By on September 29, 2009

graceful even at rest

Jaguar and V12. Two of the most lyrical automotive icons ever. One stands for grace at speed, the other for speed with grace. The combination of the two offered the prospect of a marriage made in automotive heaven. Yet when they finally enmeshed, the result fell short of the potential envisioned by the marque’s match-maker and its loyal patrons. Yes, in those rare moments when the Jag V12’s stars were aligned , and its four carburetors synchronized, the results were heavenly. But in the final judgment, the V12 was a fall from grace, straight into automotive hell.

the death wish

There’s a reason that skeleton head is sitting on the back parcel shelf of this XJ12. It’s the Prince of Darkness himself, whose presence hung over this graceful lump like a perpetual death wish, right from its genesis. Jaguar’s decision to build a V12 was a classic case of hubris, assisted by and its close relative, bad timing.

The origins go back to 1954, when it became obvious that the venerable long-stroke XK engine would no longer be competitive in racing. The first V12 designs were DOHC units, with a cylinder head arrangement similar to the XK. What Jaguar failed to take into account was that the classic wide-angle valve arrangement that worked so well on a long-stroke engine didn’t on a high-revving V12. The XJ 13 V12 racing prototype was obsolete from the get-go.

a classic faceBut Sir William Lyons was determined to have a production V12 for the new XJ sedan, due in 1968. That came with a huge price: the loss of Jaguar’s independence. The old XJ engine was built and assembled in the classic cottage-industry style: old-school castings and forgings, hand-fitted. The V12 would need an expensive modern transfer line and alloy-block casting facilities. The costs were more than Jaguar could raise itself, and thus forced the company into the arms of BMC, soon to be British Leyland. The “double-six” became Sir Lyon’s Jaguar death wish.

The V12 endured a protracted development (here’s the whole story in-depth), when it was decided that the DOHC hemi heads had to go. Instead, a SOHC (per bank) design with the combustion chamber in the cylinder/piston bowl (Heron head) was cribbed from a Coventry Climax engine. What Jaguar failed to do is ask Keith Duckworth why he had abandoned that design, due to its intrinsic limitations. Oh well. It took several more years to get it running right. It finally arrived in 1971, in the E-Type, and a year layer in the XJ, just in time for the energy crisis and tightening US smog regulations.

a tail pieceIts long gestation having begun before smog became a dirty word, the early V12 was crippled by the lack of fuel injection and a 7.8 to 1 compression ratio. In US spec, it made 241 horsepower, about the same as the best Chevy small block of the time. It did have that “turbine-like” smoothness, when the carbs were all synchronized, which was damn nearly never. That problem was swapped for others after 1975, when Lucas fuel injection appeared; its rubber lines had a bad habit of bursting, with resultant engine fires.

But the XJ6 sedan was a terrifically handsome car when it appeared in 1968, minus the V12, and would start a line of variants and successors that is just ending now. A particularly beautiful coupe graced us for a few of those years. The XJ became the definitive Jag sedan, having replaced a mish-mash of four overlapping obsolete models from which it inherited its IRS rear suspension and of course, the venerable XK engine. Only some 3k of the first series XJ came with the V12, which makes this CC a fairly rare bird, even if its wings are clipped.

the dirty dozenStateside, the V12 was mainly seen in the XJ-S, due to tightening CAFE requirements. Most XJ sedans soldiered along with the old XK engine through three series, until replaced in 1986 by the less-than satisfying XJ40 and its new but weak-chested 3.6 six. Just as well, as the old sixes are largely bulletproof, and parts will forever be available. The V12s will more likely end up like this one: nice curbside-side decoration.

It came and sat immobile, hunched over a speed hump in front of its owner’s rental house for the year they were there. Who knows what forms its ailments took; looks like mushrooms are growing on the driver’s side carpets (wet Wilton wool rugs, yumm). There were plenty of possibilities, starting from the internals out. The V12 block is an open deck aluminum affair, which means that if it overheats or blows a head gasket, the insides could end up looking like the engine photo I shot at a garage nearby (the mechanic/owner of that particular XJ-S said he wish he’d junked it, because he’ll never get his money back). You think? There’s a reason Chevy V8 swaps are so popular with the XJ-S.

