Roll-over protection is their business
What do a works rally Escort, a Middle Eastern sheikh's Range-Rover shooting brake and all standard production Lotus Elites have in common? The answer is to be found in a collection of workshops in a suburb of Cambridge, where the Safety Devices Cambridge Ltd. company run by Brian Wilkinson and Tony Willis manufactures roll-over cages for over 70 different models of car. Last year more than 10,000 Safety Devices cages were despatched from 98 Fulbourn Old Drift, Cambridge (Cambridge 42268) as protection for hard-driving customers in all corners of the world. As an unofficial stamp of approval the firm has its products in every works Escort, the Leyland TR7s and Dolomite Sprints and the Dealer Team Vauxhall cars. The Lotus Elite and Eclat have Safety Devices tubular roll-over hoops hidden in their centre pillars while the sheikh had his Range-Rover bar made into a sort of mobile gun-mounting.
Stricter legislation together with commonsense acceptance (or stronger self-preservation instincts, as Second World War memories fade) by competitors has brought an escalation in demand and a complete engineering reappraisal since the first "bent gas-pipe" rollover hoops of the mid '60s. There has also been a realisation that roll-over cages can add considerable, and usually legal, structural rigidity to saloon cars as an aid to both handling and longevity. There is no better example of these last comments than the Ford Escort Mk. 2, a model, which has become a speciality of Safety Devices and led them into a deeper involvement with competition cars: the preparation of complete body shells for rally cars. Following Completion of a batch of rally Escort shells prepared for Ford's competition department (who also continue to use Maurice Gomm's metalwork company in Surrey) has come a development and preparation contract from Dealer Team Vauxhall for the 2.3-litre Chevettes to be rallied by Pentti Airikkala and Chris Sclater next season.
The Escort Mk. 2's larger glass area and thinner pillars compared to the Mk. 1 led to some nasty banana-shaped examples in the early days of the model's rally career. The shells simply would not stand up to hard "yumping" and bent across the middle, creasing their roofs, a problem which some privateers who don't take the right precautions continue to experience. As a cure, Brian Wilkinson, the engineering half of the partnership, developed his "14 point" roll-over cage: "The guts of the Escort 2—we build a bridge inside to hold it all together." This is the cage favoured by Ford and the "14 point" refers to the considerable number of places at which it is attached to the bodyshell, the secret of its strength. In its Group 2/4 Escort guise this sturdy homologated cage has a central hoop attached to the shell's floor, waistline and cant rail. Forward legs are taken over the doors, down the screen pillars to the floor, joined at the top by the forward roof protection bar. A recent addition to the front part of this structure, following lessons observed from floor pans crashed in around navigators' feet and legs, has been a bracing bar right across the passenger. foot-well between the front roll-cage leg and the transmission tunnel doubling as a navigator's foot brace. Those front legs are vital to strength and safety. "You've got to protect those top front corners above the crew's heads", says Wilkinson. "If you can dissipate the load from there into the rest of the shell, then you've succeeded," a sentiment I'm sure Roger Clark and Jim Porter would agree with after their enormous roll on the Mintex International Rally earlier this year. The Cossack Escort's Safety Devices front cage saved the two from any injury. The twin rear legs in this Group 2/4 cage are bolted into brackets attached to the rear suspension turrets, vitally feeding rear suspension loads into the cages Strong steel structure and removing the bulk of the stresses on the rear bodywork. While the front part of the cage for Group 1 Escorts is much the same as this Group 2/4 cage, that rear stress tweak is not possible, for the vertical turret rear Suspension is not homologated for Group 1 Escorts. Nevertheless the cage does absorb sufficient stresses to prevent roof-creasing--and keep the doors openable. There might be some kinking of the rear side panels, which won't occur with the Group 4 cage, but this is unimportant.
Because of tolerance problems and the sheer difficulty of fitting these complicated cages, Safety Devices will not sell them to customers as kits: they must be fitted at their factory. For those amateurs who can't afford this luxury there is a simpler, bolt-in cage kit available off-the-shelf, capable of protecting the occupants in the event of a roll but without the same benefits of stress absorption. Wilkinson stresses that any really serious competitor with an Escort 2 must have a cage to at least his 14 point standard, or he Will simply bend his motor car.
