Thanks to all the comments and emails on the freevalve video, sorry I'm so behind on replying, I’m glad everyone enjoyed it. The Cad files are up now, the code video is going to take me a few more days to work out- sorry about the delay. There’s still a lot of bugs I’m fixing.
As someone who works on these for a living I highly recommend doing the injector hoses and fuel lines. As when they leak they tend to spray on to the dizzy and light.
@@theghosttiger1446 depending on the money you spend the same as from a GM V8 smallblock (around 450 HP with 10.5:1 compression using Shells hyperfuel and hot cams) better use a Turbo kit
@@WesleyKagan The engines are very strong, they are capable of 600+ hp. Look up the Lister cars, some of them where bored out to 7.0 and featured twin superchargers.
@@WesleyKagan Used to be very fast too. I remember being picked up one evening by a mate in one and us both rapidly motoring pub-wards. At 135 the sweeping curves of the unlit A1(M) south of Stevenage turned into right-angle bends and one got the impression of falling down a well on the straighter sections. I think this was due to the headlights being inadequate - One simply didn’t have time to focus on what was close enough to see. It was comfortable and quiet though! LOL Have you noticed the fart button BTW?
@@WesleyKagan Don't worry about the little gremlins....these are actually very reliable. You' ll be fine after sorting out the main issues. But the injector hoses are the only real weakness. I picked up one of these in Chicago many years ago, drove it back home to the east coast, picked up the family for a test drive....and it burned down just 1 mile away from home. Turned out that the previous owner had installed the wrong injector hoses with standards clamps on them. I bought another one right away and that never developed any real mechanical problems. I think these are just great cruisers that can go fast...if you want to.
@@therightnuke That's for the "Notoriously boring swaps" series. Seriously though, it would make the car a LOT more reliable and perform the way it should have been in the first place, but I don't think it's in the spirit of this kind of project.
ITBs are really difficult on this car due to the lack of clearance between the bonnet (er, hood) and the engine. Jaguar had to effectively fold the intake over, so it lies across the top of the cylinder heads (conveniently pre-warming the intake air, y'know, for the comfort of the engine or something), in order to make them fit. Mind you, they then fitted the airbox with the *tiniest* inlet size (it's maybe inch and a quarter, without going to measure one). As configured, the V12 is good for about 250bhp, but properly set up with decent FI, ITBs, proper headers and a bit of gas flowing, it should be good for 500bhp at least. Oh, and 8krpm, if you replace the stock main bearing caps... (edit: That would be with a pre-HE engine, with the flat heads. Much less scope for HP improvement on the HE head due to the exhaust valve placement)
@@christop672 check out the car wizzard channel, he is stuffing a Jag V12 into a Chevelle. And he is ditching the OEM Lucas efi and replacing it with a 2x 4barrell aftermarket efi (Holley?) setup including new intake manifolds.
@@theelectricmonk3909 absolutely, but a similar configuration could be adopted (the folded over intake) with ITBs using side draft style motorcycle throttle bodies on a modified stock intake plenum or mandril bent tubing if hood clearance was to be maintained. Alternatively cutting a big hole in the hood is also pretty effective for solving clearance like the “Black Pearl XJS” here on TH-cam.
I really appreciate and respect the variety of content. Not to put words in your mouth or misrepresent your situation but I feel like it could be easy to let the internet confine you to “the homemade freevalve guy” and end up being somewhat stuck doing that. But you’re still doing stuff with projects from before it and taking on new stuff! Really glad I found this channel
I had two XJS’s, one good and one didn’t last a week. When running they are one of the best cruise cars, only wish it had an overdrive. Love what you did with the wood, daily project idea, keep going!!
I was the second owner of a 1986 XJS, British Racing Green with Biscuit interior. Absolutely beautiful car, and drove smooth, quite and comfortable. It had decent power but nothing eye watering, but these engines are smooth, no vibration. The big letdown is the 3speed transmission. Only drove the car on weekends and couldn’t imagine using it as a daily driver. The engine is strong but leaks oil like a sieve. The rest of the car will fall apart. All the rubber bits are trash by now. But if you can get it back to running again, it will be a great car. Good luck.
Okey this was sick! This is absolutely everything that TV lacks, its real, funny as hell, no bullshit.. If I got to choose I would love to see more of this V12 behimeth! Not necessarily performance mods or things like that, but seeing how you did the wood was super cool, something that's always looked like witchcraft made simple! I appreciate all the effort you put into this.
Hahahahahahaha. Mile counter turns when starting.....hahahahhahahahaha. This is becoming one of my favorite channels. All around great content. Wesley is what happens when Vice Grip Garage goes to MIT.
@@WesleyKagan Wow, 1 year ago , basically new, This car would look good in British racing green. Do you still have it ? How did you fix the engine so fast ? Or , it needed a water pump ? How did you fix all that? It runs well in video !!
I had a '84 XJS V12 for about 10 years and the only problem I had was the powe steering pump and the auto trans, and they were both made by General Motors.
Wesley, you of all people would benefit from a lift. It was one of the best investments I ever made 25 years ago. Just picked up another 2 post lift, locally here in SoCal last month, for $1500 in excellent condition.
5sp, ITBs, and a real exhaust system. A Jaguar V12 uncorked with a manual is just amazing. They sound so awesome. Fit euro headlights on it and do a home brew front spoiler. Done. Love your channel!
YES! This.. I just rescued a craigslist 88 V12 for exactly the above (5 speed, ITB’s, etc) and would love to see somebody with this guys abilities take that on as a cautionary tale...
euro headlights?! What? I always find it crazy that we want the american styled headlights, and you guys want the euros. The quad rounds look infinitely better in my opnion.
Euro headlights look sleeker and have more than double the output of the sealed beam USA spec lights, in conjunction with a superior beam pattern. And you get European city lights, which are dead sexy. Yes you can retrofit H4s and keep the quad lamp appearance, but I prefer the flush glass euro lights as opposed to even the [foggy] composite later USA 9004 units. It’s a matter of preference I suppose. To each his own 👍
5 speed, e-fan, replace the nasty fuel injection system with something a bit more modern, and replace the nasty hand-crimped glass fuse fuse box and you'll end up with a fairly reliable car.
Glad to see another XJS being saved from the trash heap. Gonna do a manual swap on mine pretty soon here when work slows down. Didn't know that you lived near by me hehe time to host an XJS meet in the area.
There's just something that seems appropriate about having a fire extinguisher nearby at all stages of working on an old Jaguar... even interior disassembly. Also, ITBs, and a firmer/less roll-y suspension would be cool.