Even if you can keep the internals intact, there is that insane   four carb setup, a maze of fresh mushroom?vacuum hoses, wires, relays and switches, and of course, the Lucas electrics and peripherals. No wonder the owner of this XJ spent all his time messing with his vintage motorbikes in the garage, and not the Jag.

But the XJ12’s quiet brooding presence added spice to an otherwise boring block around the corner from my house. It’s not like V12s are common sights on the streets of Eugene. Nor are Series 1 XJs. It will be missed. And its departure (on a flatbed) was notably lacking the element of either grace or speed.

the tell-tale

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43 Comments on “Curbside Classic: 1973 Jaguar XJ12...”


  • avatar

    This car is out of my ken, but this is a wonderful account, with a lot of very interesting details. The under-the-hood shot is poignant, as is the shot of the skeleton head on the rear ledge.

    Another plug for PN’s Maserati Dreaming, in case you haven’t read it. One of the best, most lyrical pieces ever to appear in TTAC.

  • avatar
    Autosavant

    Beautiful (still) exterior styling, but an extremely stupid design, a 4 door is supposed to have room for 4 people min, and this one has NO ROOM in the back except for “little people” and Mini Me. Really stupid for such a large, heavy car.

    There are other problems, but let me be charitable and omit them now.

  • avatar
    KixStart

    Great article!

    I remember when this vehicle hit the streets, what a beautiful car and what an exciting concept for power. I never realized, though, how star-crossed it was.

    A neighbor (since moved) had a convertible with the V12, ten to fifteen years old at the time of our acquaintance, and it could only rarely be coaxed out of the garage and around the block. Nor was it quite as attractive as the sedan.

    Jags are still, for the most part, beautiful cars.

  • avatar
    jonny b

    Here in Vancouver there is always a number of gorgeous XJ-S V12′s for sale for a song on craigslist. These are the Sirens of a gearhead’s Odyssey. They’re very beautiful, they sing a lovely song (when running), and you will inevitably smash your ship on the rocks.

  • avatar
    Juniper

    I hope it went to a good home for some (lots) TLC and an engine transplant. Better that than behind some garage to grow ‘rooms.

  • avatar
    panzerfaust

    My guess was way off. I only got the continent right. The chipped edge of the bonnet was what was messing me up.

    You almost feel sorry, until you remember five letters: L-U-C-A-S. A greater source of bedevilment to this vintage Jag than the pentagram on the console.

  • avatar
    jpcavanaugh

    In the mid 80s I owned a 77 Chrysler New Yorker with a Lean Burn 440. I endured a constant series of electrical issues, carburation issues, and an incurable front end vibration. I now see that I only needed a Jag V12 in my garage too. Not to drive, but to provide some perspective. I would I have felt a lot better about that Chrysler.

  • avatar
    Canucknucklehead

    Truly one of the worst engines in one of the worst cars in all recorded time. Even when they weren’t blowing up they were almost impossible to keep running. I remember a late model sedan a friend just had to have, it think it was like a 1985. It often didn’t run. But to diagnose it, the engine had to be running, so you just replaced stuff (and outrageous cost) until you happened on the right part.

    The fuel rail was held on with 27,889 little Whitworth bolts and to adjust the valves you had to remove the whole shebag as wll as the cams since the shims were under the buckets.

    Not just the engine was a POS. The floorpan rusted when you looked at it. The fuel tank(s) leaked and the motor mounts broke. To complete to picture, all the secondary controls were exactly the same as that British scion of quality, the Marina.

    The passing of the British motor industry was lamented by very, very few.

  • avatar
    Nicodemus

    I think it is worth stating that the fuel injection system on an xj12 was in fact a german Bosch system merely badged up as Lucas.

