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Vintage Views: Jaguar XJS

Out of the thousands upon thousands of Readers’ Rides on our webpage, a Jaguar XJS is the sixth-highest-rated car. Okay, so it’s a full-race example prepared and campaigned by the championship-winning Group 44 team, but we still know what you’re thinking: Is this British classic worth a serious look?

“For anyone old enough to remember leg warmers and big hair, the term ‘icon’ meant more than symbols on your tablet or smartphone,” says Michael Marter of Jaguar parts house XKs Unlimited. “Mickey Mantle, Miles Davis and James Dean were icons. So was the Jaguar E-Type. Drop-dead gorgeous, it was the first volume-produced sports car to offer such a sophisticated and potent package at a comparatively low price.

“Replacing the E-Type was well-nigh impossible and the XJS didn’t exactly cause the automotive world to spontaneously combust, but the all-alloy 5.3-liter V12 returned–now sporting fuel injection–as did Jaguar’s excellent and innovative independent rear suspension. Styling was at least handsome and interior dimensions were patterned after someone taller than the average Formula One driver.”

His take-home point: “Today the XJS is a fantastic bargain with many variations from which to choose.”

How much of a bargain is it? Bring a Trailer recently sold a very clean 1983 coupe for $8100. According to the receipts, some $35,000–yes, 35 really big ones–had recently been spent on a full mechanical and body restoration. Hagerty says that good cars should cost somewhere south of $10,000.

Not only is the XJS today’s value buy, it also allows for some choices. The model line debuted for 1976 as a V12-powered coupe. Targa and convertible models were added during the 1980s. XJS production ran all the way though 1996.

While all of the V12-powered cars came with automatic transmissions, the drivetrains evolved, too. Jaguar moved to the H.E.(high efficiency) V12 engine for the 1982 model year, and a 4-liter, six-cylinder engine became an option starting in 1993. “While the V12 has instant cachet, don’t discount the later six-cylinder cars,” Marter adds. “The second-generation AJ-16 4.0 six-cylinder is dead-reliable, and there is a chance you’ll find one with a manual transmission.”

Is the XJS going to replace your WRX or Miata? Maybe not. But if you’re looking for a comfortable grand touring car that offers some panache, then the XJS could be worth a look.

Practical Guidance

Michael Marter of Jaguar parts house XKs Unlimited offers up some helpful XJS advice.

“I won’t attempt a chronology here, but a search should probably start with the H.E. models of 1982. Earlier cars with their black bumpers were not as attractive, and some of the first-generation fuel injection components are no longer available.

“If a convertible is on your list, the stopgap Hess & Eisenhardt conversions are probably best avoided–the later factory version was much improved and most parts are actually available.

“With few exceptions, there is not a dog in the entire XJ-S production run. Jaguar later dropped the hyphen. “Problem areas are few and are generally shared with any vehicle that’s anywhere from 20 to 40 years old. Expect and accept some surprises, and a pre-purchase check by a marque expert would be money well spent.

“Pay particular attention to the health of a V12; they’re complex and frightfully expensive to rebuild. Other parts of the car, however, are old-school simple and repairable by mere mortals.

“Upon purchase, your to-do list should include replacement of all cooling and heating hoses plus both thermostats.

“The three most important things to remember with a Jaguar V12 are: don’t let it overheat, don’t let it overheat, and don’t let it overheat. When things get hot, valve seats tend to part ways with the cylinder heads. Mechanical mayhem ensues.

“You might also consider dropping the I.R.S. for a thorough cleaning, replacement of the I.R.S. mounts and trailing arm bushings, plus a brake caliper inspection–all of which are eminently easier with the assembly removed.

“Enjoy the search, take pride in your purchase, and give XKs Unlimited a call when you need help.”

This article is from an old issue of Grassroots Motorsports. Get all the latest how-tos and stories for just $20 a year. Subscribe now.

Parts & Service

British Motor Trade Association
britcar.org
(616) 355-2850

Tsikuris Classics
(863) 858-7981

Welsh Enterprises
welshent.com
(800) 875-5247

XKs Unlimited
xks.com
(800) 444-5247

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Jaguar Clubs of North America
jcna.com

JaguarForums.com

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Comments

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frenchyd
frenchyd Reader
2/27/17 3:06 a.m.

I've bought Jaguar XJ-S's for as little as $300. In fact I was once given a very early (1975) XJ-S because the junk yard had almost no call for parts. That complex looking V12 intimidates most but it's amazingly strong and durable. Minor little things tend to let it down. The distributor for example gets it's lubrication when the cap and rotor are removed, a screw removed and a few drops of oil are dropped in every other oil change.. Except almost no-one is aware of that requirement. As a result a lot of mechanics get their first look inside a V12 in a vane attempt to restore the performance or prevent overheating.. I hate to tell you how many really good engines I've picked up for as little as $50 (normal junkyard price tends to be between $500-$1500) for simple issues like a seized up distributor.

Yes the rubber hoses in the vacuum/fuel systems tend to harden and crack. However they are easy enough for a D.I.Y to replace. Doing so every 5 years or so prevents a lot of issues like rough running or fires.

On the other hand everything on a Jaguar is extremely stout.. The rear ends constantly find their way into hotrods and Cobra replicas making over 500 horsepower.. The GM turbo 400 transmission has the heavy duty parts found in Ambulances and tow trucks.. and the whole engine looks like one of those 8000 horsepower top fuel engines. The Mains are over 3 inches and the rod journals are 2.3 inches (compared to a small block chevy's 2.00 or later 2.10) The iron sleeves just press out if anyone could ever actually wear one out..

From 1975-to about 1978-79 the transmission was a cast Iron Borg Warner (yep! a version of the Studebaker transmission from the 1950's) the less said about it the better! But the early (up to 1980) fuel injection is the easiest to fool and has the biggest injectors.. However it's analog not digital, not a single microchip. Only the last years with Ford had any IC networks.