Waiting for my 1976 XJS V12 Silver on Red to come out of the shop. Been there for 3 months. The mechanic reported yesterday that it is running 100% better than when I brought it in - fluid change, cleaned out the gas tank, cleaned fuel injectors, fuel rails, and reconnected some loose vacuum hoses. Can't wait to hear that V12 growl! I'll be watching this series to see how your XJS does in a daily environment.
I like your wood unshiny / unlaquered front panels too, looks real nice! Well a lot nicer then the previous shiny stuff that sold on the car originally.. also love to be able to be so relaxed as you seem to be when doing mechanical car works, Bravo! You must have a lot of experience in this type of work!
First of all, what a fantastically down to earth presentation! The manual 'box from the six cylinder model fits nicely. I wouldn't otherwise bother doing much more than just good basic refurbishment and tune up rather than chasing additional performance especially with that rather tricky engine. With lots of TLC for the brakes and suspension components, that car will feel like you're riding on air. Outstanding woodwork!
Wes..Check out the Lister lemans version of the xjs..6 litre V12..twin turbo👍👍also Harry Metcalf (Harry's garage) has a manual converted V12 xjc..loves it
Best segment title ever. This man even does woodworking! There was an episode of Wheeler Dealers where they had a shop restore a very similar if not the same wood interior. Same basic process. Nice work man! The Who song as a needed repair is interesting. I'd say drive it as is because a trans swap for example would add so much time. At least you actually get stuff done crazy fast though! Overall would like to see it reviewed after the month them move on to another car though.
I love what you did with the wood! Actual wood that you can touch in a car, not locked away behind miles of lacquer! Of course now it needs a bunch of free valves and turbskies ;-).
My mother had a 88 Vanden Plas when I was in high school. My father and I used to joke that when driving it, you should always keep one eye on the mirrors just incase any parts/pieces fall off....
This car would be well cool to modify like a resto mod, so make it reliable and faster with the original motor and some slight body mods to update the styling and make it look really nice, the wood work was on point BTW!
Wesley..just came across this video and could not help myself laughing out loud at some of your rather "laid-back" comments. As an owner of two Jaguar XJS cars, one a pristine 1995 V12 convertible (i.e. garage queen) and the other a 1993 6 cylinder 4.0 coupe with 186,000 miles on the odometer (i.e. daily driver), I certainly can relate to your concerns as to an aging XJS ever becoming a "daily driver". Each morning after connecting the battery isolator and before turning the ignition key, I say a prayer to the Brown's Lane Gods. Some days, remarkably I arrive at my destination and park the car fire engine red coupe under the admiring eyes of naive fellow workers. On other days after the usual exclamations of "mmm..that's new" or walking to my local bus stop, I, much like you start whistling the song which I think includes the lyrics "the trouble I'm in!". Then on another Saturday morning spent under or over the car tracing the latest noise, gremlin, or smell, I smile to myself with a sort of Jack Nicholsonesque manner and contemplate those same questions you asked! So, what have you or did you decide?
Absolutely continue working with this car, I love the style and the stellar pallet of video content the car has to offer (issues that need to be fixed). Throw a five speed in it if that’s your fancy, that sounds interesting. When fixing problems or doing more modifications, it would be nice to see more of your thought process and how you do things, even if that means you’re googling items and solutions- even using your own knowledge. I’m a new subscriber all because of this video!
I bought a 82 XJS from a retired fellow. He was the original owner who ordered the car with a manual transmission had 22,000 miles . Bought it for $5,500. Owner suffered from disability’s from polio so he couldn’t drive it. I spent $10,000 on a full engine rebuild due to old gaskets and seals, spent a lot between replacing the Lucas electronics, and adding a whole new Mondale exhaust system. New Perelli tires. It was my daily driver, Friday night strip car. Took her up and down the 101 freeway on the coast of San Diego every Saturday. I had lots of fun with this car. It turned head’s everywhere. I was challenged at almost every stop light to race. Never did. These cars are not for everyone. A simple tune up costs $600+
Love it!! Been watching for a basket case V12 XJS off and on, maybe one day I will find one and have the spare cash to throw away at the same time, in the meantime can’t wait to see what you do with this one!
I think that's so cool your wife joins in and helps you with your projects. My wife sticks to doing her stuff. I wish she would hang out with me when I was tooling on my various projects.
Old Jags just have a beautiful and timeless design this car in 2022 still looks beautiful even in her current state from body lines I’d look great lowered with aftermarket rims, exhaust, and a 5 speed swap
I bought one of these last July. Mine's a 1978 with a Chevy 350 swapped in (fairly common). That made it reliable enough for me to check a small bag of tools and fly halfway across the country to drive it back home. Excited to see what you'll do. This gives me inspiration to go start working on mine!
That idea with 5speed swap is as close to perfection as it could be :) I am thrilled to see you get through all the necessities to get her going reliably :)
@@WesleyKagan *inserts Shia Leboeuf meme of DO IT* But seriously, a manual and... maybe an intake mod of some sorts to let the V12 sing? Doesn't need to go freevalve especially since it's a daily, but some sorts of ITBs or a more resonant intake. Just wondering about all the awesome stupid stuff that could be done with that! I've been following for about a year since I saw you build the Porsche powered formula car. Loving the content so far!
@@PaulChoix55 Although it sounds tempting, the heads were a SOHC design, most specifically for emissions purposes. It would sound better and run a bit better, but a 327 Chebby small block and a 4 BBl carb would make more power with stock heads- both are the same displacement, the Chebby is two hundred pounds lighter. And getting rid of the zillion hoses of the emissions control system that came with air leaks from new would help too! Call John's Jaguars in Dallas , Texas, for a small block/manual swap kit! An LS 7 and a T6060 would be the boss- better engine set back, lighter and much moar powah! FR
@@fredericrike5974 The SOHC was a compromise - the original design was DOHC, but it was much too big on top to fit in the E-type (which is what it was designed for), the SOHC was a compromise. The V12 was never designed with emissions in mind, which is why it ended up being strangled by emissions equipment. The HE ("High Efficiency") engine was designed to increase MPG, which it did with remarkably little loss of power, but it does massively limit tuning options, as the exhaust valve is buried in a pocket, which hurts gas flow something chronic (by gas I mean exhaust gasses, not fuel). A lightly fettled V12 will give more than 300bhp, a heavily fettled one over 400bhp, and for a seriously modified one, 600+. You can increase the 5.3ltr displacement to over 9ltr by adding a 3/4" spacer block, a stroked crank & 4 new links in the timing chain...
Wow!! Great Channel! Just discovered you. There is soo much subtle comedy mixed in with some beautiful problem solving/engineering. Taking on an old Jag.. Much respect my friend!
If you haven't burst into flames by now I'd recommend rebuilding the fuel rail and injector assembly. The rubber on those is known to dry out and crack pretty frequently which then leads to leaking fuel and lots of fire.
