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Jaguar XJ6/XJ12 (1968 - 1992)

Last updated 31 July 2013


Model Timeline

January 1964
Development of new Jaguar begins under the codename 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 carburettor 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.

Surprisingly, the triple carburettor version seen in the E-type and MkX was not offered, perhaps because something better was on its way. The other XK was a newly-developed 2792cc variant, which Jaguar thought would sell well in some European markets as a tax break car. Jaguar claimed 140bhp (DIN) for this unit.

On both versions, Jaguar went to great efforts to improve cooling, as overheating was a common complaint about the firm’s cars. Various proposals as to what engines the XJ4 should use had been floated around Browns Lane. At one stage, it was suggested that a 3-litre version of the XK be offered alongside a 5.3-litre V12. A 2997cc XK was built and tested, and although there was plenty of top end power, it lacked low speed torque.

It appears Jaguar’s long term plans for the XJ4 involved replacing the XK engine with a modular 60-degree V8 and V12 produced on the same tooling. It was a concept that the company had been evaluating since the 1950s, and serious development seems to have started with the aborted XJ13 Le Mans racing car.

In August 1964, a quad cam V12 was first run on a test bed, but delays meant a road version was not available for the XJ4′s launch. Confusingly, the V12 project, and the attempt to make a V8 version out of it, was codenamed XJ6.

No evidence has ever come to light that Jaguar ever considered using the ex-Daimler 2.5- and 4.5-litre V8s designed by Edward Turner, even though the larger engine had embarrassed its XK when fitted to MkX test beds. There was also no place in the XJ4 line up for the 2.4-litre XK fitted to the Mk2.

Jaguar would end up gifting this sector to Rover and Triumph, who had larger engined versions of their best selling 2-litre executive saloons in the pipeline. The XJ4 would be offered with either a Borg Warner automatic or the company’s own four-speed manual, which had first appeared in 1964. The manual was also available with overdrive, something the E-type did not have.

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 wheelarches, 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.

Lyons also advocated the creation of a forward programme to assist in, ‘The commonising of components, and generally in the rationalisation of specifications, thus dealing with the problem of multiplicity of components which is such a handicap to our production… We are quite obviously now going to have little time for XJ4 development. I am sure you must agree that it is imperative we should once again have a new look at our design organisation. It must be obvious to you, as it is to me, that the lack of regard to the time factor cannot do other than result in calamity at some time in the future.’

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.

July 1966
Jaguar merges with BMC

The XJ6 design team with William Heynes and William Lyons nearest the car...

The XJ6 design team with William Heynes and William Lyons nearest the car...

By now, the pressing need for rationalisation was brought home by Jaguar’s 1966 financial results. A profit of £1.66m might have been its best to date, but it was simply inadequate to fund all the projects Jaguar had in development. 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.

This is confirmed by a memo from Lyons to his fellow Directors on 3 August 1966 ‘Although the company will continue to operate autonomously, the object behind the merger is obviously to implement mutual aid in the best interests of both companies… now essential that we should prepare a realistic programme for the development and introduction of the XJ… This to include completion of the six prototypes, the progress of which is most disappointing.’

1966 was not a good year for BMC or Jaguar. Jaguar saloon production slumped to 15,990, not helped by a government credit squeeze. Development of the XJ4 continued. On 20 February 1967, senior Jaguar engineer Bob Knight wrote this memo: ‘Three cars are now running and the first and second will be used for most of the outstanding work. The second car will be involved in development of the air conditioning system.

October 1968
Jaguar XJ6 launched at the British motor show

The launch of the XJ6 took place at the British Motor Show, where it shared the limelight with the Ford Escort, Vauxhall FD Victor, Sunbeam Rapier fastback, MGC, the Austin 3-litre and the Triumph 2.5 PI. Three of these cars were now Jaguar’s stablemates within BLMC, and clearly demonstrated just how much of a stranglehold the new Corporation had on the British automotive scene.

However, the Rover P5B was the new Jaguar’s only real British-built rival. Retailing at £2174, it was a traditional luxury saloon that had been transformed by the installation of the ex-Buick all-alloy V8 in 1967. The Rover was the favoured transport of government ministers and royalty, even if it didn’t have Jaguar’s more sporting image. Continental competition came from BMW and Mercedes-Benz. The Mercedes-Benz 280SE boasted a fuel injected 160bhp 2746cc engine, but sold for £3324, while the BMW 2800, which would make its debut in 1969, was also a rather expensive option, at £3245. In comparison with these rivals, the Jaguar XJ6 was an absolute bargain.