In 1981 they introduced the H.E. It was designed to improve fuel mileage and meet California's smog regulations. They achieved that with a combustion chamber similar to GM's fireball six of the 40's and 50's . The sad thing is the performance potential of the early (1971-1980) flathead was lost.. Those heads flowed like an inverted Hemi with the combustion chamber in the piston. In fact all race cars used that early flathead because of vastly superior flow potential.. However the H.E. went from a compression ratio of 7.8-1 to 11.5-1 while still using pump (92 octane) grade fuel. The good news was because of a more efficient transmission, taller final drive ratio, and higher compression fuel mileage went from 8-10 to 12-17 MPG.. Not bad for a 4200 pound car..

frenchyd
frenchyd Reader
2/27/17 3:22 a.m.

Be aware that at best the XJ-S is a low production car.. Early on annual production seldom reached 3000 and one year was under 1000. In fact total production of all V12 engines (including XJ-12) didn't begin to achieve break-even. That changed with the advent of the H.E. engine and it's better fuel mileage and transmission..

With the introduction of the 4 valve all aluminum six cylinder reliability took a dramatic upswing. In fact GM was considering buying Jaguar and in doing their due diligence discovered what a great engine the 4 valve all aluminum engine was. They then bought it (and tooling etc.) modified it to use in their new Mid range SUV's Trailblazer, Envoy, etc.

Once Ford bought Jaguar quality went up dramatically and so did sales.. From 1992 until end of production in 1996 the engine was stroked to 6.0 litres from it's original 5.3 increasing power 23 horsepower while still increasing slightly fuel mileage (Better fuel injection and crank fired ignition)

tripp
tripp Reader
2/27/17 3:32 a.m.

My dad had one for a few years the only car I knew that the fire extinguisher got good use in. Apparently if my memory is correct they can leak oil into the catalytic converter.

Beatiful car yes, near an e type in beauty no in my opinion. Expensive if you don't do your own work.

frenchyd
frenchyd Reader
2/27/17 4:02 a.m.
tripp wrote: My dad had one for a few years the only car I knew that the fire extinguisher got good use in. Apparently if my memory is correct they can leak oil into the catalytic converter. Beatiful car yes, near an e type in beauty no in my opinion. Expensive if you don't do your own work.

Fire extinguisher? Well it probably wasn't oil leaking rather one whole bank of the engine shut down and pumped raw gas into the converter due to the distributor issues I mentioned..

As for expense of working on? Due to the complex appearance of the engine it's extremely easy for a less than honest (or perhaps ignorant) mechanic to run up a sizeable tab. I've seen water pumps, headgaskets, radiators, fans rebuilt/replaced etc. all in a vane attempt to fix the frozen distributor issue..

A few drops of oil in the proper place every other oil change would have solved that!!

tripp
tripp Reader
2/27/17 4:29 a.m.

Highly plausible on it being raw fuel I just know there was not than 1 engine fire before it eventually had an issue that was too expensive to fix from my dad's perspective. Trying to remember back 10+ years ago for the details.

David S. Wallens
David S. Wallens Editorial Director
2/27/17 8:41 a.m.

frenchyd, thanks for the additional input. (And once you say that a transmission is ambulance-tough, you kind of have me; I have the same TH400 in my Pontiac wagon, in fact.)

sesto elemento
sesto elemento SuperDork
2/27/17 11:34 a.m.

My buddy has an rs, it's kinda cool.

wspohn
wspohn HalfDork
2/27/17 3:02 p.m.

Just be aware that a rusty Jaguar is a money pit second to none.

A friend' father owns an XJS he bought new - a very rare fawn sort of gold colour. It has less than 5,000 miles on it as it was used for sunny weekends only. It has been sitting under a carport for many years. It is rusted to ratE36 M3 just sitting there, having never seen winter or even wet driving conditions, nor salt on the road.

frenchyd
frenchyd Reader
3/1/17 4:53 a.m.

In reply to wspohn:

Just sitting is tough on any car. Surface rust isn't a real issue except it will require a repaint to make look decent again but you are lucky in that Old Jaguars have a lacquered based paint which is easy to spot in by a skilled painter. Matching a rare paint isn't as hard as it once was with the new digital matching equipment. However good luck finding a skilled painter, with access to the new equipment and someplace to blend up a small amount of paint..

As far as a money pit, a combination of a lack of knowledge and imagined complexity has caused many a trusting owner to allow an unscrupulous mechanic to "rebuild" a V12 simply in an attempt to get it to run properly or not overheat. A properly trained mechanic would check to see if the distributor is frozen due to lack of lubrication before going off on expensive rebuilding or modifications of the cooling system.

However if there are holes in the body etc.. don't waste time and a lot of money trying to rebuild rust. Go buy a car without those issues.. if the mechanical bits are that good do a swap into the good body.

frenchyd
frenchyd Reader
3/1/17 4:58 a.m.
David S. Wallens wrote: frenchyd, thanks for the additional input. (And once you say that a transmission is ambulance-tough, you kind of have me; I have the same TH400 in my Pontiac wagon, in fact.)

That V12 has a shocking amount of torque for such a small little engine.. hence the heavy duty big block internals. I have taken apart a transmission where the internals were swapped out at the transmission shop in a vane attempt to fix the hesitation caused by the common TH400 dropped seal issue. (caused by someone changing the fluid and not knowing what they are doing).. It's happened to lots of GM cars too!

Driven5
Driven5 Dork
3/1/17 10:37 a.m.

That's the first I've heard a Jag V12 referred to as a "small little engine"...Yeah, all 700lbs of it.

Dr. Hess
Dr. Hess MegaDork
3/1/17 12:44 p.m.

