The first significant change to Bentley Mark VI since its introduction in 1946 came when the cylinder bore size was increased to 92 mm in October 1951 so giving the engine a 4566-cc cubic capacity. The new Bentley R Type Saloon B7 four-door model differs from the Mark VI Saloon mainly in having a lengthened and more elegant tail with
the spare wheel housed in a tray under the larger boot.
Mark VI Drophead Coupé Park Ward
Type R Standard Saloon
R Drop Head Coupé by Park Ward.
The Motor YEAR BOOK, 1953 BRITISH CARS OF 1952 BENTLEY
Just before the Earl's Court Show of 1952 it was announced that left-hand drive Bentleys exported to the dollar markets only, could, without extra cost, be equipped with the fluid flywheel-cum-automatic four-speed epicyclic gearbox developed by General Motors, and known in the United States as the Hydra-Matic.
The technical aspects of this transmission are set out in another chapter, and the ensuing description of the 1952 Bentley cars will therefore be confined to changes made to the range in general.
Following an increase in engine size and power during 1951, the carrying capacity of the Bentley has now been increased by an addition to the luggage locker which increases the overall length of the standard steel saloon by 7 ½ in. This change has conferred two practical benefits of real value which are an enlargement of the undercover luggage space to 17.4 cu. ft., and an increase in the fuel tank capacity to 18 gal. Both the fuel tank and the luggage locker lid are made from light alloys and the latter is now hinged on its upper edge and spring loaded so as to be self-supporting. The side members of the frame have been extended to give support to the longer tail which has, incidentally, improved the appearance of the car.
To suit the increased load-carrying capacity of the Bentley, two small but significant changes have been made to the rear suspension. More weight at the back of any car can induce an undesirable degree of "oversteer", and to guard against this each rear spring has been tilted, by a lowering of its forward pivot and a corresponding raising of the rear shackle, to produce a measure of roll "under-steer". As a separate measure aimed rather at ensuring comfort of riding with the car full or empty, the rear spring shackles have now been set at an angle which has the effect of progressively stiffening the spring toward full "bump" deflection.
One other important mechanical modification has been made, this being the evolution of an automatic choke and fast-idle mechanism to eliminate two manual controls formerly provided for the twin S.U. carburettors. A butterfly "choke" is provided in the pipe from the air cleaner to the carburettors, actuated primarily by a thermostat sensitive to water temperature in the induction manifold jacket: over and above this, details include a fast-idle cam to hold the throttle partly open during starting or warming up, a diaphragm device whose operation (plus offsetting of the choke spindle) ensures that the choke will open itself slightly when the engine starts, a solenoid which holds the choke absolutely shut whilst the electric starter is energized, and an over-riding linkage which opens the choke if the accelerator is depressed fully to clear an over-rich mixture from the engine. This mechanism is claimed to give reliable fully-automatic engine starting over a very wide range of temperatures indeed.
Some details of body equipment are also aimed at meeting extreme climatic conditions, for which the rubber-mounted all-steel Bentley body has proved particularly suitable. The rear window glass can now be heated for de-misting, by the passage of electric current through some 900 virtually-invisible resistance wires embedded in the central lamination of the safety glass. An under-bonnet blower can be used to direct a de-misting blast of air on to the inner surface of the windscreen, and linked butterfly valves are provided to connect the blower inlet to either a cold fresh-air intake or, alternatively for de-icing, a fresh air intake which leads the air three times through sections of the main radiator honeycomb. Windscreen wipers of the two-speed self-parking type are standardized, and for hot-weather ventilation there are now air intakes on the sides of the scuttle and no-draught ventilator windows opening through 120 deg.
Other details of the Bentley in its latest form include dual exhaust manifolds applicable equally to left- or right-hand drive cars, and heat shields over the four exhaust silencers. Left-hand drive cars are supplied with a twist-to-release handbrake and a steering-column gear lever, and, for some while past, production models have been incorporating an independent front wheel suspension layout much improved in its detail geometry over the earlier design.
