Line of improvement
The Ford Cortina-Lotus, developed for the public by the Competitions Department
When the 1967 Cortina-Lotus was introduced, perhaps rather quietly by Ford’s standards, there was a general feeling that this was a toned-down version of a car which had earned so many competition successes, and perhaps much of the character had been removed.
But the proof of the pudding is in the eating. On paper the specification has been improved, driving the car underlines its superiority, and detailed investigation shows that nine months of rigorous development, in the right hands, has made it a vastly better product. Much of the groundwork experience was put into the Cortina GTs taking part in the Safari Rally, and their mechanical reliability was such that, presuming Ford take part again next year, there will be virtually no specification changes other than running with the Lotus twin-cam engines.
Towards the end of the GT’s proving trials last April two new cars were fitted with Special Equipment Lotus engines developing 115 b.h.p. gross and handed over to Henry Taylor’s Competitions Department at Boreham Airfield, Essex. Under the supervision of Bill Meade, the Rally Engineer, two mechanics commenced a punishing programme of development to eliminate the faults of the previous Lotus version.
First of all the cars, one with left-hand drive, were lowered by one inch front and rear and fitted with wide-rim wheels and Goodyear or Pirelli radial-ply tyres. Early testing consisted of high-speed runs over a “rally route” at Bagshot Heath to prove the strength, and the selected drivers, Ken Wiltshire and Mick Jones, put in favourable reports about the improved suspension, finding it particularly good through a trough which could break the front struts of the old cars. Heavy-duty export bodyshells are used exclusively for the Lotus versions, having stronger welds around the suspension mountings.
During the summer and right through to January testing continued at Bagshot, at the Motor Industry Research Association proving ground, and at Lommel, a Belgian proving ground. Each car covered up to 25,000 miles in this time, including 5,000 miles on corrugations and pave, 4,000 miles at maximum speed and 2,000 miles testing engine durability.
It took five weeks at Lommel to select the damper settings, the suspension going into production with higher spring rates. Compared with the previous model, the new car has forged top camber arms, angled front springs and specially treated bushes to reduce “stiction” and offset the side loading. Rear Suspension geometry has been altered so with the wider track and lower centre of gravity the handling has been altogether transformed, eliminating the “lurch” that preceded roll previously.
Mechanical changes are more far-reaching than we imagined, partly because the Lotus version has been specially developed by rally engineers and partly because it is now in production on Ford’s own production lines at Dagenham and Halewood, subject to an extremely strict quality control which demanded at least a dozen improvements straight away. Engine durability testing revealed piston failure, which has been cured by a new specification, and the throttle linkage has been made heavier and stronger. Thicker gauge metal in the exhaust manifold has cured a resonance and the system is suspended in 0-rings instead of straps. It was also found possible to incorporate two mufflers in the system instead of three.
Noise level was a major consideration and it took several months to evolve a new, large AC air cleaner which has cut induction noise to a minimum. Such is the size of the unit that the battery had to be moved to the boot, incidentally improving the car’s weight balance. Ignition timing has been altered, again in the interest of durability, and the dynamo has been made more reliable with thicker field wire. Trouble on the Safari Rally, incidentally, was caused by dust entering the generator and should not therefore be a problem in normal use.
A hydrostatic (self-adjusting) 8-in, clutch is incorporated with much lighter pedal pressure, 30 pounds instead of 50, and the gearbox is improved. The box, similar to the one used latterly on the old version and now fitted to the 2-litre Corsair, has a better shift integral with the extension housing which cuts out the “fizz,” and it will be noted that reverse is located right-and-back instead of left-and-back. The driveshaft is now split and jointed, eliminating whip which occurred at high speeds, and with competitions in mind it will cope with speeds up to 8,000 r.p.m. in top gear, possibly over 130 m.p.h. depending on gearing. Also new is the 3.77 ratio axle, exclusive to Lotus versions and much stronger than previously; having high-tensile nuts and bolts on the differential carrier, it is known to cope with up to 140 b.h.p. in competition use.
Brakes, with servo assistance, are the same as those used on the Corsair 2000 and a dual system has also been developed for the American market. Handbrake efficiency is improved, while all markets share a benefit of better crankcase emission control demanded by U.S. regulations. Finally, a 10-gallon petrol tank replaces the 8-gallon tank fitted previously, increasing the range to approximately 250 miles.
With pride, Ken Wiltshire and Mick Jones claim that the ride is better than on the GT even though the car is an inch lower, using the same spring rates but higher damper settings. There is no export specification now since the suspension was developed mainly on the Continent and is considered suitable for all territories except possibly darkest Africa, so far as the customer is concerned. It was with new respect that we drove the test car back to London from Boreham, appreciating that it certainly handles better than the old Lotus.