A guy I know has a hobby of building V12 motors. Any V12. He says the stock Jag V12 bottom end was good for 1,000 HP.

frenchyd
frenchyd Reader
3/4/17 11:42 a.m.
Driven5 wrote: That's the first I've heard a Jag V12 referred to as a "small little engine"...Yeah, all 700lbs of it.

It starts out at 326 cu.in. so yes it's small. It's also very narrow, 22 inches,24 with exhaust manifolds. Most in-line sixes are as wide or wider. Only 24 inches high to the top of the manifold. It is also at least 32 inches long

As to weight, while the block and heads are aluminum. The crankshaft alone is 100 pounds made of a high quality forged steel. Boring the thick iron sleeves out, offset grinding the crank and using aftermarket connecting rods, using modern small alternators, gear reduction starters, replacing the cast iron pulleys with modern multirib pulleys, it can approach 550 pounds.. Considering that is within 40 pounds of what a Small block Chevy weighs, it's not bad for an engine that can easily go over 500cu.in.

GTXVette
GTXVette HalfDork
3/5/17 1:51 p.m.

I did it,I feel great about it and FULLY intend on it Being a Daily Driver, a Jet Black 1989 (2/89) convertable.Fuel pump went out and it was parked 10 years ago. I looked for an Hour and cannot find any rust, the interior is trashed from Sitting in the Sun and every thing else that needs replacing from Time and just sitting. I am so Stoked!!! also Has the Lace pattern wheels and very dry rotted Tyres (I will have to learn the Queens English)

crxmike
crxmike Reader
3/5/17 2:02 p.m.

Need pics of said purchase! I am looking myself for an XJS convertible... Different than the miatas or bmws I'm familiar with.

Dr. Hess
Dr. Hess MegaDork
3/5/17 2:22 p.m.

Y'all need to come to our Brits in the Ozarks car show in September in NW Arkansas.

frenchyd
frenchyd Reader
3/6/17 1:32 a.m.
Dr. Hess wrote: A guy I know has a hobby of building V12 motors. Any V12. He says the stock Jag V12 bottom end was good for 1,000 HP.

I would say that he's being conservative, 4 bolt mains of over 3 inches, Forged steel crankshaft, Rod journals of 2.3 inches , a block that looks similar to those 8000 horsepower top fuel engines except for 12 cylinders instead of 8, The heads are held on by high quality studs 52 per engine 26 per head. Plus the oil pump is massive compared to a typical engine.. The connecting rods look as if designed to rev over 8000 rpm and in fact were tested to 8300 RPM without issue..

The later V12 from 1992 until the end of production (1996) has a much better crankshaft seals and even bigger oil pump. However only the first 2 years had the Forged steel crankshaft. The last years were made of sintered Iron.

GTXVette
GTXVette HalfDork
3/6/17 6:34 a.m.

Frenchy, Thanks for looking in, this one isn't without some issues but NO FEAR it is what it is and it's A Beauty. My Vette Is the Hot Rod and I promised my Wife that I wouldn't Start Modifying it before It's Running.

I am a little supprised the rims are only 6 " wide and well it needs Tyres so I will look for some a tiny bit Wider. 90% of the inside will need replacing, all good behind the seats. his son backed the Boat trailer into the D.S. Tail Light but other than a deep scratch on the driver door it's great! Must keep saying NO Mods.

frenchyd
frenchyd Reader
3/11/17 4:22 p.m.
GTXVette wrote: Frenchy, Thanks for looking in, this one isn't without some issues but NO FEAR it is what it is and it's A Beauty. My Vette Is the Hot Rod and I promised my Wife that I wouldn't Start Modifying it before It's Running. I am a little supprised the rims are only 6 " wide and well it needs Tyres so I will look for some a tiny bit Wider. 90% of the inside will need replacing, all good behind the seats. his son backed the Boat trailer into the D.S. Tail Light but other than a deep scratch on the driver door it's great! Must keep saying NO Mods.

I agree with the No-Mods idea.. The XJ-S I picked up had been sitting for 10 years while the previous owner had tried to sort out the differences between the later fuel injection and the original. Had he asked I would have told him there was no power or mileage difference. Marginal reliability improvement maybe and yes cosmetic.(assuming you feel the 6.0 litre looks nicer than the earlier 5.3 in that regard)

Interior parts in a lot of cases are no longer available. Your best option may be another car!!!Find a project or a collision car someone has given up on but the interior bits are still in good shape.. You can budget about $3-500. You may be able to recover all of that by selling off pieces and parts not used. Don't worry that the leather may feel like cardboard there are products out there (my favorite is called leatherique (sp)) that solve that issue and I hate to say this for fear of starting a war but all leather is painted!!! Natural leather is too spotchy to be used raw so it get's painted.. I re-sprayed my MGTD interior back in 1973 and it still looks good today. If the leather isn't badly worn/torn try sanding it down with 400 or 600 grit sandpaper to remove the ridges etc.. I've seen super glue used successfully to rejoin small tears (but it's strictly a one shot approach do not use to excess!!!) If the seam has given up bring it into an upholstery shop to be re-sewn.

Wider tires only increase the turn radius TO UNACCEPTABLE numbers. Unless you are willing to go to fender flares (and then it's resale value will take a really intense trip south).. Accept it as a cruiser without any racing pretensions..

It's weight is the main issue you need to overcome, 4200 pounds. While I've taken one down to 2700 pounds it was completely stripped to race car status.. Yes it would be possible to get it down to around 2300 pounds with Carbon Fibre replacing steel.

Pattyo
Pattyo New Reader
3/11/17 6:38 p.m.

French is there a "cheap" way to convert these engines to carburation? It sounds like the fuel injection is not terrible but I like the look of carbs.

sergio
sergio Reader
3/11/17 7:03 p.m.

My guess is webbers are the only ones and they aren't cheap.

GTXVette
GTXVette HalfDork
3/11/17 7:16 p.m.