In the case of Group 2/4 cars, this .successful little company prefers to prepare bare shells incorporating their effective 14-point cage, though they have occasionally put their cages into customers' part-prepared shells. Most Group 1 cars begin life as ready-trimmed, fully-finished shells, however, which brings with it further problems of stripping out roof-lining, carpets, side panels and rear side-window glass and laying down fire blankets whilst cant rail brackets, strengthening plates and so on are welded in place. The task takes at least ten hours.
Correct fitting of roll cages and bars really is critical, says Wilkinson. "We've had a lot of trouble with people fitting our standard cages improperly, bolting them on to bare steel. You must always weld a backing-plate on to the mounting points—they practically double the efficiency of the roll-over bar." In the case of the Escort 2s even the Ford competitions department hasn't been entrusted with their fitment until recently. All the Safety Devices shells had them ready builtin of course, but, when Gomm-prepared shells were involved, Wilkinson went to Boreham to fit the Safety Devices cages. Now he thinks he has trained the Borcham mechanics well enough to fit their own.
Preparation of an Escort 2 Group 2/4 rally shell is an expensive, time-consuming business, yet Safety Devices have an ever-growing queue of privateers and semi-works sponsored customers. What they get are exact replicas of the shells prepared for Boreham, and what is good enough for them . . . By applying a few production engineering techniques Wilkinson has reduced shell preparation to 86 hours each, compared with a best of 100 hours amongst their competitors. And time, of course, is money. Work starts with a bare shell, which must be to at least 1600 Sport specification so that it incorporates the doubleskin strengthening round the McPherson "legs". The shell is slung on pivots front and rear so that it can be rolled over for access to the floor pan. Paint is then stripped off in the areas to be welded (the original spot-welding is not man enough for rallying), the whole of the floor pan is seam-welded and 14-gauge steel skids smooth the vulnerable lips on the floor. Every critical area is rewelded, particularly around the front pillars and the facia corners, where rally Escorts tend to break up under the strain. Minor attention to detail includes blanking off all the holes in the floor to keep out the dust.
Attention then moves to the major area around the rear suspension. Boxes for the rally suspension's four-link locating system are welded into the rear seat well, the vertical steel turret boxes for the shock-absorbers, together with the roll-cage brackets, are welded in and the boot sealed off by an alloy fire wall. Beneath the car a Panharcl rod bracket is attached, cantilevered for strength by a tube which goes back into th.e boot. New rear inner arches are seam-welded into place and the original body flanges turned out before the wide arches are riveted in place and smoothed in with body filler. These "spats" can be of glassfibre or aluminium to customer choice; aluminium is dearer but makes it easier to repair minor ravages of banks and braes. All the holes in the boot are welded up as a fire precaution, the filler cap hole plugged, for the customer will be fitting a safety tank with in-boot filler, and brackets attached for fuel and dry-sump oil tank. Inside the car the roll-cage is welded and bolted into place to complete the integrated structure. The onus to build the rest of the car now falls on the customer, but with all the awkward bits already fitted, the rest should go together fairly easily. The cost of all this specialised preparation will have been approximately £450 plus "spats", which sounds extraordinarily reasonable for 86 hours' work and the main hones of the ultimate in competitive rally cars. Thirty such shells have been completed so far this year. "They are cheap because we have productionised them instead of building each as a Stradivarius", says Wilkinson, who likes to supply axle casings for these Group 4 Escorts to ensure correct location—the right correspondence between body and axle brackets. These competition axles are re-tubed by Gartrac of Godalrning and special halfshafts fitted. Throughout this preparation only CO., welding is used. "We won't use brass at all", says Wilkinson. "Unless it is done very carefully with nickel bronze you can make the area brittle around the weld. Such care takes too much time."
