AS WE celebrate 40 years of the six-cylinder option which gave the XJ-S such a massive boost in the market, it’s easy to forget what a massive undertaking an all-new powerplant was for a company the size of Jaguar at the time.
The brand’s postwar success had been built on the legendary XK engine, but by the late ’70s it was starting to show its age in some areas. Famously worked up during fire watching sessions at Jaguar’s Browns Lane plant as Luftwaffe bombs rained down on Coventry, the XK had served Jaguar well and in fact would serve even longer in parallel with the AJ6, the final production units being built in 1992 for the DS420 limousine.
As the 1980s appeared on the horizon however, efficiency and emissions became ever more important and it was clear that something more modern was needed – especially when the thorny issue of fuel consumption was raised. The XK’s age meant it was never going to win any economy prizes but the V12 was in a different league, even in HE form.
Work began on what would be only the third new engine in Jaguar’s history as early as the 1960s. Early thinking centred around creating production cost efficiencies by creating a V8 engine by effectively losing four cylinders from the V12 engine – the idea being that
