Learn me-Jaguar XJS V12

In reply to NOHOME:

Not as well executed, reliable, or powerful as the Mercedes M120 v12, but it is pretty haha

justthatguy wrote: Excellent name, Chiodos, by the way. That band takes me back.

I just listened to All's Well That Ends Well last week for the first time in years. Forgot how good that album is, those guys were one of my favorites in high school.

I've got nothing to add on the Jag, aside from the fact that a Challenge priced 12 cylinder beauty like that is a dangerously intriguing idea.

In reply to frenchyd:

This car will mostly see street use, and I do very much intend to do HPDEs, VIR is like 10 miles down the road from me. I also like the styling of the 6.0 XJS. Looks elegant but still like a Jaguar.

If I were to convert to carb it would be strombergs or 6 2 barrel American carbs of some make.

I think working on the intakes, bigger throttle bodies, and a tune might be the best way to go here, possibly reground cams too.

In reply to justthatguy: The stock Intakes flow 1200 CFM good enough for 450 Horsepower. The cheapest way to 400 horsepower is buy bigger injectors and run it on E85 Cams are a double edged sword.. Ones that make serious power lose it at low RPM Since most street driving is done between 1500 and 4500 rpm a camshaft is one thing you don't want.. However once you are on the race track power from 4000 to 7000 becomes important.. There a cam can help. However real power comes from the Kent Billet cam.. it has lift and duration you simply cannot grind into the stock camshaft.. However you pay for it..

The advantage of a 1993-94-95-96 XJS is it has the 6.0 which has the 3.54 rear end (instead of the 3.08) and outboard brakes which while a technical step backwards is a real advantage on the race track because they are bigger and easier to cool. Plus the automatic is an overdrive so you have a slower turning engine with more grunt from a stop.. The first year and a 1/2 of the 6.0 the crankshaft is a forging later ones are sintered Iron. Please note engine production and which cars got which engine seems to be a bit fluid. I've seen 1992's with 6.0 and 5.3 engines..

The manual conversion transforms the nature of the car. Sort of like driving an older Impala with a 4 speed or an automatic.. but not all conversions wind up happy. There are kits out there that put the transmission too close and as a result shoves the crankshaft against the thrust bearing which quickly destroys the engine.. Plus the gears of a 5 or 6 speed have either a 1 or 2 speed overdrive.. Combine that with the typical 3.08 or 2.96 final drive ratio gives you a 4200 pound car with the first gear so steep it's bog slow under acceleration.

You need the 3.54 ratio in order to have decent first gear acceleration

A conversion kit is expensive it's not uncommon for it to cost $5500+ installed. On the other hand later 5.3's and all 6.0's have a cheap and easy solution. The locating pins on the block line up with a GM bell housing.. While the block holes don't line up it is relatively easy to make an adaptor plate to convert.. You will need a flywheel and clutch etc.. but that's too terribly expensive..

NOHOME wrote: frenchyd's description of the V12 reminds me of the SU carb. Based on core design principles, both read like a recipe for the planet's greatest cake; cake that then gets covered with a generous lathering of fecal matter frosting on the way to production. "Quirky" is a kind way to describe the supporting cast of parts and quality that undermine a great design. The other commonality is that it is the paying customer who must adjust to dealing with these endearing quirks...perhaps something to ponder while waiting for the tow-truck?

I think we need to decide who we are talking about. Some owners lead with their wallet and expect because they pay good money for something they will hopefully get good value. (without actually knowing anything) Others bother to learn the important stuff and as a result have a wonderful experience with good reliability.

It's like the myth of the unreliable SU fuel pump. People beat on them with a hammer or stick and bemoan it's failure. I learned that the contacts develop a coating that needs to be cleaned off periodically. So once every other oil change I slide a double sided piece of very fine emery paper through the points and add a couple of drops of oil to the pivot point on the springs. It might take me 5 minutes. The one on my 1953 MG TD is now 6 decades old and if I go into the shop, turn on the key I will hear a pleasant drumming sound telling me that my the fuel pump is still working..

Most mechanics won't spend the 5 minutes or don't even know it's that simple. They would rather sell a new pump and get the mark-up and wages of installing a new pump.. complaining about unreliability..

Owners feel the torque of the V12 and don't realize it's running poorly because the distributor hasn't been properly maintained. They don't understand the overheating is caused by the timing frozen advanced. Until some mechanic tells them the engine needs to be rebuilt. Well heck even mechanics need to make house payments and they are entitled to have the fun of taking your engine apart... And so the myth of poor quality get's caulked up against Jaguar..

Go ahead take one apart, you will be amazed at how well they are built, and the quality of parts in them.. I've pulled engines apart with 100,000+ miles on them and found them within new production specs. While I like my Chevy V8 there is no way I would race it in the stock form. many of the parts won't hold up. However in racing a Jaguar a lot of stone stock parts hold up wonderfully

No at the low volume (Some years production was around 1000) Jaguar didn't have the state of the art manufacturing equipment and as a result they had to have people sorting and batching matching components together... That's one thing Ford's millions did do for them..

