Round the clock with a Bentley S-Series

A fast return run from London to Scotland underlines the silent high-performance, powerful braking and luxurious specification of the latest model of this fmous make. Every conceivable comfort and convenience, including servo brakes and automatic transmission.

Bentley is not a name to be taken lightly, even by Bugatti fanatics ! Indeed, the development of the Rolls-Royce-built cars has been steady, sensible and continuous. From the original 31/2-litre “silent sports car” came the more powerful 41/2-litre cars, later endowed with overdrive gearboxes and developed as the war-time Mk V with independent front suspension. Other, similar but always slightly better, Bentleys followed, leading to the recent B7 and culminating in today’s S-series 4.9-litre model, of which Motor Sport was recently able to conduct a road test extending over more than 1,360 miles.

The modern Bentley has a specification in which traditional engineering is blended with the requirements of the present. The six-cylinder engine has a bore and stroke of 95 by 114 mm (4,887 cc) and uses a modest compression ratio of 6.6 to 1 and twin SU HD6 carburetters with automatic starting control. The power output remains locked in the bosoms of the Rolls-Royce technicians. Piston speed at 2.500 fpm is equivalent to 3,330 rpm. Push-rod actuated oh valves are set above side-by-side exhaust valves. The pistons each have three compression rings, the top one chromium plated, and one scraper ring, and the nitrided crankshaft runs in seven copper-lead-indium-lined steel-shell main bearings and possesses integral balance weights. The lubrication system is conventional, except that the connecting-rods are drilled for lubrication of the little-ends. The sump holds 16 pints of oil. A light-alloy cylinder head with six separate inlet ports is employed. The camshaft is driven by single helical gears, with a drive for the oil pump in the centre. It runs in four plain bearings. The cooling system contains 31/2-gallons of a 25 per cent anti-freeze solution, and incorporates a belt-driven five-bladed fan and a thermostat. The latter can be supplied to open at a coolant temperature of 75-77 deg C, or at 84-86 deg C as required. Fuel is supplied from an 18-gallon tank by two independent electric pumps. The 12-volt electrical system incorporates a Dagenite or Exide battery, Lucas C-47 dynamo. Lucas M-45G starter motor and a main fusebox containing eight fuses, with separate horn fuse. Lodge or Champion plugs are specified, and twin Lucas ignition coils fitted. The drive is taken via an automatic gearbox comprising a fluid coupling and a set of compound planetary gears through a divided propeller-shaft to a semi-floating hypoid-bevel back axle with four-star differential, giving a final-drive ratio of 3.42 to 1. The axle holds 11/2 pints of lubricant.

The chassis is of welded-steel closed-box-section construction with cruciform centre bracing, a steel front pan carrying the suspension and steering units and box-section and tubular rear cross-member. Centralised chassis lubrication is fitted, supplied from a scuttle mounted reservoir. Front suspension is by unequal-length wishbones and coil-springs, and a normal back axle is sprung on 1/2-elliptic leaf-springs and located by a Z-type anti-roll bar. At the front opposed-piston dampers of Rolls-Royce construction and a torsional anti-roll bar are used, while at the back the piston-type shock-absorbers are electrically controlled by the driver. The back springs are enclosed in gaiters and the shackles possess rubber bushes.

Steering is cam and roller to a transverse link and three-piece track-rod linkage, and 15-in steel disc wheels are carried on five studs. The brakes have 11 in by 3 in cast-iron drums with peripheral cooling fins, and are applied hydraulically at the front and by combined hydraulic and mechanical operation at the back, through the famous Rolls-Royce gearbox-driven friction servo motor introduced in 1924, which runs at approximately one-fifth propeller-shaft speed. The proportion of braking at the back is 60 per cent hydraulic, 40 per cent mechanical. The hand-brake applies the backbrakes only, through part of the pedal linkage. The front brakes have twin trailing shoes.

“Static” observations

In a car of this price and reputation one expects every conceivable luxury appointment, and in this the Bentley does not disappoint the most fastidious. The car we tried was the standard four-door 5/6-seater saloon of stressed-skin pressed-steel construction.

It is endowed with seats upholstered in deep high-grade leather, with every possible kind of armrest, those on the front doors being adjustable for height. The front squabs are adjustable for inclination, aircraft fashion, by means of little levers beside the cushions, and their backs carry ashtrays and folding tables for the convenience of rear-compartment travellers. Upholstery is in English hide and foam-rubber overlays on spring cases, and dash and garnish rails are finished with french walnut veneer. The floor is covered with deep carpets. Incidentally, although the body is of steel, luggage-boot lid, bonnet and doors are made of aluminium in the interests of keeping the kerb weight under two tons.