As the basis for these several refinements, the Bentley chassis remains unchanged in essentials. Details of the specification include an immensely strong X-braced chassis frame, a six-cylinder, 4.6-litre engine with seven-bearing crankshaft using overhead inlet valves and side exhaust valves, independent front wheel suspension by coil springs, and a one-shot lubrication system which eliminates the need for maintenanceance work at frequent intervals.
An announcement has just been made in America regarding the special high-speed version of the Mark VI Bentley which has been under development for some time. This car, to be known as the Bentley Continental sports saloon, is now going into production in very limited numbers and will be reserved exclusively for export.
The chassis is the normal Bentley Mark VI with the larger engine of 4,566 c.c. introduced last year, but various modifications, including changes in carburettors, induction and exhaust manifolds, compression ratio and gear ratios, have considerably improved both power output and performance.
The coachwork is a close-coupled two-door four-seater saloon built by H. J. Mulliner and Co., Ltd. It is panelled in aluminium, and a considerable amount of light alloy is used in the construction, profiting from the experience gained on the lightweight Bentley Coupé shown by Mulliner at Earls Court two years ago. A considerable amount of weight is saved and the Continental saloon weighs approximately 3,700Ib compared with 4,0701b, which is the figure for the standard four-door saloon in running trim.
Considerable attention has been given to drag reduction both in the general form of the vehicle and in derail equipment. It will be noticed, for example, that the dummy filler cap and winged B mascot have been eliminated from the radiator shell. In the course of development work last year the car did an officially certified lap at Montlhery at an average speed of 118.3 m.p.h., indicating an absolute maximum speed of over 120 m.p.h.
It is expected that owners of the new model will be asked to give an undertaking that they will not use the car in competitions.
The Motor YEAR BOOK, 1953 BRITISH CARS OF 1952 BENTLEY
For those requiring exceptional performance, a car known as the "Continental" is built in very small numbers. Carrying two-door aerodynamic saloon bodywork by H. J. Mulliner, Ltd., this model is lighter and higher-geared than the normal cars, and with a slightly tuned engine is quoted as being capable of speeds in the region of 120 m.p.h.
The task of evolving sleek but dignified coachwork for this lightened, higher-geared touring car was undertaken by this famous London house in close collaboration with Rolls-Royce, Ltd. The resulting two-door four-light saloon is elegant without being outré—a car for long distances, but one that will not be out of place on more formal occasions. The roof-line has been lowered by dispensing with the built-up artificially flat floor usually employed on these chassis, and a new radiator shell, wider and lower than that of the standard Bentley has been designed by H. J. Mulliner. The new front blends well with the rest of the car; a vee-windscreen gives an air of leanness to what is none the less a capaciously-wide motorcar, while a sharply dropping roofline and full-length wings, upstanding at the rear like knife edged stabilizing fins, give a strong autoroute silhouette. Back wheels are fully enclosed, with a pair of recessed external nuts to fasten the "spat".
Inside, two bucket seats of lightweight construction are provided for driver and passenger, plus a bench for two persons behind, while the luggage-boot, though necessarily shallow right aft, is both long and wide, with access via a spring-balanced lid. Long, hinged quarter-lights have an extractor action when opened, and should the sharply-inclined rear window mist-up, a fan, drawing air through ducts from the boot, blows direct upon the inside of the glass. The instrument-board, formed in one piece with the dash-rail fillet below the screen, sweeps round in a graceful bow to merge into the finishers of the doors. Special "wrap-around" bumpers with large over-riders are provided on this export-only model; these are of aluminium, for lightness, backed with steel liners for strength. The complete car is stated to weigh about 33 cwt., which is substantially less than the normal Bentley saloons. Hence the model is both lower, lighter, and considerably faster than normal and it may be accounted as a new type rather than as a modification of an existing model.