A Very Fast Car!

To Scotland and the Lake District in a Jaguar XK150S.

It was a happy coincidence that resulted in a Jaguar XK150S coupé being available for test at a time when we were committed to cover the recent R.A.C. International Rally, because we thus had an opportunity of trying this very fast British car over long distances to tight schedules.

In a week of intense motoring which took us up to Scotland and at night through the more steeply inclined areas of the Lake District this XK150S proved to be an extremely good motor car, docile yet exceedingly fast, comfortable, safe and handsome. You cannot well demand more from a car.

A full road-test of the less potent Jaguar XK150 appeared in Motor Sport in October 1958 and in general layout the XK150S resembles that car. It is under the bonnet that the exciting differences are found. For example, the engine has the straight-port cylinder head (painted old gold for purposes of identification) with a 9 to 1 compression-ratio, triple 2-in. S.U. DH8 carburetters, a lightened flywheel and lead-bronze lined big-end bearings. These modifications result in a power output of 250 b.h.p. at very smooth 5,500 r.p.m., hence the use of the term “exciting.” In keeping with this useful power output there is a high-pressure clutch, twin petrol pumps and Dunhill disc brakes all round with brake pads of the quick-change pattern.

Overdrive is provided on top gear, controlled by an electrical flick-switch convenient to the right hand on the test car but replaced on later cars by a lever, operating mechanically, and placed ahead of the remote-control central gear lever.

Stationary, this Jaguar coupé is low-hung and eager-looking, its very low roof-line stylish and impressive. In action it combines immense acceleration and a maximum speed of M1 potential with velvet-glove smoothness end commendable quietness. The 250 b.h.p. engine emits a subdued roar when it is opened up but is otherwise in no way obtrusive, while the absence of wind-noise round the body at speeds well over “the ton” is truly commendable.

It was into the capacious luggage boot of this Jaguar that we packed the paraphernalia inseperable from going away to watch a day-and-night rally and slid out of London just before the worst of the rush-hour traffic got off the leash. An the November daylight faded and the myriads of lights began to twinkle on the skyline of the Metropolis under banks of sombre clouds that suggested a night of rain, the XK150S thrust its way onto the Barnet By-Pass, aiming for the Motorway. While Londoners prepared to vacate office and factory and fight their way home to enjoy numerous leisure pursuits we in the Jaguar headed north, covering miles in the time it took the maelstrom behind us to cover as many yards.

Comfortable if not 100 per cent. perfect seats, a very efficient heater, and the whispering power of the turbine-smooth 3.4-litre twin-cam engine combine to render this 130 m.p.h. coupé a very restful form of fast transport, its tremendous resources of acceleration from the lowest speeds to near its maximum being both insurance against emergency and an effective means of getting through slow-moving traffic.

On the Motorway the Jaguar settled for 120 m.p.h. on its only mildy-optimistic speedometer, hardly fell below 100 m.p.h., and went to 5.000 r.p.m. in overdrive top gear, or some 128 m.p.h. not allowing for tyre growth at this speed—suffice it to say that in half-an-hour after entering M1 we were back on A5, a Motorway average of fractionally under 114½ m.p.h.

This sort of sustained high-speed cruising does not disturb the equanimity of the Jaguar’s water or oil temperature, nor did the nylon Dunlop RS4 tyres appear to become more than normally warm. However, one of the exhaust hinge gaskets had begun to blow when the car was delivered and this high-speed cruising made it worse so, after having spent the night in Chester, we had this repaired by the Jaguar agent in Blackpool the next day. The efficient way in which this was done while we watched the Rally competitors doing evolutions on the sea-front, and the courtesy extended, suggests an excellent understanding between the Jaguar Company and its agents, which is reflected in a happy and worthwhile customer relationship.

Now we settled down to follow part of the Rally in earnest, confident that the performance of the XK150S would get us where we wanted to be in ample time. So it proved, for we were able to eat a satisfactory dinner at the “Traveller’s Rest”  at Ulpha before spending the night observing at a choice r.h. bend at the front of Wrynose Pass!

There is no need to deal in detail with the control arrangements and appointments of the XK150S because these resemble those of the XK150 coupé already road-tested by this journal. Suffice it to say that there is the same excellent gear change, so pleasant to use, a fly-off hand-brake set to the left of the considerable propeller-shaft tunnel, that both front wings are visible to an average-height driver but that the screen pillars seem somewhat thick to a tall occupant, and to permit the very low roof line the seats are set low. The passenger has a rather shallow cubby-hole, the lid of which can only be kept shut by locking it with a key, which is a minor irritation.

The driver has an adjustable steering column and room for his left foot beside the clutch pedal. The 140 m.p.h. speedometer is somewhat blanked by the steering wheel rim but the dial possesses trip with decimal and total mileage readings and the needles of the Smith’s rev.-counter and speedometer move steadily round their big dials. The instruments are set on a leather-padded panel and the facia possesses crash-padding. Normally the water temperature remains at 70 deg. C., oil pressure at 40 lb./sq. in., as shown on separate dials.

