LOTUS CORTINA
A tiger among the pussycats

'Road & Track', July 1964


The FORD LOTUS Cortina is the result of a successful marriage between Colin Chapman's tiny Lotus factory and the vast English Ford operation. The purpose of the car is to give EnFo (the FoMoCo's English branch) a GT class winner with all the resulting publicity, and also to incorporate the Lotus name in a sporting version of a standard Ford product. By using the Lotus facilities to assemble the car, Ford has successfully avoided the disruption to its production lines entailed by any form of limited and specialized construction. At the same time, Lotus benefits from a steady income derived from the "mass production" of some 30 cars a week.

The result is one of the most exhilarating small sedans we have ever driven, and it seems unfortunate that there are no plans at present of marketing the car the car in America. It appears that the English market is able to absorb all the cars Lotus can produce, and it would be necessary to convert to left-hand drive for the American market, which would require considerable modification of this particular car. However, Rod Carveth of San Carlos, Calif., who has handled Lotus products for a long time, offered us his personal car for testing and we were very glad of the opportunity. As usual when testing cars in the the San Francisco area, we were offered the use of Cotati Raceways, where the strong arm of the law can't reach us and where the drag strip is ideal for acceleration tests.

The main feature of the Lotus Cortina is the twin cam Lotus engine which produces 105 bhp at 5500 rpm from its 1558 cc. However, the remainder of the car has been tweaked by Chapman in many subtle ways so that the road holding, braking and general handling are the equal of the power output. Even the bodies are altered by the addition of aluminium doors, hood and trunk lid to compensate in part for the weight of the other Chapman modifications, although the resulting car still weighs about 150 lb more than the standard Cortina. On the other hand, the power output of the Lotus version is almost double that of the standard car.

The bodies are shipped from Ford to Lotus already painted white, and the aluminium parts are then added by Lotus after they have been painted. The result is that the potential customer can order his car in any color he chooses, provided it is white with a distinctive green flash along each side.

Surprisingly enough, the standard of fit and finish is very high indeed and this has not been a particularly notable feature of Lotus products in the past. However, it appears that the object of the car is to offer a degree of luxury not usually found in small sedans, in addition to the car's superlative performance. This is achieved by including such items as heavily-padded, competition-type front seats, a handsome instrument cluster, a gearshift knob with a tiny Lotus crest and a wood-rimmed steering wheel.

The Lotus engine is based on the same power unit that swept the Formula Junior field and, with its five main bearings, short stroke and extremely rugged design, it can easily withstand the additional demands of the twin-cam head layout. The clutch is an 8-in. diameter unit with a diaphragm type cover assembly, and it is quite stiff and has a very positive engagement. However, any deficiencies in the clutch department are made up in full by the transmission, which is superlative.

Due to the high rear-axle gearing and the close gearbox ratios, the Lotus Cortina is definitely an open road car requiring intelligent use of the transmission to extract full performance. In town the car is not at its best, and the clutch requires some practice before it can be operated smoothly, but here again the transmission, with its synchronized first gear, is a great asset because the car will achieve 45 mph in first. Thus, one is confined to first and second for city driving.

The suspension of the Lotus Cortina has undergone considerable modification. It is evident that the complete rear suspension of the stock Cortina was unacceptable to Chapman, as the conventional leaf springs have been thrown out and replaced with coil suspension units. These are retained by trailing radius arms on each side and a central A-frame.

Another modification is the aluminium differential housing to reduce unsprung weight, and two tubular strengthening struts inside the trunk. To improve the weight distribution and permit more room under the hood, the battery has been relocated in the trunk, and the spare wheel lies flat on the floor of the trunk instead of being carried upright. Although the result of modifying the rear suspension is a great improvement in road holding, the whole layout seems to produce considerably more noise, and a loud clonking sound is evident if the clutch is engaged suddenly.

As part of the suspension modifications, the car is fitted with 6.00 x 13 tires mounted on special lightweight wheels with a rim section of 5.5in. The recommended pressures are 22 lb front and 27 lb rear but, as is usual with English manufacturer's recommendations, better results are obtained if the the pressures are increased; to 32 lb all around. The steering has a strong self-centering action and is comparatively stiff, although the stiffness disappears at higher speeds.

On the road, the Lotus-Cortina is a revelation in what can be done for a small sedan through racing experience, provided it is driven in the manner required. It starts easily from cold and idles at 800 rpm, but prolonged idling in traffic tends to load up the plugs, so it is not ideal for short hauls to the supermarket. On the open road its ability to cover long distances is remarkable. As we have mentioned before, the axle ratio is low and the transmission ratios are close so 70 mph is attainable in second and 90 mph in third. The power does not really come in until 3500 rpm is reached and a good shifting point under normal conditions is 5500 rpm. However, one can go as high as 6500 rpm if necessary, but the engine is starting to buzz rather alarmingly at that speed.

The whole car has an extremely firm feel and the road holding is best at high speeds. One can enter a fast bend and maintain a predetermined line without any sense of insecurity because the car is basically understeering, the wide tread on the 6.00 x 13 tires seems to glue the car to the road and the steering is very positive. In the event of an emergency, the brakes are much more than adequate for the car. The Girling system employs 9.5-in. discs in front and 9 x 1.75 in. drums at the rear, with a vacuum booster to give the pedal a light but progressive feel.

