sourced a state-of-the-art DeKon Chevrolet Monza from the US. With 6.0 litre Chevrolet V8 power, it was immediately more than a match for the best sports sedans in the land.

Even so, the RS 3100 Capri still had an important role to play as the controversial Monza was sidelined midway through the ASSC due to questions over its eligibility. So while that was being sorted out, Moffat dusted off the Capri for two crucial rounds at Wanneroo in Perth (which he won) and A.I.R in Adelaide (where he came second). The Capri proved it was still highly competitive, effectively sealing the title for Moffat and finishing its Australian career on a high note.

Today, Moffat’s Cologne Capri - still largely in its 1974 ETCC factory specification - lives in New Zealand under the ownership of enthusiast Mike John.