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. Trying to meet the demand for the XJ6 was not helped by the industrial climate of the time with wildcat strikes, both internal and external, restricting production. On 5 June 1969 the company announced that due to a dispute at Wolverhampton Die casting that had been ongoing for six weeks, XJ6s being delivered to the home market during the next few weeks were being fitted with temporary wire mesh radiator grilles and metal cover plates to the various front air ducts in place of the distinctive pressure die-castings which formed the cars’ normal wear. Supplies of the standard front end fittings had been almost exhausted since the cessation of deliveries, as a result of a prolonged strike at the suppliers’ factory.

October 1969
Daimler Sovereign launched

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.

Only the MkX/420G survived the cull of old models – for the time being. By October 1969, the range topper was listed at £2671, compared to £2475 for the XJ6 4.2. It was sold as a luxury car powered by the more powerful 265bhp XK engine, but demand wasn’t strong and Browns Lane probably built no more than around 30 cars per week. The demand for the XJ6 was such, that big car was phased out in June 1970, leaving the XJ as the sole saloon representative in the range.

In addition to this, Jaguar decided that the E-type replacement, the XJ27/28 , would be based on an XJ4 platform as a way of reducing costs, this in time emerging as the XJ-S. The success of the XJ6 convinced Jaguar management that the time was right to make XJ27/28 a more upmarket car than the E-type in order to earn the company some serious money.

July 1972
Jaguar XJ12 launched

XJ12 raised the bar in terms of smoothness...

XJ12 raised the bar in terms of smoothness...

In July 1972, Jaguar announced a new variant of the XJ4 platform, the culmination of Walter Hassan’s career, the Jaguar XJ12. This was followed in August by the badge engineered Daimler Double-Six. In those pre-oil crisis days, the 5343cc V12 met with instant acclaim; Jaguar had managed to create an even better car than the original XJ6…

Why did Jaguar opt for the V12? In layman’s terms one of the causes of noise in a car’s cabin is engine vibration. The smoother an engine could be made to run, the less noise and vibration would be transmitted into the passenger cabin. Jaguar had been successfully using the in-line six cylinder XK, and the logical next step in the search for yet more refinement was to go for a V12.

The XJ12 and Double Six’s smoothness became legendary. The V12 had been unveiled the previous year, under the bonnet of the E-type Series 3.

In the E-type, the new all aluminium V12 was fuelled by four Zenith-Stromberg carburettors to meet forthcoming US emission laws. This restricted power to a disappointing 272bhp (DIN) at 5850rpm. The XJ12/Double Six installation retained the XK exhaust system which further reduced power to 265bhp at 5850rpm. Jaguar had intended to use an AEI-Brico fuel injection system on the V12, but by February 1971 the company had been informed that this had been cancelled, and the decision was taken to proceed with a V12 fuelled by carburettors. Whereas the E-type V12 was available with manual transmission, the XJ12 was only marketed with an automatic gearbox; a Borg Warner three-speed.

The Jaguar XJ12 was sold for £3726 (the Daimler Double-Six, £3849), which reflected the upmarket aspirations for the brand that Browns Lane had. Only one thing marred the launch of the V12 saloons, something that would happen quite often when a British Leyland car was launched, the workforce that was supposed to produce it went on strike – for ten long weeks. Only around 500 XJ12 and Double-Sixes had been produced when the strike began on 1 June, and they were soon selling for a £1000 premium, such was the demand. The dispute was over a call for increased piecework earnings, and was eventually settled when the workforce agreed to accept measured day work.

The ten-week dispute was the longest strike in the UK motor industry in the whole of 1972, and perhaps was a turning point in Jaguar’s history as from this point, the company probably lost the co-operation of its workforce in the battle for quality. This was 1972, the year of a miner’s strike and the TUC’s fight with Edward Heath’s Conservative Government over the Industrial Relations Bill – times were turbulent. The strike was not a good start to new chairman, ‘Lofty’ England’s, reign.

September 1973
Jaguar XJ Series 2 launched

Slimmer grille and raised front bumper were immediate Series 2 identifiers...

Slimmer grille and raised front bumper were immediate Series 2 identifiers...

In May 1973 to mark the fifth anniversary of the formation of British Leyland, Lord Stokes announced some ambitious plans. In the case of Jaguar he said: ‘Although Jaguar now benefits from the financial strength as well as the marketing and planning expertise of a large corporation, we are determined that this company shall retain its identity as a manufacturer of superbly engineered individually styled luxury saloon and sports cars. A significant proportion of our investment therefore is to be channelled into new Jaguar models as well as installing new plant to double our present capacity.’

On 13 September 1973, Jaguar announced the XJ Series 2. The major visual change was that American regulations demanded that the front bumper needed to be raised so that is was 16 inches above the ground. That resulted in a shallower grille, and the under bumper air intakes were enlarged. The electrical system and the interior was also revised.