As I Am Making Payments to get this car, no Hurry's, but will take me 'till the end of the summer to pay out . so looking for parts and or repairs I can Plan ahead and be ready for them. I'm excited and will go by tommorow to get some Pics. this takes me out of the Challenge for Financial reasons but not to worry as someone has offered me a seat in their car, Old Dog's stick togeather, aka "Pack Mentality"

frenchyd
frenchyd Reader
3/12/17 5:57 a.m.
Pattyo wrote: French is there a "cheap" way to convert these engines to carburation? It sounds like the fuel injection is not terrible but I like the look of carbs.

Carbs vs Fuel rejection, The early V12's all had carbs. from 1971-1974 California carbs were 242 horsepower while European carbs were something like 271 horsepower. Then they switched to fuel rejection, it kicked it up to 292 horsepower so roughly carbs cost about 50 horsepower over fuel rejection.. (OK I know it's supposed to be injection) But wait that's not all folks!!! the problem with carbs is the stupid dog leg in the manifold to get the carb to fit under the bonnet of an XK-E. When that is cut off there is a 50 horsepower gain.. (Done by the guy with the MGB GT V12 )

Here's the issue with fuel injection.. Most Jaguars don't have any real way to adjust them. Oh there is a slight adjustment built in for slightly richening or leaning out the mixture but nowhere near modern systems.. There isn't an IC network to be found.. Believe it or not, it's analog not digital!!

An outfit in England (AJ6 Engineering) can adjust things for you depending on what you do to the engine but it's very much a case of you shipping your "computer" to them, telling them what you need and they "adjusting" it to what they hope solves your requirements and shipping it back..

There are ways to trick the system. When I turbo'd a V12 I used a simple FMU (fuel modification unit) that took the boost pressure and as the signal increased it sent a lean mixture signal to the computer so it fattened up the mixture.. It was only $85 back then. Dealing with the timing I took a H.E. distributor and switched it for the Carb distributor basically trading advance for retard. It very much was a kludge system done just to give me a shot at Lemons racing until talking with some official's I found out that basically they wouldn't allow it.

The real power gains that cost next to nothing are to switch to E85 gas. On the V12 there is 100 horsepower waiting for you without having to open the engine up!!** But you need to really fatten up the mixture.. (by about 65%) If you use the earliest injectors in the latest engine you can't get there! So you are forced to resort to something like a Megasquirt computer and while it might exist for a V12 I'm sure no one has mapped the requirements of E85 in a V12 Jaguar..

My solution is to cut the end off the fuel injection manifold and with the aide of a piece of aluminum angle weld on a plate to take 3 (three) Stromberg carbs per side.. (six total) There are a lot of 1&3/4 inch Stromberg carbs around basically the go-to carb of the early pollution control solution.. Jaguar, (6&12) Volvo, Triumph, MGC, etc. etc..

Six carbs instead of 4 gives you 50% more flow and it's merely a needle and jet away from the required enrichment.. Burlen (sp?) carbs is still in business..

Now here's where things get really good! The early flathead engines had only a 7.8-1 compression ratio. while the later engines called the H.E. had not only the needed fuel injection manifold but also 11.5-1 compression ratio.. perfect to take advantage of one of the real benefits of all that alcohol!!!

The flaw will be the distributor! Grab a distributor off the early one and the advance curve in it will work a lot better than the retard curve in the H.E. If you can find one from a European car for the best curve.. (pretty much hens teeth since most early V12's came here to American)

** while fuel mileage in a H.E. will go down to about 7-9 (compared to maybe 14-17) the lower cost of E85 will get you a similar cost per mile..

frenchyd
frenchyd Reader
3/12/17 6:14 a.m.
sergio wrote: My guess is webbers are the only ones and they aren't cheap.

No they aren't cheap, but a set of Webers is only the start.. you can easily spend that cost again trying to get the right set of jet's so the carbs work properly.. That and dyno time.. No they aren't simply bolt on and mess with the screws a bit. Too lean and they will backfire maybe causing leaking fuel to ignite.. Yep there will be leaking fuel.. Too often fuel bowls won't be properly tightened or fuel lines will work loose with all the switching jets etc.. Or the fuel lines will crack from old age/ the wrong line selected/etc. Only a complete compulsive can eventually get a set of Webers running properly..

And here is the main issue with Webers.. The hood!(bonnet to the British) the little stub manifolds required to clear the hood offer no possibility of proper intake runner length. (unless you give up on the less expensive IDF's and use the DOE's with long horizontal runners).. So you spend thousands of dollars and can't make significantly more horsepower because of the short stub manifolds! Not to mention the fact that you may be working with only 3/4 of an inch for air-cleaner!!!

frenchyd
frenchyd Reader
3/12/17 6:25 a.m.
GTXVette wrote: As I Am Making Payments to get this car, no Hurry's, but will take me 'till the end of the summer to pay out . so looking for parts and or repairs I can Plan ahead and be ready for them. I'm excited and will go by tommorow to get some Pics. this takes me out of the Challenge for Financial reasons but not to worry as someone has offered me a seat in their car, Old Dog's stick togeather, aka "Pack Mentality"

That's too bad because a XJ-S can be bought for as little as $300, Ok with a degree of tinworm damage to the body !! That only makes it a perfect candidate to completely gut to get it down to weight and make nice fat fender flairs to cover those Corvette wheels you buy for a song. Oh and for Brakes there are always Wilwoods..If you want to stop on a dime and get 9&1/2 cents change!! (they bolt right on) plus they are massively lighter than the originals..

GTXVette
GTXVette HalfDork
3/12/17 7:43 a.m.

Don't think I haven't looked,I found a complete Suspension and Drive train For a Grand Up in Tennessee But whole Running Cars are few and Far between here in Ga. What do you have For Sale? I can put togeather a car from Parts but starting with a complete car is best to me. If you have a 6.0L with a good Interior that will run for 300.00 I will get a Loan.