I daily drove a 1990 xj-s for over 3 years. I had to change plug wires which took almost 4 hours and a rear wheel bearing. Other than that it was surprisingly reliable. I got rid of it at 180k miles because 1: I was averaging 16 mpg and 2: my kids could no longer fit in the back seat. It's a beautiful car to look at but nothing spectacular about the performance. I don't regret owning it but I probably wouldn't buy another.
There are 2 sayings about Jags. the first is, "Hang a picture of one on the wall and the next day you will have oil spots on the floor under it." second "The electrical system sucks." Can't do much about the picture but in the 2 I had, An Allison electronic ignition solved hard starting problems in both. Don't overheat the V 12 .It's the kiss of death. I did mine and it swallowed a valve. Still got me 30 miles to home on the right bank of 6 cylinders.
The wood is probably a dark walnut, the cracking is the clear coat lacquer that can be stripped off without damaging the walnut veneer. Nearly all the motor’s accessories are GM and easy to locate, including the 3 speed GM transmission. Rear inboard breaks and four catalytic converters will be a challenge though.Old fuel injection hoses should be replaced as they can notoriously lead to engine fires. The V12 is a beauty, last of Malcolm Sayers designs too. Glad to see it come back to life, good job!
The power window switches can be cleaned if the plastic hasn't gone brittle. If you want to get the window up just jumper the plug. They don't cost much anyway. The problem with these cars is this, they get let go in the maintenance and and because they're complex to work on it never gets done. This is good for us mechanics. We can pick them up cheap but as you pointed out in your list it can take some time to sort out. Before I go, I should mention the fan and fan clutch. The plastic fan gets cracks in it and when you rev them up the fan flies to pieces. They do like to rev up these engines, so before you do I would recommend replacing the engine mounts (cheap same as Range Rover) and replacing the fan and fan clutch. Also I should mention the brakes are excellent in these, so don't accept mediocre as normal. Perhaps they aren't as good as a modern car but for the time they had decent brakes. Re tranny: in the 6 liter they used a Jaguar case GM4l80e. You can buy an adapter for a GM case to the Jag V12 if you can't be bothered finding a Jaguar 4l80e. I wouldn't recommend the the TH700r4 because the 1-2 ratio is too wide for the characteristics of the V12. In the 5.3 liter with the TH400 the rear gear ratio was 2.88 (or 2.78 or something) whereas in the 6 liter they used the 4l80e and a rear gear ratio of 3.54:1. It turns out the diff is based off a Dana 44 and D-44 ring and pinion fit - however - the D-44 pinion shaft is U bolt style so maybe maybe not you might have to mod the driveshaft.
I recently just picked up a beautiful to almost pristine condition XJS. It runs and drives already BUT has the worse kinds of oil leaks coming from valve covers and possibly from oil pressure sending unit. Wish me luck!
Wes: "a bit of corrosion" Water Pump Internals: _[Is practically made of rust, white stuff, __-cursed mud from the holy grail-__ and what looked like copper oxide. Well, at least at first glance]_ You did good on the wood trim, that was nice, and, you know, getting it to run. I love the XJS, its a beautiful car and has a nice engine (when it works of course XD)
@@WesleyKagan Probably caused by the wrong coolant ratio, which should be 50/50. The fuel lines also need replacing though out the car otherwise you are in dire risk of one of them bursting and causing a fire. I'll be re-installing the rear sub frame after a major overhaul on my V12 convertable in the next couple of days.
When i was 14 my local bike shop bought one of these from a scrapyard and allowed us to ride on it with our trials bikes and bmx bikes before it was used for banger racing during a town fairground event, it was fun to jump over the car with ramps, manualing on the roof and bonnet absolutely trashing a car which would probably be worth a fair bit of money here in the UK.
Had an old Jag. It never failed to run, but something was always not working. New rear end was the most expensive, but there were minor problems daily. good luck! But it was the most comfortable car to drive!
I daily drive a 1988 Xj40. It’s got half of the 5.3 V12 basically as an engine. It’s really such a great car. I’ve put 100 000kms on in the past year and I’m on 300 000 now. These era Jaguar XJ’s (not the series 1,2, or 3) were really built well as well as the XJS’s. A lot of people will tell you that they’re rubbish but don’t understand that every car that gets 30+ years old will need work done to it. If these cars are properly maintained they can last a lifetime. As goes with most cars.
I have a 1990 xjs v12 with a 5 speed garage from the 6 cylinder engine car and it is great, transforms the car. I would suggest doing the injector pipes, all rubber bushes, rod the radiator and you could end up with a reliable daily, I did.
I’m in the garage looking at my ‘82 XJS right now, same color paint but “starfish” wheels, amazing how few changes there were in that many years of production. The only obvious difference I see are the steering wheel and sill plates. Many of the same issues, lots of electrical weirdness, brakes, steering rack or pump. Fuel tank leak has it sidelined right now, having trouble finding one.
I just finished restoring the zebra wood trim in my Mercedes w123. I removed the top layer of shellac or lacquer stuff, stained it with Honey 272, and put Minwax Polyurethane on it. It came out great, and yeah the old lacquer or whatever was an awful choice for longevity and made the wood look dull and cheap. Also, I wanted to buy a junker XJS exactly like this one a few years ago. It was in much worse shape, I don't regret passing on it lol.
I live near the Land Rover Range Rover factory here in the UK, so I know a little about the pitfalls daily driving british engineered cars- but with this you are really taking the brave pill with this one! Best of luck :)
Fair play taking that beast on! Even with the Jag parts network here in England I wouldn't much fancy touching one of those with a barge pole, let alone the V12. Have fun replacing all the wiring!
These V12 Jag's with 'Lucas' electrics scare the daylites outta me Makes me wonder what they might have been like if the original build quality was way better Glad to see someone else taking the chance Gr8 videos
I knew someone who had one of these when they were like 5 years old. He said you'd be going like 87mph and push the foot down and it'd take off like you just pulled out from traffic lights and you'd be straight up to 100mph. Only car he had with strong acceleration while it was already going fast.
God bless. I looked at a manual stick shift V12 XJS of this vintage it feels like going on 20 years ago - the owner said it was very rare for the stick as I recall. It had several issues and I took a pass.
It'd be interesting if Wesley was to go this route. I'd love to see it, but the amount of work to do that and keep the car in one piece is probably overwhelming. For now, we'll just have to wait and find out how many times the Jag breaks down!
@@DJDiarrhea yes obviously but you dont usually install such a tech for lulz (miata might be an example just to prove that he could make it work). But wuy install it and have a ton of work for no reason?
Please please please check the tubing from the fuel rail to the injectors, they are notorious for going bad and starting a huge fire. Along with the fuel injector wiring harness down in the v. Other than that have fun with it, and I sure hope it doesn't lose its exhaust system and has to be driven that way!
Beautiful job on the wood dash pieces - the effort you put into them really enhances the interior. If only the flaking clearcoat were that easy to repair.
Yes... 5 speed swap and performance... The IRS subframe assembly with the inboard brakes and differential (especially if it has a Salisbury powerlock diff, but the DANA rear ends are valuable as well) in that car as a single unit are highly sought after by custom rod builders.
"I've never been a fan of glossy lacquer - I'm going to use Tung Oil" - man after my own heart. Amen, brother. Tung oil is amazing, although you really should try to get some proper, pure tung and dilute it down with citrus terpene or gum turpentine.
I have a 1990 Jaguar XJS. I have driven it daily, raced it down in Mexico and a few races here in the states. It starts every time. one thing I can tell you is you have to let everything pressure up, then start it. I have owned it for 21 years.
I remember an old episode of top gear magazine in like 2004 or so where they tested how much nitrous one of these could take before popping, and I would love to have a full audiovisual experience of that if it turns out not to be an example worth saving
I remember working on a slightly newer V12 when I was a Jag tech. Beautiful car, so smooth, but lazy. I always thought it needed a clutch pedal and camshafts. The stock cams are all about being quiet and smooth. That V12 needs something with more valve lift to wake it up.
They were good cars I used to work on them when they were new, check the rubber hoses between the fuel rail and injector they split when old and will spray fuel onto the distributor and cause a fire. The radiator will be clogged if the water pump looks like that.
Having worked on old British cars, including Jaguars and including the XJS, for 50 years here in the UK I strongly suggest you change all the suspension bushes. The way the car rides, steers and handles will be transformed. I don't think you need a 5-speed gearbox - with the engine running correctly and the auto transmission properly serviced you will have sufficient performance. Also, look for sorting out the driveline clunk before you end up causing damage. Often the problem is with the gearbox mounting spring; it loses tension and should be replaced every ten years or so. The brakes will always feel a bit crap if the rear calipers are not properly maintained; they are not easy to get to and a real pain to bleed properly so many mechanics ignore them and the braking is never right. Good luck with it. When they are properly maintained they are super reliable and a joy to drive - only their prodigious thirst for petrol lets them down.
I owned an XJS with a V12 for about 6 years and daily drove it. In addition to daily driving I did drive it to and back on every other weekend Cincinnati OH to Cherry Hill NJ. It had 2 continuing problems. Electrical gremlins and oil leaks that caused rubber parts to disintegrate. It is bad news when the Jaguar dealer service knows your name before you get out of your car. I loved the car but toward the end I thought I owned the service department. I would not buy another ICE Jaguar. I am thinking about an I-Pace. Maybe they fixed the problems of the 90’s. .
Jag is a car that if it is used frequently.. It will be reliable.. Issues come from too much "sitting" (I have a 90 Rouge ED- upgrade trim/wheels).. Drivers are best- do not "baby them". You will learn to tolerate issues.. The V-12 is a tank.. Things around the car tend to give trouble! Frank
Funny that you mentioned this... There's a guy that I'd occasionally spot on my drive home in a V12 XJS. I don't take the same path home anymore though, so we'll never know if it still lives.
Thanks to all the comments and emails on the freevalve video, sorry I'm so behind on replying, I’m glad everyone enjoyed it. The Cad files are up now, the code video is going to take me a few more days to work out- sorry about the delay. There’s still a lot of bugs I’m fixing.
Take your time, my dude!
Thank you Wesley! I have a couple things in mind for the pneumatic valvetrain!
freevalve xjs pls
You actually can for a few days... lol... or you can toss your wallet out the window and save yourself a lot of time..
You should do a free valve bike for Bonneville
As someone who works on these for a living I highly recommend doing the injector hoses and fuel lines. As when they leak they tend to spray on to the dizzy and light.
How much naturally aspirated horsepower can you build out of the v12 5.3?
Excellent advice.
@@theghosttiger1446 depending on the money you spend the same as from a GM V8 smallblock (around 450 HP with 10.5:1 compression using Shells hyperfuel and hot cams) better use a Turbo kit
@@Schlipperschlopper Can they be bored and stroked? Id imagine a fully forged built jag v12 motor with a turbo would be murder on the streets.
@@theghosttiger1446 Arden and Lister did that decades ago but that tuning was so expensive that you could buy an entire Ferrari for that work
The wood trim looks great. The XJS is a fantastic car, shame people don't look after them better.
Thank you! It is quite comfortable and quiet.
@@WesleyKagan The engines are very strong, they are capable of 600+ hp. Look up the Lister cars, some of them where bored out to 7.0 and featured twin superchargers.
@@WesleyKagan Used to be very fast too. I remember being picked up one evening by a mate in one and us both rapidly motoring pub-wards. At 135 the sweeping curves of the unlit A1(M) south of Stevenage turned into right-angle bends and one got the impression of falling down a well on the straighter sections. I think this was due to the headlights being inadequate - One simply didn’t have time to focus on what was close enough to see. It was comfortable and quiet though! LOL
Have you noticed the fart button BTW?
@@WesleyKagan Don't worry about the little gremlins....these are actually very reliable. You' ll be fine after sorting out the main issues. But the injector hoses are the only real weakness. I picked up one of these in Chicago many years ago, drove it back home to the east coast, picked up the family for a test drive....and it burned down just 1 mile away from home. Turned out that the previous owner had installed the wrong injector hoses with standards clamps on them. I bought another one right away and that never developed any real mechanical problems. I think these are just great cruisers that can go fast...if you want to.
@@andylewis7360 fart button?
ITBs and Manual swap would be awesome to see, excited to see this project regardless!
Lsx
@@therightnuke That's for the "Notoriously boring swaps" series. Seriously though, it would make the car a LOT more reliable and perform the way it should have been in the first place, but I don't think it's in the spirit of this kind of project.
ITBs are really difficult on this car due to the lack of clearance between the bonnet (er, hood) and the engine. Jaguar had to effectively fold the intake over, so it lies across the top of the cylinder heads (conveniently pre-warming the intake air, y'know, for the comfort of the engine or something), in order to make them fit. Mind you, they then fitted the airbox with the *tiniest* inlet size (it's maybe inch and a quarter, without going to measure one). As configured, the V12 is good for about 250bhp, but properly set up with decent FI, ITBs, proper headers and a bit of gas flowing, it should be good for 500bhp at least. Oh, and 8krpm, if you replace the stock main bearing caps... (edit: That would be with a pre-HE engine, with the flat heads. Much less scope for HP improvement on the HE head due to the exhaust valve placement)
@@christop672 check out the car wizzard channel, he is stuffing a Jag V12 into a Chevelle. And he is ditching the OEM Lucas efi and replacing it with a 2x 4barrell aftermarket efi (Holley?) setup including new intake manifolds.
