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Original Six: 1971 Jaguar XJ


While browsing a car lot a few years back, I asked the salesman about an old Jaguar parked out back. He quickly responded, “You don’t want that car. They are riddled with problems”. Since then I have noticed that many Jag sedans have had their engines pulled and replaced with American V8s. Luckily, this 1971 Jaguar XJ has not undergone the surgery as of yet. Find it here on eBay out of Costa Mesa where bidding starts at $3k with a BIN of $7k.


Jaguar introduced the XJ in 1968. It was powered by their XK inline-six which had resided in some of their most famous sports cars. It was smooth and powerful and when combined with four-door bodywork, created a great luxury sedan.


Eventually Jaguar started fitting V12s to keep the power up while complying with emissions regulations. I have never owned one of these British beauties in 6 or 12 cylinder form, so my question for you is, are they really that bad? Is a big V8 really an improvement over this inline-six? Or should that swap only be reserved for later V12 models?


  1. scottski

    It was never the drivetrain that was the problem… it was Lucas (electronics), Prince Of Darkness.
    The six-cylinder was a natural oil-burner… but, nothing else ever sounds like it when it’s in tune and happy.

    Yeah, you can drop an 8-cyl in there… but, if you don’t fix the wiring, it’s gonna sit ion the driveway.
    Then, it’s Hell to pay…

    …says a former 3.4 S-type owner.

    Like 1
  2. Dolphin Member

    These are very elegant cars, but we`ve all heard the same things that the salesman said to Jesse….there can be lots of problems with these. This one might be from before Jaguar forced Lucas to clean up their act and build reliable parts or lose the business. If so, it could be a problem.

    OTOH, it`s an iconic luxury brand, it`s from Southern California and looks good, it`s got low miles and square yards of Connolly leather, and it`s cheap. If you want it despite the automatic transmission, look over the maintenance & repair receipts and then go and talk to the mechanic(s) who worked on the car to see if they say the same thing that the car salesman said to Jesse.

    No receipts,….walk.

    Like 1
  3. dan Farrell

    They were called Jagrolets and I knew someone who did the conversions long ago. I agree with Scottski, every complaint I ever heard about Jags had to do with the electrical wiring and switches.

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  4. Michael Stewart

    I helped a friends dad swap a small block chevy into a 74 from a l6. The problem indeed was the wiring not the motor itself. the problem was getting the cars wiring fixed to match the engine. We used a donor 78 malibu wagon with very few miles on it (T-Boned, totaled), and the advantage was the HEI ignition was a complete unit. Most of the rest of the engine harness came from the donor car, as well as fuse box and other sundries. I think the most expesive single part was the custom made driveshaft and we never did get the speedometer to work. But after the surgery it was a very quiet and reliable car.

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  5. Randy Rush

    I had one of these except mine was green, Your right about oil burners, mine did that, then you had the electric window motors and the ac control switches and the rust. But I would never butcher a reasonably clean car like this by doing a v8 conversion. Wish this was closer .

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  6. paul

    Please, please, keep it stock, why are these great cars always on the ” other ” coast? Trick with these cars is finding a private owned Jag shop, these guys know all the tricks to keep these happy. CRAP I would kill for this one.

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  7. Blindmarc

    Lucas was the culprit. Same thing on the sunbeams before them too.

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  8. Jeff

    my 96′ XJR with the Supercharged Inline 6 (4L) is a 4-door racecar with class. FORD really cleaned the car up, with the 95-97 years the epitome of automobiling. The intro of the 4L V8 wrecked the car mechanically. The 255/45/17 stock tire size was a dead giveaway along with a 8.5 qt oil capacity for speed. The lines and chrome on mine are surely missed in todays models. i’m just fortunate to have a great private mechanic, no dealership cowboys.

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    • Mike P

      Once the Nikasil and timing chain tensioners were sorted out, the Jaguar V8 turned out to be a pretty good engine.

      Like 0
  9. Brian C

    What a great looking car!

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  10. stigshift

    From a British friend’s father-
    Why do the British drink warm beer?
    They have Lucas refrigerators,
    Why don’t the British build computers?
    We haven’t figured out how to make them leak oil.
    My apologies to Her Majesty, The Queen.

    Like 1
    • TVC15

      Stigshift you forgot one , The Lucas factory motto .. Home before dark

      Like 1
  11. Craig

    From Peter Egan Lucas electrics: Dim, flicker, and off

    Like 1
  12. Horse Radish

    I sometimes wonder if pouring money into a restoration on an old Mercedes is unwise.