Reverting to the luxury of the “static” appointments, the high-backed front seats, lacking only a headrest, can be adjusted separately or set as a three-passenger bench seat. The front doors possess normal windows, calling for 21/2 turns of the handles to fully raise or lower, ventilator windows with unpleasantly stiff catches, and well-pockets, while the armrests act as “pulls.” The rear doors have rigid metal “pulls” and the window handles call for almost 21/2 turns up-to-down. Fixed quarter-lights match the front ventilator windows. External push-button handles are used. Recessed mirrors, with a cigar-lighter adjacent to the off-side mirror, flank the back seat. Locks are fitted in both front doors.

The front-seat passenger has a very large, lined cubbyhole before him, closed with a lid which matches the dashboard and possesses a Yale lock. A similar cubbyhole, unlidded but with a useful step to retain small objects, is provided in front of the driver. Behind the rear seat is a very wide parcels shelf. Under the dash is a pull-out table, with the HMV radio above it, the radio using a roof aerial elevated by turning an interior knob.

The air of high quality and refinement conveyed by the beautiful upholstery and veneered instrument panel is enhanced by the sense, from contemplation of small details, that this is a car in the true Rolls-Royce-built Bentley tradition. The large non-sprung three-spoke black steering wheel, unencumbered save for a sedate plated horn-push in its boss, the switch-gear in separate panels, the type of direction “flashers”control set on the right of the dashboard sill, and the shape of the brake-pedal in this now two-pedal car are typically Bentley.

The instrument panel contains a Smith’s 110-mph speedometer with trip and total mileometers, matched by a dial incorporating fuel gauge, water thermometer, oil gauge and ammeter. These gauges have only superficial calibrations such as “Hot” and ”Cold,” “High” and “Low,” and, in the centre, a Smith’s clock. Between these main dials is the panel containing the detachable ignition key, which is turned to start the engine (after the gear-lever has been set to neutral) and its removal locks various circuits according to its setting, rendering the car tamper-proof, generator and fuel-warning lights (the latter indicating when less than three gallons of petrol remain), and a switch for selecting side and tail-lamps, head, side and tail-lamps or fog, side and tail-lamps, as required. On the left of this panel is a cigar-lighter, on the right a switch for releasing the flap over the petrol-tank filler, which is in the near-side back wing and has a screw cap, rather small and secured by a wire—not a filler for your chauffeur to approach with dignity and a can. Two further panels carry switches for controlling demisting and ventilation, wipers and washer, panel and map lights and ventilation and heating, these being cleverly arranged to perform several functions by either turning or pulling them ; thus hot or cold air is selected by pulling out to one of two positions the appropriate knob, fan speed by turning it, and the wiper switch controls the two-speed, self-parking screen-wipers by turning, the screen-washer by pulling it out, etc. A button enables sump oil level to be read on the petrol gauge. There is provision for an inspection-lamp.

A little switch on the left of the steering column selects hard or soft ride control, the left foot operates the automatic chassis lubricator, which requires two strokes every 200 miles, and a lever on the right of the steering column provides a degree of control over the automatic transmission, a button on the end of the lever guarding the neutral and reverse positions.

The Bentley has an old-style bonnet, levers on each side of the scuttle interior releasing the appropriate, centrally-hinged bonnet panel. The roof lamp is operated automatically as the doors are opened, with an overriding finger-switch on the near-side door pillar.

Visibility through the big curved windscreen is excellent, thanks to slim screen pillars, and both front wings are just visible to a driver of average height. In-built headlamps are naturally fitted, the semi-inbuilt sidelamps above having tiny red inserts to show them to be alight. The headlamps provide good but not exceptional light for fast night driving and are dipped by a big rubber knob on the floor. Lucas fog-lamps are effective in mist and fog.

The doors of the modern Bentley do not close with quite the “coachbuilt” action of pre-war models and we have to report some minor body rattles and an irritating creak from the region of the near-side screen pillar.

Nevertheless, one of the first impressions is of the wonderfully quiet functioning of the car. The 4.9-litre engine is inaudible and with all the windows closed wind-noise dies away to less than a whisper, so that it is possible to converse in low voices while cruising at a speed of 100 mph. To enable the full benefit of this charming absence of effort to be enjoyed, very thorough air-conditioning and heating is provided, each system separate, so that the car can be driven with all windows shut as a matter of course. A separate duct ventilates the rear compartment. Demisting is looked after by cold or hot air feeds to the windscreen, and by an electrically warmed rear window.