Pattyo
Pattyo New Reader
3/12/17 1:00 p.m.

sorry, I'm kinda slow... so to recap: find a 92-94 car (that gets you the good crank, oil pump, high compression, good heads, and turbo 400. Then find an early european distributor and oil the crap out of it before installing it. Then, cut the dog leg and the end off of the manifold and install 6 strombergs?

yupididit
yupididit Dork
3/12/17 3:35 p.m.

My buddy from back home has a really nice xjs.

Terry's xjs

If only I could find an xjs or an xj12 to swap in a turbo 4.8, that would be splendid. Or maybe swap in the Mercedes m120 v12.

frenchyd
frenchyd Reader
3/13/17 4:23 a.m.

In reply to GTXVette:

You are looking in the wrong places.. Forget Craigslist, forget running for $300. Only two places to find such a low price.. Either through a network of Jaguar owners, or the wrecked cars wholesalers like co-part or IAA. Patience too is required.. It took me several months to find a nice XJ-S at a price I was willing to pay.. Then the lead was discovered by a friend and given to me..

The previous owner had owned it for a decade before giving up on it. He'd taken a fully running, shinny, car with a nice interior and through the idea of "improvement" turned the engine into boxes of parts, leather the stiffness of cardboard, and heavily oxidized paint.

The paint will buff out, the leather will be treated to make it soft as it was when new, and I'll either put the parts together and restore the car. Or put a 6.0 litre in with a few other upgrades.

The free one was given to me by a junk yard owner who hadn't sold a piece off it in years. It was an early 1975 about number 125 or so. Nice, nearly completely rust free, and I kept it for many years before another home was found for it.. (other priorities at the time)..

You do need to think outside the box though.. Sedans used the same engine, transmission, and running gear and they have almost no value if they aren't pretty, shinny, and running, I've had my share of rusty ones hauled home free or for a few bucks, taken apart for engines and other pieces..

frenchyd
frenchyd Reader
3/13/17 4:49 a.m.
Pattyo wrote: sorry, I'm kinda slow... so to recap: find a 92-94 car (that gets you the good crank, oil pump, high compression, good heads, and turbo 400. Then find an early european distributor and oil the crap out of it before installing it. Then, cut the dog leg and the end off of the manifold and install 6 strombergs?

What are you trying to achieve? The use of 6 strombergs is to allow the use of E85 gasoline.. E85 is magic elixir, a cheap magic elixir!! It will add about 100 horsepower to a nearly stock engine.. If you try to use E85 in a stock V12 it won't run!!! If by some miracle you do get it to run it will ruin the motor..

The good heads come on the early engine, 1971-80. As does the good distributor.. Now Any V12 head will fit on any V12 engine. However if you go to early heads on a later (1981 and newer) engine you must buy new pistons for it. Prices on good aftermarket pistons will approach $100 each times 12.

If you don't want that hassle just use a later engine with the early distributor.. You won't make as much power but approaching 400 horsepower in a nearly stock motor isn't bad especially when you look at all the torque you will have..

The 6.0 V12 gains an additional 25 horsepower over the 5.3 V12 The stock crank in any V12 is massively overbuilt. It's just if you plan on all out racing the early forged crank is slightly better..

As far as the distributor, the lack of oil seizes up the distributor and prevents it from advancing or retarding properly.. Most can easily be taken apart, cleaned up, re-oiled and used again.. they work like any distributor just with 12 wires instead of 4-6or8.
However with the advent of the 6.0 litre V12 Jaguar went to distributor less ignition..

frenchyd
frenchyd Reader
3/13/17 4:57 a.m.
yupididit wrote: My buddy from back home has a really nice xjs. Terry's xjs If only I could find an xjs or an xj12 to swap in a turbo 4.8, that would be splendid. Or maybe swap in the Mercedes m120 v12.

That is a very pretty XJ-S and I do like how low they've gotten an already low car!!

I realize you are joking about the Chevy!! But too many people ruin Jaguars with that swap.. The problem is the wiring will make any swap unreliable. Among other things the tach won't work. the air-conditioning needs major changes to work, the heating system become a nightmare, and you still have a 4200 pound car so it won't be very fast! As for turbocharged, I've done that to a XJ-S and it really makes that V12 scream! Mine was rude and crude meant to be a race car but it still runs around here smoking tires

GTXVette
GTXVette HalfDork
3/13/17 5:58 a.m.

I have my Life Screwed up to a Point that Jumping into the Jaguar Life is only Going to be minimal,I am just Too Divested into American Iron and can't Dump enough to make a total changeover. They will be a life long desire and the saying is "Go With What You Know" I'll do what I Can with this car and keep My Eyes and Ears open I have tried to Hire on at a Jaguar Restoration Shop Here In our Little Town Called SPEEDWELL But Being Older Than Even Their Parents I guess They Don't Think I would Fit In. I say Their Loss.

yupididit
yupididit Dork
3/13/17 10:34 a.m.
frenchyd wrote:
yupididit wrote: My buddy from back home has a really nice xjs. Terry's xjs If only I could find an xjs or an xj12 to swap in a turbo 4.8, that would be splendid. Or maybe swap in the Mercedes m120 v12.

I realize you are joking about the Chevy!! But too many people ruin Jaguars with that swap.. The problem is the wiring will make any swap unreliable. Among other things the tach won't work. the air-conditioning needs major changes to work, the heating system become a nightmare, and you still have a 4200 pound car so it won't be very fast! As for turbocharged, I've done that to a XJ-S and it really makes that V12 scream! Mine was rude and crude meant to be a race car but it still runs around here smoking tires

I wasn't joking about swapping it. Though rethinking, I would probably put a 2jzgte in it like Aaron. He even makes and sells xj 2jz motor mounts. But, an LS or m120 would be great as well.

I'm not a fan of trying to get a v12 jag to run. The Mercedes m120 v12 is much better in my opinion. It's easier to work on, simple compared to the jag, more reliable, more powerful out the box. I know you think the only fault of the jag v12 is incompetent mechanics. I know the m120 has its own issues but I rather deal with those than the jaguar.

wspohn
wspohn HalfDork
3/14/17 2:43 p.m.
There are a lot of 1&3/4 inch Stromberg carbs around basically the go-to carb of the early pollution control solution.. Jaguar, (6&12) Volvo, Triumph, MGC, etc. etc..

FWIW the MGC did not use Strombergs, they used SU HS6 carbs. I really don't like the 175 CDSE Strombergs that cars like the TR-4A used - smogger carbs with limited adjustment.

frenchyd
frenchyd Reader
3/14/17 7:20 p.m.
yupididit wrote:
frenchyd wrote:
yupididit wrote: My buddy from back home has a really nice xjs. Terry's xjs If only I could find an xjs or an xj12 to swap in a turbo 4.8, that would be splendid. Or maybe swap in the Mercedes m120 v12.

I realize you are joking about the Chevy!! But too many people ruin Jaguars with that swap.. The problem is the wiring will make any swap unreliable. Among other things the tach won't work. the air-conditioning needs major changes to work, the heating system become a nightmare, and you still have a 4200 pound car so it won't be very fast! As for turbocharged, I've done that to a XJ-S and it really makes that V12 scream! Mine was rude and crude meant to be a race car but it still runs around here smoking tires

I wasn't joking about swapping it. Though rethinking, I would probably put a 2jzgte in it like Aaron. He even makes and sells xj 2jz motor mounts. But, an LS or m120 would be great as well.

I'm not a fan of trying to get a v12 jag to run. The Mercedes m120 v12 is much better in my opinion. It's easier to work on, simple compared to the jag, more reliable, more powerful out the box. I know you think the only fault of the jag v12 is incompetent mechanics. I know the m120 has its own issues but I rather deal with those than the jaguar.

Well I hope you can accept the power loss.. Chevy into a Jaguar.. Let's take a 1984 Jaguar XJS and compare it to it's 1984 counterpart, a Corvette. Jaguar has 295 hp. Corvette 205 and the torque of a V12 makes it no contest!!! OK let's compare a newer Corvette Say a 1986? (I owned one) A Corvette improves with the tuned port injection Jaguar has been using since 1975 All the way up to 230 horsepower!!! only 65 less than the Jaguar.. I'm sure you can find all sorts of decent Corvette motors really cheap,, er, can't you? I'm pretty sure the sedans and pickups of that era had less power.

As far as getting a V12 to run? What is so complex about it? pistons, conrods, crankshaft, valves, timing chain, sparkplugs, fuel injection, etc.. Is it that you can't count to 12 without taking off your shoes Jaguar even makes that easy. All you need to do is count to 6 and remember side A and side B

frenchyd
frenchyd Reader
3/14/17 7:22 p.m.
wspohn wrote:
There are a lot of 1&3/4 inch Stromberg carbs around basically the go-to carb of the early pollution control solution.. Jaguar, (6&12) Volvo, Triumph, MGC, etc. etc..
FWIW the MGC did not use Strombergs, they used SU HS6 carbs. I really don't like the 175 CDSE Strombergs that cars like the TR-4A used - smogger carbs with limited adjustment.

The last few I've looked at had Strombergs but I suspect you are correct, the earlier ones did have S.U.s

frenchyd
frenchyd Reader
3/14/17 7:25 p.m.
GTXVette wrote: I have my Life Screwed up to a Point that Jumping into the Jaguar Life is only Going to be minimal,I am just Too Divested into American Iron and can't Dump enough to make a total changeover. They will be a life long desire and the saying is "Go With What You Know" I'll do what I Can with this car and keep My Eyes and Ears open I have tried to Hire on at a Jaguar Restoration Shop Here In our Little Town Called SPEEDWELL But Being Older Than Even Their Parents I guess They Don't Think I would Fit In. I say Their Loss.

Don't change anything unless you really know what you are doing.. you will simply make it worth less..

GTXVette
GTXVette HalfDork
3/14/17 9:07 p.m.

Me Comprenda and respect your advise even to the point of not changing wheel width's.

yupididit
yupididit Dork
3/14/17 9:27 p.m.
frenchyd wrote:
yupididit wrote:
frenchyd wrote:
yupididit wrote: My buddy from back home has a really nice xjs. Terry's xjs If only I could find an xjs or an xj12 to swap in a turbo 4.8, that would be splendid. Or maybe swap in the Mercedes m120 v12.

I realize you are joking about the Chevy!! But too many people ruin Jaguars with that swap.. The problem is the wiring will make any swap unreliable. Among other things the tach won't work. the air-conditioning needs major changes to work, the heating system become a nightmare, and you still have a 4200 pound car so it won't be very fast! As for turbocharged, I've done that to a XJ-S and it really makes that V12 scream! Mine was rude and crude meant to be a race car but it still runs around here smoking tires

I wasn't joking about swapping it. Though rethinking, I would probably put a 2jzgte in it like Aaron. He even makes and sells xj 2jz motor mounts. But, an LS or m120 would be great as well.

I'm not a fan of trying to get a v12 jag to run. The Mercedes m120 v12 is much better in my opinion. It's easier to work on, simple compared to the jag, more reliable, more powerful out the box. I know you think the only fault of the jag v12 is incompetent mechanics. I know the m120 has its own issues but I rather deal with those than the jaguar.

Well I hope you can accept the power loss.. Chevy into a Jaguar.. Let's take a 1984 Jaguar XJS and compare it to it's 1984 counterpart, a Corvette. Jaguar has 295 hp. Corvette 205 and the torque of a V12 makes it no contest!!! OK let's compare a newer Corvette Say a 1986? (I owned one) A Corvette improves with the tuned port injection Jaguar has been using since 1975 All the way up to 230 horsepower!!! only 65 less than the Jaguar.. I'm sure you can find all sorts of decent Corvette motors really cheap,, er, can't you? I'm pretty sure the sedans and pickups of that era had less power.

As far as getting a V12 to run? What is so complex about it? pistons, conrods, crankshaft, valves, timing chain, sparkplugs, fuel injection, etc.. Is it that you can't count to 12 without taking off your shoes Jaguar even makes that easy. All you need to do is count to 6 and remember side A and side B

That joke was so condescending and ironic. Ironic because I was born with 6 toes on each foot and 6 fingers on each hand. Jokes on you .

The Jag V12 is a beautiful (when all shiny), unnecessarily complex, finicky, garbage motor. Though they did sound nice when someone goes through the drama of keeping it to run.

Okay okay maybe it's not as bad as I say but not as good as You try to convince everyone. You talk it up to be the God of all piston engines....I want what you're having.

Also, who said anything about using a motor from any 80s GM vehicle? Keep up Frenchy dear!

GTXVette
GTXVette HalfDork
3/15/17 7:26 a.m.

Ain't Skeered, Unnessaraly Complex, Wow I have to back Frenchy here,at 18 I worked for the Lotus dealer, That was SIMPLE,late 70's through early 80's I worked for Caddilac when they changed over to Computer driven FI that was getting Complex, the First Porsche 911 twin Turbo W/Air I looked at I closed the Deck lid and walked Away,and I was at a MB/Porsche salvage shop,I wanted nothing to do with it. I have seen several Chevy Swapped Jag's but they were All In a Junk Yard.

frenchyd
frenchyd Reader
3/18/17 4:27 a.m.
yupididit wrote:
frenchyd wrote:
yupididit wrote: My buddy from back home has a really nice xjs. Terry's xjs If only I could find an xjs or an xj12 to swap in a turbo 4.8, that would be splendid. Or maybe swap in the Mercedes m120 v12.

I realize you are joking about the Chevy!! But too many people ruin Jaguars with that swap.. The problem is the wiring will make any swap unreliable. Among other things the tach won't work. the air-conditioning needs major changes to work, the heating system become a nightmare, and you still have a 4200 pound car so it won't be very fast! As for turbocharged, I've done that to a XJ-S and it really makes that V12 scream! Mine was rude and crude meant to be a race car but it still runs around here smoking tires

I wasn't joking about swapping it. Though rethinking, I would probably put a 2jzgte in it like Aaron. He even makes and sells xj 2jz motor mounts. But, an LS or m120 would be great as well.

I'm not a fan of trying to get a v12 jag to run. The Mercedes m120 v12 is much better in my opinion. It's easier to work on, simple compared to the jag, more reliable, more powerful out the box. I know you think the only fault of the jag v12 is incompetent mechanics. I know the m120 has its own issues but I rather deal with those than the jaguar.

It's nice that you prefer other engines.. I'm glad because if everybody wanted a Jaguar They'd be too expensive and I couldn't have as much fun as I do.. I don't understand why you'd take a V12 out of a Mercedes if you like Mercedes though, is it just putting a square block in a round hole sort of thing?

frenchyd
frenchyd Reader
3/18/17 5:11 a.m.
yupididit wrote:
frenchyd wrote:
yupididit wrote:
frenchyd wrote:
yupididit wrote: My buddy from back home has a really nice xjs. Terry's xjs If only I could find an xjs or an xj12 to swap in a turbo 4.8, that would be splendid. Or maybe swap in the Mercedes m120 v12.

I realize you are joking about the Chevy!! But too many people ruin Jaguars with that swap.. The problem is the wiring will make any swap unreliable. Among other things the tach won't work. the air-conditioning needs major changes to work, the heating system become a nightmare, and you still have a 4200 pound car so it won't be very fast! As for turbocharged, I've done that to a XJ-S and it really makes that V12 scream! Mine was rude and crude meant to be a race car but it still runs around here smoking tires

I wasn't joking about swapping it. Though rethinking, I would probably put a 2jzgte in it like Aaron. He even makes and sells xj 2jz motor mounts. But, an LS or m120 would be great as well.

I'm not a fan of trying to get a v12 jag to run. The Mercedes m120 v12 is much better in my opinion. It's easier to work on, simple compared to the jag, more reliable, more powerful out the box. I know you think the only fault of the jag v12 is incompetent mechanics. I know the m120 has its own issues but I rather deal with those than the jaguar.

Well I hope you can accept the power loss.. Chevy into a Jaguar.. Let's take a 1984 Jaguar XJS and compare it to it's 1984 counterpart, a Corvette. Jaguar has 295 hp. Corvette 205 and the torque of a V12 makes it no contest!!! OK let's compare a newer Corvette Say a 1986? (I owned one) A Corvette improves with the tuned port injection Jaguar has been using since 1975 All the way up to 230 horsepower!!! only 65 less than the Jaguar.. I'm sure you can find all sorts of decent Corvette motors really cheap,, er, can't you? I'm pretty sure the sedans and pickups of that era had less power.

As far as getting a V12 to run? What is so complex about it? pistons, conrods, crankshaft, valves, timing chain, sparkplugs, fuel injection, etc.. Is it that you can't count to 12 without taking off your shoes Jaguar even makes that easy. All you need to do is count to 6 and remember side A and side B

That joke was so condescending and ironic. Ironic because I was born with 6 toes on each foot and 6 fingers on each hand. Jokes on you .

The Jag V12 is a beautiful (when all shiny), unnecessarily complex, finicky, garbage motor. Though they did sound nice when someone goes through the drama of keeping it to run.

Okay okay maybe it's not as bad as I say but not as good as You try to convince everyone. You talk it up to be the God of all piston engines....I want what you're having.

Also, who said anything about using a motor from any 80s GM vehicle? Keep up Frenchy dear!

I'm enjoying the discussion and accept the fact that you fail to see what I do with regard the V12 Jaguar.. I hope it's because you haven't taken one apart and looked at it.. Little details like the con-rod bolts. To get a similar bolt in a Chevy you have to buy them aftermarket from ARP.. The Block on a Jaguar honestly looks like a top fuel block with 4 extra piston bores.4 bolt mains on all seven crank journals, a forged crankshaft made from the same steel found in Formula 1 crankshafts of the era.. The elegant simplicity of the early Jaguar head belies it's powerful capability. It has a total of 56 bolts to hold it tight enough so the engine doesn't need the added weight of a top deck!

Is the engine as installed in production cars complex? Absolutely!! Is the 1975 fuel injection finicky? Well yes because all early fuel injection was. The earliest system is one from a Volkswagen. But in the 70's- 80's and even into the early 90's there were so many issues with fuel injection systems burning they were called car-B-ques!! I had a Chevy Blazer live up to it's name, burst into flames and melt right to the freeway pavement with my wife and two daughters driving in it.. (luckily they got out in time) that was on a 2 year old vehicle that had been maintained by the book at the dealership. Near the end of production all those issues had been sorted out and cars became much less troublesome and maintenance prone.. Not just Jaguar but cars in General..

But that all goes away on a race car.. This is an engine that stone stock the factory ran up to 8300 RPM without a single issue!! That made 750 horsepower and won Le Mans twice! Group 44 won race after race and a championship as well. An engine that can be taken from 326 to 500 cu.in. without buying a new block or crankshaft!

frenchyd
frenchyd Reader
3/18/17 5:51 a.m.
David S. Wallens wrote: Out of the thousands upon thousands of Readers’ Rides on our webpage, a Jaguar XJS is the sixth-highest-rated car. Okay, so it’s a full-race example prepared and campaigned by the championship-winning Group 44 team, but we still know what you’re thinking: Is this British classic worth a serious look? “For anyone old enough to remember leg warmers and big hair, the term ‘icon’ meant more than symbols on your tablet or smartphone,” says Michael Marter of Jaguar parts house XKs Unlimited. “Mickey Mantle, Miles Davis and James Dean were icons. So was the Jaguar E-Type. Drop-dead gorgeous, it was the first volume-produced sports car to offer such a sophisticated and potent package at a comparatively low price. “Replacing the E-Type was well-nigh impossible and the XJS didn’t exactly cause the automotive world to spontaneously combust, but the all-alloy 5.3-liter V12 returned–now sporting fuel injection–as did Jaguar’s excellent and innovative independent rear suspension. Styling was at least handsome and interior dimensions were patterned after someone taller than the average Formula One driver.” His take-home point: “Today the XJS is a fantastic bargain with many variations from which to choose.” How much of a bargain is it? Bring a Trailer recently sold a very clean 1983 coupe for $8100. According to the receipts, some $35,000–yes, 35 really big ones–had recently been spent on a full mechanical and body restoration. Hagerty says that good cars should cost somewhere south of $10,000. Not only is the XJS today’s value buy, it also allows for some choices. The model line debuted for 1976 as a V12-powered coupe. Targa and convertible models were added during the 1980s. XJS production ran all the way though 1996. While all of the V12-powered cars came with automatic transmissions, the drivetrains evolved, too. Jaguar moved to the H.E. (high efficiency) V12 engine for the 1982 model year, and a 4-liter, six-cylinder engine became an option starting in 1993. “While the V12 has instant cachet, don’t discount the later six-cylinder cars,” Marter adds. “The second-generation AJ-16 4.0 six-cylinder is dead-reliable, and there is a chance you’ll find one with a manual transmission.” Is the XJS going to replace your WRX or Miata? Maybe not. But if you’re looking for a comfortable grand touring car that offers some panache, then the XJS could be worth a look.

Group 44 Racing XJ-S V12 too rich for your blood? Why not build a tribute car? Ratty XJ-S's start in the hundreds of dollars.. Taking weight out won't cost anything. If something might have market value sell it! You'll need to get rid of everything to reduce weight and even with a rollcage (Adapt a Camaro kit) you can approach 3000 pounds. It will take a ruthless approach to get it to 2700 pounds but even less is possible with replacement fenders, doors, hood, and trunk lid.

Transmission? 1977 and later used the GM turbo 400. Hint; the dowels line up a scattershield or aftermarket bellhousing..4-5-6 speed? Want nice fat racing brakes? Wilwood!

Want cheap wheels and tires? Corvette

Want a rear end with outboard brakes? (easier to work on than the inboard ones without the issues of brake heat overheating the differential) Look at 1992 or later Sedan or XJ-S most also have a better 3.54 ratio and they all have positraction..

The stock engine will sound pretty sporty without cat's or mufflers and whatever you do duct some nice cold fresh air to the air filter (cut off that power reducing air horn from the filter housing..) Use the high beam of the headlights for cool air for the engine and low beam for cool air for the brakes.

Next if you have the computer upgraded for E85 and buy the bigger injectors required you'll be near enough to 400 horsepower that things will start to get fun..

Headers won't make much difference.. The stock manifolds are only 4 pounds each (total of 4) and unlike a V8 the firing order exhaust pulse doesn't interfere with adjacent cylinders.. Oh sure for an all out race motor there are some horsepower to be found if the headers are actual headers and not just tubular exhaust manifolds. Primary, collector length, and tube-size determined by camshaft. But you're going to have to stuff something like 27 feet of tubing in a really tight compartment..

If you want to see what can be done go to Rob Beere Racing's site.. all the stuff to checkbook your way to a snarling XJ-S

For information on particular injection systems used in XJ-S's Go to AJ6's site..

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