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Jag-Lovers Model Guides : The XJS
Jaguar Model Guides : The XJS
by Pascal Gademer

Line of XJS at the 2001 JCNA Challenge Championship in Franklin Tn

With so many pristine late model XJS still seen on the road every day, it's hard to believe that Jaguar longest running model is just about to turn thirty. In North America, the XJS largest market, this milestone which will be celebrated at the 2005 JCNA Challenge Championship, in Braselton Ga between September 21st and 25th. In the UK, information on XJS anniversary celebrations can be found in the Jag-Lovers Event Calendar as they become available.

Flashback to 1974: sales of the once popular E-type are declining rapidly despite the introduction of the all new V12 engine three years earlier and as the last E rolls off the line in Coventry, Jaguar engineers are hard at work working on a replacement. Finally, in September 1975, the new jaguar sports car is presented to the world at the Frankfurt auto show and... surprise! Even though its mechanical roots can be found in the series 3 E-type with the silky smooth V12 and Jaguar's superior rear independent suspension, everything else has more or less been thrown out of the window.

Even the name signals a break from Jaguar's sports car past; the new two door isn't called the F-type as expected but instead carries an XJ badge, just like the saloon. Good-bye sports car, hello grand tourer. And adding insult to injury, the XJS is only available as a Coupe, no more convertible: after 40 years of producing the world's best looking open cars, Jaguar succumbed to safety regulations and would no longer offer a ragtop until the mid 80s. Original reception by the press and car enthusiasts was barely lukewarm, something very unusual for the Coventry marque whose designs over the preceding 40 years were usually met with jaw dropping looks of admiration.

The XJS is really the last Jaguar of the Lyons era as Jaguar's founder was still at the helm in Coventry when work started on the E-type replacement. It's also the last Jaguar influenced by legendary aerodynamist Malcolm Sayer, whose mathematical formulas helped shape the D-type, E-type and XJ13 prototype; sadly, he died in 1970 before work was completed. The rear end of the car, with its rear window, buttresses, large tail lights and thick dark bumpers, was like nothing ever seen on a Jaguar.

As Jaguar buyers demanded more features and luxury, especially in the US, the XJS was equipped with power windows, power locks, climate control, improved noise and heat insulation and full instrumentation. It also had to deal with increased safety regulations, once again from across the pond, with 5mph bumpers, thicker doors, relocated fuel tank, fuel pump inertial cut out switch and more. Despite the added luxury, the XJS sported a wood less, dark interior trim in stark contrast with the hot selling XJ saloon's luxurious cabin. The instrument panel was very 1970ish with space age inspired drum gauges for the engine vital sighs flanked by a pair of primary instruments (tach and speed). Not what Jaguar drivers were used to...

Mechanically, the heart of the XJS was the V12 engine. Although not new after four years in the E-type and three in the XJ12 saloon, its turbine like smoothness and seemingly endless torque quickly became the XJS selling point. The 5.3 litre, 60 degree angle, 9:1 compression ratio V12 developped 285hp at 5500rpm and over 300 lb./ft of torque at 3500rpm. In contrast to the simple carburetors used on the E-type, this V12 was fed with electronic injection from Bosch/Lucas giving it its smooth running characteristics. Nothing new in the transmission department where European drivers had a choice of a four speed manual or the Borg Warner three speed automatic. No such luck for US drivers who could only get the slush box... In either case, final gearing was a low 3.07.

Suspension was conventional for a Jaguar with the now proven independent rear suspension in its subframe assembly with inboard brakes (2 piston calipers and solid rotors). Up front, the geometry was similar to the E-type's (except for springs replacing torsion bars) with anti dive geometry, an uprated roll bar. Front brakes used 4 piston calipers with vented rotors and new Kent alloy wheels with specifically designed Dunlops rounded up the package offering handling and ride qualities typical of a Jaguar : firm enough for some serious driving but comfortable.

