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Jaguar Drivers Club of South Australia

Est. 1973

Club News

Fifty Years of the Jaguar XJ Series 1

Posted by Philip Prior on August 2, 2018 at 8:40 AM

Simply the Best—The Story of the Jaguar XJ Series 1


If one were to draw up a list of the greatest British cars of all time, by just about any criteria the Jaguar XJ6/12 would be included. During a production run that spanned more than two decades, it was frequently acclaimed as the greatest car in the world.


And yet, there was nothing particularly innovative about the XJ. However, so good was the overall package that it set new standards for the luxury car market for many years after its launch in 1968.


The story of the original XJ saloon is by and large the history of Jaguar Cars itself during its production life. The ‘official’ version of events that has been propagated by most writers in so many books, magazines and indeed the original online draft of this article has come to be accepted as the truth. However, a closer look into contemporary newspaper archives reveals a much more complex story, and nothing is as straightforward as it seems.


The origins of the XJ6/12 date back to the early 1960s, when Jaguar was producing no less than five different basic models. At the time, it was building around 25,000 cars per year and was winning many admirers across the globe.


In 1965, for example, Jaguar produced the following models.

E-type: introduced in 1961, 4.2-litre XK engine

Mk2: introduced in 1959, 2.4-, 3.4- and 3.8-litre XK engines S-type: introduced in 1963, 3.4- and 3.8- litre XK engines

MkX: introduced in 1961, 4.2-litre XK engine

Daimler V8 250: introduced in 1962, 2.5-litre Daimler V8 engine

Total production 24,601


By this time, sales of the Mk2 were in decline, and the 2.4-litre version was being shown the way by the compact new 2-litre saloons from Rover and Triumph; while the new S-type was merely an evolution of the older car, but with (effective) independent rear suspension and new frontal styling. The MkX was a bulbous looking range-topper, at one stage the widest car ever sold in Britain. The Daimler V8 250 was little more than a Mk2 powered by the excellent Edward Turner-designed V8 engine Jaguar had inherited when it took over Daimler in 1960. And for 1966 the company had yet another model, the 420/Sovereign, an S-type with a redesigned nose.


Quite simply, Jaguar’s model range was far too complex, and if it was to survive in the long term, a policy of rationalisation and cost-cutting was the only way forward. A plan was devised to develop a new car to replace this mid-range morass in one fell swoop, and quickly crystallised to become Project XJ4.


Development of the XJ4 began in 1963/64. Jaguar soon settled on a 9ft 0.75in wheelbase, and wheel tracks of 4ft 10in. This was a slightly longer wheelbase than the Mk2, but the track was far wider, weighing in at the same size as the MkX – upward expansion was the name of the game here. The engine bay was going to be more capacious than the Mk2, too; the idea being to future proof the XJ4 for the new and exciting engines Jaguar had in development.


The engines destined for the XJ4 were variants of the XK DOHC unit first seen in 1948. The range topper was the twin carburetor 4235cc, which Jaguar claimed produced 173bhp at 4750rpm. The 4.2-litre engine powertrain, both manual and automatic, made its debut in the 420/Sovereign in 1966, enough time to iron out any bugs.


On both versions, Jaguar went to great efforts to improve cooling, as overheating was a common complaint about the firm’s cars. 2997cc XK was built and tested, and although there was plenty of top end power, it lacked low speed torque.


Styling was overseen by Jaguar’s founder and chairman Sir William Lyons, who evolved the quad headlamp nose from the the earlier MkX and 420 (nee S-type). For the rear of the car, Lyons tried an E-type treatment, and then modified it by ‘chopping’ part of it away, to devise the now-familiar XJ’s drooping boot line. According to senior Jaguar engineer Bob Knight, the styling of the XJ4 had been finalised around 1964/65, but it took a further three years to sort out the running gear and tooling in order to get the car on sale.


The car also had flared wheel arches, under which lurked Dunlop ER70 VR15 tyres on 6in wide rims. Dunlop developed these high performance tyres especially for the XJ4. Jaguar’s engineers went all out to reduce vibration, engine, and road noise, to create the most refined car possible. Topping off this enviable specification list, there were disc brakes all round, with triple pot Girling calipers at the front.