  • avatar

    Multi-carb setups are a little like herding cats. Throw in the Lucas “Prince of Darkness” electrical system and you have yourself a full-time British car hobby with this Jag. http://www.mystarcollectorcar.com/

  • avatar
    twotone

    Fun on a Friday night, but I would not want to marry one. The XJ-S still holds the Cannonball Run Record (32 hours and 51 minutes) in 1979.

    Twotone

  • avatar
    JTParts

    I sell Jaguar spares, I MISS these cars. Whatever will I do when the last V-8 timing chain job is done?

  • avatar
    porschespeed

    ‘Nightmarish’ does not begin to describe what that engine compartment was like.

    But I do have a soft spot for the look of the old 4-doors. As long as it comes with a 6.

    The XJS in 6cyl/5speed config was pretty nice, when they ran.

  • avatar
    dmrdano

    I once saw one of these in immaculate showroom condition. All was as it ought to be. Especially the 454 Chevy engine completely hidden under the bonnet. And the big tires hidden in the tubs.

  • avatar
    blowfish

    I talked to one owner, he said if the A/C condenser ( the thing infront of the rad) gets clogged, the air doesnt move thru as freely, then they look for dirt, leaves. Once caged up between the rad and cond then u have a real pressing issue. As air cannot pass thru the whole engine will heat up. Next thing u could end up with drop valve, and the nice thing after then heat stopped.
    Many yrs ago a fnd tried to pay his Jag repair bill, it went above his limit, was declined. He was pretty mad.
    A fnd drove his XJS V12 up thru the Coquihalla Hwy
    here in BC, the heat made his engine gave up its ghost.
    That was AKA the killer Hwy, it had burned up numerous Audi et al.

    None the less Jag Vee 12 is probably one of the cheapest to enter the club, but the membership due can be as steep as peeble beach.

  • avatar

    Most American and imports from this era look out of proportion today. The rear overhang on this car is ridiculous. It is amazing how differently we perceived design back then.

  • avatar
    panzerfaust

    Nicodemus wrote: “I think it is worth stating that the fuel injection system on an xj12 was in fact a german Bosch system merely badged up as Lucas.”

    And proof they hadn’t quite gotten over Dresden.

  • avatar
    Ingvar

    @blowfish: Could you please rewrite your comment? It’s nearly unintelligible with all the internet shorthand.

  • avatar
    Paul Niedermeyer

    akear: The rear overhang on this car is ridiculous.

    Not so much so in light of the fact this is not a big car; it’s exactly the same length overall as a new Camry.

    I will admit that many of the big American cars had excessive overhangs.

  • avatar
    ZoomZoom

    I had guessed a Rolls; boy was I wrong.

    One look at that sad engine and all that cancerous rust and I was instantly happy that this was before my time of working on cars.

    Thank you, God!

  • avatar

    Actually those old aluminum Jaguar V-12 blocks make excellent and wonderful gearhead cred wine bottle racks. The bore of the cylinders is just over a standard 750ml wine bottle. Rack up the Cabernet Jeeves!

    –chuck

  • avatar
    panzerfaust

    ^ Britons are so clever!

  • avatar
    forditude

    A beautiful car with an often maligned (and somewhat undeserved) reputation. I am a bit familiar with these, and am seriously leaning toward getting a mid-90′s model once I am done with my other projects.

    Let me shed a little light on these cars. The V-12 in itself isn’t all that horrible of a motor, but the main problem is that Jaguar designed the engine bays to be as tight as possible to prevent Leyland from installing Rover engines in them. The result is overheating, resulting in dropped valve seats which usually require an engine rebuild.

    The 6.0 models were vastly superior to the anemic 5.3, as Jaguar fixed most of the 5.3′s shortcomings while trying to hide the blatant cost-cutting. However, they do have a reputation for engine fires thanks to the Marelli-designed ignition system. (Let’s say that you might have quality issues when the Lucas system is more reliable.) Marelli’s design ran the engine as two inline-6′s. The system would fail in a way that allowed one entire bank of cylinders to not get spark, causing raw fuel to be dumped into the hot catalytic converter. When Ford took over and installed their distributorless ignition system in late 95/96, the fires stopped, so these models are a bit more desirable.

