Morris Mini-Cooper

Press, Volume C, Issue 29625, 22 September 1961, Page 9

Morris Mini-Cooper

AN addition to the popular B.M.C. range of minicars has been announced. It is called the ADOSO Cooper, or the Morris Mini-Cooper. The Mini-Cooper has a 997 c.c. high-output engine and disc brakes. This with the improved power it provides and together with the improved instrument panel, to which has been added an oil gauge and a temperature gauge, will almost certainly add to the vehicle’s popularity among enthusiasts. The Mini-Cooper has been developed by B.M.C. engineers in conjunction with the well-known Cooper Car Company, and it is claimed that it will provide a standard of travel approaching that previously obtainable only from highly-priced sports saloons. More Speed The new 997 c.c. engine makes the vehicle capable of speeds approaching 90 miles an hour, and very rapid acceleration 0 to 50 miles an hour in 12.8 sec, 0-60 miles an hour in 18.5 sec is claimed by the makers. Another feature which will be appreciated by enthusiastic drivers is a new remotecontrol gear change; the lever is floor-mounted between the front seats. The primary safety factor on the new model is that disc brakes are fitted to the front wheels. As high-speed braking conditions produce a considerable weight transference to the front wheels, this is a logical development.

Braking The over all effective braking area is increased from 67.5 to 157 sq in, with a reserve which, expressed in easily recognisable terms, means that the new Cooper version when stopped from 90 miles an hour taxes the braking system no more than the ordinary Mini-Minor braking from 60 miles an hour. The pressure limiting valve which obviates locking of the rear wheels has been modified to suit the new braking system while an “intensifier” has been added to boost the line pressure to the front brakes. Like all other B.M.C. vehicles, the new Cooper is fitted with built-in anchorage points for seat belts. The new model has a restyled radiator grille and the interior of the-vehicle has a marked difference with upholstery of vinyl-treated fabric in new designs. New sports car type seats are fitted: bucket seats at the front and tailored bench seat at the rear with a back rest of increased height. The facia panel has been re-designed and no longer incorporates the interior light, this is mounted in the roof. A new instrument cluster is incorporated in the facia, comprising a speedometer (which still incorporates the fuel gauge) and two separate instruments, one for oil pressure and the other for water temperature.

Engine The engine produces 55 b.h.p. at 6000 r.p.m. compared with 34 at 5500 for the basic Morris Mini-Minor. This increase in power has been obtained by two methods: by increasing the stroke to give a cubic capacity of 997, and by improving the "breathing” in all its aspects. To obtain the larger capacity, the bore and stroke dimensions have been changed from 62.9 x 68.26 m.m. to 62.43 x 81.28 m.m. A new cylinder head is employed, similar to that used on the M.G. Midget. This uses larger inlet valves and ports, double valve springs, and a modified combustion chamber shape giving improved gas flow. Other modifications are the twin carburetters, a free-flow three-branch exhaust system, and special camshaft. The compression ratio is raised to 9 to 1 from 8.3 to 1. Extended testing has shown that the modified engine can be run consistently at sustained high speed without approaching the accepted stress limits, and it is expected to achieve a good record of mechanical reliability. Acceleration The accelerative powers of the new car are remarkable, the Cooper model showing a 55 per cent, improvement in the time taken to accelerate from rest to 60 miles an hour on the old time. The top and third gear acceleration shows a similar improvement throughout the range amounting to 63 and 90 per cent, in top and third gears respectively through the 40 to 60 miles an hour range, the makers claim. In almost every aspect of road performance, the new model is as fast and as accelerative as the average 2tJlitre United States compact car. Maximum speed, standing start and top gear acceleration figures are, in fact, identical to those of the compacts, say the makers. To illustrate these claims, performance figures obtained by B.M.C. road proving engineers on the new model under strictly controlled conditions are compared below with those recorded by a leading British motoring journal on the unmodified Mini-Minor. All tests were conducted using premium fuel and standard tyres, with carburettor and ignition settings calculated to give the best balance of performance and economy. Load carried in all cases consisted of two persons and test equipment Figures Figures for the Mini-Minor are given with those for the Mini-Cooper in parentheses. Maximum speeds: second gear. 39 miles an hour (43 miles an hour), third gear, 61 miles an hour (67 miles an hour), top gear, 72 miles an hour (87 miles an hour). Acceleration (through gears): 0-30 miles an hour, 6.4 sec (s.lsee); 0-40 miles an hour, 11.3 sec (B.lsec); 0-50 miles an hour, 18.1 sec (12.8 sec 0-60 miles an hour, 28.7 sec (IB.ssec>. Comparative figures for 0-70 miles an hour and the standing quarter-mile are not given. Acceleration figures for tests in top gear and in third gear also showed very substantial improvements. B.M.C. claim that the fuel consumption figures obtained at steady speeds on an early production model of the Mini-Cooper were (almost identical with those obtained on the basic Mini-Minor.