HILLMAN ENTERS MINI-CAR MARKET

Press, Volume CII, Issue 30127, 10 May 1963, Page 11

HILLMAN ENTERS MINI-CAR MARKET

rpHE long-awaited Hillman A Imp—the Rootes Group mini car—has been announced in Britain. The Imp joins a highly competitive field, but would appear to have features which will appeal to many. The Imp is the first ear to be made in Scotland for more than 30 years, and is produced at a new Rootes Group plant at Linwood. The Imp is powered by a rear-mounted high-perform-ance overhead camshaft engine of 875 c.c. capacity. AH major castings are of aluminium, the first time this type of engine construction has been used in a volumeproduction British car. The functional saloon car body, reminiscent at the front of some Continental designs. is only 139 in long. The factory claims it will carry four or more persons in comfort.

The factory quotes top speed as 75 miles an hour, fuel consumption (touring) between 40 and 45 miles a gallon, and acceleration from 0 to 50 m.p.h. as 15.5 sec.

No Greasing Suspension is all-independ-ent and there are no greasing points, a major contribution towards greater economy. There are two luggage comparments, under the “bonnet” at the front and through the opening rear window at the back. There is a parcel tray under the

dash and pockets in the doors. All forward gears are synchromesh, front windows are of the wind-up type, there is an automatic choke and a headlamp flasher. The Imp has its engine at the rear in a fore-and-aft position, but inclined at an angle to save space and keep a low centre of gravity. The engine is readily accessible and can be easily removed for maintenance.

In addition, the use of diecast aluminium in both the engine and gearbox-trans-axle units has given a good weight balance and produced maximum output with minimum weight. The power-to-weight ratio of the Imp is unusually high. The car, when unladen, weighs only 13Jcwt, which gives a ratio of more than 61 b.h.p. a- ton unladen.

the aluminium power unit develops 42 b.h.p. at 5000 r.p.m. and has a maximum torque of 52 lb ft at 2800 r.prn. Its compact, wedgetype combustion chamber allows a very high compression ratio of 10:1. The whole engine weights 1701 b—approximately half the weight of a cast-iron engine unit of the same size.

Its single overhead camshaft valve gear not only allows it to develop its high power at high speed, but ensures that the engine stays in tune and is free from constant tappet setting.

The engine was designed in the early stages as a result of

collaboration between Rootes and Coventry Climax, who, with their experience of designing engines for ■ racing cars, had been concerned for some years with engines .incorporating aluminium. Another interesting feature is the use of a completely new accelerator system. The problem of transmitting the motion of the accelerator the comparatively long distance to the carburettor at the rear of the car has been solved by using air pressure to replace rod or cable. A diaphragm under the accelerator pedal exerts air pressure along the tube to a diaphragm at the rear of the car which works the carburettor mechanism.

The body has been developed through wind tunnel tests to give high aerodynamic efficiency. One of the features of the styling is the low waistline which produces a large glass area for good all-round visibility. The Imp is only 54 jin high, 60jin wide and 139 in long. The rear seat squab can be folded flat to give extra luggage space, with easy access from the rear window, which opens in normal estate car fashion.

The gear box, the casings of which are in aluminium, and which incorporates the hypoid final drive, is of new design, forming a trans-axle assembly in unit with the engine at the rear. The whole of the Imp’s transmission unit, with oil, weighs only 651 b.

The general design and construction of the car have produced excellent handling characteristics, the makers say. Independent coil springs with telescopic shock absorbers are used on all four wheels. To give simplicity and low weight and the required high roll centre, a swing axle is employed at the front with trailing links at the rear end, and these are mounted on easily detachable subframes. The rack-and-pinion steering unit fitted is oil sealed and requires no maintenance.

Drum brakes Bin in diameter are fitted to all wheels, giving a total lining area of 75 sq. in. The front brakes

have two leading shoes, with leading and trailing shoes at the rear.