Click for more pictures :
1990 US Coupe "Classic": front view , rear view , side
1989 US Coupe - side view - rear view
(owned by Barry Moss, South Florida JC)
Trans Am legend Bob Tullius and one of his Group 44 XJS

Direct competition for the XJS were the Mercedes 450SLC, Maseratti Indy, Lamborghiny Espada, Ferrari 365GTB or Aston DB6, ranging respectively from 20% to 90% more expensive... Despite all its mechanical qualities and competitive price, soaring gas prices following the seventies fuel shortages and volatile economic conditions took their toll on the XJS; its first years were the most difficult for Jaguar, with sales not reaching the levels expected or even needed to keep it in production. From a high of 4000 in 1977, sales slumped to just over 1000 in 1980. Little was changed over these first five years except for the introduction in 1977 of an improved transmission, the GM 400, replacing both the venerable Borg Warner and the four speed manual. In 1980, a new Bosch/Lucas digital electronic injection system brought in a little more power but caused fuel economy, or lack of, to get even worst dipping into single digits under spirited driving conditions. Despite being the only V12 engined car available on the US market, lack of demand brought the XJS to the verge of extinction. Success on American race tracks didn't help boosting sales either despite Bob Tullius' Group 44 team winning both driver and constructor Trans Am championship in 1978.

HE to the rescue

1980 saw the arrival of John Egan at the helm of Jaguar facing a critical situation after years of slumping sales and declining quality during the dark British Leyland years. Egan saw the XJS potential and commissioned work by an independent Swiss engineer, Michael May, who designed a new revolutionary head for the thirsty V12. Despite using a high compression ratio (12.5 : 1), his "fireball" combustion chamber design prevented detonation even with leaner mixtures; the result is not only more power and torque but reduced fuel usage by as much as 20%.

Launched in 1981, the XJS HE (for High Efficiency) literally gave the XJS a new lease on life. In addition to the improved engine, the interior was redesigned with a new veneered dash (burr elm) and simplified instrumentation. Outside, new five spoke Starfish alloy wheels, twin coachlines, revised bumpers and mirrors gave the XJS a new updated look. In addition to these changes, Jaguar's new boss committed to improving quality with a new slogan : The Legend Grows. 1982 saw a sharp increase in sales with some 3000 XJS delivered.

While the V12 engine was a symbol of power and smoothness, the venerable inline six XK engine was the work horse powering the majority of XJ saloons. With its roots dating back to the 1940s, it was time for Jaguar engineers to come up with a replacement : the AJ6. In typical Jaguar tradition, the new engine would first be used in a sports car and in 1983 Jaguar launched the AJ6 powered 3.6 liter XJS offering prospective buyers a more economical alternative to the high end V12 XJS although it would not be available in the US. With dual overhead cams and four valves per cylinder, the 3.6 Litre engine delivered 221 hp and offered good performance helping boost sales of the XJS. The 3.6 litre XJS gained a bonnet bulge to clear the camshaft cover.

Topless is back!

Also in 1983, and after a nine year absence, open top motoring was revived by Jaguar with the introduction of the XJS Cabriolet. First available only with the AJ6 engine, the XJS Cabriolet was a compromise to bring back a topless car to the market without a complete redesign. Starting with a standard bodyshell, the roof was removed and cant rails added along with a tubular steel reinforced Targa centerbar. Fixed quarter windows remained while the transmission tunnel was stiffened and a ladder frame bracing added under the rear suspension. The result was a body shell actually stiffer than the later full convertible. A pair of fiberglass Targa panel closed the space of the driver and passenger while a manually folded half top enclosed the space behind the front seats, which included a carpet luggage area with lockable boxes. As XJS sales rebounded, the Cabriolet became available with the V12 HE and quickly outsold the 3.6 liter variant. Altogether, 5000 cabriolet (a majority of them V12 with 3800) would be build until replaced by a full convertible in 1988.

XJS Cabriolet : Closed - Open
(Jack Williams, South Florida Jaguar Club)
H&E Convertible - Top Down
(Bill Streitenberger, JOC Los Angeles)
1990 XJS Convetible with "Classic"badge
Only 100 made: 1993 XJR-S
(Phyllis & LesChysholm, Suncoast JC)
1992 convertible (facelift)
1996 Convertible (owned by Jo-Ann Pruett,JC North Florida,
note: "optional" Florida Panther presented by C.A.R.E. )

Between 1983 and 1988, the XJS remained for the most part unchanged until an updated 3 speed automatic appeared in the 12 cylinder model along with a new engine management system. Antilock brakes appeared both in the six and twelve cylinder versions along with an optional sports suspension package and interior upgrades including power seats.