@@theelectricmonk3909 absolutely, but a similar configuration could be adopted (the folded over intake) with ITBs using side draft style motorcycle throttle bodies on a modified stock intake plenum or mandril bent tubing if hood clearance was to be maintained. Alternatively cutting a big hole in the hood is also pretty effective for solving clearance like the “Black Pearl XJS” here on TH-cam.
Car Wizard has fixed an XJS V-12 and has some excellent tips on sourcing replacement parts
Car wizard is a hack
I don't know, but there's just something about an old Jag. That puts a smile on someone's face when they start driving it.
I really appreciate and respect the variety of content. Not to put words in your mouth or misrepresent your situation but I feel like it could be easy to let the internet confine you to “the homemade freevalve guy” and end up being somewhat stuck doing that. But you’re still doing stuff with projects from before it and taking on new stuff! Really glad I found this channel
I had two XJS’s, one good and one didn’t last a week. When running they are one of the best cruise cars, only wish it had an overdrive. Love what you did with the wood, daily project idea, keep going!!
I was the second owner of a 1986 XJS, British Racing Green with Biscuit interior. Absolutely beautiful car, and drove smooth, quite and comfortable. It had decent power but nothing eye watering, but these engines are smooth, no vibration. The big letdown is the 3speed transmission.
Only drove the car on weekends and couldn’t imagine using it as a daily driver. The engine is strong but leaks oil like a sieve. The rest of the car will fall apart. All the rubber bits are trash by now. But if you can get it back to running again, it will be a great car. Good luck.
I really want to paint this car BRG but don’t want to go through the trouble of door jams and engine bay.
Okey this was sick! This is absolutely everything that TV lacks, its real, funny as hell, no bullshit.. If I got to choose I would love to see more of this V12 behimeth! Not necessarily performance mods or things like that, but seeing how you did the wood was super cool, something that's always looked like witchcraft made simple! I appreciate all the effort you put into this.
Thanks for the kind words! I find woodwork very relaxing because it's a very easy material to work with.
@@WesleyKagan
Hmm so this car had that bad water pump. Amazing that electrical was still working in it.
@@WesleyKagan
I want this car !!! Once you get rid of it !!!
Hahahahahahaha. Mile counter turns when starting.....hahahahhahahahaha. This is becoming one of my favorite channels. All around great content. Wesley is what happens when Vice Grip Garage goes to MIT.
Thanks so much! haha.
Does the odo turn too if you crank for over a mile?
At least it doesn´t go backwards, then you´d have a Christine!
@@WesleyKagan
Wow, 1 year ago , basically new,
This car would look good in British racing green.
Do you still have it ? How did you fix the engine so fast ? Or , it needed a water pump ? How did you fix all that? It runs well in video !!
I had a '84 XJS V12 for about 10 years and the only problem I had was the powe steering pump and the auto trans, and they were both made by General Motors.
Yeah most of the stuff on this car accessories wise is AC delco
Wesley, you of all people would benefit from a lift. It was one of the best investments I ever made 25 years ago. Just picked up another 2 post lift, locally here in SoCal last month, for $1500 in excellent condition.
I really would, I need shop space something fierce. It's hopefully coming soon, I miss a lift.
5sp, ITBs, and a real exhaust system. A Jaguar V12 uncorked with a manual is just amazing. They sound so awesome. Fit euro headlights on it and do a home brew front spoiler. Done. Love your channel!
YES! This.. I just rescued a craigslist 88 V12 for exactly the above (5 speed, ITB’s, etc) and would love to see somebody with this guys abilities take that on as a cautionary tale...
euro headlights?! What? I always find it crazy that we want the american styled headlights, and you guys want the euros. The quad rounds look infinitely better in my opnion.
Euro headlights look sleeker and have more than double the output of the sealed beam USA spec lights, in conjunction with a superior beam pattern. And you get European city lights, which are dead sexy. Yes you can retrofit H4s and keep the quad lamp appearance, but I prefer the flush glass euro lights as opposed to even the [foggy] composite later USA 9004 units. It’s a matter of preference I suppose. To each his own 👍
Yeah I can see why this car would need "Won't get fooled again" by the Who :D
at sheperton studios/1978...pretty specific for this bri'ish car.
as a former v12 xjs owner you have my deepest sympathies
I have a sweet spot for old Jag's. Love the channel!
5 speed, e-fan, replace the nasty fuel injection system with something a bit more modern, and replace the nasty hand-crimped glass fuse fuse box and you'll end up with a fairly reliable car.
Yup.
That's kinda my plan going forward I think.
This car is easy to modernize and Megasquirt. I have done most of the research into this already if you would like any detailed information.
@@Kamwi_003 would be curious to hear more!
your work with the wood makes you a legend of restoration alone.
Glad to see another XJS being saved from the trash heap. Gonna do a manual swap on mine pretty soon here when work slows down. Didn't know that you lived near by me hehe time to host an XJS meet in the area.
There's just something that seems appropriate about having a fire extinguisher nearby at all stages of working on an old Jaguar... even interior disassembly.
Also, ITBs, and a firmer/less roll-y suspension would be cool.
I've had these cars catch on fire on me. I'm taking no chances.
A manual swap would be brilliant. These Jag V12 have a relatively short stroke and like to rev once the mushy torque converter is removed.
Absolutely one of the best car channels out there. Taking the risks on "unreliable" cars so we don't have to, and fully documenting it. Incredible!
Waiting for my 1976 XJS V12 Silver on Red to come out of the shop. Been there for 3 months. The mechanic reported yesterday that it is running 100% better than when I brought it in - fluid change, cleaned out the gas tank, cleaned fuel injectors, fuel rails, and reconnected some loose vacuum hoses. Can't wait to hear that V12 growl! I'll be watching this series to see how your XJS does in a daily environment.
Those look like harbor freight jack stands. if you haven’t already, check to see if they are the recalled ones, being crushed by a v12 would suck.
They are, luckily they aren’t the dangerous ones.
Only way I’d like to go out 😂
The longer you keep it the more i will watch your channel, "Deal"
I like your wood unshiny / unlaquered front panels too, looks real nice! Well a lot nicer then the previous shiny stuff that sold on the car originally.. also love to be able to be so relaxed as you seem to be when doing mechanical car works, Bravo! You must have a lot of experience in this type of work!
I have always wanted to see someone build an xj
This might be the perfect candidate.