Jaguar also used the opportunity to preview the beautiful coupe version, even though it wouldn’t enter production until 1975. The short wheelbase V12 was dropped, along with the unpopular 2.8 version – no one mourned that car’s loss, not least those owners who had suffered from the piston problems that had plagued this engine. The XJ6 4.2 was also tweaked, and now produced 170bhp at 4500rpm.

Despite the raft of improvements the XJ received, Jaguar’s reputation as a quality car manufacturer began to deteriorate rapidly. This can be attributed to low workforce morale, poor quality control within Browns Lane, as well as from outside suppliers. XJ Series 2 bodies suffered from being ill-prepared; the paint and chrome quality was abysmal; and the fit of body panels was bad even by BLMC’s standards. Even the door locks caused grief, and electrical problems, as epitomised by ‘Lucas, Prince of Darkness’ jibes, were at their worst in the Series 2.

Also, in the autumn of 1973, BLMC boss Lord Stokes appointed 34 year old Geoffrey Robinson as Jaguar’s Managing Director, fresh from running Innocenti in Italy. Robinson gave an illuminating interview to Graham Robson for his book, ‘Jaguar XJ-S The Complete Story‘. He said, ‘When I arrived, there were no plans to increase production, and I think it’s fair to say that the thinking of Sir William, then Lofty, was to keep production fairly tight, and to keep it to the order book if they could. But when I arrived – this was before the energy crisis, of course – we had a 2 1/2 year order book, with Jaguars in terrific demand throughout the world, and we could sell more motor cars than we had been planning to build.

‘There was another aspect, that the Jaguar factory was so tight – physically tight – in production facilities, that the quality of the product was suffering. The first thing we did, therefore, was to lengthen the tracks, to give more track space, to give more room and easier access around the cars. As part of the strategy, we also planned to bring in a new paint plant: the paint system was very antiquated.

‘The levels we were looking at were to go up to a comfortable 50,000 or 60,000 cars a year, all of the XJ6 (and XJ12) and XJ-S. We could get this much out of Browns Lane, but it wasn’t possible to have more than one basic model.’

April 1975
Jaguar XJ-C launched

Perhaps the most beautiful XJ of them all... the XJ-C.

Perhaps the most beautiful XJ of them all... the XJ-C.

Development of the XJ Series 2 continued. In April 1975, the shortlived Jaguar XJ Coupe was introduced. Codenamed XJ35 for the XK, and XJ36 for the V12 version, the Coupe was based on the short wheelbase chassis. Featuring two longer doors and pillarless construction, the model was intended as a lighter more sporting derivative of the existing saloon. Available in both a Jaguar and Daimler form, there were issues – the sealing the side windows proved difficult in production and this, in turn, affected refinement.

Another downside of the XJ Coupe was its premium pricing. The customer effectively paid more less car, and in these pragmatic times, it effectively sealed its fate. Jaguar already had the XJ-S waiting in the wings, and that limited the company’s commitment to the XJ-C. Production ended in November 1977, after a mere 10,426 had been built.

May 1975
Fuel injection phased in

In May 1975, Bosch-Lucas fuel injection was introduced on the XJ12, and that boosted power to 285bhp (DIN) at 3500rpm. The following month, a new entry-level 3.4-litre XJ was launched, finally completing the Series 2 range. Powered by an XK engine in its original 3442cc capacity, the block was actually based on that of the 4.2-litre engine. With 161bhp (DIN) available, it was much quicker than the original 2.8-litre car, powering on to a top speed of 117mph.

April 1979
Jaguar XJ series 3 launched

Series 3 models were tastefully brought into the 1980s - and that new roofline was hailed a success.

Series 3 models were tastefully brought into the 1980s - and that new roofline was hailed a success.

Today, in the view of many, the XJ Series 3 was a case of saving the best ’til last. However, in reality it got off to such a bad start that it nearly sank Jaguar. Revising the XJ had cost £7m, and that included the Pininfarina restyle – and although it wasn’t a lot of money, it was enough when there was none to go around. The Series 3 incorporated a raft of new body panels, and an increased glass area had left the interior feeling far airier.

The roof line was raised by 3in at the rear to create more passenger headroom. Although it’s difficult to quantify why, the overall effect of the new roof was to turn the XJ into a sleeker-looking car. The major mechanical changes were restricted to the XK-engined cars – both the 3.4- and 4.2-litre versions gained the option of the LT77 five-speed manual gearbox, thus consigning Jaguar’s own four-speeder to the parts bin of the history. In addition to this, the 4.2-litre XK received Bosch-Lucas L-Jetronic sealed fuel injection, and that boosted power to a far more realistic 205bhp at 5000rpm. The 3.4 was now the only Jaguar available with carburettors.

