Jaguar - Jaguar XJ6 and XJ12
The Jaguar XJ6 was the model that replaced the spacious Mk10 / 420G in late 1968, initially with both 2.8 and 4.2 litre versions of Jaguars XK engine. A Daimler badged version of the XJ6 was the Daimler Sovereign. The Jaguar XJ6 really set the tone for Jaguar saloons for decades to come and was the last creation of William Lyons before he retired at the age of 70 in 1972. Various changes were made to the 6 cylinder car, including an upgraded gearbox and detail changes and by 1972 a longer wheelbase option was made to give more rear passenger legroom. 1972 also saw the addition of the new 5.3 litre 12 cylinder XJ12, the fastest 4 seater on the planet! The Daimler version or the XJ12 was called the Daimler Double-Six, harking back to the Daimler Double Six of the early 1930's.
The "Series 2" XJ6 was first shown in 1973 and looked virtually identical as what went before it, other than for a lowered front grille, and quite a different dashboard. The XJ Series 2 came either with 6 cylinder 4.2 with the XJ6 or as a 12 cylinder XJ12 (which was also called the XJ5.3), but in 2 wheelbase lengths. Within a year the original shorter length was deleted and only the longer wheelbase was offered. Over the years, continual improvements and upgrades were made, the most significant being in 1977 when the British made Borg Warner gearbox was dropped in favour of the American General Motors gearbox, due to quality control problems at Borg Warner. The XJ6 and XJ 12 Series 2 range ran to 1979. During the production of the XJ Series 2 a batch of cars was also produced called the XJ Coupe, a two door version, based on the short wheel base (9 ft 1 inch) XJ, and again these came with the 4.2 and V12 5.3 engines in both Jaguar and Daimler models, the Daimler types being the Daimler Sovereign Coupe, or Daimler Double Six Coupe.
The Series 3 range of the XJ was started in 1979, staying in production to 1992 with the XJ12 version. Bodywork tweaks were at the hand of Pininfarina, but keeping to the original William Lyons format. A 3.4 litre option had been introduced with the Series 2, so for the Series 3 XJ's everything continued as normal with the 3.4 and 4.2 six cylinder cars and the XJ12 5.3 litre, the larger engines now fuel injected. An interesting side note was Swiss Michael May (the first person to put a spoiler on his car - a Porsche 550, that the organisers would not allow) altered the V12 cylinder head combustion chamber, and cars with this design of head fitted were called the HE (High Efficiency). Although XJ6 production ceased in 1987 to be taken over by it's replacement the XJ40, the Series 3 XJ12 's carried on in production until 1992.
Tyre sizes for all XJ6 was 205/70VR15 (also called ER70R15) with the larger tyre size 215/70VR15 as an option. Tyre size for the Jaguar XJ12 was initially the same 205/70VR15 as standard, but this changed by 1973 when Jaguar fitted the XJ12 with the larger 215/70VR15 tyre as standard. Blockley produces both these high speed rated tyre sizes which we guarantee will transform the handling of the XJ's - see full details below:
