The most prominent of these was the Jaguar XK6 engine, which reportedly was developed over long nights during World War II when Jaguar founder William Lyons and his staff were on fire watch duty in the Jaguar factory in Coventry, and made use of the time to design a new engine. The result was displayed in the Jaguar XK120 at the London Motor Show in 1948. The twin overhead camshaft XK6 engine was highly advanced compared to previous British engines. The Jaguar XK120 and the XK-powered Jaguar C-Type and Jaguar D-type, went on to score victories in races and rallies in the UK, Europe and North America. They dominated the 24 Hours of Le Mans during the 1950s, where Jaguar C-Types won in 1951 and 1953, and the D-Types had three more wins in 1955, 1956 and 1957. Subsequently, fitted to Lister Cars Lister-Jaguar, the D-type engine contributed to their success in international sportscar-racing in the late-1950s. The engine design, enlarged to , reached its apogee in the Jaguar E-type introduced in 1961, which was capable of . In 1964, the XK engine was again enlarged to , which was considered the most powerful and refined of the series. The last XK-engined Jaguar went out of production in 1986, but some XK-engined cars such as the Daimler DS420 limousine were still available into the 1990s. A variant of the 4.2 L engine powered some Scorpion light tanks. The XK6 engine was followed by the AJ6 and AJ16 engines. After Jaguar was acquired by Ford, these engines were replaced with the Ford Duratec-derived Jaguar AJ-V6 engine.