    But I know it is foolish to do so on an old Jaguar, at least the sedans.
    Unfortunately I love these cars just as well and that’s why the progress of resurrecting those cars of mine has stalled. I have a series 1 xj12L and it’s been sitting the whole 10+ years I’ve owned it. What a shame…..
    Until I have too much money nothing will change.

    Like 0
    • paul

      The 12 is the problem, too much effort & $’s to keep them up, the 6 is a winner & these early sedans handle amazingly, both because they were lighter then the 12’s in the nose & because of their fantastic sub frame suspensions.This is the one to have, ditch the 12 & pick up this one.

      Like 0
  13. Eic van Domselaar

    When I used to have my shop Jaguars came in and sat…….. Major problems with Lucas electrical…. Usually a good rewiring got them back on the road….. replacement of the distributor or putting a type of unilite ignition system…… then replacing the carbs with Weber DCOEs………. and the last problem the location of the cats…… they heat your engine up and cause all sorts of head gasket problems………. Especially in the heat of the South……. when you did these modifications to the car it really made it work well.

    Like 0
    • paul

      Very well put Eic, the trick is a good independent Jag shop, these guys know all the tricks.

      Like 1
  14. David

    The low miles here might be an indicator of past problems: this car might have spent half of its sitting at a garage awaiting First Aid LOL

    Like 0
  15. Loits

    I’ve had lots of XJ 6’s and 12’s over the years and the engines are great, I had one XJ6 that I ran pretty much trouble free to over 180,000 miles. What you have to remember (apart from the admittedly piss poor electrics) is the state England was in in the 70’s. The unions ran the country, before Maggie kicked them into touch, and as such the parent company, the thankfully defunct, British Leyland made cars of a quality so poor that Lada would have been ashamed.
    It is such a shame because these are wonderful cars, and drive beautifully but can suck money away very easily. There are companies here in England specializing in putting these thing right, at a price, such as KWE engineering.
    With such a nice example as this, rewire it drive it love it.

    Like 1
  16. Slotblog

    The reputation of Jaguars as being unreliable is way, WAY overblown. Keep in mind that the classic XK engine was in production essentially unchanged for 40 years and powered LeMans winners three times.

    The comment regarding the build quality of the Series I sedans is accurate, though. Certain parts for the Series I cars are getting very scarce, trim pieces especially. The mechanicals are no problem. The biggest problem with Jags is owners who didn’t/don’t maintain them properly.

    And while the V12 cars can be great vehicles, there is virtually no one left now who knows how to work on them. The V12 Jags can be huge money pits and extremely time-consuming to maintain and repair.

    The opinions of someone who just left one of the key Jag parts vendors in the US after 16-1/2 years…

    Like 0
  17. John

    I would love this car.

    I can rewire it. A proper exhaust shop could fix the CATs, I can buy lotsa Mobil 1.

    And the switches can be easily rebuilt.

    These are the most wonderful cars to drive or to ride in.

    If I had a spare $7k. I’d be on a plane to Costa Mesa. 29R is calling.

    Like 0
  18. Tom S.

    I think the early models are the most attractive of the XJ line. The big grille and thin bumper makes me go “Mmmmmmm…”. This one deserves preservation.

    Like 0
  19. Grant

    If it works leave it well alone. (Ex Pre XJ 420 owner) Nothing sounds better than a well tuned straight 6 Jag, or Triumph for that matter, but electrics are a problem especially if the climate is wet…..dry climate seems to cause far less problems. The autobox not the best, but some last for ever….expensive to repair when it does give problems but the old MOSS MANUAL BOX is long lasting if a little agricultural and I think lighter on fuel too!!!
    Great under- appreciated car!!!

    Like 0
  20. Andy

    It’s true that the problems with Jaguars were mostly related to the poor quality of ancillary systems like cooling and electrics. The basic architecture of the engine and transmission is very hardy, if sometimes difficult to access for repair. If the engine runs, keep it. Don’t turn it into a Frankenstein monster unless it’s absolutely necessary from a cost standpoint. These cars are available for a lot cheaper than 7K, and the later models were probably more reliable. We had an ’87, the last year of the original XJ, and it never stranded us. They are beautiful and fun to drive classics available cheaply, because you will spend money keeping them going.

    Like 0
  21. Tom S.

    RE: “poor quality of ancillary systems like cooling and electrics”. My wife just asked me if Jaguar had anything to do w/the Boeing Dreamliner.

    Like 0
    • paul

      I don’t know about that but I do know of some current VW / Audi’s that seem to have problems with ancillary systems.