Although the ride is slightly firmer than that of the GT we soon ceased to worry about running over potholes, because the anticipated shock is not transferred through the car. Most of the testing was done on Pirellis, which are fitted to about half the production cars, but the test car was shod with Goodyear tyres which have a new rubber mix, perfectly adequate on the wide rims to cope with wet weather conditions. The only complaint about the car is that rain gathers at the bottom of the screen at high speed and is forced upwards, proving too much of a task for the single-speed wipers.
Without the pronounced induction noise the “C-range” Lotus is not the boy-racer some people expect, being quiet, comfortable and refined – it needs a stopwatch to prove that it is quicker, the extra horsepower rating having overcome a small weight disadvantage. All the controls are very light, the clutch particularly so, and right up to maximum speed the car is smooth and restful to drive. Clearly there is a ready market for “performance-plus” cars, since a sixth of the 1,500 Cortinas manufactured every day are GT or Lotus versions. Whereas in the past difficulty may have been experienced in obtaining modified parts for competitions, dealers should now be ready, willing and able to supply a car modified practically up to the specification of the works cars raced and rallied. We say practically because on April 29th Graham Hill was due to drive a Cortina-Lotus at Silverstone equipped withthe new Ford-Cosworth 16-valve Formula Two engine, and there is a long waiting list for this power plant! Among the performance items which can be supplied are Jackson-Tecalemit petrol injection (£60), alloy door panels (£13 10s. each) or bonnet and boot-lid (£12 10s. each), a limited slip differential £(25), close-ratio gearbox (£60), stamp-shield (£12 10s.), high-ratio steering box (£11 19s. 6d.), engine modifications and a good many more items listed in a catalogue.
As we started off by remarking, there is a good deal more to the new car than meets the eye. – M. L. C.
On the road the Cortina-Lotus, although the most exciting of the C-range of Ford cars, accomplishes extremely well what Dagenham intends it to do, namely constitute a saloon of exceptional performance (see table) so docile and well-mannered that it will be bought by family men, whether for prestige purposes or because it will appeal to the older members of a household while offering the competition flavour younger drivers desire.
The test car was in 2-door form, carrying the Lotus badges and “speed flashes” along the body-sides. This twin-cam Cortina is nicely finished within, with comfortable seats, although long-legged drivers will probably prefer to reverse the brackets of the driver’s seat, so as to raise the cushion when the seat is in the fully-back location. The full instrumentation of the push-rod Cortina GT, the “Aeroflow ” ventilation and Weber 40DCOE carburation, are amongst the car’s best features. Indeed, until it is driven hard this Cortina-Lotus feels and sounds almost like the Cortina GT, except for faintly more cam noise from under the bonnet. The ride is not too bad, and the old understeer and weaving tendency have been eliminated. Indeed, there is a tendency for basic oversteer to make the nose dive inwards on corners, even on a light throttle opening, and in the wet power oversteer can be provoked, although normally the wide-base Goodyear G800 tyres hold satisfactorily. The servo brakes are powerful and progressive; cornering normally quite neutral, with little roll. The steering ratio is the same as on the GT (3 1/2 turns lock-to-lock, plus sponge), the action light and precise.
Gone are the heavy clutch, high bottom gear and notchy close ratio box. of the first exciting Cortina-Lotus I enjoyed so much in 1963. The 1967 Ford-built version has an extremely light clutch and well-chosen gear ratios, with a sensible bottom gear. It is a far more refined car than Chapman’s version, or even the version I tried last year, but I am delighted that it is back in the Ford catalogue. The Ford/Lotus/Cosworth engine now gives 108(net) b.h.p. at 6,000 r.p.m. (it is governed to a maximum Or 6,500) and in spite of slight misfiring at high revs., the test car would hold a sustained speed of nearly 100 m.p.h. without anxiety. In catalogue trim, costing £1,068 2s 11d., this is a fascinating, easy-to-drive, dual-purpose car for which there are available a host of enthralling extras, like durable magnesium wheels, for instance. Fuel consumption of 100-octane petrol averaged 24.6 m.p.g. and after 600 miles sump level had scarcely dropped. The “racing-engined” Cortina is now a very nice, fast saloon; the only version of similar urge and even more effortless functioning is the Pirelli-shod car Henry Taylor commutes in. This has the 3-litre V6 Ford engine mated to a Corsair gearbox, in a two-door Cortina body shell. But this one is not in the Ford catalogue! – W. B.