    This engine was constantly under revision, so lots of parts don’t interchange from year-to-year, and good Jag V12 mechanics are rare and pricey. Probably not the car for you if you’re a beginner or don’t like to get dirty. These cars like to be driven and easily get sit rot, so don’t be afraid of giving it the Italian tune-up. This car needs a patient craftsman, not a dilettante who wants to swap in a Chevy because he/she doesn’t understand the intricacies of an overhead cam engine or how to synchronize multiple carburetors.

    I wish Ford would have been able to keep the V-12, but they weren’t going spend the money to clean sheet a new 12 cylinder for such a low volume car. For the money, I’d take one of these over a similar year V-12 BMW or Benz any day.

  • avatar
    Andy D

    I never wanted a V12, but I would love a good running XJ 6 that didnt have rusted out gas tanks. I consider the XJ Jaguar as one of the prettiest cars built in the last 50 yrs.

  • avatar
    mpresley

    Have a colleague with an XJS V-12 drop top. The thing is beautiful–almost sinful. Half the dash electronics don’t work, and they probably can’t be fixed. But so what? It’s a REAL Jag. Completely impractical, unbelievably expensive to maintain, but there’s nothing else like it–at least from a modern-day Jaguar standpoint. The new Jags might as well be Lexi. If the company were smart, they’d resurrect the old design using new and reliable components. At least they’d be worth looking at. I expect the company to be out of business in a few years, anyway.

  • avatar
    ZoomZoom

    Nice wine rack! I would have made the base wider so as to avoid accidents with shins, knees, and hips, but other than that it’s a great idea.

  • avatar
    gslippy

    I’ve always admired the XJ and Jaguar’s V-12s… and been glad I never owned one. But that photo of the engine almost made me cry.

  • avatar

    I have wanted an XJ ever since I sat in a new one at a car show ten or so years back. Articles like this help me resist their (considerable) charms. But it’s hard.

    Some lunatic put a Jaguar V12 in a Miata. He detailed the build on miata.net. The car is up on ebay now. Probably the most, er, unique Miata engine swap ever done.

  • avatar
    Nicodemus

    “Most XJ sedans soldiered along with the old XK engine through three series, until replaced in 1986 by the less-than satisfying XJ40 and its new but weak-chested 3.6 six. Just as well, as the old sixes are largely bulletproof, and parts will forever be available. The V12s will more likely end up like this one: nice curbside-side decoration.”

    The old sixes are far from bullet proof. I’ve owned plenty of them in various sizes. The later 4.2s have inherent flaws first amongst which is the head stud which goes through the water gallery and thus corrode, neck and finally ping at an inappropriate moment. V12s

    “Instead, a SOHC (per bank) design with the combustion chamber in the cylinder/piston bowl (Heron head) was cribbed from a Coventry Climax engine. What Jaguar failed to do is ask Keith Duckworth why he had abandoned that design, due to its intrinsic limitations.”

    This is totally specious, firstly the engine wasn’t ‘cribbed’, they were designed by the same guy, Wally Hassan and such share similar concepts.
    And secondly they were designing a road car engine not a race engine. But as it happens the Jaguar V12 turned out to be a very successful race engine winning Le Mans just as many times as Cosworth.

  • avatar
    Steven Lang

    I still believe the best XJ’s were the late 1990′s models. In British Racing Green they are completely drop dead gorgeous.

    Having said that they are also expensive as hell to keep up… and I’m talking about the ‘GOOD’ Jaguars. Every time I see one going through the lanes I see $ signs floating in the breeze behind it.

  • avatar
    ajla

    Well, it’s only money.

  • avatar
    John Horner

    I nearly bought a very nice XJ12 several years ago. Something stopped me after I had the cashiers check drawn up and before I handed it over to the car’s owner. Boy was I lucky that I put that money back into the bank.

