Ford Escort Twin-Cam
While other sporting Ford's could be called sedans capable of being raced or rallied, the Twin-Cam Escort was unashamedly a racing sedan de-tuned for road use.
In production form, with quantity sales needed to justify its homologaation as a Touring Car, the Twin-Cam gave the customer exactly what they expected; a high perrformance competition car that could be converted into a real projectile by spending a little more money on approved Ford equipment.
Allowing for the noise, vibration and harshness, the Twin-Cam was always incredible fun to drive, guaranteed to take years off any jaded motorist who was lucky enough to get one. Apart from the (optional) artillery-style road wheels and the black painted grille the Escort Twin Cam was hardly recognizable as such, often astounding other road users by its remarkable acceleration and handling.
The Escort Twin-Cam was born from a desire of Ford UK to develop a new model for outright successes in racing and rallying, and as a replacement for the Cortina-Lotus, preferably using the well-known twin cam engine and transmission in a much lighter car.
The Escort (code named the 1968
Anglia) had been under development for some time, but it was not until 1967
that the Competitions Department was finally given the go-ahead to develop a road version of their future competition car.
The Twin-Cam was based on the Escort GT's bodyshell, and it was a credit to Ford's forward planning that the only real changes forced upon them were to flare out the wheel arches slightly to accommodate much wider wheels (and to allow for even wider racing wheels to be fitted), and to mount the Twin-Cam engine slightly askew in the shell to improve alignment of the power line and cut down vibrations.
Out-Performing The Lotus-Cortina
The major drawback of the Escort GT bodyshell was that Ford were stuck with unsatisfactory rectangular headlamps on their competition car, a definite handicap in rallies and long-distance saloon car racing where control of the beam pattern counts.
But there were few other concerns, as the Twin-Cam offered startling performance for the time. Mechanically - engine, gearbox, final drive and brakes - the Escort Twin-Cam was identical with the Cortina-Lotus; but as it was obviously lighter than the bigger car the acceleration is very much better throughout.
The bodyshell had less frontal area and was better shape aero-dynamically making for a better maximum speed. The ignition distributor cut-out that Ford always fitted to their Lotus-built engines was a hinderance; set nominally for 6,500 rpm, many found the engine had plenty more lusty breathing still in reserve. Removing the cut-out invalidated the warranty, so new owners were forced to respect the red-line. Nevertheless the Twin-Cam was capable of a very healthy 113 mph.
Many had believed the Cortina-Lotus to be the ultimate in road cars, but the Escort Twin-Cam beats its performance on all counts except initial getaway. The Twin-Cam sprinted to 60 mph in 9.9sec (Cortina-Lotus, 11.0sec), to the quarter-mile in 17.2sec (18:2sec), and to 100 mph in 33.6 (44.0sec). The Cortina-Lotus was good for only 104 mph.
Plenty of spare grip from the fat 165-13in.
India Autoband tires meant that wheelspin sprint starts were possible only on low friction surfaces and then only by letting in the clutch viciously from about 5,000 rpm. Wheelgrip and clutch grip combined were so firm that standing starts took some learning. The 0-30 mph time of 3.8sec was not as quick as the power/weight ratio suggested, but then bottom gear was high. Once on the move, the twin-ohc engine got busily down to its task, rushing up to the rev limit with no torque curve steps or flat spots, and an unusual eagerness...
Big engines in smail cars usually means efforttless performance, and so it was that the deep-lunged Lotus unit made light work of high speed. The engine itself was by no means smooth nor silent, but the pleasantly refined camshaft chain whine made up for the low-speed gobblings of Webers, the rumbles and the odd vibrations. The throttle response was immediate once the engine had warmed through from cold, there being strong and vigorous torque from as low as 1,000 rpm, but transmission judder usually encouraged a down-change as soon as the revs dropped to 2,000.
The choke was never needed when starting from cold, provided you remembered the stab-throttle priming Webers liked before starting the engine. Both engine and gearbox were bolted down rigidly, so hard driving brought a lot of clamour with it; to a keen driver this was music to the ears, but less enthusiastic passengers were prone to being over-whelmed by the deep-throated roar. The engine was mounted askew, with the nose at least 1in. offset to the left'side of the car, this in-turn providing adequate clerance for the steering rack and bodyshell.
The gearbox and transmission were very nicely matched to the 110 bhp engine. The close gear ratios common to the Cortina-Lotus, Cortina GT and Corsair 2000 were used along with the 3.78-to-1 Cortina final drive. The gearbox gate was narrow and absolutely precise, with a very nice feel, and the synchromesh was unbeatable. It also offered a very "quick" change that felt right for this sort of car.
Suspension and Handling
One of the problems with the Twin-Cam was the relatively small 9-gallon fuel tank, identical with all the other Escorts. Spirited driving, something the car begged you to do, was not the recipe for low fuel consumption figures, and owners would quickly find themselves always on the look-out for yet another petrol station. Thankfully you could option an extra tank (at extra price) which was fitted in the other side of the boot after delivery. On a compression ratio of 9.5-to-1 Ford recommended Twin-Cam owners to use 5-star 100-octane fuel.
