A Hurried Run to Devon and back, in the Experimental Independently-sprung 4¼-litre Bentley. High Average Speed and Extreme Refinement, in what will be a Post-War Rolls-Royce Production.
THE opportunity arose to most aptly conclude a year of war, and yet one of not-too-stinted motoring, by taking an example of the new Mark V 4¼-litre Bentley, only recently released from the experimental stage by the Rolls Royce engineers, down to Devon in something of a hustle. The test was such as would bring out the good and bad points in even a fast-average car very clearly, for while over 500 miles in some twenty-seven hours may not sound especially trying, it has the qualification that the first half of the journey was completed in the December “black-out” and that we contrived not to cut down sleeping and meal times unduly; moreover, a very late start marked the return to what was once civilisation. This latest model of the famous 4¼-litre is described elsewhere in Mr. Robotham’s own words, and it is well known that coil-spring independent front suspension and a new chassis are salient features of the specification. Looking to the future, Rolls-Royce Ltd. have carried on with experimental work and the Mark V Bentley represents this research finalised. However, they have no intention of commencing production until the next armistice has happened, so the latest 4¼-litre remains the plaything of the Rolls-Royce Research Department and of a handful of fortunate motor scribes, being unattainable even to permit-possessing prospective purchasers. We were very interested to try the car, particularly following the high-speed run to John o’Groats put up with a normally-sprung, pre-overdrive type 4¼-litre Bentley three seasons ago. War work necessitated a start in the “black-out” and without a moon, and with the same crew as on the former drive, supplemented by an Alvis Speed Twenty owner and a recently acquired wife (not the Editor’s!), we planned to sleep that night in North Devon. At once confidence for carrying out such a plot is instilled by first impressions of the car. In the gloom it seemed a very large vehicle, in outline rather reminiscent of a certain V12. But it handled like a very much more compact car, and the excellent brakes, shorter bonnet and, in a different sphere, the twin rear lamps, largely compensated for the enforced suppression of light. There was also the entirely effective fog-lamp, mounted centrally above the ribbed front apron (the starting handle, if used, passes through its mounting), which cleared the mist patches so that they presented actually less strain than the clear visibility of the “black-out” itself.
Very soon after taking the wheel the smoothness and extreme silence of the car, its accurate handling, and its perfection of detail, ready response to every control included, began to draw praise from occupants of other seats besides the driver’s. As the night grew chilly the heater, comprising a fan which distributes air from a radiator fed by the cooling system, was put to use and loudly acclaimed by the front seat occupants. In the rear seat the effect was not so noticeable, but daylight revealed that the rheostat control of the fan-speed had only been placed at “low,” while the windows were not fully closed, owing to a slight “hot-water-pipe” odour, undoubtedly due merely to the newness of the heater’s plumbing. The long night run was accomplished uneventfully and a climb of Porlock was an almost unnoticeable achievement, although bottom gear was employed. No oil or water had been consumed, and a very casual check on “Pool” consumption gave approximately 18 m.p.g.