    Another car I’ve long lusted after but repeatedly backed away from is the Citroen SM. Beautiful, but costly to keep going just right.

  • avatar
    Paul Niedermeyer

    Nicodemus, granted, regarding the XK engine, I should have said “relatively bulletproof” (as compared to the V12).

    Regarding the V12 head design; this is from Roger Bywater, former power units engineer at Jaguar:

    Certainly Duckworth was amazed to hear that Jaguar intended to proceed with the V12 as a flat head engine. Perhaps the conclusions reached by Climax were because of a fortunate combination of bore and stroke, valve sizes or whatever, but the usage pattern of an industrial engine may also be significant, spending long periods at about 75% load, rather than full load as in a race engine, or mostly light load as in a road car. It is not a criticism of Walter Hassan, who by now was deeply involved with the V12, or any of his team to point out this quandary. In his 1972 paper to the SAE Hassan admitted that at that time the knowledge of what happened to the charge in the cylinder of the flat head V12 was very much open to conjecture and that charge turbulence may well stagnate in some conditions.

    The issues/challenges regarding that particular head design also apply to road cars. In any case, the challenges did delay the V12′s introduction, and it seemed to suffer disproportionately under the loss of compression ratio from the first 10.0 to 1 version.

    It’s also why Jaguar abandoned the Heron head after some years in favor of the May “Fireball” design.

  • avatar
    Paul Niedermeyer

    John Horner, I wouldn’t have taken you for such a risk taker. Two very seductive cars indeed, but…

  • avatar
    John Horner

    LOL Paul, I’m torn between passion and practicality on a regular basis. I blame the fact that I’m both part Scotch-Irish and part German :). Note that I lusted after those cars, but didn’t actually buy one.

  • avatar
    Morea

    Nicodemus : But as it happens the Jaguar V12 turned out to be a very successful race engine winning Le Mans just as many times as Cosworth.

    Yes, twice each (Jaguar V12s in 1988 and 1990 and Cosworth DFVs in 1975 and 1978) but it is a specious argument because Cosworth concentrated on Grand Prix racing not endurance racing. These are two very different venues as far as race engine design is concerned. Also, ‘VERY successful’ is a bit of an exaggeration as several engine designs have more victories.

  • avatar
    Autosavant

    “# akear :
    September 29th, 2009 at 3:26 pm

    Most American and imports from this era look out of proportion today. The rear overhang on this car is ridiculous. It is amazing how differently we perceived design back then.”

    Not only that, look at the tiny size of the passenger compartment, compared to the hood AND the trunk, it really looks like a DUMB design, the opposite of Honda’s “machine Minimum, peoplke maximum” hatchbacks.

    Paul Niedermeyer stated that this was not a large car, because it is as long as a Camry. To rephrase it, this proves NOT that the Jag was not long enough, but that the Camry has grown quite obese with each new generation.

    In addition, the Jag’s WHEELBASE is WAY too small for a car of this type and length. That is the reason for the overhangs, and makes for a really poor, dumb design as far as highway comfort is concerned.

  • avatar
    salhany

    I still believe the best XJ’s were the late 1990’s models. In British Racing Green they are completely drop dead gorgeous.

    Hell, a neighbor’s got a 2008 XJ Vanden Plas in the driveway in BRG, and it’s spectacular. I keep looking for signs that they might sell it some day so I can jump on it.

  • avatar
    Sinistermisterman

    It’s amazing how the fortunes of an engine, a car and a car company are often the direct by-product of the ego of the Man In Charge.
    Most of the time when there is just one MIC the design process outcome is something like this Jag. A car that you could love, if only it wasn’t so damn complicated and frustrating.
    There is often the rare exception where the MIC gets it right, overseeing a car that is awesome, well engineered and a good seller with the public, but as I said, this is the rare exception.
    And so most cars these days are designed by committees, statistics and sales figures – not by a passion and a dream. Sad really.

