(first posted 10/05/2011) 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 properly synchronized, the results were heavenly. But in the final judgment, the V12 was a fall from grace, straight into automotive hell.
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.
But 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 later in the XJ, just in time for the energy crisis and tightening US smog regulations.
Its 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/Bosch 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 version even 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.
Stateside, 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 relatively 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 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.
Postscript: This car got a Chevy LS-1 implant not long after I shot it.
I drove a friend’s V-12 XJ-S coupe once, expecting the thrill of a lifetime. I was disappointed. It felt so heavy and ponderous, a lead sled, and took a while to build up steam. We were on a quiet suburban two-lane, not rural or freeway, so maybe I didn’t get the car to a proper speed. All the same, I’ve had more fun in a Fiat.
The Jags of that time are like very nice, high-end kit cars. They supplied a rolling chassis with very nice suspension, steering, and complete body and interior. It was up to the customer to redesign the electrical system and install the small block Ford or Chevy engine. You just can’t believe how much a Ford 5.0 improves this car.
The shortest car ownership experience was a 1969 XJ6 I bought from my Uncle when I was 18 for $50. Of course, because going off to college in a 30 year old Jag was a brilliant idea.
But the slinkiness, the sumptuous blood red leather interior contrasted with the silver exterior. These were such works of art, that I don’t know if they were meant to be driven. Possibly just to sit in and look at. Although when they do run, there’s nothing more delightful than the helm of an XJ6.
I need to start a car charity for my own automotive indulgence….
“Of course, because going off to college in a 30 year old Jag was a brilliant idea. ”
You win the prize for the best sentence I have read today! Maybe because I have teenaged boys.
If only these had come with a small block Chev from the factory they would have. been a brilliant car
“If only these had come with a small block Chev from the factory they would have. been a brilliant car”
They were… called the Iso Fidia. ;^)
Or why not a DeTomaso Deauville… closer
Gorgeous and seductive, especially the Series III which, despite the big bumpers, had resolved and tightened up the nose of the car beatifully. One of my all-time favorite designs.
The XJ is perhaps the all-time best sedan design, and the XJ12 is perhaps the all-time worst execution of that design, mechanically. No wonder so many people put small-block Chevys in them (both XJ6s and 12s)–who cares if it’s authentic; better to roll around in that classic shape with an engine that runs, than have a “pure” car that stays parked.
There’s a first-series XJ6 that’s always parked in the same place in Pasadena, though it’s not deteriorating–I sometimes think about leaving the owner a note and asking if he’d like to sell, after which I’d scout around for a decent SBC to drop in it. Love those early taillights.
There’s a reason that several guys are making a good living off Chevy V8-into-Jaguar engine swaps. I suspect that John’s Cars in Dallas, TX, is the leader – anyone read his blurbs in HMN?
Roadkill came up with the best thing to do with one that was left for dead.
I have gotten to look forward to the adventures of Finnegan and Freiberger every month.
Lucas electrics are the reason the British drink warm beer.
I don’t know what this means, but I approve.
I heard it (and saw it on a bumper sticker on an MGB) expressed as: “Why do the British drink warm beer? Because they have Lucas refrigeration.”
Ha ha, that’s a good one!
73ImpCapn: A lot of electric components (and all the electrics for many British cars) were made by Lucas Electric. They were all rubbish. Do a google search for “Lucas, Prince of Darkness” and you’ll get the picture.
Thanks! I knew Lucas was bad but I was too dim to connect the dots and think “refrigeration.” 🙂
The strange thing is I have a British classic that starts every time with ease and it has Joe Lucas electrics including a dynamo not alternator for charging but its not from BL/BMC thats the big difference.
Jaguars of that era frequently wore bumper stickers that said “Every part falling off of this car is the finest British workmanship”
Lovely real ale is why we drink warm beer. The taste would be terrible if cold! Lots of people do drink lager here nowadays, and take it as cold as Americans or Germans would, to disguise the awful taste.
Great Lucas joke though!
