Why the Jaguar XJ is the world’s best saloon car

By Martin Buckley

| 7 Jun 2019

Classic & Sports Car – Why the Jaguar XJ is the world’s best saloon car

It might be more than 50 years old but, to me, the Jaguar XJ6 remains the perfect British saloon car.

It’s also the perfect British compromise, a skilful blend of earlier, well-proven concepts and components, massaged and refined into a beautiful new shape.

This long-running benchmark of saloon-car refinement was a masterful fusion of tradition and modernity such that no subsequent Jaguar saloon – indeed, perhaps no other saloon car from any manufacturer – has ever recaptured its brilliance.

It could hardly have been otherwise, benefiting as it did from the taste and judgement of Sir William Lyons. As well as being that curious combination of hard-nosed tycoon and artist, Lyons had an equal talent for nurturing the best engineering brains in the industry; the likes of Bob Knight, Wally Hassan and, perhaps most important of all, Technical Director Bill Heynes.

The engine makes itself apparent more by the whirring of fans and drivebelts than any true mechanical sound

Heynes’ original idea for the XJ project in the early ’60s was to create a four-door, four-seat E-type, a low-slung sports saloon that would take the fight to the Europeans in the ’70s and recapture the interest of an American market that still loved its XKEs but never quite took the MkX or S-type to its heart in the same way.

The XJ was, in fact, a long-overdue fillip to the Jaguar range when Lyons personally launched it in September 1968. The optimism and certainties of the 1950s and early ’60s were fading. The existing saloons were looking old, sales were tailing off (the MkX/420G was proving a particular disappointment) and it was no longer true to say that Jaguar could sell every car it built.

Lyons himself was tiring. He had no heir after the death of his son John and was already two years into an uncertain merger with BMC, to form BMHC. As a means of securing supplies of bodyshells for his new car from Pressed Steel-Fisher (which had become part of the BMC group in 1965), it was an alliance of necessity that can’t have sat well with a man who had been very much his own boss for 40 years.

SI’s low-slung cabin is elegantly appointed

Learning the chassis lessons of the S-type, 420 and MkX/420G, the XJ was conceived around wide-track, anti-dive, double-wishbone front suspension, with a quad-damper independent rear and a new kind of low-profile ER70VR15 tyre specially developed for it by Dunlop.

It was the first Jaguar saloon with rack-and-pinion steering and, with five different kinds of synthetic and natural rubber in the front subframe mountings alone, it represented a giant leap forward in the understanding of what caused road-excited noise inside a motor-car bodyshell, so much so that even 20 years later (when the last Series III XJs were being built) the opposition was struggling to match it.

Lots of resonance damping, carefully isolated engine mountings and a double-thickness bulkhead were part of the secret and the XJ always enjoyed a remarkable lack of wind noise, too, around that beautifully resolved, thin-pillared glasshouse.

It also represented an advance in detail refinements now that Jaguar, for the first time, took complaints about its slithery armchair seats, feeble heating and ventilation systems seriously.

The new body was virtually built around a sophisticated heater box feeding modern eyeball vents, while front passengers were supported in semi-bucket seats that were more E-type than MkX in shape. This was important in a saloon car that could now generate cornering forces more akin to the former than the latter.

Space is part of the luxury for the rear-seat occupants

Quickly settling down to a 25,000 output (about 650 a week, 56% for export), the XJ6 easily outsold the so-called ‘compacts’ (240/340/ S-type/420) and the bulbous 420G. By the end of 1970 it had replaced them completely, usefully simplifying a once-complex range and streamlining the production lines, and gained a new badge-engineered sister, the Daimler Sovereign.

Even so, the XJ remained in short supply for years, so much so that a black market of £1000 over list on delivery-mileage cars was soon established in the UK. Irate Swiss customers even felt moved to picket Lord Stokes, outside the British Leyland headquarters in Berkeley Square, over the length of the waiting lists.

Browns Lane couldn’t build them fast enough, to the extent that Jaguar published full-page ads in the motoring press thanking customers for their patience. Press reports dripping with superlatives about the XJ’s poise and refinement only whetted buyers’ appetites further for a car widely considered to be the best saloon in the world at any price, never mind the mere £2365 Jaguar asked for an overdrive-equipped 4.2.