  • avatar
    Nicodemus

    “Yes, twice each (Jaguar V12s in 1988 and 1990 and Cosworth DFVs in 1975 and 1978) but it is a specious argument because Cosworth concentrated on Grand Prix racing not endurance racing. These are two very different venues as far as race engine design is concerned. Also, ‘VERY successful’ is a bit of an exaggeration as several engine designs have more victories.”

    Cosworth may be reknown for GP engines, but they cast their talent in many area. By far their biggest money spinner (not including licencing casting technology) was supplying engines to the CART series, so understandably this is where most of their efforts were focused not F1. Of course GP and endurance racing are different disciplines, but obviously not from a engine design point….the DFV won both on account of being reliable.

    Likewise as smart a chap as Duckworth was and regardless of how theoretically correct he might have been regarding the Jag V12s valvetrain shortcomings, he was clearly full of shit. It ended up being a hugely successful race engine..i’d hardly call victories at Daytona x2, Le Mans x2, Spa 24 Hours, Bathurst 1000, European Touring Car Championship series title, Trans-Am series titles x2, World Sportscar titles x3 and numerous others an exageration. Apart from the Ford Windsor and Chevy small block I can scarcely think of a more successfully raced production engine.

  • avatar
    Russycle

    Autosavant, I’m going to guess you’ve never had the pleasure of driving one of these on the highway. The ride is exceptional, and although the passenger compartment is small on paper, it’s quite comfortable, even the back seats.

    Unfortunately my ’85 Series 3 has become a Driveway Classic, but you’re welcome to drive up the road to Corvallis and take a picture of it Paul. Heck, I might even let you take it home…might need to bring a trailer. :-)

  • avatar
    Compassion

    Caveat: I am a Jaguar owner of comparable series and have a bit more in-depth knowledge by performing my own service on these cars.

    I’d like to clarify some of the information regarding the the early Series XJ’s.

    The Series I model years ran through 1968 till 1973. They rectified the cramp issues by releasing a long-wheel base version, that added 4 inches in the back, which was released in 1972. They also designed the XJ body to accept the V12 5.3L motor, with the aforementioned 4 carbs of hell, later in that 1972 year, although none of those V12 cars would be long wheel base, like the 1973 XJ12 depicted.

    The mention of the British-Leyland Rover V8-proof engine bay didn’t come into play until the design of the XJ40, the replacement to the Series XJ’s, that came out in 88. Ironically, this led to production of the XJ12 in this body until 1992. And by the time it mattered, Ford got in the mix by buying Jaguar.

    The AJ6/AJ16 4-valve motor wasn’t a complete disappointment as mentioned above. It did achieve better performance than the XK predecessor, and wasn’t as weak-chested as described. Not not as nearly remarkable, IMO.

    Jaguar was very aware of how terrible the situation was with the 4 carbs and later released the rebranded Bosch Fuel Injection, D-Jetronic, if memory serves, for the V12. There were some quality control issue with the hoses, but with all cars with this style of high-pressure fuel line fuel injection system, the replacement of the hoses every 5 years was a complete must.

    I do agree that the cooling system is of the utmost importance to be in working order on the all aluminum V12 motor. All it takes is one serious overheating and terrible things can be
    had to the motor.

    I have dealt with some of the rust issues, but they are nowhere near as exaggerated as above. There was a design deficiency in the cowl drains that could lead to condensation ending up leaking onto the front floorboards, and that was the typical cause of death for them. Keep that sorted and with some modern POR15 and life goes on nicely.

    Note:
    I am currently restoring a Series II Jaguar ’79 XJ6L 4.2L, own a Series I XJ6 4.2L that is generally comparable to the depicted car above. I’ve also spent time inside and driving a ’77 XJ12L. It is a delightfully smooth drive and a delight to work with, even if the Lucas electrics **** me off sometimes.

  • avatar
    Joss

    I wonder why the young mod old Honda and not tweek out something elegant like ol’ jag? 
    They’d have a cat that goes and not some beefed snuffbox…


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