By 1986, US customer demands for a true convertible prompted Jaguar to commission Ohio coachbuilder Hess & Eisenhardt to build convertibles based on coupes. Over the next 20 months, some 2100 cars would be shipped to Cincinnati where the roof would be removed, formed steel members added to the bodyshell and an electric convertible top fitted. The top was not padded, allowing it to fold deeper in the body than the top would on the cabriolet or upcoming Jaguar build convertible. In march 1988 at the Geneva Auto Show, Jaguar presented its first true convertible since the end of the E-type in 1974 with production beginning in September as an 89 model and available in all market. The new convertible featured a padded top with headliner yielding a taller profile when folded. Other modifications for 1989 included a new steering wheel, multispoke alloy wheels, redesigned seats and new burl walnut trim.

During the 1980s, Jaguar worked closely with Tom Walkinshaw Racing to develop the XJS into a winning race car in the FIA World Sports Car Championship. Increased power for the V12, weight reduction, larger AP brakes were part of the recipe to take the fight to BMW along with meticulous preparation. it didn't take long for Tom Walkinshaw to get results with wins in 1982 at Brno, Austria, Nurburgring, Zolder and most importantly on Jaguar home soil at Silverstone.

To celebrate the 1987 Championship and the 1988 Le Mans victory of a V12 power XJR race car, Jaguar introduced a limited edition XJR-S V12 coupe in 1989. Only 100 of the European market only cars were built, all Tungsten colored, featuring TWR ground effect package, special wheels and special interior. North American customers would have to wait until 1993 for their own XJR-S with either Signal Red or Jet Black paint and available in Convetible or Coupe. Again only 100 would be built, with special body kit, wheels and interior. This would be the first appearance of a 6 litre V12, developping 318hp thanks to a new Zytec engine management, mated to a GM 400 Turbo automatic transmission and limited slip differential. Note that this 6 litre engine was a stroked version of the 5.3, unlike the the standard model 6 litre soon to appear in the XJS and XJ12.

Final facelift

1991 would see the final major cosmetic update to the XJS with what is known as the facelift model launched as a 1992 model. Little is changed mechanically but the big news in the US is the availability of the AJ6 engine although now enlarged to 4 litre and mated to a four speed automatic. Outside, the slightly softer lines were only the tip of the iceberg as the bodyshell was now build from far fewer panels than the earlier version with additional rust proofing treatment. While the front end was for the most part unchanged, it is the rear which underwent the most changes with revised quarter windows, a new rear window and all new tail lights. Inside, the instrument panel was all new, loosing the drum styled engine gauges replaced by conventional dials flanking the two primary instruments, identical to the XJ40 panel. Extra veneer in the instrument cluster added a touch of luxury along with a new steering wheel and center console. V12 car received the same power bulge on the bonnet as the AJ6 models and US market XJS were now equipped with one piece Euro style Carello headlights. In Europe, the original one piece Cibie were also replaced with a Carello, although different from the US spec'd version.

In 1994, a 6 litre version of the V12, diiferent from the 6 litre used a few month earlier in the limited edition XJR-S, replaced the 5.3 litre unit, along with a new four speed GM400. New body colored bumper replaced the smaller chrome and rubber version and the V12 model gained a boot lid spoiler. Inside, dual airbags were added and the convertible received back seats making it a 2+2.

1995 would mark the last major engine upgrade in the XJS line with the arrival of the 237hp AJ16 engine although not available with a 5 speed manual as a new electronically controlled ZF 4 speed automatic became the only transmission available. Modified engine management netted the V12 another 23 hp to 301. This would be the last year for the coupe, at least in the US, and XJS production came to an end in 1996.

Ironically for a car which received a less than warm welcome when introduced, it would become Jaguar longest running model remaining in production for 20 years and 7 months during which over 115 000 units were built.

V12 or Inline 6 ?
If the stock V12 isn't enough how about adding twin superchargers ? 600+hp under the bonnet of this highly modified XJS: Engine - Front - Rear
(owner Bradley Smith, NewYork)

Buying an XJS

Without a doubt, the XJS is one of the most popular Jaguar ever made and while it may not have the appeal of the legendary E-type it is an excellent choice for someone who wants to enjoy Jaguar ownership at a reasonable cost; and who wouldn't!