The suspension and handling blessed the Twin-Cam with a very definite character; most owners recognized the delicate set-up as a semi-rallying one, however for those not so inclined they would find it "nervous and twitchy" when on the limit. Compared with basic Escorts, the susspension was lowered and stiffened all round, with twin radius arms used to assist the rear axle location. Very wide (5.5in.) roadwheels, radial-ply tires and a front anti-roll bars were all special to the Twin-Cam; the Lotus hubs and brakes helped to ensure that there was a modicum of negative camber to the front wheels; the steering rack had a more direct ratio than the basic Escort and there were only three turns lock-to-lock.
Helped by these factors, which were the results of careful development by the Ford Competition Department, the Twin-Cam had almost neutral handling characteristics at normal speeds. Just a touch on the wheel was needed to send the car scurrying round long. main road corners with hardly a trace of roll. But if the corner suddenly tightened up, a bit more steering wheel movement produces more roll and just enough roll over-steer to change the cars attitude, and when the Twin-Cam was really pressed the inside rear wheel lifted and spun to limit the speed. In the wet rear wheel spin occured fairly readily, but the changes of attitude were caught very quickly and somehow felt in keeping with the character of the car.
A penalty of this set-up was the extreme sensitivity to side winds, and road camber changes affected it quite strongly. There was very little suspension feed-back to the steering wheel, but out-of-balance vibrations could often be felt through the steering column.
The complete Cortina-Lotus braking system was adapted to the Twin-Cam Escort (there was ample room within the same 13in. wheels); and it is well able to deal with the vigorous performance.
Fade tests conducted at the time showed that effort increased slightly during persistent use, but on the road, even when driving very hard, there was negligible loss in efficiency. Helped by the servo and the fat tires, the Twin-Cam's braking could best be described as superb. With only about 60lb pedal pressure the Twin-Cam would pull up four-square without locked wheels and with the manometer. reading well over 1.Og. The handbrake, a sturdy pull-up lever between the seats, was also powerful, holding the car easily facing either way on a 1-in-3 inclinel, just managing to lock the rear wheels and being good for 0.42g as an emergency brake. Front disc and rear drums are all self-adjusting so the only servicing checks are to replace pads and linings at infrequent intervals.
'Inside the car the trim and furnishings are exactly the same as the Escort GT; in fact Twin-Cams started life with GT bodies before being plucked off the assembly lines for final assembly in Halewood's Twin-Cam facility. The only really significant body modification was to flare the wheel arches slightly to give more clearance. The instrument panel and seats too were the same as used on the Escort GT. Unfortunately only the standard plastic Escort steering wheel was fitted; though nicely small at 14in. dia it still looked out of place. Another instrument issue concerned the oil pressure gauge, which was completely obscured by the steering wheel rim, and there is no low-pressure warning light.
The Escort remained a small car despite advertising campaigns conducted at launch to convince potential buyers otherwise. The seat adjustment was none too generous and there were no adjustable backrests. The control switches all worked on the rocker principle and looked nice and safe in case of accidents. With the seat belts tugged up good and tight, it was not easy even for a tall driver to reach the lighting and wiper switches without a
stretch. The washer control was conveniently on the floor in the "dipswitch" position, and dippping was incorporated in the multi-action steering column stalk which also operated the indicators and sounded the unworthy horn. Heel-of-foot pedal operation was easy.
The ventilation system would take some learning, especially as the facia vents could be twisted to face, windscreen, occupants, or the side windows across the car. The through-flow was efficient and a steamed-up rear window cleared very quickly; there was a good supply of hot air when needed.
Under the bonnet, the twin-ohc Lotus engine togther with its large air-cleaner filled all the available space. The distributor was masked by the big Weber carburetors, and the oil filler cap (a type that was prone to work loose) was hidden behind the air cleaner tube. An oil cooler was standard, mounted to the right of, and parallel with, the water radiator in the nose. The dipstick was relocated to the back of the engine and was clearly marked.
The battery has had to be moved into the boot because of the bulky twin-ohc engine, but it lived in the left-side rear wing recess and had a protective cover (fitting the optional extra fuel tank would require the battery to be again re-located). It has also displaced the spare wheel which was bolted directly to the boot floor, spoiling what would have otherwise been a roomy boot. The spare wheel was not covered to protect luggage, and suprisingly there was no tool kit included, only a jack, wheelbrace and wheelnut spanner.
Viewed as a potential competition car, the Twin-Cam Escort was well-conceived. As a regular road car it lacked refinement in certain respects but had nothing to be ashamed of. Putting the Cortina-Lotus power plant into a much lighter body-shell gave startling performance for such a small car. Vigorous torque delivery and a wide power range were only dulled by a high rev ignition cut-out. The Twin-Cam had well chosen gear ratios and excellent gear change. Sure, the handling of the car was not ideal for day-to-day driving - but that was not the purpose for which it was built.
Escort Performance Specifications
A 'Hemi' features Lotus designed cylinder head with opposed layout; two 2-barrel Weber carburetors; 4 branch free-flow exhaust system; valve operation by twin overhead camshafts.