4.2 ‘six’ is smooth

The XK straight-six, at 20 years old, was still a magnificent engine and drew almost nothing but praise for its smoothness and torque. But Lyons was not satisfied. Keen to unleash his V12 secret weapon, it was with some reluctance that he had agreed to launch the car in six-cylinder form only, with the short-stroke 2.8 offered as a supplementary variant mainly for European markets, where engines over that swept volume were heavily taxed.

The 2.8, later infamous for burning holes in its pistons, was sweeter and freer-revving, but gave away a lot of urge to the burly 4.2. Since few wealthy European buyers cared about the extra tax on an already-expensive car, or the fact it got two or three extra miles per gallon, they tended to buy the 4.2 anyway.

The original plan had been to offer this short-block XK engine in 3-litre form as the six-cylinder alternative to the V12. The decision to fit the twin-SU 4.2 was made late in proceedings, its additional height necessitating last-minute changes to the bonnet pressing.

Development of the flathead, single-overhead-cam-per-bank V12 was languishing in the midst of punishing new safety requirements that were taking up too much of the tiny Browns Lane development team’s time and attention.

The evidence of this could be seen in the fact that the XJ6 was the first Jaguar saloon without a bonnet ‘leaper’ to maim pedestrians and the first to have crash-friendly rocker switches rather than eye-gouging toggles; the ignition switch moved to the steering column for similar reasons, so no more push-button starting.

When the XJ12 finally appeared in the summer of 1972, it almost seemed like overkill.

Nobody really needed an even-more eerily silent, near 150mph, 11mpg four-door saloon powered by the world’s only mass-produced V12 engine, but Jaguar decided to build it anyway. After all, the XJ bodyshell had been designed to take the V12 from the beginning and it only weighed 60lb more for a power increase of 70bhp. The exquisite one-upmanship factor over the ‘mere’ V8s of Mercedes, Rolls-Royce and the Americans must have been hard to resist.

XJCs were widely touted as surefire future classics, but have only recently begun to be appreciated for their rarity

Revisit any of the three XJ series today and you will be surprised by how genuinely low-slung they are, particularly in a motoring environment where everyone wants to sit sky-high in their SUVs.

You slide down to assume a driving position that is close to perfect, the superb vision and the sense of isolation relaxing you immediately; it feels like coming home.

‘Our’ early, dark blue, low-bumper Series I looks and even smells of the ’60s inside, and there’s a strong appeal to its no-nonsense rocker-switch dash, its line-up of minor gauges and its cool, slim-rimmed steering wheel. The Series II dashboard, with its chunky push-buttons, stalk-controlled wipers and improved air-blending heating system, is more rational, but less pleasing.

Short- and longwheelbase SIIs were offered alongside each other until the LWB was standardised late in 1974, just before the introduction of the XJ 3.4 poverty model (to replace the 2.8) and Lucas injection on the V12 to curb its monstrous thirst.

Our SII representative is an XJC, the most exciting new model in the revised high-bumper/ narrow-grille Series II range of 1973. It was also a supposed personal favourite of Lyons, who had conceived this pillarless version of the XJ in the mid-’60s as a response to a trend towards two-door hardtops on the American market; his US dealers were even telling him they would struggle to sell a four-door XJ6.

Just 9119 two-doors were built; gentle evolution inside; muscular ‘six’

Sadly, the coupé was a project that kept getting put to one side, not helped by the fact that pillarless side windows proved hard to seal against wind noise. That was why the first XJCs didn’t reach customers until 1975, by which time the arrival of the XJ-S had made it somewhat redundant.

In fact, XJCs were only offered for two years and, while it was widely touted as a surefire future classic (almost from the day production ended), it is only recently that the coupés have begun to be appreciated for their rarity. Just 9119 were built (fewer than 1000 of those being V12s) and they came, naturally, as Jaguars or Daimlers, this one being the latter.