Wilkinson and Willis are excited by the prospects of Vauxhall's new rallying project, which they consider will give the Escorts a run for their money. The first of these Chevettes, a Group 4 car, was built up with the slant-4; 2.3-litre engine at Safety Devices, a complex job when starting experimentally from scratch. Wilkinson reflects that the hatchback shape, used in preference to the 10 per cent heavier saloon, is very stiff "because of the amount of shape put into the floor wells, though unfortunately we have to chop it about to accept all the 2.3 bits. The biggest problem has been to accommodate the sloping engine's big exhaust system." Vauxhall stylists have produced a glassfibre front spoiler and Wilkinson has developed the glassfibre wheel-spats. Strengthening of the shell has been done in much the smile way as that of the Escort and an integrated roll-cage fitted. The tunnel too has been reshaped in much the same way as that for the Escort, again to accept a ZF box. A three-link rear suspension system is allowed for. The second Group 4 shell is now in the course of completion at Safety Devices, who are "tidying it up and productionising what we did on the first one." At least one lightweight club rallying Chevette is planned for next season, so we gather from another source.
Until now Safety Devices have not been really interested in full-preparation of rally cars, though Dick Beeby's Escort 2 being prepared for the RAC in our photographs is an exception, being a rebuild from his end-ove-rended Mk. I Escort. However, now Willis and Wilkinson intend to develop a Clubmans Escort rally car using a Group 4 shell fitted with a 2-litre Pinto engine and 4-speed Rocket gearbox. The idea is that it will be much cheaper to build and run than a BDA engine/ ZE gearbox car, yet still be reasonably competitive. A BDA 16-valve engine could be dropped straight into the shell as the driver developed more experience and money. They have recently built a Group 1 RS2000 too, and may build more if they can find a customer who can prove its competitiveness.
Returning to the roll-bar and cage side of the business, all the homologated bars are manufactured from 38 mm., 12-gauge, cold drawn seamless steel tube, a highly expensive commodity, which explains why non-homologated cages are made from the cheaper 14-gauge ERW steel. A few aluminium cages are made on request, though Wilkinson's frown showed that he wasn't too happy with that idea. Each prototype roll cage is made up by "cutting and shutting" tubes until the shape is right. Then a bending formula is devised so that the bar can be made in one piece and a jig constructed which doubles as a check for size and shape and as a welding jig. It takes three days' work to build a prototype cage and two more to do the jigging, the reason the 70 red jigs hung around the walls of Safety Devices' new workshop cost £200 each. Upon them the company's ten men construct bars for a wide home and export market, Sweden being the largest of the latter. They have their own distributors and stockists in Germany, Sweden, Iceland, Canada, the United States, Hong Kong and Holland, the partners travel abroad frequently to do their own selling and have recently done a deal with the Middle East which will see them exporting cages for Range-Rovers, Camaros, Mercedes and so on to these prosperous nations where presumably camel racing is falling out of favour.
"The manufacture of bars for older cars is a pain in the . . . really, but we have no choice but to make them," Wilkinson commented. "In most cases you can't productionise them because of variations in measurements, as we have found with MG TCs, for example. Each bar has to be a one-off, a Stradivarius." The result is expensive. Wilkinson himself is interested in more recent vintage, being in the last stages of an immaculate and painstaking rebuild of an E-type roadster for his own use.
Brian Wilkinson can claim to be one of the originators of the roll-bar idea. In the early 60s this New Zealander had a panelbeating shop at Steeple Morden, where an occasional visitor was an insurance assessor for the Prudential. His name was John Aley, who just happened to be .a rather well-known saloon car racer of the day. This One-time European Saloon Car Champion upended his works DKW at Oulton Park, flattening the roof, so he and Wilkinson devised a roll-bar to hold the roof up if Mr. Aley should decide to up-end the car again. Later the two and Bill Blydenstein collaborated in the production of £400 Mini racers into which they put roll-over bars, from which developed a rollover bar business. Wilkinson sold his business and returned to New Zealand in 1968, but came back to join Airy at the latter's request in 1970. This coincided with the introduction of FIA roll-over bar regulations. Wilkinson designed the first FIA bars and suddenly Aley had big business. Wilkinson remained Aley's roll-bar expert until Aley sold his business in 1972, thus forcing Wilkinson into business on his own in September 1972. Willis, the admin. part of the partnership, joined him straight from college. In four years they've built up quite a success story on other peoples potential accidents.—C.R.