A Jaguar Model Progress Meeting of 27 April 1966 noted that XJ4 development ‘was running three months late’. The following month the first prototype XJ4 was built. No.1 was a Warwick grey car fitted with a 4.2-litre XK engine.


These were tough times for Jaguar and In July 1966, Jaguar merged with BMC and Pressed Steel to create British Motor Holdings (BMH). This move was astute because it also secured Jaguar’s body supply from Pressed Steel.



In addition to this, Lyons now had the financial backing to get the XJ4 into production. Although Lyons later regretted Jaguar’s merger with BMC – who as it turned out, was weaker than he thought – in the short term he got him what he wanted. The new saloon, which he later called the XJ6, was brought to fruition thanks to having BMC’s financial resources on hand.


By June 1967 the state of play with XJ4 development was as follows. XJ4 prototype no.1 had by this time completed 8619 miles fitted with a manual 4.2-litre XK engine. No.2, a light green car, was fitted with a 3-litre XK engine mated to a Borg Warner model 35 automatic transmission. No.2 had completed 1048 miles. No.3, a black car, was also fitted with a 3-litre engine, but had manual transmission. No.3 was used for air intake and exhaust silence development work and had completed 1277 miles. Car no.4 had just been built, fitted with a 4.2-litre XK engine mated to a Model 8 automatic transmission. It had completed a mere 16 miles. XJ5/MkX registered 5437 RW was the development hack used, and had completed 61,325 miles, but was now considered unroadworthy. In January 1968 BMH merged with the Leyland Motor Corporation to form British Leyland. The merger came into effect in May, the same month the Jaguar board had to reluctantly accept that the V12 engine would not be ready in time for the XJ4 launch.


Unveiled to the public on September 26th 1968, the XJ6 ended up costing Jaguar over £6m to develop. Prices ranged from £1797 for the manual 2.8 to £2398 for the 4.2-litre de Luxe Automatic. As the XJ6 was the first all new Jaguar since 1961, it aroused great interest, and although no cars were made available to the press for road testing until 1969, a waiting list soon built up.


It was Autocar that managed to publish the first driving impressions of the XJ6 in September 1968. The car’s superior ride and handling and the uncanny lack of noise was a theme echoed by rival publications, but in pre-launch briefings Jaguar was already tantilising journalists with the news that it was developing V8 and V12 engines as part of its future engine plans. ‘Vee engines will be offered as options on the XJ model within the next two years,’ the magazine enthused.


As the waiting list built up and the press clamoured for the opportunity to conduct full XJ6 road tests, Jaguar got down to the task of rationalising its range. By axing its existing models, the company freed up Browns Lane to satisfy demand for the new car. First to go was the Jaguar 420 in August 1968; that was quickly followed by the Mk2 240 in April 1969; the Daimler Sovereign in July 1969; and the V8 250 in August 1969.


After the production stagnation of the 1960s, the big cat had been let off the leash and the race was on to build Jaguar Cars into major force in the premium car sector before the opposition caught up


In October 1969, Jaguar announced the Daimler Sovereign, basically a badge-engineered Jaguar XJ6. This was a snapshot of Daimler’s future now as the company’s Radford factory now supplied Jaguar with engines – leaving the highly regarded V8 consigned to automotive history.


In 1969 the Jaguar XJ6 was the best car in the world. That year Jaguar built 13769 XJ saloons, the best individual model total since 1962, and it was about to get better. The same year chairman Sir William Lyons began driving an XJ saloon with a V12 engine as his personal car. A taste of things to come.


Sir William concluded: ‘But the most satisfaction has come from the completion of the XJ6. We worked for a long time on it, and it has been very successful. If you really want to credit me with anything I’m proud of, it’s that we’ve never fallen below a 50% export ratio.’ It had been a job well done. As he had himself stated he had worked long hours building Jaguar up, battling against all kinds of odds.


Acknowledgment: The words of this article have been drawn from an article written by Ian Nicholls


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