The next morning no attempt was made to rush out of Devon, and we could take stock of the car. The body is a Park Ward four-door four-light saloon. The rear doors carry particularly wide windows, and there is far more room in the rear seat than formerly, without the use of foot wells; headroom is rather restricted, as is permissible with extreme stability. The front seats are Leveroll-adjusted heavy buckets, and we still think the support to the shoulders a thought inadequate. Upholstery is leather and the rugs and rear blind, the latter now electrically operated, match the interior most effectively; indeed, it is difficult to tell where the blind is positioned when it is in use. The rear luggage locker is extremely capacious and should obviate the need for carrying anything inside the car, even on a long tour, although there is a useful shelf behind the rear seat for oddments required on the run. The rear windows wind on the one-direction of handle system and the front doors have pivoting half-windows as well as winding rear panels, of which the driver’s has a quick-action release—on the car tried this was inclined to jam. There are no running boards, but entry and exit is very comfortably accomplished, and the altered positioning of the right-hand gear and brake levers is a definite improvement. The walnut facia carries, from left to right: a hand grip; a big locker with lid; cigar-lighter; ignition and lighting panel; clock below; heater control; fuel gauge below; dash-lamps; rev.-counter reading to 5,000; speedometer; fuel pumps switch; combined oil gauge and water thermometer; ammeter; fog-lamp switch; and rear blind control. In the steering wheel centre you have the divided horn push for operation of the loud and soft Lucas horns; and the hand throttle and suspension over-ride control, working in the famous Rolls-Royce manner. The pedals are small and well placed and the Lucas Bijur one-shot system of chassis lubrication is operated with the left foot. Ventilator panels in the scuttle are opened and closed by a tiny remote control about by the driver’s right knee. In addition, there are big fuel and ignition warning lights on the facia. It is these details that emphasise the quality of the car you are about to handle. The ignition switch is separate from the lock, you have the choice of either or both fuel pumps, and the fuel gauge is dead accurate, the warning light coming in with three gallons remaining in the 16-gallon tank; it is best obscured, if one has to continue driving at night without immediately replenishing. To continue this account of small but highly appreciated minor matters, speedometer and rev.-counter dials are beautifully calibrated and the white-tipped needles move in the same plane in top gear, while those of the oil gauge and thermometer sit in a straight line at normal readings.
The doors are restrained from falling fully open, “pulls” assist in leaving the rear seat, the sliding roof operates very easily, there are independent screen-wipers, and the switch for the self-cancelling direction indicators is right below the steering wheel rim for actuation by the left forefinger. There is a folding arm-rest in the rear seat squab and a tiny one for the front seat passenger. Every switch moves with smooth certainty. It is thus possible to offer praise in matters which are yet still hardly out of the experimental stage, as the wooden plug in lieu of an ashtray and the gaping hole which revealed itself when the radiator filler-cap was unscrewed, reminded us. Outside the car, one observes the excellent lines of the new body, compact by reason of the forward-mounted engine and 2 inches shorter wheelbase, yet imposing and beautifully finished withal. The frontal aspect encompasses the huge Lucas headlamps with Cornercroft mask on the near-side one, neat ribbed apron, central fog-lamp aforementioned, the twin horns, and the fixed radiator slats, the thermostatic control now being applied only to the water flow. An excursion beneath the car reveals the unenclosed coil springs of the i.f.s. system, a new frame with cruciform central bracing, and Girling brake actuation via the Rolls-Royce mechanical servo-motor. The brake drums are ribbed. The bonnet is of the fashionable four-piece opening top variety, locked by single handles through a system of rod-remote-control to the bonnet clips. The engine is the same six-cylinder push-rod o.h.v. unit as before, magnificently finished in black and polished alloy, but now flexibly mounted, with a pressed mounting at the front. The twin SU carburetters with enormous air-cleaner on the off side have virtually the same layout, but a thermostatic mixture control on the rear one eliminates the old hand choke, and the petrol pumps are out of sight. The water pump seems to have been reduced in size possibly to obviate too great a pressure in the heater, and the sump contents indicator is of needle-type. On the near side the three branch exhaust system appears to be of smaller bore than formerly and there are twin coils (one a spare) and the latest type external oil purifier. The oil filler orifice no longer has the “B” breather, but the huge air-cleaner is still over the engine and the dynamo, the accessible fusebox and the whole of the electrical equipment is typically Bentley. The starting handle clips beside the near-side bonnet panel, adjacent to the jacking equipment, while the tool case clips inside the scuttle in the passenger compartment, closing flush with the upholstery. The radiator filler, reminiscent of the domestic thermos-flask-stopper, is under the bonnet in a new square-section header tank. The front suspension is aided by a stabiliser. Underneath, the car is well-cowled, and the wings of sweeping, semi-streamline type, have wire-mesh mud-catchers. The body lines conform well to the wing shape and the curve of the raised waistline is seductive. The spare wheel now lives in the off-side wing, with a fire extinguisher in the bracket, and all the wheels carry “Ace” discs—the tyres being 6.50″ x16″ Avon. The central rear view mirror gives adequate, if not extensive vision. That, then, comprises the new Bentley on first acquaintance.