Its cloth seats, common in the coupés, pandered to ’70s tastes, but the vinyl top was there to disguise the additional heft in the rear roof pillar. On the move, these early and middle-period ‘sixes’ drive fairly similarly, except that the manual SI really does feel like a close relative of an E-type, whereas the Borg-Warner three-speed auto-equipped SII is more suavely ‘executive’; there is nothing much to do except point it in the right direction, enjoy the general mechanical hush, and the still-remarkable lack of rumble and bump/thump in the car’s ride.

All three generations remain a dream to drive

SIIs had more pollution-control equipment even in UK-delivered form, although the apparently startling difference in power compared to the SI (170 versus 245bhp) is mainly due to the more realistic DIN rather than gross measurement.

Both will purr through traffic like mayoral limousines if required, but the manual has lots of low- and mid-range thrust, long legs and an effortless authority that belies its years, so much so that you would happily forgive the mismatch of its fairly heavy but smooth clutch and power steering that summons a strange combination of accuracy and almost American-style over-lightness. You soon get the hang of it, though, by not over-steering the car; rather, guide it gently with your fingertips.

While the manual is fun, an automatic transmission was what the XJ was all about from the beginning: they far outsold the three-pedal versions and the XJ12s – or XJ 5.3s as they were called from late 1975 – were only ever Borg-Warner Model 12 or GM400 autos.

The 12-cylinder unit makes for refined and deceptively rapid progress; cocooned in comfort within the SIII cabin; the big saloon is still a joy to drive

Introduced in March ’79, the Series III cars were an unintended holding operation while the XJ40 was being developed. No doubt missing the input of Lyons (he retired in 1972), Jaguar turned to Pininfarina for styling tweaks that included a taller, more crisp roof and glass area, injection-moulded bumpers and flush-fitting doorhandles.

The Series II dash architecture largely remained – hardly the latest in ergonomics, but ‘traditional’. A variety of brittle plastic details are less welcome, the trip computer on this late Double-Six being particularly grating, but this is understandable when you consider the value for money the cars represented.

You still have to swap between the 11-gallon pannier tanks in the rear wings, using a switch on the dashboard, but the HE (High Efficiency) V12s, featuring Michael May’s swirl-action combustion chambers, made 20mpg a realistic possibility for the first time.

In Series III Double-Six Daimler form it is still the most silky car imaginable to drive. From the outside, the engine makes itself apparent more by the whirring of fans and drivebelts than any true mechanical sound. From within the cocoon-like cabin, cooled by deliciously efficient air-conditioning, the V12 feels more like an electric motor than a reciprocating unit.

The car covers ground with an ethereal rush of energy that perfectly complements its superb chassis refinement; even by the early ’80s it was more than a match for its fresh-faced German rivals, which were still on the drawing boards in Munich and Stuttgart when the original XJ was five years into its production run.

“A masterful fusion of tradition and modernity that no subsequent Jaguar saloon has ever recaptured”

The end for the Series III V12s finally came in 1992, five years after the last of the ‘sixes’. Those were too heavy and too expensive to build compared to new XJ40s, which were nimbler and supposedly better-quality vehicles. Reluctant as many were to point it out at the time, though, these were nothing like as pretty as their predecessors – even if they were traditionally Jaguar in layout and feel.

Through the 1970s and ’80s the XJ became such a routine sight on British roads that we tended to forget how superlatively good they were – and still are. They are truly great machines, even when you remove your rose-tinted spectacles and waft away the fog of nostalgia that tends to surround anything with a Jaguar badge on it.

In a funny way, these cars seem almost better now, at 50, than they did 20 years ago (when we first considered them truly ‘classic’), possessed of a lithe and compact curvaceousness that is in startling contrast to the obesity of 21st-century luxury saloons.

Like every Jaguar four-door before it, the 1968 XJ6 was fast and refined beyond its price-tag, yet offered a modern interpretation of saloon-car elegance that would have floored the opposition even if the engineering underneath had not been so accomplished.

It was a brilliant parting gift from Sir William Lyons to the company he created, the final car designed under his autocratic but wise leadership. It is widely acknowledged as his masterpiece in a career of superb cars.