The fascia panel is simple, with the instruments clearly visible and the controls carefully planned to come easily to hand. Close to the steering column on the left of the fascia and at the finger tips, is a switch which operates the lights from three positions—main beam, dipped, or flashing. On the fascia panel to the right of the steering column is a direction-flashing indicator lever which also operates the horn.

Luggage is carried at the front of the car in a compartment affording more than three cubic feet of space. A further area of five cubic feet is available behind the rear squab; When the seat is folded flat, however, this space is increased to 121 cu. ft. The petrol tank has a' capacity of six gallons, giving a range of more than 250 miles. The Imp’s 12in wheels carry large section profile tubeless tyres. There are ventilation slots in the wheels to assist brake cooling. The spare

wheel is housed vertically in the front luggage compartment. Fittings for safety belts are provided as standard for the front compartment. The windscreen is zone-toughened. Testing

The Hillman Imp has undergone a testing programme of more than usual severity. In adiition to all normal testing, including extensive trials at the Motor Industry Research Association’s testing ground at Nuneaton, it was subjected to strenuous programmes in Canada and Scandinavia, including cold-weather starting and general durability under Arctic conditions: in Switzerland, including high-altitude and climbing tests: in Spain and Kenya, including heat and dust conditions; and of course endured years of rough handling on the roads of France, Germany, England, and Scotland. Maker's specifications:

ENGINE: Four cylinders with overhead valves operated by single overhead camshaft. Aluminium alloy cylinder block with detachable aluminium alloy

cylinder head. Bore and stroke: »' 68 by 60.375 mm. Cubic capa- • city: 875 c.c. 8.H.P.: 42 at Z 5000 r.p.m. Maximum torque: J 521 b ft at 2800 r.p.m. Com- • pression ratio: 10 to 1. Cam- • shaft: cast iron with three steel ! shell white-metal bearings. • Crankshaft: steel forging with • three steel shell, lead indium- ■ lined main bearings. Pistons: ! aluminium alloy, solid skirt ; with offset gudgeon pin and ■ chromed top ring. Lubrication ; system: pressure pump with • full-flow filter, capacity. 5.5 ; pints. Fuel system: Solex ■ downdraught carburettor with * pneumatic throttle control and • automatic choke. Mechanical ■ pump Tank capacity: six imp. * gallons. Tank located below • front luggage compartment • floor. Cooling system: water • with centrifugal pump and ! polypropolene nine-blade fan. J Capacity: 6.75 pints. Ignition ; system: 12-volt coil and distri- ■ butor. !

TRANSMISSIOI: Clutch, Laycock diaphragm, 5.5 in diameter with self-adjusting hydraulic operation. Gearbox: four-speed in unit with engine. Synchromesh on all forward gears. Gear ratios: .852. 1.174, 1.833. and 3.417 to 1. Reverse. 2.846 to 1. Final drive: Hypoid transaxle crown wheel and pinion with 4.857 to 1 final drive ratio. Aluminium alloy casing. Oil capacity, including gearbox. 4.5 pints. SUSPENSION: Front independent by swing axle and coil springs. Rear—independent by trailing arms and coil springs. Shock absorbers: telescopic hydraulic front and rear.

STEERING: Rack and pinion with two-spOke steering wheel. Turns of wheels from lock to lock. 2.75.

BRAKES: Hydraulic two-lead-ing shoe with mechanical handbrake.

WHEELS: Pressed steel. Spare wheel in front luggage compartment. Tyres 5.50 by 12in; pressures, front 151b/sq. in, rear 301b/sq in. GENERAL DATA: Wheelbase. 6ft Idin; track (front). 4ft 1 l-10in, (rear) 3ft 11 9-lOin; overall length, lift 7in; over-all width. sft OJin; over-all height. 4ft 6‘.iin; ground clearance (laden). s‘,iln; turning circle. 30ft 6in. Weight, unladen (with petrol and water), 13cwt 3qrs.