Needless to say, with such a long run and model variations, XJS can be found from very cheap, as in needing plenty of work, to excellent condition. As with any "special" car (it's still a little early to call the XJS a classic - no hate mail please...) buying the best you can afford instead of the cheapest possible pays off. Maintenance history is important to make sure an XJS has received the care it needed, especially for the V12.

As a hobby or week end car, there is really no reason to stay away from an early coupe especially if the price is right and if you don't mind a trip to the woodless plastic age of the 70s. The V12 is without a doubt one of the very best engine ever build by Jaguar or by any builder for that matter. It is a rugged and reliable engine capable of high mileage with very little problems. However, it doesn't like to be overheated so keeping the cooling system in top shape is important. Any evidence that a prospective V12 XJS maybe running hot is cause for concern and engine condition should be checked thorougly by doing a compression check. Even if the engine appears to be running well, rebuilding a V12 is an expensive job ($8000 to $10 000); a compression test prior to purchase is cheap insurance...

At the other end of the spectrum, the later XJS can make a very good daily driver with decent fuel economy in the case of the AJ6 / AJ16 powered versions. Needless to say, the V12 is anything but economical although when driven sensibly it won't be worst than most of the SUVs seen on the roads today. While the AJ6 and AJ16 engines may not have won Le Mans, they are just as reliable as the V12 and easier to work on. Maintenance on the V12 is more costly than on a 6 cylinder car, not only because there are twice as many plugs, wires, injectors, etc... but because with such a big engine access is limited; this is the price to pay for the glamorous V12 badge.

Like any Jaguar, condition of the body is extremely important when buying an XJS. Rust is a problem and can be very costly to fix; beware of recently painted cars as that shiny new paint can hide poor repairs. Facelift models (92-96) were build from fewer body panels and received improved rustproofing.

If you are looking for an open car, it maybe a little hard to decide between the Cabriolet, the H&E convertible or the later convertibles. Despite its Targa bar and fixed rear windows, the Cabriolet certainly has its charms starting the various configurations one can choose: fully open, rear convertible open or close, each Targa panel on or off. US buyers face an other decision when it comes to the "true" convertible between the H&E with its unpadded top but lower profile when open or the Jaguar built version with the more luxurious padded top but sticking out when folded down.

- XJS Timeline -

Sept. 10, 1975 : XJS is launched
1977 : GM400 replaces Borg Warner 12 transmission
1980: new Lucas/Bosh digital EFI
1981: introduction of the HE V12 with revised cylinder heads, Jetronics fuel injection, higher rear ratio,
revised interior with burl elm veneer on dash, door trim, new switch gears and steering wheel (from XJ6),
new chrome mirrors on both doors,
revised bumpers and new Starfish Alloy wheels
1983 : 3.6L AJ16 engine introduced (except in the US), Cabriolet model
1986 : Hess & Eisenhardt XJS Convertible (US only)
1987 : powerseats
1988 : introduction of the XJS convertible
antilock brakes, revised interior, optional sports suspension.
1989 : Le Mans XJR-S model (Europe only). New Marelli ignition system (except XJR-S)
1990 : XJS Rouge Coupe (US only)
1991 : Classic Collection XJS
May 1991 : introduction of facelift model with revised body, tail lights and rear windows, XJ40 based instrument pack, single piece Euro style headlights on US model
1992 : 4.0 AJ16 engine, new 5 speed Getrag manual gearbox and new dual mode automatic
May 1993 : new larger plastic bumpers, V12 enlarged to 6 litres, 4th gear overdrive equipped GM400 transmission, outboard rear brakes. New limited edition XJR-S available in the US
1994 : revised AJ16 engine with sequential fuel injection, new seats
1995 : Celebration model
1996 : XJS replaced by XK8, end of the line as well for Jaguar's legendary V12 replaced by the new AJ-V8

Driving an XJS

Torque is really the key word when driving a V12, this is no 7000rpm buz machine, and 80% of peak torque is available from as low as 2000rpm. On the road, downshifts are only needed in tight passing situations. The early 3 speed automatic is adequate but for pure driving enjoyment a manual gear box is best. Unfortunately, manual XJS were never exported to the US but it is possible to upgrade an automatic XJS to a 5 speed manual, a costly upgrade but the best way to improve performance.