Images: John Bradshaw; thanks to Satiris Shangolis (SII) and Robert Hughes (SI and SIII)

Anorak’s guide

SERIES I 2.8/4.2 & V12 (1968-’73)

59,077 built in 4.2 form, plus 874 LWB cars. No ‘Jaguar’ badges anywhere on the car at first, such was Lyons’ confidence in the public’s recognition of the shape. £2254 for non-overdrive car, £1897 for the 2.8 De Luxe; supposed ‘standard’ 2.8 with Ambla seats, manual steering and no rear armrest was never built. Auto-only XJ12s from 1972 were £3726 (the simpler grille had vertical bars only) and had four Zenith carbs plus a manual choke, giving 146mph and 11mpg. Mercedes engineers admitted that this V12 was “the best production engine in the world”.

SERIES II 2.8/3.4/4.2/5.3 (1973-’79)

The long-wheelbase 4.2 was far and away the most popular, at 57,804 cars out of a total of 127,000 SIIs (all engines and bodies). Short- and long-wheelbase versions at first, after which the SWB was reserved for the XJC coupés with 4in-longer doors. All four-door V12s were LWB, but still on carbs until the 285bhp/147mph injected 1975 car, badged XJ 5.3. ‘Blazer button’ steel wheels with hubcaps or GKN alloys on SII. Greatest oddity of the SII was the 170 exportonly 2.8s, but the 1975 3.4, with cloth seats and other luxury items deleted, is much preferred.

SERIES III 3.4/4.2/5.3 (1979-’92)

Injection for the 4.2 (the 3.4 stayed on SUs), and a limited range of solid colours on early cars from the troubled new Castle Bromwich body plant. Later improvements meant that with the final update for ‘sixes’ in 1985, Jaguar came fifth in that year’s JD Power customer satisfaction survey with the standard XJ6 (tweed trim) and Sovereign (leather trim) that bowed out in April 1987. Rare five-speed manual from the Rover SD1 later replaced four-speed, but most XK ‘sixes’ have Borg-Warner auto; the GM400 was later mandatory with the V12, which became the HE in 1981, boosting economy to 20mpg.

DAIMLER SOVEREIGN & VDP (1969-’92)

Today the Daimler marque is dormant, but it was important to the XJ line-up until the early ’90s, for customers who thought Jaguar ownership a trifle racy. The first XJ-based 2.8/4.2 Sovereigns of ’69 featured overdrive, updated trim and a heated rear window. The V12 Daimlers, named Double-Six, were first to get the long-wheelbase shell with the option of Vanden Plas trim. There were Sovereign and Double-Six versions of the coupés, the latter very rare at 407 examples.

Life after the SIII

XJ40 (top), XJ8 (bottom left) and X350 kept the line going

XJ40 (1986-’94)

‘XJ40’ was the internal code for the Series III replacement. It was better built, easier to service and cheaper to run. Later cars are the best, but aren’t immune to rust. They were all AJ6 ‘sixes’ at first – including the single-cam 2.9 – with the 6-litre V12 offered for the final year. Today, interest is quietly growing in these cars.

X300 & X308 (1994-2003)

A better-looking successor using 3.2- or 4-litre twin-cam ‘sixes’, voted ‘most beautiful car in the world’ by a panel of Italian style gurus. The XJR was the first to use Eaton’s M90 supercharger, meaning 0-60mph in 5.5 secs. For the 1997 XJ8 (X308), V8s replaced ‘sixes’ and V12s. The XJR 4-litre was then the most powerful Jaguar roadcar engine, boasting a supercharged 370bhp – with a rare Daimler variant called the Super V8.

X350 & X358 (2003-’09)

This laid to rest the XJ40 geneology with an allnew aluminium monocoque, bonded rather than welded for huge weight savings and gains in strength. There were petrol V6s and V8s, plus a diesel V6. The supercharged V8s give the most thrills, but complex technology and electronics don’t auger well for today’s enthusiast owners. The 2007-on facelifted X358 attempted to answer critics of the car’s ‘golf-club’ styling.

X351 (2009-DATE)

The current, Ian Callum-styled flagship is based on the previous model and is one of the lightest cars in its class. Standard- and long-wheelbase versions plus lavish specs maintain the XJ’s reputation for refinement and value. There are V6s and V8s, while the 2013-on XJR is a 542bhp rocketship. Special versions include an armoured variant, as used by the British PM.

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