Keep up the needlessly good content Wesley
First of all, what a fantastically down to earth presentation!
The manual 'box from the six cylinder model fits nicely. I wouldn't otherwise bother doing much more than just good basic refurbishment and tune up rather than chasing additional performance especially with that rather tricky engine. With lots of TLC for the brakes and suspension components, that car will feel like you're riding on air. Outstanding woodwork!
Awesome work with the wood trim! Subtle and elegant. And hell YES this needs a 5-speed!! And ITBs! Because V12.
ITBs are great for race cars, but I’d be worried about the drivability for this one. It would clean it up a lot
Nicest exhaust sound I ever heard was a race prepped XJS with Super Trapp pipes revving at the lights in front of me. Oh lordy.
That water pump was the most ridiculous thing ive ever seen lol
And that new trim looks great
Much love from England (where we mostly buy German and Japanese cars...).
Yeah even the Rovers are starting to go downhill after Ford started putting their Axles on the Discovery.
Wes..Check out the Lister lemans version of the xjs..6 litre V12..twin turbo👍👍also Harry Metcalf (Harry's garage) has a manual converted V12 xjc..loves it
Best segment title ever. This man even does woodworking! There was an episode of Wheeler Dealers where they had a shop restore a very similar if not the same wood interior. Same basic process. Nice work man! The Who song as a needed repair is interesting. I'd say drive it as is because a trans swap for example would add so much time. At least you actually get stuff done crazy fast though! Overall would like to see it reviewed after the month them move on to another car though.
I love what you did with the wood! Actual wood that you can touch in a car, not locked away behind miles of lacquer! Of course now it needs a bunch of free valves and turbskies ;-).
My mother had a 88 Vanden Plas when I was in high school. My father and I used to joke that when driving it, you should always keep one eye on the mirrors just incase any parts/pieces fall off....
This car would be well cool to modify like a resto mod, so make it reliable and faster with the original motor and some slight body mods to update the styling and make it look really nice, the wood work was on point BTW!
What a brilliant transformation making those wood pieces was! Thats the kind of stuff I love to see.
Wesley..just came across this video and could not help myself laughing out loud at some of your rather "laid-back" comments. As an owner of two Jaguar XJS cars, one a pristine 1995 V12 convertible (i.e. garage queen) and the other a 1993 6 cylinder 4.0 coupe with 186,000 miles on the odometer (i.e. daily driver), I certainly can relate to your concerns as to an aging XJS ever becoming a "daily driver". Each morning after connecting the battery isolator and before turning the ignition key, I say a prayer to the Brown's Lane Gods. Some days, remarkably I arrive at my destination and park the car fire engine red coupe under the admiring eyes of naive fellow workers. On other days after the usual exclamations of "mmm..that's new" or walking to my local bus stop, I, much like you start whistling the song which I think includes the lyrics "the trouble I'm in!". Then on another Saturday morning spent under or over the car tracing the latest noise, gremlin, or smell, I smile to myself with a sort of Jack Nicholsonesque manner and contemplate those same questions you asked! So, what have you or did you decide?
love the woodwork in the interior that you did -- inspiring!
PLEASEE MAKE MORE VIDEOS WITH ITT. THERE ARE NOT ENOUGH VIDEOS ON FIXING REPAIRS FOR XJSs!!
Lovee this channel!
Absolutely continue working with this car, I love the style and the stellar pallet of video content the car has to offer (issues that need to be fixed). Throw a five speed in it if that’s your fancy, that sounds interesting. When fixing problems or doing more modifications, it would be nice to see more of your thought process and how you do things, even if that means you’re googling items and solutions- even using your own knowledge. I’m a new subscriber all because of this video!
I bought a 82 XJS from a retired fellow. He was the original owner who ordered the car with a manual transmission had 22,000 miles . Bought it for $5,500. Owner suffered from disability’s from polio so he couldn’t drive it. I spent $10,000 on a full engine rebuild due to old gaskets and seals, spent a lot between replacing the Lucas electronics, and adding a whole new Mondale exhaust system. New Perelli tires. It was my daily driver, Friday night strip car. Took her up and down the 101 freeway on the coast of San Diego every Saturday. I had lots of fun with this car. It turned head’s everywhere. I was challenged at almost every stop light to race. Never did. These cars are not for everyone. A simple tune up costs $600+
Love it!! Been watching for a basket case V12 XJS off and on, maybe one day I will find one and have the spare cash to throw away at the same time, in the meantime can’t wait to see what you do with this one!
Yeah deep pockets are something I’m seeing to be needed. It’s not cheap!
Great video 👍 That is some project as a english man I have the greatest respect for your effort.
Thank you! It’s been fun so far!
I think that's so cool your wife joins in and helps you with your projects. My wife sticks to doing her stuff. I wish she would hang out with me when I was tooling on my various projects.
Old Jags just have a beautiful and timeless design this car in 2022 still looks beautiful even in her current state from body lines I’d look great lowered with aftermarket rims, exhaust, and a 5 speed swap
Love your "can do, will do, AM DOING, oh, that's what I have to do next" attitude.
Great job on the interior parts and thank for the ending meme =)
Thank you!
A man of my own torture. Love the channel and subscribed. Got me a jag and been obsessed even though I’m a Benz guy
I bought one of these last July. Mine's a 1978 with a Chevy 350 swapped in (fairly common). That made it reliable enough for me to check a small bag of tools and fly halfway across the country to drive it back home. Excited to see what you'll do. This gives me inspiration to go start working on mine!
Very nice! I've seen a lot with small blocks .
That idea with 5speed swap is as close to perfection as it could be :) I am thrilled to see you get through all the necessities to get her going reliably :)
Always wondered if you could stick a manual in it and have a V12 manual on the cheap
You can and it's very tempting.
@@WesleyKagan *inserts Shia Leboeuf meme of DO IT*
But seriously, a manual and... maybe an intake mod of some sorts to let the V12 sing? Doesn't need to go freevalve especially since it's a daily, but some sorts of ITBs or a more resonant intake. Just wondering about all the awesome stupid stuff that could be done with that! I've been following for about a year since I saw you build the Porsche powered formula car. Loving the content so far!
Easy to do. The engine itself is problematic
@@PaulChoix55 Although it sounds tempting, the heads were a SOHC design, most specifically for emissions purposes. It would sound better and run a bit better, but a 327 Chebby small block and a 4 BBl carb would make more power with stock heads- both are the same displacement, the Chebby is two hundred pounds lighter. And getting rid of the zillion hoses of the emissions control system that came with air leaks from new would help too! Call John's Jaguars in Dallas , Texas, for a small block/manual swap kit! An LS 7 and a T6060 would be the boss- better engine set back, lighter and much moar powah! FR
@@fredericrike5974 The SOHC was a compromise - the original design was DOHC, but it was much too big on top to fit in the E-type (which is what it was designed for), the SOHC was a compromise. The V12 was never designed with emissions in mind, which is why it ended up being strangled by emissions equipment. The HE ("High Efficiency") engine was designed to increase MPG, which it did with remarkably little loss of power, but it does massively limit tuning options, as the exhaust valve is buried in a pocket, which hurts gas flow something chronic (by gas I mean exhaust gasses, not fuel). A lightly fettled V12 will give more than 300bhp, a heavily fettled one over 400bhp, and for a seriously modified one, 600+. You can increase the 5.3ltr displacement to over 9ltr by adding a 3/4" spacer block, a stroked crank & 4 new links in the timing chain...
Wow!! Great Channel! Just discovered you. There is soo much subtle comedy mixed in with some beautiful problem solving/engineering. Taking on an old Jag.. Much respect my friend!
If you haven't burst into flames by now I'd recommend rebuilding the fuel rail and injector assembly. The rubber on those is known to dry out and crack pretty frequently which then leads to leaking fuel and lots of fire.
I daily drove a 1990 xj-s for over 3 years. I had to change plug wires which took almost 4 hours and a rear wheel bearing. Other than that it was surprisingly reliable. I got rid of it at 180k miles because 1: I was averaging 16 mpg and 2: my kids could no longer fit in the back seat. It's a beautiful car to look at but nothing spectacular about the performance. I don't regret owning it but I probably wouldn't buy another.
There are 2 sayings about Jags. the first is, "Hang a picture of one on the wall and the next day you will have oil spots on the floor under it." second "The electrical system sucks."
Can't do much about the picture but in the 2 I had, An Allison electronic ignition solved hard starting problems in both. Don't overheat the V 12 .It's the kiss of death. I did mine and it swallowed a valve. Still got me 30 miles to home on the right bank of 6 cylinders.
The wood is probably a dark walnut, the cracking is the clear coat lacquer that can be stripped off without damaging the walnut veneer. Nearly all the motor’s accessories are GM and easy to locate, including the 3 speed GM transmission. Rear inboard breaks and four catalytic converters will be a challenge though.Old fuel injection hoses should be replaced as they can notoriously lead to engine fires. The V12 is a beauty, last of Malcolm Sayers designs too. Glad to see it come back to life, good job!
Thanks! Yeah the cats are gone already, and the plethora of GM parts is kinda nice to see. I don’t mind it at all!
The power window switches can be cleaned if the plastic hasn't gone brittle. If you want to get the window up just jumper the plug. They don't cost much anyway.
The problem with these cars is this, they get let go in the maintenance and and because they're complex to work on it never gets done. This is good for us mechanics. We can pick them up cheap but as you pointed out in your list it can take some time to sort out.
Before I go, I should mention the fan and fan clutch. The plastic fan gets cracks in it and when you rev them up the fan flies to pieces. They do like to rev up these engines, so before you do I would recommend replacing the engine mounts (cheap same as Range Rover) and replacing the fan and fan clutch.
Also I should mention the brakes are excellent in these, so don't accept mediocre as normal. Perhaps they aren't as good as a modern car but for the time they had decent brakes.
Re tranny: in the 6 liter they used a Jaguar case GM4l80e. You can buy an adapter for a GM case to the Jag V12 if you can't be bothered finding a Jaguar 4l80e.
I wouldn't recommend the the TH700r4 because the 1-2 ratio is too wide for the characteristics of the V12. In the 5.3 liter with the TH400 the rear gear ratio was 2.88 (or 2.78 or something) whereas in the 6 liter they used the 4l80e and a rear gear ratio of 3.54:1. It turns out the diff is based off a Dana 44 and D-44 ring and pinion fit - however - the D-44 pinion shaft is U bolt style so maybe maybe not you might have to mod the driveshaft.
I recently just picked up a beautiful to almost pristine condition XJS. It runs and drives already BUT has the worse kinds of oil leaks coming from valve covers and possibly from oil pressure sending unit. Wish me luck!
Most underrated car channel! Love it when you are nerding out.
Wes: "a bit of corrosion"
Water Pump Internals: _[Is practically made of rust, white stuff, __-cursed mud from the holy grail-__ and what looked like copper oxide. Well, at least at first glance]_
You did good on the wood trim, that was nice, and, you know, getting it to run. I love the XJS, its a beautiful car and has a nice engine (when it works of course XD)
I've seen worse. this one moved so that's an improvement. But yeah it's not perfect.
@@WesleyKagan Probably caused by the wrong coolant ratio, which should be 50/50. The fuel lines also need replacing though out the car otherwise you are in dire risk of one of them bursting and causing a fire. I'll be re-installing the rear sub frame after a major overhaul on my V12 convertable in the next couple of days.
When i was 14 my local bike shop bought one of these from a scrapyard and allowed us to ride on it with our trials bikes and bmx bikes before it was used for banger racing during a town fairground event, it was fun to jump over the car with ramps, manualing on the roof and bonnet absolutely trashing a car which would probably be worth a fair bit of money here in the UK.
Had an old Jag. It never failed to run, but something was always not working. New rear end was the most expensive, but there were minor problems daily. good luck! But it was the most comfortable car to drive!
My brother had one when i was younger. Im interested in cars now and thinking of getting one. Loved this car
"A few chicken-fried steaks short of a Cracker Barrell..." Holy Fuck LOL XD
I daily drive a 1988 Xj40. It’s got half of the 5.3 V12 basically as an engine. It’s really such a great car. I’ve put 100 000kms on in the past year and I’m on 300 000 now. These era Jaguar XJ’s (not the series 1,2, or 3) were really built well as well as the XJS’s. A lot of people will tell you that they’re rubbish but don’t understand that every car that gets 30+ years old will need work done to it. If these cars are properly maintained they can last a lifetime. As goes with most cars.
I have a 1990 xjs v12 with a 5 speed garage from the 6 cylinder engine car and it is great, transforms the car. I would suggest doing the injector pipes, all rubber bushes, rod the radiator and you could end up with a reliable daily, I did.
"oh no, the cat is about to fall off" XD funny how that happens
I’m in the garage looking at my ‘82 XJS right now, same color paint but “starfish” wheels, amazing how few changes there were in that many years of production. The only obvious difference I see are the steering wheel and sill plates. Many of the same issues, lots of electrical weirdness, brakes, steering rack or pump. Fuel tank leak has it sidelined right now, having trouble finding one.
I just finished restoring the zebra wood trim in my Mercedes w123. I removed the top layer of shellac or lacquer stuff, stained it with Honey 272, and put Minwax Polyurethane on it. It came out great, and yeah the old lacquer or whatever was an awful choice for longevity and made the wood look dull and cheap.
Also, I wanted to buy a junker XJS exactly like this one a few years ago. It was in much worse shape, I don't regret passing on it lol.
I live near the Land Rover Range Rover factory here in the UK, so I know a little about the pitfalls daily driving british engineered cars- but with this you are really taking the brave pill with this one! Best of luck :)
I got a Volvo twin turbo inline 6 from an xc90 that really needs to go in a jag.
Oh damn. That would be interesting!!
Will love watching this and Harry's Garage Jag being done together :)
Fair play taking that beast on! Even with the Jag parts network here in England I wouldn't much fancy touching one of those with a barge pole, let alone the V12. Have fun replacing all the wiring!
Honestly the parts network here is frightening. It's not fun.
I like what you did with the wood. Would be nice to see what you could do to the plastic
Thank you! Yeah It cleaned up nice in my opinion.
@@WesleyKagan I agree!.you should watch the car wizrd episode, where he put dual carbs on one of those engines
These V12 Jag's with 'Lucas' electrics scare the daylites outta me
Makes me wonder what they might have been like if the original build quality was way better
Glad to see someone else taking the chance
Gr8 videos
I knew someone who had one of these when they were like 5 years old. He said you'd be going like 87mph and push the foot down and it'd take off like you just pulled out from traffic lights and you'd be straight up to 100mph. Only car he had with strong acceleration while it was already going fast.
God bless. I looked at a manual stick shift V12 XJS of this vintage it feels like going on 20 years ago - the owner said it was very rare for the stick as I recall. It had several issues and I took a pass.
Are you planning a freevalve V12 lol
It'd be interesting if Wesley was to go this route. I'd love to see it, but the amount of work to do that and keep the car in one piece is probably overwhelming.
For now, we'll just have to wait and find out how many times the Jag breaks down!
All I know is that Freevalve is the only way we can make our ICE into the 21 century.
@@hamster9135 probably not worth it since the block and pistons most likely would be unable to take this much power
@@D3nn1s Freevalve-ing in itself doesn't make any power if you're running stock valve timing and lift
@@DJDiarrhea yes obviously but you dont usually install such a tech for lulz (miata might be an example just to prove that he could make it work). But wuy install it and have a ton of work for no reason?
Please please please check the tubing from the fuel rail to the injectors, they are notorious for going bad and starting a huge fire. Along with the fuel injector wiring harness down in the v. Other than that have fun with it, and I sure hope it doesn't lose its exhaust system and has to be driven that way!
Yep, I already pulled and replaced the rubber lines, 928’s have the same issue.
Beautiful job on the wood dash pieces - the effort you put into them really enhances the interior. If only the flaking clearcoat were that easy to repair.
we had a 1977 XJS as the daily driver from approx 1992 to 1996, then occasional drive since then, still have it today.
Yes... 5 speed swap and performance... The IRS subframe assembly with the inboard brakes and differential (especially if it has a Salisbury powerlock diff, but the DANA rear ends are valuable as well) in that car as a single unit are highly sought after by custom rod builders.
Yep, Salisbury diff and the inboard brakes while a pain to work on are actually very cool.
@@WesleyKagan Yeah those old Salisbury units are bulletproof... Do it justice and throw some more horses at it lol
Omg i had one when i was 23. It was a notorius angst producer. But it is one of the most beautiful cars made...
"I've never been a fan of glossy lacquer - I'm going to use Tung Oil" - man after my own heart. Amen, brother. Tung oil is amazing, although you really should try to get some proper, pure tung and dilute it down with citrus terpene or gum turpentine.
It was my first car in 85. I drove her everywhere. I adored that car.
I have a 1990 Jaguar XJS. I have driven it daily, raced it down in Mexico and a few races here in the states. It starts every time. one thing I can tell you is you have to let everything pressure up, then start it. I have owned it for 21 years.
I remember an old episode of top gear magazine in like 2004 or so where they tested how much nitrous one of these could take before popping, and I would love to have a full audiovisual experience of that if it turns out not to be an example worth saving
Love the wood trim, nice work man!! I'd love to see more on just trying to use this as a daily and what it takes to get it to be vaguely usable....
Thanks! I'm excited to see as well.
@@WesleyKagan
Whats the year on it ?
I remember working on a slightly newer V12 when I was a Jag tech. Beautiful car, so smooth, but lazy. I always thought it needed a clutch pedal and camshafts. The stock cams are all about being quiet and smooth. That V12 needs something with more valve lift to wake it up.
After your initial goals are met, twin turbos and track time are in order.
They were good cars I used to work on them when they were new, check the rubber hoses between the fuel rail and injector they split when old and will spray fuel onto the distributor and cause a fire. The radiator will be clogged if the water pump looks like that.
Having worked on old British cars, including Jaguars and including the XJS, for 50 years here in the UK I strongly suggest you change all the suspension bushes. The way the car rides, steers and handles will be transformed. I don't think you need a 5-speed gearbox - with the engine running correctly and the auto transmission properly serviced you will have sufficient performance. Also, look for sorting out the driveline clunk before you end up causing damage. Often the problem is with the gearbox mounting spring; it loses tension and should be replaced every ten years or so. The brakes will always feel a bit crap if the rear calipers are not properly maintained; they are not easy to get to and a real pain to bleed properly so many mechanics ignore them and the braking is never right. Good luck with it. When they are properly maintained they are super reliable and a joy to drive - only their prodigious thirst for petrol lets them down.
I vote to keep it around and keep improving it. But I have a xj myself so that might be a bit biased.
There is a dual four barrel manifold available for these. It relieves the problems arising from that antique FI system.
I owned an XJS with a V12 for about 6 years and daily drove it. In addition to daily driving I did drive it to and back on every other weekend Cincinnati OH to Cherry Hill NJ. It had 2 continuing problems. Electrical gremlins and oil leaks that caused rubber parts to disintegrate. It is bad news when the Jaguar dealer service knows your name before you get out of your car. I loved the car but toward the end I thought I owned the service department. I would not buy another ICE Jaguar. I am thinking about an I-Pace. Maybe they fixed the problems of the 90’s. .
Jag is a car that if it is used frequently.. It will be reliable.. Issues come from too much "sitting" (I have a 90 Rouge ED- upgrade trim/wheels).. Drivers are best- do not "baby them". You will learn to tolerate issues.. The V-12 is a tank.. Things around the car tend to give trouble! Frank
Funny that you mentioned this... There's a guy that I'd occasionally spot on my drive home in a V12 XJS. I don't take the same path home anymore though, so we'll never know if it still lives.