As there is no longer a hand ignition-timing control, it is not possible to start the engine on that alone, a game you could play on the old 4¼-litre, but the starter works silently, and after a night in the open in winter the car starts instantly and idles happily with no controls with which to juggle. The Borg & Beck clutch is in every way excellent; very light, very positive, and absolutely smooth, and an improvement on the earlier component. The flexible mounting of the power unit is observable when idling and results in rather a harsh sound as the engine first fires, but once under way there is no sound, no fuss, not a trace of vibration from beneath the bonnet. The body, too, is devoid of serious rattles; the tyres are silent, and even the tramp of the wheels riding over inequalities is absent. One goes at once up to high speeds and there is merely the wind-rush to indicate the pace; that is as true of 80 m.p.h. as of 60. Sixty is a very ready cruising gait, when the engine is doing under 2,500 r.p.m. in the overdrive top. This really is an overdrive gear, as distinct from a high direct drive, although selected quite conventionally by using the gear lever. It is possible to hear the gear whine within a certain limited speed range, if one listens for it, but to all intents and purposes this gear is as silent as the other three. The makers intend, of course, that it shall be used to save effort and fuel on long straights, but, anxious to conserve “Pool” on so long a run, we used it as a normal top gear and can definitely state that to do so is perfectly satisfactory. A change to the normal top gear give extra performance up main road hills and better behaviour in town driving, and an enthusiastic driver might take the very slight whine of the overdrive as a signal to drop down into the next ratio. But so flexible and powerful is the engine that it pulls away cleanly on overdrive from 1,000 r.p.m. or 26 m.p.h. with very reasonable acceleration, and will run down to some 8 m.p.h. on this ratio. So we felt quite justified in regarding the box as a normal four speed. On the other hand, it must not be overlooked that it is, in fact, a three speed unit, and that second is as high as you expect the middle gear of such a box to be; the car can be started on second, but we preferred to use first and to go into this ratio too for serious hill-storming. It had also be remembered that top-gear acceleration is not so great as that available if second gear is employed. The direct-drive top ratio is 4.3 to 1 and the overdrive is 3.64 to 1, so that quite an appreciable difference in engine speed results. For example, in top gear 40 m.p.h. is equivalent to 2,000 r.p.m., but if overdrive is used the engine speed falls to 1,700 r.p.m.; or, conversely, if the same engine speed is maintained, the road speed rises to 48 m.p.h., and at higher speeds, of course, the contrast is greater. Incidentally, the top-gear ratio of the pre-overdrive 4¼-litre was 4.1 to I and later 4.25 to 1.
The right hand gear lever has been re-positioned to give more room when the driver’s door is in use, but it is easy to reach and typically Bentley. Synchromesh has now been applied to second gear and it works admirably, if one discounts an occasional tendency to catch-up on the change from top to second. The upward changes go through just as quickly as the lever can be moved (though a pause is desirable between first and second), and the same applies particularly to the downward change between overdrive and top, for which double-declutching may be resorted to without embarrassing the automatic selection. The gear lever is depressed to locate reverse, which is forward on the inside of the gate, and the difficulty was to decide whether or not a gear was already engaged, so silkily does the lever move. Incidentally, there was just the merest trace of warmth or well-being about the lever, where it emerges from its draught-excluding gaiter, after a deal of hurrying. The hand brake is also on the right-hand side, cranked at right angles to follow the good example set by the new gear lever. It is perfectly placed and has a beautiful ratchet-action, although it is essentially only a parking brake. The main braking system is a revelation. It slows the car decisively and in an entirely progressive manner without a trace of protest, under the lightest pedal pressure we have ever experienced. Incidentally, a severe impromptu test of this aspect of the Mark V was indulged in when the first climb of Porlock was spoilt by our carelessness in running out of fuel, so that it was necessary to run the car down the greater part of this notorious hill backwards. The brakes proved entirely adequate and lost none of their power, so that next day we had no compunction about coasting in neutral at very considerable speeds down some of North Devon’s more appreciable gradients, an oft-condemned practice. So immensely powerful are the Bentley’s brakes that under very hard application on a dry road the car deviated from the straight and compressed its front suspension quite noticeably; such braking would never need to be resorted to normally, even in an emergency, but as a test it was interesting and a tribute to the silent-tread Avons, which did not protest.
