1948’s game changers: Jaguar XK120

By Aaron McKay

| 20 Jun 2023

Classic & Sports Car – 1948’s game changers: Jaguar XK120

75 years ago, the motoring world changed for ever as a clutch of iconic vehicles made their debuts on a wave of post-war optimism. Here we look at the Jaguar XK120…

William Lyons was a man of high ambition, but grounded in the business reality of managing priorities.

At the top of his list in 1945, and that of his team of gifted engineers including Bill Heynes, Walter Hassan and Claude Bailey, was producing a 100mph luxury saloon car that would match his higher-priced rivals.

He probably had good reason to quietly believe he’d beat them, too.

The ‘Super Sports’ concept was an immediate hit when it appeared at London’s Earls Court in 1948

Desks at the Holbrook Lane works were covered with plans for a new, monocoque saloon powered by a sophisticated straight-six with hemispherical combustion chambers in a double-overhead-cam aluminium head.

With Lyons’ trademark style and commercial daring, a best-seller was in the making.

But another project stirred in the background.

To make the first run of post-war motor shows while the MkVII saloon development ran on, Lyons indulged his affinity for low, rakish lines with an aluminium body over a shortened MkV chassis with the new XK ‘six’ fitted in the nose.

‘It glides, just as its flowing lines suggest, with its clean disc wheels spinning as silent partners in its refined drivetrain’

Suspension was by wishbones locating torsion bars up front, with leaf springs at the rear, and Lockheed hydraulic drum brakes all round.

With the assistance of Fred Gardner, the ash-framed ‘Super Sports’ went from concept to reality in just a matter of weeks.

Perhaps Lyons didn’t have time to realise just what an impact it would make at Earls Court in October 1948.

Nor did the newly renamed Jaguar have time to respond to the overwhelming demand that resulted.

The long-serving XK ‘six’ delivered grace and pace for 44 years

It took nearly two years for XK120s with production-friendly steel structures and bodies – though the doors, bootlid and bonnet remained aluminium – to flow out of Coventry in real volume.

The starting price was a modest £1263, for a proven 126mph car, but you still had to be lucky, wealthy and, ideally, American to own one of the first 200 made.

It’s difficult to consider those who owned the remaining 11,861 steel cars as anything other than extraordinarily lucky, too, particularly when you catch sight of Dave Nursey’s silver 1951 example: “It was 1975 and I was looking at either a big Healey 3000, a Daimler SP250 or the XK, but I had a conversation with Philip Porter at Shelsley Walsh and he said ‘Forget the others, go for the Jag’.”

The swiftness of the XK120’s straight-six engine must’ve been mind-blowing in 1948

Dave, then aged 24, echoed the image that had been drawn around the XK120: that of a younger generation of sports-car-mad drivers, attending and often taking part in competition events.

“I ran it every summer, and sparingly in the winter, including trips to Le Mans in 1982 and ’83,” says Dave, though it was then only as his transport, rather than laying rubber on the track.

“And I have never used the roof,” he adds.

Jaguar initially struggled to match the demand for the XK120

The car was laid up for restoration in 1984, re-emerging in the 2000s, after which it returned to sports car duty – visiting Le Mans three more times and Shelsley Walsh hillclimb often. Today, it’s Goodwood.

Entering with the preconceptions that the driving position will be cramped – the pedal box too narrow and the steering wheel too large – and the Moss gearbox recalcitrant, leads to a pleasant surprise: none of it is difficult.

The seat is soft, the cabin wide and accommodating, and even your first start is unlikely to be no worse than a flurry of airy revs and a relaxed click into second gear.

The classic Jaguar XK120’s cabin is snug but classy

It glides, just as its flowing lines would suggest, and its clean disc wheels, hidden at the rear behind steel spats, spin as silent partners in its refined drivetrain.

The engine hums, and the driver feels duty-bound to take care with each gear, slotting in with rev-matching finesse.

Delicate steering inputs have the XK120 almost sailing around Goodwood’s green circuit.

You can imagine the same in the British countryside or in the glamorous setting of the California coastline.

Flowing lines on the Jaguar XK120’s steel bodywork

But with a well-marked apex and a straight lined up ahead of its curved wings and bonnet, the temptation to recreate the hard-charging, canyon-carving antics of those early owners is impossible to resist.

The hum quickly turns into a snarl when the twin SU carburettors are opened fully, and the XK120 gains pace with sparkling energy.

So smooth is the delivery and so gratifying the exhaust note that you are easily teased into rushing for another gear, but the Moss ’box does need a moment.

“It just become instinctive,” says Dave, and when you master the timing, gears do slot home with a sense of finely honed tightness.

With 160bhp on tap, the XK120 still feels quick today

You approach the handling with a similar appreciation of timing and delicacy.

Perched, it feels, on the edge of veering eagerly into whichever direction you hint at, the Jaguar is almost nervously light.

But dial in lock at a considered rate and it settles reassuringly into a long-striding sweep of whichever line you care to tailor with the throttle.

Sensations of the road build subtly through the controls, as if by warming up it really is transforming into its remembered club-racer identity.

This gorgeous classic Jaguar looks right from any angle

Leading the second chapter in the world’s love affair with sports cars, the XK120 became far more than an engine showcase.

It inspired an appreciation of the genre beyond the driving goggles of pre-war racers, stirred a movement powerful enough to almost rival the sales of its more commercial saloon siblings, and created a legacy that has filtered down to today’s F-type.

Most of all, the XK120’s beguiling spirit is one of simply grabbing attention and never letting go.

In that, there may be no higher ambition.

Images: Luc Lacey

To read about our other game changers from 1948, check out the Morris Minor, the Land-Rover, the Porsche 356, the Citroën 2CV and the Ferrari 166MM

From XK to E-type

The Jaguar’s feline shape mimics the animal it’s named after

Speed tests cemented the XK120’s legend in May 1949, with 132.6mph achieved with a pared-back windscreen and undertray, 126mph in standard form, on the Jabbeke highway in Belgium.

A year later, it took the TT at Dundrod and the Alpine Rally, and nearly won at Le Mans.

In 1951, the fixed-head coupé arrived, followed by a 180bhp Special Equipment package.

The XK150 gave way to the 1961 Jaguar E-type

A drophead coupé completed the range in ’53, before the softer-edged XK140 came a year later.

The ’57 XK150 introduced all-disc brakes, and in ’59 a 3.8-litre unit came in ultimate 265bhp form before the E-type arrived in 1961.

The XK engine lived on in various forms until the last Daimler DS420 of 1992.

Factfile

Jaguar XK120 OTS

Sold/number built 1948-’54/12,061 (all)
Engine iron-block, alloy-head, dohc 3442cc straight-six, twin SU carburettors
Max power 160bhp @ 5400rpm
Max torque 195lb ft @ 2500rpm
Transmission four-speed manual, RWD
Weight 2855lb (1295kg)
Mpg 16.2
0-60mph 10 secs
Top speed 126mph
Price new £1263
Price now £60-90,000*