From Herald Wheels:
Classic car showcase: Jaguar XK120
Of the many British sports car brands that arrived in North America after the Second World War, arguably the most famous was the Jaguar XK120. Jaguar had built sports roadsters before the war, most notably the SS-100, but felt an all-new post-war car was needed for a clean break with the past.
Chief engineer William Heynes headed up the design of the mechanical components while company co-founder William Lyons did the styling. The engineering design parameters were quite daring. The engine was to develop 160 horsepower at a high 5,200 rpm and have double overhead camshafts, a feature then usually found in racing cars.
Heynes came up with a 3.4 litre inline six with a massive crankshaft, seven generous main bearings and a surprisingly long stroke - bore and stroke were 83 by 106 mm (3.27 by 4.17 in.).
This twin cam six was originally intended for a Jaguar sedan but was installed in the roadster as a temporary test bed while the sedan was being readied. They called it the XK120 roadster and it was so overwhelmingly popular that it was put into production. The big Mark VII sedan arrived in 1951 with the twin cam engine.
Lyons created a long, sensuously flowing hood and fender line with headlamps nestled between hood and fenders. He used a delicate vertical bar grille, slender bumpers and rear fender skirts that gave full-length continuity of line. The skirts could not be used when centre-lock wire wheels were fitted because the knock-off hubs extended too far out.
The new 1949 XK120 Jaguar was introduced at the 1948 Earls Court Motor Show in London displayed on a rotating tilted platform. The impact on the crowd was electric. The motoring world was stunned at this graceful lithe roadster with a twin-cam engine that promised the 120 mph (193 km/h) that inspired its name. And this new Jaguar was priced at a modest 1,275 pounds sterling, a figure so low that sceptics predicted it would never come to market for that, if it came at all.
Lyons and Heynes soon capitalized on the good publicity. In May, 1949 they took an XK to the famous straight and level Jabbeke highway in Belgium to demonstrate its performance. Fitted with an underpan and tonneau cover, but without a windshield, the XK120 achieved a top speed of 213 km/h (132.6 mph), making it the world's fastest production car. In standard road trim it did 203 (126).
Further evidence of durability was displayed in 1952 by an XK120 coupe (introduced in 1951) on a track in Montlhery, France. A team of crack drivers, including a young Stirling Moss, pounded the Jaguar continuously around Montlhery for seven solid days and nights. By week's end it had covered 27,148 km (16,862 mi) averaging 161 km/h (100.31 mph), a remarkable demonstration of mechanical endurance.
While the XK120 was raced, it was intended as a touring car, not a racer. To prove it had competition credentials, Heynes developed the Jaguar C-Type, also called XK120C ("competition") racing version. A three-car team of Cs entered the 1951 Le Mans 24-hour race in France. One of them won at an average speed of 93.49 mph (150 km/h). It was the first of five Jaguar victories at Le Mans in the next seven years.
When the XK120 arrived in North America it was equally impressive. Road & Track (5/'51) reported a top speed average of 196 km/h (121.6 mph), and zero to 96 km/h (60 mph) in 10.1 seconds. In the Florida Everglades Tom McCahill of Mechanix Illustrated recorded zero to 96 in 9.0 seconds and a top speed of about 196 km/h (122 mph).
There were some quality problems, however, and the forthright and humourous "Uncle Tom" reported them too. He called it "A rather crudely assembled job...put together like a Chinese laundryman's version of a western sandwich," adding that “it would have been better if they had just shovelled the unassembled parts of the car I drove into an old bag and shipped them over parcel post."
In spite of the quality problems Tom was enthralled by the Jaguar, calling it the finest high speed touring car in the world,” lavish raise indeed. He said it rode “like a bubble in a washbasin.”
Although not really meant for racing, the XK was raced and rallied and scored several victories. Brakes that were prone to fading were its greatest competition weakness. Its steering was also heavy, although front torsion bars contributed to quite good handing.
In spite of some shortcomings, the XK120 Jaguar combined stupendous performance, stunning beauty and a relatively reasonable price of under $5,000. During its model run from 1949 to 1954, when it was replaced by the XK140, 7,630 roadsters, 2,678 coupes and 1,769 convertibles were produced. It is one of automotive history's benchmark cars.