A central, scuttle-mounted mirror provides the driver with a good rear view, at the expense of slightly impaired left-forward vision. The hand-brake is a pull-out toggle on the right under the scuttle; on the car tested it did not hold very well and came out so far that the driver was in danger of hurting his knees on it when vacating the driving seat. The doors are amply wide, for dignified entry and egress, although. as the seats are high, one steps down quite a long way.

The body lines of the S-series Bentley are beautifully proportioned. rendering this big car handsome as well as imposing. The luggage boot is of very generous capacity, with a flat floor broken only by the fuel filler-pipe, as spare wheel and tools, the small tools in a tray, the large ones in clips, are stored beneath it. The lid has overcentre hinges, and locks. The radiator is, of course, a dummy, the actual cooling element being located some way to the rear of it. Twin screen vizors are fitted, arranged to swivel sideways when detached from clips, the passenger’s having a vanity mirror. The steady white-tipped needle of the speedometer provides for easy reading of the Bentley’s speed but the matching rev-counter of earlier cars was missed, albeit with automatic transmission the driver has little control of engine speed towards maximum rpm. The beautiful hand-throttle control, too, is missing on the modern Bentley. There is no choke. starting being automatic.

Road behaviour

Having thus set down the technical specification of the S-series Bentley and examined its complete and luxurious detail appoint, we set about discovering how the present-day representative of this famous make performs on the road.

Following a preliminary canter of some 230 miles we set out to drive to Scotland and back, and, being gluttons for punishment and having to compress the test into as short a space of pre-Motor Show time as possible, we decided to return without an overnight stop, thus gaining experience of the modern Bentley in strenuous round-the-clock motoring. We had anticipated without thought of road conditions in Britain. From London that Sunday until “over the border” we had to contend with an almost continual stream of week-end traffic, nosing along at 20-30 mph, as well as with congested towns (Doncaster !) and long hold-ups at one-way road blocks. That the Bentley was able, under these conditions, to average 47.6 mph to beyond Abington, including getting clear of London and two stops, respectively for refuelling and screen-cleaning, is a clear measure of its excellent roadholding and high performance.

A very big car to contemplate at the kerbside—it has a track of 5 ft and is 17 ft 8 in long—it has that elusive but desirable quality of seeming quite small when gaps in tight-packed traffic have to be negotiated. It was up to 100 mph in a very short distance and is arrested from such high speeds very easily by the servo brakes, in spite of its considerable weight. Because of these characteristics we made comparative light of the appalling traffic conditions, making Stamford from East London in 1 hr 591/2 min, Granthatn in 2 hr 23 min. Doncaster in 3 hr 211/2 min, Boroughbridge in 4 hr 251/2 min, and arriving at Scotch Corner in 5 hr 2 min total time. Carlisle was reached in 6 hr 16 min, Gretna in 6 hr 33 min, Abinton, where we branched off A74 for A73, was accomplished in 7 hr 28 min, after which in rain and mist, over incredibly slippery roads which had resulted in one unfortunate in a Ford overturning into a field, we crossed to Edinburgh and, after about an hour’s sleep at daybreak, were in Cambridge, looking at the new F II Lister-Climax, soon after 9 am on the Monday.

This journey had not been devoid of interest. Our best hour’s average while hop-scotching the mimsers was 53 mph. Just before Newark a police Austin did a lurid dive across the oncoming traffic, presumably to make sure of “escorting” the Bentley through the town, and at Grantham we noticed the “Antone” Rolls-Royce van rolling steadily South on its way from Oulton Park. Just before Boroughbridge a Type 44 Bugatti tourer was encountered, and towards the end of Bowes Moor a Cooper, bearing racing No 50, was spotted on its trailer outside a garage. A forlorn traction engine with tattered tarpaulin was noted by the Editor as being on the left of the road out of Locherbie. The object of the run, however. was to check the behaviour and habits of the Bentley. Its automatic gearbox provides a brisk step off, after which progressive upward changes occur at 6, 11 and 20 mph using a light throttle opening or at 18, 31 and 65 mph if full-throttle is employed. Similarly, when the accelerator is lifted. automatic downward gear changes occur at 14 (top to third), 8 (third to second) and 4 (second to bottom) mph. The gear-lever, however, enables second and third gears to be held up to the normal maxima when desired, and by dropping into the third position excellent acceleration can be obtained, although one never quite loses one’s desire for a normal gearbox. That acceleration isn’t stifled by the automatic transmission is indicated by times of 10 sec from 0-50 mph in either fully automatic or third gear and of 18.4 sec from 0-70 holding third gear, which increased to 19.5 sec, using fully-automatic transmission. A steady 50 to 70 mph in top gear occupied 9 sec, and 10-30 mph in third gear took 6.5 sec, actually improved to 4,6 sec in automatic control.