In negotiating Devon lanes, Somerset by ways and the main roads of Wiltshire, the new suspension was put to an excellent all-round test. The greatest compliment one can pay it is to observe that the Bentley over-ride suspension control now seems less effective than formerly. While it stiffens the springs up in the “hard” position so that the car can be slid round open bends instead of rolled round, the ride remains so remarkably comfortable that there is less contrast than before with the “soft” setting; albeit the latter is still worth having for completely luxuriating the ride in town or over rutty going. That the Derby design Staff have evolved a quite outstanding independent front suspension system is evidenced not only by the cornering stability, but by the entire absence of unwanted up-and-down motion. So far as the former is concerned, there is some roll, but nothing which approaches that still common with i.f.s., while as to the latter, there is no fore-and-aft pitching, only a gentle corner-to-corner motion at speed over bad surfaces; nor do the occupants leave the rear seat when humped bridges are taken very fast. The only time that the i.f.s. makes itself known, other than by virtue of these pleasing ride-characteristics, is under the unnecessarily heavy braking aforementioned, or when an acute corner is entered so rapidly as to promote a front wheel slide, when some wheel spragging happens. To a certain extent, too, the return motion through the steering wheel is greater, but this varies in direct proportion to the roughness of the surface and is practically non-existent on main roads. The new suspension can be praised for the exceptionally fine steering lock and an ability to run up a kerb if occasion arises, without the passengers having any reason whatsoever for comment, far less for protest. Frankly, we did not altogether like the lower-geared steering, which asks 2½ turns of the fairly small, thin rimmed wheel, lock to lock, against the former 2¼. There is extremely quick and vigorous castor action, and if an attempt is made to control this on a fast bend the car does not return soon enough to a straight course. Let the wheel play through your fingers and the control becomes 100 per cent, accurate under all conditions of fast main-road motoring, while being outstandingly light. The rather low gearing then only becomes a thought unhandy in narrow, winding lanes or up trials hills, which the average 4¼ litre owner would probably not take at the gaits we invariably employ. Definitely, this is finger-and-thumb steering up to the car’s maximum and there is scarcely any column movement; the whole frontal aspect of the Bentley is commendably rigid. The big front wings, with their in-built side lamps, do not seem quite so visible as before, and, for a while are slightly embarrassing in restricted going, but accurate steering, and the compact overall dimensions, soon permit the Mark V to go down and along the back ways with complete confidence.
The engine is smoother than before, if that is possible, by reason of the flexible mounting, idling with only a subdued exhaust beat, instantly responsive, and then entirely silent up to very nearly the end of the speed range. The rev.-counter colour-marks suggest peak speed as 4,500 but 4,000 r.p.m. seems a more reasonable limit, giving 33 m.p.h. on first, and 61 m.p.h. on second gear. Upward changes would normally be made at 3,000 r.p.m. (22 m.p.h.) in bottom, 3,100 r.p.m. (41 m.p.h.) in second, going into overdrive at about 2,500 r.p.m. or at 50 m.p.h. In possession of such performance capabilities, the prospect of a long run even under existing conditions, is that of keen anticipation, so, although we did not leave Brendon, in Devon, until nearly midday on the Sunday, there seemed no immediate need to take to “A30.” First, we tried some hill climbing, taking Lynnatt at a maximum of 2,900 r.p.m., or 24 m.p.h. in bottom gear, and afterwards tackling Beggar’s Roost in the same ratio at the same speed. Thereafter, a timed ascent of Hookway gave a reading of 38.8 secs. for a nasty loose gradient approached via a water-splash and having two hairpin corners on which severe wheelspin could not be entirely avoided. That we took this hill and the notoriously rough “Roost” without damage to the wings clearly shows that they represent a sensible balance between modernity and practicability. The Bentley was thrown joyously about on typical Devonshire going, when all the excellent qualities aforementioned were fully