PAST IMPERFECT:The Jaguar XK120 was one of the best of British cars, setting standards that were hard to beat, writes Bob Montgomery
MY CURIOSITY was recently aroused by a Jaguar advertisement in the American magazine ROAD and TRACK. The ad was in the April 1953 issue and declared the Jaguar XK120 Coupé as being the first car ever to exceed "100 mph for seven days and nights".
Even today, this would be a significant achievement but in the early 1950s when record breaking was much in vogue, it seemed an outstanding achievement, and thus I determined to find out more.
The Jaguar XK120 was manufactured between 1948 and 1954 and was Jaguar's first post-war sports car. Shown at the 1948 London Motor Show as a testbed for the new XK engine, it caused a sensation and led to William Lyons being persuaded that it should become a production model. At the time of its launch it was the world's fastest standard production car and the '120' in its name referred to its top speed. It was available as a convertible and from 1951 as a closed, or 'fixed-head' coupé.
In May 1949, Jaguar demonstrated an XK120 roadster on a specially closed section of the auto route between Jabbeke and Aeltre in Belgium. This car, the second XK120 built, was to have been driven by Walter Hassan but he fell ill and test-driver Ron "Soapy" Sutton substituted for him. With the only modification being a flat aluminum undertray, the Jaguar was timed through the flying mile at 126.448mph (203.498km/h) by the Royal Automobile Club of Belgium officials.
The hood, sidescreens and windscreen were then removed and a metal airflow detector fitted in front of the driver together with a tonneau cover over the passenger seat. This time the XK120 achieved a speed of 136.596mph (219.830km/h) putting Jaguar's claim that this was the world's fastest production car beyond any doubt.
As it turned out, this was just the first of many records and motor racing successes for the XK120. Cars were entered at Le Mans, the Mille Miglia and the Targa Florio with mixed results, but were successful at Silverstone and achieved an outstanding 1-2-3 victory in the Tourist Trophy race at Dundrod. Meanwhile in rallying, Ian Appleyard won the French Alpine Rally and a coveted Coupe des Alpes in the 1950 Alpine Rally.
Jaguar also continued its interest in record-breaking with the XK120. Leslie Johnson achieved an outstanding 131.83 miles in one hour at the steeply banked French Autodrome de Montlhéry. When one considers the g-forces generated by the 30 degree banking as well as the 1940s technology the XK120 employed - particularly the leaf spring suspension and crossply tyres, this was an outstanding achievement. Afterwards Johnson remarked that the car felt as if it could have gone on for a week.
The result of this off-hand remark was a return to Montlhéry in 1952 when Johnson was joined by Stirling Moss, Hadley and Jack Fairman in an attempt to establish new records for a 7 day and 7 night run.
When well into the run a spring broke on the track's rough surface and mindful that it's replacement would make the car ineligible for any records apart from those already achieved, Johnson drove a nine hour stint at undiminished speed so that the other drivers would not be put at risk. When the XK120 finally rolled to a halt after 7 days and 7 nights it had established no less than 10 World and Class records. An outstanding achievement by an outstanding car and team of drivers.