The beauty of driving this fine car is that it is always well within itself. By this we mean that the engine is by no means under-geared. It is unnecessary to go “into the red” on the rev.-counter to obtain all the acceleration normally required, and if 5,500 r.p.m. is used in third gear there is a useful maximum of 86 m.p.h. In second the maximum at this speed is 59 m.p.h. By using overdrive, as has been seen, the engine runs well below peak speed, even approaching the Jaguar’s maximum of over 130 m.p.h.

The bonnets-ful of highly impressive and beautifully-finished machinery is something over which the most blasé owner will enthuse and the legendary smoothness and quietness of the Jaguar twin o.h.c. power unit is well maintained in this 250 b.h.p. version.

The steering is perhaps on the spongy side but is quick and responsive, while road-holding is eminently satisfactory, providing the necessary discretion is used with the throttle out of bends on slippery roads.

Coming south from Scotland, traffic conditions made it impossible to average 50 m.p.h. in spite of vastly improved roads below Abington and the many miles of dual carriageway on A1. However, average speeds very close to this target were achieved in complete safety at night. Here tribute must be paid to the Dunlop disc brakes, which slow the Jaguar from 100 m.p.h. to a crawl without conscious pressure on the pedal, and, what is more, enable the driver to obtain extremely sensitive and progressive retardation when required.

Our dash south from Scotland was interrupted when it seemed expedient to investigate a noise which had developed in the near side back wheel. Again a Jaguar agent, this time S.M.T. in Carlisle, gave us willing and courteous attention. The trouble was traced to worn splines on the wheel hub, probably accentuated by demonstrations of the car’s remarkable “step-off” from a standstill. Replacing the suspect wheel with the spare improved matters and our high-speed journey continued.

In due course this XK150S was returned to Jaguar’s, after proving an ideal car in which to travel far and fast in the November nights. It covered, in fact, over 1,750 miles in our hands and was returned with real reluctance.

Petrol consumption of 100-octane fuel worked out at a commendable 17.05 m.p.g. over 1,000 of the faster miles. Oil thirst was less satisfactory—altogether 14 pints were consumed and according to the dip-stick another three or four pints would have been welcome at the end of the test. Consumption was thus less than 900 miles a gallon.

A quick check of acceleration, after speedometer correction, gave 0-60 m.p.h. in third gear in 9.8 sec. or, holding second gear to 6,000 r.p.m., 8.6 sec., 0-100 m.p.h. (to 5,000 r.p.m. in top) taking 24.4 sec. on the best run.

There are few cars made anywhere in the World which combine the speed, acceleration, economy of petrol and docility of the three-carburetter Jaguar XK150S and none which offers better value-for money, at its list price, inclusive of purchase tax, of £2,110.

This potent Jaguar justifiably takes its place amongst the great high-performance motor cars of the present day and age. And if, like some correspondents to Motor Sport, you are hard to please, you can now obtain it with the 3.8-litre power unit. . . .W. B.

The Jaguar XK15OS

Engine : Six cylinders, 83 x 106 mm. (3,442 c.c.). Inclined overhead valves operated by twin overhead camshafts. 9-to-1 compression-ratio. 250 b.h.p. at 5,500 r.p.m.

Gear ratios : First, 13.81 to 1; second, 7.6 to 1; third, 5.24 to 1; top, 4.09 to 1; overdrive, 3.18 to 1.

Tyres : 6.00 x 16 in. Dunlop “Road Speed” RS4 on centre-lock wire wheels.

Weight : Not weighed. Maker’s figure: 29 cwt. (kerb weight).

Steering ratio : 2 turns, lock-to-lock.

Fuel capacity : 14 gallons. (Range upproxiinately 230 miles.)

Wheelbase : 8 ft. 6 in.

Track : Front, 4 ft. 3¾ in.; rear, 4 ft. 3¼ in.

Dimensions : 14 ft. 8½ in. x 5 ft. 4½ in. x 4 ft. 6¾ in. (high).

Price : £1,487 (£2,110 4s. 2d. inclusive of purchase tax).

Makers : Jaguar Cars Ltd, Coventry, England.

Performance Data

Speeds in gears at 5, 500 r.p.m. :

Second .. 59 m.p.h.

Third .. 86 m.p.h.

Acceleration :

0-60 m.p.h. at 5,500 r.p.m. in thrd gear .. 9.8 sec (9.9 sec.)

0-60 m.p.h. to 6,000 r.p.m. in second gear .. 8.6 sec. (8.9 sec.)

0-100 m.p.h. .. 24.4 sec. (24.7 sec.)

(Figures of run in parentheses are mean of runs in both directions)