proved. Then, when it seemed time to hurry in search of that now elusive item, a satisfactory lunch, and later, when daylight had but a few hours to go, we enjoyed the all-too-rare pleasure of holding a sustained 70 m.p.h. in complete silence, cornering at scarcely reduced speed round open bends, slowing the car with the merest pressure on the brake pedal and maintaining the pace up long gradients by snicking in the direct-drive top. Throughout, the oil pressure held a steady 25-30 lb. per square inch, and the water temperature stayed at 75-77°C., only rising to 80°C. during some standing start acceleration tests. Incidentally, the Bentley carried its full complement of passengers throughout, and some idea of the performance available on the overdrive is afforded when it is mentioned that the long hill out of Yeovil was entered at 40 m.p.h., the speed rising to 46 m.p.h. at the corner, the car going over the summit at 52 m.p.h., in spite of a momentary check. Even on overdrive the Mark V can, if so desired, be regarded as virtually a one-gear car, in ordinary going and once under way. That it has more urge than formerly through the gears is indicated by a casual acceleration check, when 0-50 m.p.h. was achieved in 10.6 secs., and 0-60 in 16.8 secs. The excellent output of the engine at moderate crankshaft speeds is indicated by the fact that a better time was recorded by changing into second gear at 3,500 r.p.m. than when bottom gear was held up to 3,800 r.p.m. and 4,000 r.p.m. The silence of the engine makes it difficult to judge when to drop the clutch in for a racing start, and we did nothing sensational in that direction, although this component is designed to withstand such treatment up to the engine’s absolute maximum of 4,500 r.p.m. Before returning home we could not resist carrying out one more test, and, deviating to Middledown, a climb was made, using bottom and second gears, from before the first left-hand bend to a point some way along the straight beyond the third and hairpin bend. The writer confesses to ragged cornering and a time of 54 secs. Only on really fast corners do the wide-tread Avons protest, and then not at all objectionably. Incidentally, the recommended pressure is 23 lb. per square inch front, and 25 lb. per square inch at the rear, but recalling how rather hard tyres improved the old 4¼-litre, we put things up to 28 lb. all round at the commencement of the drive. They attained rather a temperature after rapid motoring, but gave no trouble whatsoever. Indeed, no water and no oil were needed, nor any adjustment of any kind, in some 550 miles running. Owing to the restriction on leave from work of national importance the car had to be hastily put through its paces and handled by several drivers and, under the circumstances, it was not easy to make a fuel consumption check, but it would seem that, driving very hard and with all the hill fun-and-games thrown in, and with no real attempt at coasting, the Bentley gave approximately 18 m.p.g. throughout. That is extremely creditable, especially as in normal times a higher grade of fuel would undoubtedly be employed.
That, then, is a car, now only emerging from the experimental stage, which those fortunate mortals who have tried it proclaim to be the finest all-rounder ever built and which will unquestionably establish a great reputation amongst British fast cars when it goes into production after the war. It seems likely that the price of the model tested will be in the region of £2,000. This long test of the Mark V Bentley has convinced us that it retains all the qualities and performance characteristics which resulted in the earlier 4¼-litres achieving a record popularity in the sphere of high-grade cars, while being most adequately modernised by the introduction of i.f.s. and an over-drive top gear, as well as improved in detail and mechanically in several important respects. It only remains to add that the front suspension system employs exposed coil springs and transverse wish-bones rather reminiscent of the pioneer Packard wide-spaced wish-bone i.f.s. system, in conjunction with lower centre of gravity by reason of smaller wheels, and that the change in the gearbox, already well-tried, has been quite simply carried out, the actual ratios being 0.4199, 0.6693, direct and 1.181 to 1, respectively, in conjunction with an axle ratio of 10/43, or 4.3 to 1. We returned “FYH 539” with respectful regard for Rolls-Royce foresight and a re-awakened enthusiasm for their always near-perfect productions.