I had a couple of T-shirts with this message imprinted.
Those Jaguar V-12 engine blocks make for awesome wine racks. 750 ML bottles fit right in.
That car shows off the genius of British styling, when they get it right. Overall proportions are as natural and correct as any Pinin Farina, but then there are those charmingly odd details, like the taillights or the shape of the rear windows and backlight, that actually work. Like a pretty face with a birthmark.
Was there EVER a reliable Jaguar?
Yes, recently. Ford must have treated Jaguar better than the usual captive.
Some would say they really are Fords, but let’s not go down that rathole.
I was looking for a 2-3 year old XJ for my dad recently. Surfed the jaguar forums to see if any issues I should know about, and the answer was, far and away, yes. I can’t recall the issues plaguing the recent Jags, but they were big enough and common enough to scare us off completely. Really a shame, as beautiful, low mile ones can be bought for a fraction of new.
Ford got into bed with PSA and got modern diesels out of it and put those in Jags, reliable as the sun.
The only one I’ve seriously considered is the X300, also known as the last XJ6 for the US market. 1995-1997 leaves a pretty small window, but I hear they are near Camcord reliability levels.
Yes just not in the US where mechanics are poorly trained.
Saw some of BLs finest today in natural pose
If I could only afford to buy one of these and a crate engine transmission at the same time from the GM Performance cataloge.
Dan, if you knew why that ’87 Caprice from your school district’s auction doesn’t run…if it could be easily fixed – and assuming it was a Chevy 305/350 with a Turbo 700 – not the Olds 307/Turbo 200-4R some of those old Caprices came with…and assuming not-too-high miles on the drivetrain…(ok that’s a lot of assuming!)…there’s a company in Livermore CA that could help make your dreams come true.
Jaguars That Run, http://www.jagsthatrun.com/
I’ve spoken with owner Mike Knell and he knows his stuff…back when I swapped the Olds 307 for a TPI 350 in my ’89 Caprice…he gave me the best piece of advice I ever could’ve asked for when doing one of these swaps…
“Make the engine think it’s still in the car it came out of”.
JTR isn’t in the toy business, they sell parts and manuals for people who want to build a drop-dead reliable vehicle using the TBI/TPI/LT1 engines. It looks like they’re just starting to dip their toe in the Gen III/Gen IV waters.
With JTR’s parts and manuals and the original shop manuals for both the donor and recipient vehicles, I was able to do the swap and turn a turd into a fun ride.
Of course you still have to find a suitable Jag to drop that engine into…
Love the look of this Jag. I even went as far as considering bringing one from Japan (even with 20-30 kkm on the odo, with LHD, they were 2 times cheaper than a Mercedes or a Beemer). Then I read a buyer’s guide in the Jag owner magazine and was appalled with the fact that this car does not have any strong sides – everything, and I do mean everything in it is a trouble spot that either rots, breaks down, burns or fails to maintain a reliable contact.
Funnily enough, the later, EFI V12 was claimed to be the least problematic of then current engines (from late 80’s – 1995), but that was “compensated” with insatiable glut for gas.
Is that not a Cougar in the driveway? Looks suspiciously like the one that ran the motorcycle off the road in Texas a couple of weeks back.
Is that what white Cougars are known for now? Good to know, maybe the bikers around here won’t be cutting lanes past me anymore!
Dropping a SBC in these cars really ruins the appeal for me. Maybe the GM 4.2 inline 6 dohc atlas engine. At least that fits the character.
I had a friend who was dropping a Ford 250 from a Falcon into his series I 1 XJ, because the 2.8 six was too expensive to rebuild. It bolted right up to the BW35 gearbox, and just needed engine mounts made to fit.
The 2.8 was a tax special in the UK, I didnt even realise they exported it none were available new here.