Handling and ride qualities have always been a key part of the Jaguar driving experience with just the right balance of comfort and handling. The XJS is no exception although models with sports suspensions, wider wheels and lower profile tires will have a stiffer ride. Brakes are adequate for normal use but the XJS is a heavy car and long downhill drives may require special care.

Over the years, the interior of the XJS has been constantly improved and refined with the later models setting standards in comfort and refinement. Even the early XJS are far more "civilized" than the E-type it replaced with far better sound and heat insulation, improved climate control, etc...

Maintaining an XJS

The XJS, whether V12 or AJ6/AJ16 powered, is not the maintenance nightmare some claim it is. It is a complex luxury car with an exotic V12 engine which will require a little more attention than your basic Chevy. Speaking of which, sadly a number of XJS have been "lumped" with V8 over the years as ignorant mechanics convinced owners that the original V12 was the source of their problems. Needless to say, these cars aren't worth much.

As mentioned earlier, the Jaguar V12 is a reliable engine capable of producing far more power than the 300hp or so it delivers in the XJS however there are a few issues related to auxiliary systems, mostly cooling and ignition. The cooling system is adequate but needs to be maintained; any overheating can result in severe damage lke dropped valve seats, blown head gaskets, etc... Many owners have chosen to upgrade the radiator to single pass alloy unit.

The V12 is a big engine installed in a fairly small engine bay resulting in a lot of heat trapped especially after shutdown. Not shutting down the car immediately after a hard run helps reducing chances of heat damage to ignition and injection components. Until 1989, Jaguar used Lucas electronic ignition, first the same OPUS system used in the E-type and after 1982 a Constant Energy Ignition system. Despite the common jokes related to Lucas, both systems are reliable but shared a common problem with the distributor centrifugal advance having a history of seizing resulting in power loss and overheating. In 1989, Jaguar switched to a Marelli electronic system using crank sensors to adjust timing (no more frozen centrigugal advance) and a single distributor with a separate coil for each bank of the V12. Because each bank uses a separate coil, it's possible for one bank to fail while the other will still be running; the engine will obviously lack power but still run smoothly. If the driver doesn't stop the car right away, the fuel injection keeps sending fuel to the dead bank and the unburned fuel sets the catalytic converter on fire... Periodic inspection and replacement of the cap and rotor is key to avoiding this problem although there are a number of modifications which can also eliminate the risk. Regular inspection of fuel injection hoses is equally important, there is nothing like fuel spiling over a hot engine to ruin your day!

Servicing the rear brakes on earlier XJS is harder because of the inboard brake design until 1993. Rear brakes were mounted near the differential to reduce unsprung weight and improve handling but are harder to service, requiring dropping the rear suspension to change rotors and calipers. Routine service like bleeding or pad changes is no problem though.

The AJ6 and AJ16 engines are easier to maintain, having more space around in the engine bay, and are equally well designed as the V12. One potential problem lies with the head gaskets which can fail sometimes under 100k miles. Repairs are easy and even well within the capabilities of any good DIYer.

Regardless of age or engine type, parts availability is still excellent with a number of specialists carrying virtually any part needed. In some case, good used parts can also be found resulting in substantial savings. Choosing the right shop for service is absolutely critical and official Jaguar dealerships are no longer the best choice to service or repair an XJS; now almost 10 years out of productions, training for dealers technician focus on the new generation of V6 and V8 engines and fewer of them are familiar with the V12. Finding an independent specialist with Jaguar experience is key to enjoying an XJS; someone who knows the car and its engine inside out. For those who can do at least some of their own maintenance, there is one must have / must read resource that no XJS owner should be without : The XJS Book by Kirby Palm. Written by an XJS enthusiasts, this 700+ pages book is in part a compilation of owners posts from our forums/mailing lists; best of all it is free! Visit the Jag Lovers XJS website to download it.


Four generations of Jaguars sports cars : XK120, E-type, XJS and XKR in the background.




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