Background
Jaguar's legendary 5.3-litre V12 engine was available in the XJ range from 1972 through to 1992. For the Daimler version the Double-Six name was plucked from the archives, dusted off and given a new lease of life.
The well established and already iconic XJ silhouette was given fresh design impetus by Pininfarina to create the Series III model line which, by the time it began to roll off the production line at Coventry, embodied more than a decade of production quality lessons learned on the Series I and II models.
The Series III was set a very high bar by its designers and engineers: to boldly claim the title of ‘Best Car In The World’ and, in so doing, metaphorically slap our Teutonic friends lightly on both cheeks with a Browns Lane duelling glove.
The integrity of the car’s engineering and its ability to live up to Jaguar’s Grace, Space and Pace mantra was never in question and was ably demonstrated by the XJ6. But a car that could hold its own, or better, with the cream of the crop from Stuttgart and Munich really needed the magnificent 5.3-litre V12 under that beautifully sculpted and proportioned bonnet.
Did it succeed in its ambitions? Well, many journalists of the day felt that it probably was the best car in the world. It’s reasonable to assume that none of them were called Jürgen or Wolfgang.
Equipped with the high-compression ‘Fireball’ cylinder head designed by Swiss racing driver Michael May (the presence of this engine was signalled by an ‘HE’ badge on the XJS V12), the V12 now developed 299bhp, a lot more torque and better fuel economy. Clearly ‘better’, in the context of a V12 engine, doesn’t mean ‘good’.
Production of the six-cylinder Series III XJs continued until early 1987, after which it was replaced by the all-new XJ40, while production of the 12-cylinder Series III XJs continued until 1992.
132,952 Series III cars were built, 10,500 with the V12 engine.