The Ford Lotus Cortina comes in various stages of tune, and the ultimate is the 145-bhp model, produced specifically for competition. This has a maximum speed of 128 mph at 7000 rpm with the 3.9 axle ratio and is reputed to have achieved 140 mph on the banked circuit at Monza. It has been extremely successful in European GT racing but, by no stretch of the imagination, could it be called a road car. Apart from the engine modifications to increase the power output, the car is gutted internally and comes equipped with Plexiglass instead of safety glass in the side windows, lightweight fiberglass seats and a higher ratio steering box, among other items.

Our test car appeared to be an excellent compromise between performance and comfort, and our assessment of the car is that it would find a small but ready market in America if it was offered for sale. It is the perfect answer for the sports car enthusiast who has a family, because its performance is as good as many sports cars (and better than some), while at the same time it offers the accommodation and comfort of a sedan. On the debit side, it is not very satisfactory around town because of its gearing and lack of torque at low speeds, but this is a small price to pay for the pleasure of driving the car on longer trips.

 

Specifications
 


Price:

FOB Cheshunt, England: £910 ($2548)

Engine:
No. cyl, type: 4-cyl, dohc.
Bore x stroke, in: 3.25 x 2.86
Displacement, cc: 1558
Equivalent cu in: 95.06
Compression ratio: 9.5:1
Bhp @ rpm: 105 @ 5500
Equivalent mph: 95.5
Torque @ rpm, lb-ft: 108 @ 4000
Equivalent mph: 69.4
Carburetor, no., make: 2 Weber.
No. barrels, diameter: 2, 40 mm
Type fuel required: Premium.

Drive Train:
Clutch diameter & type: 8 in., single plate diaphragm spring.
Gear ratios:
4th (1.00): 3.90
3rd (1.23): 4.80
2nd (1.64): 6.40
1st (2.50): 9.75
Synchromesh: On all four.
Differential ratio: 3.90
Optional ratios: 4.10, 4.40

Chassis & Suspension:
Frame type: Unit with body.
Brake type f/r: Disc / drum.
Swept area, sq in: 282
Tire size & make: 6.00 x 13 Dunlop
Wheel revs/mi: 890
Steering type: Recirculating ball.
Overall ratio: 13.4:1
Turns, lock to lock: 3.0
Turning circle, ft: 34.0
Front suspension: Independent with MacPherson struts, lower A-arms, coil springs.
Rear suspension: Live, located by A-arm and trailing radius arms, coil springs.

Accommodation:
Normal capacity, persons: 5
Hip room, front, in: 2 x 21.5
Rear: 51
Head room, front: 38
Rear: 36
Seat back adjustment, deg: None.
Entrance height, in: 51
Step-over height: 13.2
Floor height: 10.9
Door width, front/rear: 32 / 0
Driver Comfort Rating:
For driver 69-in. tall: 95
For driver 72-in. tall: 85
For driver 75-in. tall: 80

General:
Curb weight, lb: 1930
Test weight: 2245
Weight distribution with driver, percent: 52/48
Wheelbase, in: 98.4
Track, front/rear: 51.6 / 50.2
Overall length: 168
Overall width: 62.5
Overall height: 53.9
Frontal area, sq ft: 18.7
Ground clearance, in: 5.3
Overhang, front: 28.5
Overhang, rear: 46
Departure angle, no load, deg: 14.5
Usable trunk space, cu ft: 11.6
Fuel tank capacity, gal: 9.6

Instrumentation:
Instruments: 140-mph speedometer, 8000-rpm tachometer, oil pressure, water temperature, fuel.
Warning lamps: High beam, ignition, turn signals, oil pressure.

Miscellaneous:
Body styles available: 2-door sedan as tested.

Accessories:
Included in list price: Heater, cigar lighter, windshield washer.

Calculated data:
Lb/hp (test wt): 21.3
Cu ft/ton mi: 84.8
Mph/1000 rpm (4th): 17.3
Engine revs/mi: 3460
Piston travel, ft/mi: 1650
Rpm @ 2500 ft/min: 5230
Equivalent mph: 90.5
R&T wear index: 57

Maintenance:
Crankcase capacity, qt: 3.5
Change interval, mi: 5000
Oil filter type: Full flow.
Change interval, mi: 5000
Lubrication grease points: 10
Lube interval, mi: 5000
Tire pressures, front/rear, psi: 22 / 27

 

Road Test Results
 


Acceleration:

0-30 mph, sec: 4.0
0-40 mph: 5.7
0-50 mph: 7.8
0-60 mph: 10.5
0-70 mph: 14.1
0-80 mph: 19.0
0-100 mph: 38.1
Passing test, 50-70 mph: 6.2
Standing 1/4 mi, sec: 17.5
Speed at end, mph: 77

Top Speeds:
High gear (6500), mph: 106
3rd (6500): 90
2nd (6500): 68
1st (6500): 45

Grade Climbing (Tapley Data):
4th gear, max gradient, %: 10
3rd: 14
2nd: 20
1st: 28
Total drag at 60 mph, lb: 110

Speedometer Error:
30 mph indicated, actual: 29.4
40 mph: 39.8
60 mph: 58.3
80 mph: 77.6
100 mph: 96.8

Fuel consumption:
Normal range, mpg: 18-24
Crusing range, mi: 170-230

 

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