This excellent acceleration, accomplished in complete silence without any suggestion that the big six-cylinder engine is even running, carries one past the worst of the hold-ups, and along the double-track piece of road before Scotch Corner the speedometer went to the stop at 110 mph, as it was to do again on several occasions. This performance is matched by the aforesaid exceedingly powerful, mechanical-servo, hydrostatic brakes, which are certainly a feature of the Bentley. With practically no effort on the driver’s part it is possible to pull the car up on dry roads in a straight line, and so powerful is the action, with a slight lag as-the servo comes in, that some practice is needed to make smooth, progressive non-emergency stops. A slight squeak from the servo was occasionally noticed, otherwise the brakes are vice-free—in the dry. On exceptionally slippery roads care is necessary, as the back wheels lock first and the tail of the car slides all too easily.

Roadholding and cornering are very good for a large and heavy luxury car of this sort, and rapid cornering calls forth only mild protest from the Dunlop Fort tubeless tyres. Moreover, the tail-wag we recall on the Mk V has been completely eliminated. There is neither appreciable over or understeer and roll in subdued, especially with the ride-control set to “hard,” although the difference in suspension characteristics seems less pronounced than on pre-war Bentleys, the ride being fairly hard on both settings. This transmits some slight shake to the steering wheel, but return action through the front wheels is conveyed only over really bad surfaces and then not as pronounced kick-back.

The steering asks four turns from one to other of a generous lock (turning circle 41 ft 8 in) and is exceptionally smooth and light at all times save for very low-speed manoeuvring, although it is essentially spongy steering. There is little sense of low-gearing at speed, but the driver is called upon to do considerable wheel twirling when making pronounced changes of direction, in which he is aided by very strong castor-action. In future on overseas models, power steering will be available and it seems probable that this will be provided more from a desire to raise the ratio of the steering than from any need for nicer or lighter action at speed. The automatic transmission does not jerk excessively, although once or twice it juddered in moving the car away from rest and on slippery roads automatic upward gear changes tend to promote momentary wheelspin and loss of adhesion. Incidentally, it seems a pity that this transmission is of American origin, especially as once upon a time Rolls-Royce made most of their own equipment, even the electrical components.

There is no gainsaying the ease of control provided by the Bentley in its present form. As one eases up to a traffic obstruction and stops the car merely by depressing the brake pedal, the nose with its winged-B badge dipping faintly in gentle acknowledgement of the superb braking power, the car ready to glide away in bottom gear, engine inaudible, with no movement of the owner’s hands from the wheel, appreciation of first-class engineering is unrivalled, especially in view of the very high performance, in terms of speed, acceleration and road-ability, combined in this comfortable and elegant motor car.

We made a careful check of the essential fluids on our fast run to Scotland and back. Petrol consumption was 13.6 mpg. Unfortunately, this represents a fuel range of only 245 miles, which, on Continental roads, could be covered in some four hours. A larger tank seems to be called for. No water and less than half a pint of oil was consumed in the hard 1,000 miles, which is eminently satisfactory, while the antomatic chassis-lubrication virtually obviate chassis maintenance. On long runs the front seats, for all their depth of cushion, feel hard and a headrest for the front-seat passenger would be a worthwhile addition. In the back compartment however, sheer luxury and comfort prevail, while in all seats there is ample leg-room and an entire absence of fumes.

Other cars can equal the Bentley’s top speed and its vivid acceleration, but it is the astonishing mechanical silence and absence of wind noise when the windows are shut, alied to the manner in which the vehicle can be driven in and out of traffic obstructions, steering accurately with but a light touch on the wheel, those outstandingly powerful brakes in reverse, that render it the supreme high-performance luxury car. At its price of 5,243 17s inclusive of pt not many can afford it, but for those who can the genuine quality of its interior appointments, no less than the splendid finish of the engine and the air of security imparted by the deep veneered dash and broad bonnet, will be a source of constant pleasure and inspiration. In the course of our round-the-clock drive we counted many Bentleys, and at least seven of the latest S-series, in which hydramatic transmission coupled with the over-riding gear-lever represents the ultimate in automatic gearboxes.

The British lion may spend much of its time lying down these days but it is still capable of getting up and facing the world in a bold and dignified manner, and such productions as the Bentley S-series remind us that this is so. This is the Company Director’s motor car par excellence, and it is fitting that men who control British destiny should drive these fine cars from Crewe rather than chromium-draped floating drawing rooms of other than British origin. WB