A professor of Electrical Engineering at the college where I formerly worked had an absolutely beautiful Series II XJ12. Finished in a metallic rose color with a tan interior, looked almost new despite its being 30+ years old at the time (mid 00’s). One of my two favorite cars owned by anyone on campus (the other being a gray-market E24 M635CSi). I never got the chance to ask him what was under the hood and I don’t recall the exhaust note, but it was his daily driver as long as it was not raining or snowing. It could have been SBC swapped, I suppose, or maybe as an engineering professor (and a British expatriate at that) keeping the finicky V12 running was a labor of love.
This repost just reminded me, what happened to Keith Thelen and the official CC project Jaguar? This appears to be the last update, when he was close to securing a replacement gas tank.
He disappeared. Well, he took a demanding new job in another city, and bailed on the series and Jag. I wrote him and asked if you would consider offering it to someone else at CC to continue the saga, but nothing ever came of it. I think he was going to just sell it locally.
You could say it ended like so many other old car projects: abandoned.
That’s unfortunate. Thanks for the update. At least the project wasn’t abandoned simply due to lack of fortitude to see it through, as many are.
This was the first mass produced new V12 post war. The Lincoln V12 was really a carry over from pre war days. A rugby club mate of my brothers bought a non runner V12Jag cheap and it failed to spark up despite much time and even more money being spent on it.
Make sure you’re a good mate of Nigel the mechanic, you’ll need him. Hasn’t stopped me wanting one though
I think the partially disassembled engine in the photo is a later HE version with flat top pistons.
my dad was Scottish and mechanic. came to Canada in 1949. he was very proud of his British heritage but never owned a British car. he looked at a couple jags and rovers but always passed and went back to his favourite luxury ride, cadillacs.
when I asked him why one time he said his definition of a luxury car was you sitting in air conditioned leather seats enoying the ride rather than someone telling your feet how beautiful your car looked while you were under it trying to fix it for the third time that week!
The V12 ENGINE itself was a good design let down by its fuel delivery system (well, at least until the later versions). A later V12 can do more than 300,000 miles without being opened – assuming maintenance is being observed. But I agree the money they spent on it would have been better used to develop an engine to replace the aging (and, in a world in which more countries were starting to have roads where you could cruise at high speed for hours, flawed) XK. Just imagine what would have happened if the AJ engine were available in 69…
What problems did the XK have with sustained high speeds? I realize it’s probably the engine most often replaced by something from a different manufacturer in history, but didn’t know that was due to a specific failure mode.
Over here in continental Europe these Jag V12 had a very poor reputation simply as they were never VOLLGASFEST. That means, a quick run from Bremerhaven (unloading the Jag from a vessel shipping it in from GB) to Munich ended up frequently even before Frankfurt came into sight. “A new head gasket and no more Autobahn, please, Sir, never!” It screamed! A friend of mine ended up implanting a Mercedes 4.2 L Engine. Straight, reliable and vollgasfest. Full Stop!
Once Again, Paul and I agree on a car.
Double Your Pleasure, Double Your Fun.
Empty your bank account.
I’ve only driven one, on a test drive after I did a wheel alignment Smooth, and you barely knew the engine was idling. And the alignment itself was surprisingly easy too.
I just like that the people at 1985 Whatever-street-this-is appear to be “cat people”, with that Cougar also in the driveway.
I guess that it’s time for another round of Jaguar as pinata! Like all old cars they have their problems, obviously the more complicated the car, the more extensive the problems can be. These V12s are about the best buy in complexity per dollar, and that’s not a good deal! Blown headgaskets due to overheating, will ruin these engines and pretty much anything made since the late 1990s. Newer late model V8 models are also very likely to be ruined by over heating.
Back in the day an old iron American six or V8 could shrug off a blown head gasket, and be easily owner repaired.
Actually Jag V12s are not that bad from a reliability point of view, but the complexity and crowded working access makes maintenance difficult. It isn’t very easy to find a mechanic willing to work on these cars. From a DIY standpoint the six is a better bet.
I am as guilty as others as getting involved with cars that are above my pay grade, so I know how tempting it can be. The best advice I can give is not to disassemble anything on the car until you are ready to fix it, a basket case is almost impossible to sell.