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Ford's FWD rally Fiesta with a 4-WD secret
The 1979 Monte Carlo Rallye will certainly go down in history as a dramatic motoring event, but away from Darniche's last night surge through the field to win by just six seconds there was another battle going on. A struggle that should also attract the attention of motoring historians. The fight within a fight was that of the major manufacturers with their front wheel drive hatchback designs.
The usual protagonists were there. In the Italian corner Fiat had sent along a pair of fuel-injected Ritmo 15005. From France there came the defenders of the unofficial FWD crown, Renault. Last year La Regie had pulled off second and third overall! This year the same drivers were back with their Renault A5 i .4-litre machines.
The Germans were not directly represented, but they had an excellent chance of winning the FWD battle with the car most saw as the best -the Golf GTI, one of which was driven very ably by Jean-Luc Therier.
Representing "Multinational Enterprises Inc." and drawing on skills from Britain and Germany were Ford Motor Co. The Fiesta was making its rallying debut for the factory upon the Monte! That is a fairly harsh spotlight to enter the arena beneath, so we thought we would interview the men responsible at the Boreham end of things about the rapid behind-the-scenes development that made such a debut possible.
The Fiestas did not win first time out, but if it had not been for the Ford strike An Vatanen might well have finished eighth instead of tenth, and scooped the FWD honours from eighth-placed Guy Frequelin in the R5. How so? The Fiesta Vatanen used had to bs built in a hurry in Germany and did not feature the same driveshaft spacer arrangement as the British entry; this made an effective cut in driveshaft length and led to a failure that cost Vatanen dearly. Without the road penalties he would have finished eight seconds behind the Renault, but since he was catching time hand over fist at the stage the failure occurred it seems reasonable to suppose that the young Finn would have won - neither the Golf (which was the fastest combination as well as the largest engined at 1.6 litres) or the pair of Ritmos finished.
Britain's Roger Clark, MBE, finished ijth with very few problems encountered, though it was perhaps a little nostalgic for him to be back in a FWD car after so many years of Cortina and Escort motoring. They did have a problem with a fuel filter "O" ring failure on the road down, but otherwise the British entry had a pretty undramatic run. A fact emphasised by the photographs which came back, none of which show Mr. Clark in his normal sideways stance.
The reasons for the lack of drama were apparent when talking to Ari Vatanen about his first competition FWD drive. "The steering is very good, you just point and drive." A slow grin spread over the young Finn's face as he added, "it needs all kinds of trick to get the tail out! The left foot is very important in this car, always braking and driving to keep the engine working. They say I can use 8,500 r.p.m. but I don't do this: it sounds enough at less, so why take a chance?"
Co-driver Richards added that:"The interior is very well laid out. A lot of thought has gone into making sure everything is where you want it. Noise? Much less than in a Group 4 car. Ari definitely needs to drive FWD more, I had the feeling he always had something in reserve."
Both noticed that the engine needed quite a lot of revving to keep running smoothly and it seems that, with near-racing power output extracted from the 1,599 c-c- Kent cross-flow motor, an extra spread of torque might be more welcome.
For the 1978 season a number of low-key Fiesta development projects were announced or authorised by the factory. Russell Brookes took one out on a club rally; John Taylor looked at the rallycross and tarmac potential with a 150 horsepower plus version that featured the first of the Hewland gear sets within a modified production casing and Bill Meade, the Ford RS high performance parts engineer (as opposed to the competition engineer Allan Wilkinson whom I wrongly mentioned last month) produced a number of quicker Fiestas.
All this was peripheral to the Group 2 Fiesta we are discussing here. That really started with the homologation on May I 1977 of the US Federal Fiesta 1600. That gave Ford a 1.6-litre pushrod engine base to build on.
Just about a year ago, in the early months of 1978, former Weslake engineer and well known member of the Boreham staff John Griffiths was assigned responsibility for the construction of a Group 2 Fiesta, utilising the parts already homologated on that May '77 form.
The first step was to assign design responsibilities to Len Bailey (not Len Terry, as we had last month!), and Hewland. The latter were to produce a suitable pawl-type differential for the Fiesta, having already completed a perfectly satisfactory four-speed set of ratios for the competition Fiesta.
Bailey drew up the suspension for the Fiesta (which I will outline later), but there was sufficient doubt about the drive characteristics of the pawl-style differential to also investigate what Ferguson's four-wheel drive experts could offer up in Toll Bar, Coventry. Why Ferguson? Remember those 4-WD rallycross Capris? They used the Ferguson system, and such a production car was put up as a serious limited-run project.
The link was Bill Meade and the others at Boreham, who had persevered with those rallycross Capris. Meade was not officially brought into the project until the recent strike pushed the development schedule way off, but once in he displayed his usual full-blooded enthusiasm for anything new (he was an integral part of the J25 Escort Twin Cam project, amongst others) and the Ferguson differential had an ardent supporter on its side. Since they had used it in the Capri, Ferguson's transfer box had been notably refined by the deletion of mechanical clutches and the substitution of a viscous coupling. It was and is this component that gives the FWD Fiesta the snatch-free driving manner of a RWD car - though the handling is still FWD. The heart of the matter is a sealed canister to which both driveshafts are attached, but only one enters within. Inside the space is divided amongst multiple discs with small gaps between them and holes cross-drilled in the faces. The discs move through a silicon-based fluid. The faster the discs are turned, the more resistance is generated with attendant heat rise and pressurisation.
Therefore the effect is a very progressive.....
Top-Right - Roger Clark demonstrates on the Monte-Carlo Rally the new non-sideways style he has had to adopt for the front-wheel-drive Fiesta.
Bottom-Middle - Mechanics work on the front "corner" of Clark's Fiesta, which boasts ventilated front discs and four-piston calipers.