September 1981
Jaguar XJ12 HE launched

And it was the V12 that was the subject of the XJ’s last major modification. In September 1981, Jaguar announced that the XJ12 and Double-Six would now be fitted with a high-compression Fireball cylinder head developed by Swiss engineer, Michael May. This superior flowing head improved both top end power (299bhp at 5000rpm), torque and fuel economy. With this revision the Series 3 line up was now complete.

August 1984
Jaguar privatised

In August 1984, Jaguar was privatised, and although to some on the left of the political spectrum, it was a case of selling the family silver, the floatation was more complex than that.

One thing not taken into account by the City of London whizzkids in their analysis of Jaguar’s prospects was that the company owed its success to an ageing model range and even older manufacturing equipment. Even the newest model, the XJ-S, dated from 1975. The company had had years to iron out any bugs from its products, the resurgence of Jaguar was down to the cars now being built properly with more durable components. The all-new XJ40 would not have this advantage. The Government was accused of selling the company too cheaply by opposition politicians and swindling the taxpayer, but what was a fair price for the company and who was really qualified to answer that question, City analysts, opportunist politicians or someone trained in production engineering?

Series 3 sales continued to grow until 1986, when the much-delayed XJ40 finally appeared. Manufacture of the Series 3 XJ6s continued until May 1987, mainly for those markets where the XJ40 had not been launched. In 1987 Jaguar produced 5415 series 3 XJ6/12s. Like the Mini in 1980 after the launch of the Metro, the series 3 XJ saloon now became a bit player in the drama it had once dominated centre stage. The XJ40 was the new star in town. Demand for the XJ40 peaked in 1988 with 39,432 produced, a year when 10,284 XJ-Ss emerged from Browns Lane.

This was when Jaguar Cars at Browns Lane reached its absolute zenith. The XJ12 and Double-Six continued for the time being, gradually being detuned as they lost the battle against emissions regulations. In 1988 Jaguar produced 2003 XJ12s and in the following year a further 1785, showing that there were still those willing to pay for the older design. While this was going on, the company ran into trouble, as the XJ40 developed a reputation for electrical, steering and suspension problems.

November 1989
Ford buys Jaguar

Having clawed itself out of the mire, Jaguar’s reputation for quality was fading away again, along with car sales and profits, and as the strength of sterling further hindered matters so badly that the once bright swan of the UK industry was rapidly turning into a lame duck. The XJ40 was Jaguar’s second big chance of expanding and taking on the big boys in the premium sector and this time the thwarting of this ambition was to a degree self inflicted. They wouldn’t get another chance until the XF and X351 XJs came along in the ‘Noughties’. By the end of 1989, Jaguar was purchased lock, stock and barrel by Ford for a whopping £1.6bn.

It was only after the deal was sealed that senior Dearborn management discovered just how antiquated Jaguar’s manufacturing facilities in Browns Lane actually were.

By March 1990 Ford estimated it had paid five times Jaguar Cars’ actual net asset value, which would place the value of the company at around £320 million, not far off its 1984 privatisation price of £297 million. Shortly afterwards Sir John Egan departed. He had brilliantly sold Jaguar to car buyers, the City of London and ultimately, if unintentionally, convinced the mighty Ford Motor Company to purchase the whole shooting match. Now Detroit felt they had paid over the odds, and Egan’s departure from Jaguar was inevitable.

January 1990
Jaguar XJ12 remains in production

Ford ordered a review of Jaguar’s activities, and one of the casualties was the XJ81, the V12 version of the XJ40. Ford was allegedly concerned by quality issues and ordered a fresh start. This gave a stay of execution to the Series 3 XJ12 and Double-Six. Even as late as 1991, it was impressing the automotive press – Autocar & Motor magazine, commenting, ‘there’s still something about the Jaguar – its innate restraint, good taste and grace – that the others lack entirely. It’s a beautiful car and for some, that will always be enough.’

Although the XJ12 was still selling in small numbers, 1746 were produced in 1990, 1526 in 1991 and 1375 in 1992, the new 4-litre version of the XJ40 was a match for it in performance terms if not perhaps refinement. The XJ12 was handicapped by having an archaic three gears in its automatic transmission when the XJ40 automatic had moved on to four speeds and lacked the 4 valve per cylinder technology of the new generation of car engines. The new Lexus V8 engine had redefined the luxury car powerplant, showing that exceptional refinement could be attained without resorting to the V12 layout which required a large capacity for volumetric efficiency and was by definition thirsty on fuel.

November 1992
Jaguar XJ12 production ended

The end for the Series 3 finally came in November 1992, after a production run of 400,732 cars since 1968. So was the XJ saloon a success? Yes and no. It was a critical and technical success designed by a small team of brilliant engineers who managed to build what many critics regarded as the best car in the world, regardless of cost.

By Ian Nicholls

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