      Like 0
  22. Doug M Member

    Keep it STOCK!! a v-8 conversion should only be a “last resort.” These are very good motors, and this one is even clean. The whole car is a “work of art” and should be appreciated as such. It’s kinda like when you like the patina on a car-find and someone wants to throw a quick paint job on it. The comments are always begging to leave it in it’s purest and best form. Same goes here…

    Like 0
  23. FRED


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  24. Wayne Norman Delegate

    To the high bidder on E-bay: Several years ago a local Brit car shop near by closed up and I bought a bunch of his parts inventory and I managed to acquire 3 tanks of Jag Part No. 71-3LGL95-8/GRAY. Factory “Lucas Smoke”, NOS in the original packaging, If this XJ is low and needs the smoke injected back into the wiring system, give me a call.

    Like 0
    • Horse Radish

      is this interchangeable with Lada -smoke ?
      or does it have it’s own specific qualities ?

      Like 0
  25. mtshootist1

    The only experience I ever had with one of these cars was about 1978, my wife and I were looking to buy a house, and the real estate salesman had one of these, we rode around in it looking at claptrap houses, and I rolled the electric window down, and it wouldn’t go back up, the car was at the most a year old. After that, I never ever wanted one. I happily went back to driving my 58 Chevy Biscayne that I had bought in college for 300 bucks.

    Like 0
  26. Jeff

    Best deal I’ve seen for a “True” classic with heritage, its “Turn-key”, a no-brainer for a collector/enthusiast with the spare $$$$.

    Like 0
  27. Jeff williams

    Had mine since 1973. 2.8 version, these were notorious for piston brake up. Mine did this when i was in Germany in the middle of winter, heavy snow and all. It got me back 650 miles to England. I repaired it myself. Been using it all this time, with 10’s of thousands of miles around Europe. Never a hitch and never anything wrong with the electrics. Lucas or not. A great iconic style and virtually silent engine. 125000 miles on the clock. No rust, perfect wiring. Dont let a good one go to the breakers.


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  28. webby

    Re the V8 conversion. I recall a “Road & Track’ edition with the “Ten best used cars”
    article- sometime back in the 1980s. The article warned against buying Jags converted to SBC engines. Next issue, there are half a dozen letters to the editor, all praising the V8 conversion. Runs cooler, a decent auto, not that POS Borg Warner, better mileage, lighter engine. And with the Jag’s forward opening hood, the dizzy on the SBC is finally easy to access.

    I’d do the conversion, with EFI, a 4 speed auto. Cut no metal & keep the original engine
    as a coffee table base. If the oil leaks permit.

    Like 0
    • paul

      OK but do this to one that is shot, not this really nice, original, missing nothing, sweet piece, when you do those conversions, you loose all value, so your doing it for yourself & will have a hard time reselling it.

      Like 0
  29. ian

    I know lots of people who have owned these in 6 and 12 form and never had any problems other than any issues you would get with old cars. Funny though as in the UK most US domestic vehicles have a terrible reputation for poor reliablilty, mechanically and electricly, shocking fuel consumption and terrible build quality. Just goes to show not all rumours are true!

    Like 0
  30. Paul

    The BIN price is a bit high but; this car can be a fine reliable automobile. Parts are readily available

    Like 0
  31. Alec McCutcheon

    I am from the UK and own two Series 1 XJs – both mine are Daimler Sovereigns (same car as the Jaguar but badge engineered with a different grille and even more luxurious interior) a ’71 4.2 (long term project) and a ’72 2.8 (mint, low mileage, rust free and original). Have also owned over the last 20 years a ’78 Series 2 and an ’84 Series 3.
    They are simply a superb driving experience the ride, handling and performance are up to modern standards and they are gorgeous to look at, but they do feel built down to a price – the XK engines always use a bit of oil (the valve stem seals go soft); early 2.8s had a problem where carbon built up on the top of the pistons and then blew a hole in the top. Biggest problem in the UK with XJs is rust and cars that have been badly repaired – over the years I have viewed some horrors including one car where the suspension radius arm mounts (structural) had rusted and were repaired with body filler (lethal). The series 3s from the mid 80s are probably the best built (John Egan was running Jaguar as an independent company by then and he got the quality under control). If you go to Google Images and type in “Daimler Sovereign Series 1” or “Daimler Sovereign Luton” a pic of my 2.8 comes up – its the dark blue car license plate: VBY284L – in my eyes the Daimler has the prettiest grille but its really a matter of personal taste :-) Which do you prefer?

    Like 0

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