Furious_E wrote:

justthatguy wrote: Excellent name, Chiodos, by the way. That band takes me back.

I just listened to All's Well That Ends Well last week for the first time in years. Forgot how good that album is, those guys were one of my favorites in high school. I've got nothing to add on the Jag, aside from the fact that a Challenge priced 12 cylinder beauty like that is a dangerously intriguing idea.

Well a 12 cylinder Jag isn't a good race car in stock form. You start out at 4200 pounds and as little as 242 horsepower.. (7.8 compression ratio) Later ones had the so called H.E head and 11.50-1 compression ratio. But the later head is designed to meet California smog regulations (and get better fuel mileage) and racers all want the early heads. They further handicapped it with a 3.08 or 2.96 ratio in the rear end.. (sluggish is the word you are looking for) OH they will get up to 150 MPH eventually but are rather casual about it though..

If you are extremely diligent (and brutal) you could get one down to about 2700 pounds. And by taking molds of the fenders, doors, trunk lid, and hood and making carbon fiber parts in those molds get the weight down around 2300 pounds.. Take the early engine with it's 7.8 compression ratio and then a couple of Junkyard Turbo's out of Saab's or Volvo's it's possible with a tiny budget to make 500 horsepower Or close enough to spit at..

Now the Bolt pattern is the same as a Corvette so big tires & wheels can be affordable. Springs and sway bars are better on the early ones and work pretty well if the weight is reduced from 4200-2300

In reply to frenchyd:

I've heard of Hamilton auto in Van Nuys recommended as the go to diff guy. I was thinking with a T56 and a 4:56 rear I can get the acceleration I want with not too many engine mods, plus a double overdrive I can use on the highway. I've heard good and bad about the driven man kits, are those something to shy away from or something to consider? I'm too Jag-ignorant to know any better, to be frank. The quality of the parts and kit looks good, from my American-Japanese car perspective.

frenchyd said: It's like the myth of the unreliable SU fuel pump. ... I learned that the contacts develop a coating that needs to be cleaned off periodically.... It might take me 5 minutes....

No it does not take 5 minutes. More like a morning for the average owner doing it for the first time. And since the new guy stands a 50% chance of screwing it up, probably longer. For example, they wont know that they should have bought new crush washers, so the car will be off the road for a week while waiting for MOSS to deliver. Or they will spend some time finding out that you can anneal then washers. Or maybe they will split the pump housing by over-tightening the banjo bolts by trying to stop that fuel drip caused by old crush washers.

Majority of people I know that have tried this repair mess it up by using sandpaper; that makes it worse..."how were they supposed to know?" I Learned a lot mucking about with Brit cars for 40 years, but the main thing I have learned is that the maintenance with old Brit cars is endless and when you stop enjoying the maintenance and learning curve side of the hobby, you had better be rich or bail. Jags take this to to the Nth degree just because there is so much more to maintain and the parts cost an order of magnitude more because they are "Jaaaaaaaggggg".

Knew a doc back in the day that bought one of these new. He loved it when it wasn't in the shop. No major issues with the driveline, IIRC, but the "little" things that make a luxury GT car a luxury GT car were always breaking.

1988RedT2 wrote: Knew a doc back in the day that bought one of these new. He loved it when it wasn't in the shop. No major issues with the driveline, IIRC, but the "little" things that make a luxury GT car a luxury GT car were always breaking.

My point exactly. If you ever read John Delorean's book "On a Clear Day You Can See GM" he has a passage where he talks about his new Jag. He took it out twelve times and twelve times it had to come back on the hook. Got rid of it. Amazing car when it was self propelled.

In reply to 1988RedT2: Well that's perfect. All the GT stuff is coming out of it so it should be pretty reliable.

In reply to justthatguy:

And it's at that point I question how good the chassis actually is and start looking at Mustangs and F-bodies again.

In reply to NOHOME: Why new crush washers? If they aren't leaking don't mess with them.. Take the little knurled knob off and remove the plastic cap. Take a folded over piece of 1000 grit emery paper about 2 inches long and slide it between the points. Add a few drops of oil on the rubbing point of the springs and replace the cap.. Jobs done. OK some cars put the pump where it's harder to get at then the firewall of my TD So add a few minutes for needed for Access.
If a British car is your daily driver then yes maintenance will be endless if you want it to be pristine and flawless. But that very nature of human interaction is what endears these cars to their owners.. They have a sense of empowerment knowing the car that well. A bond you don't get with the mundane and ordinary but reliable transportation unit.

I'll grant that some people seek the easy path through life. Others actually seek challenges. I'm guilty of that. Learning to fly an aircraft off and on an aircraft carrier was extremely hard But today 48 years later it's still a sweet memory.. Racing my home made vintage Jaguar race car against Sir Stirling Moss driving the factory prepared Aston Martin Took every bit of skill and mechanical knowledge but when I watch the video of myself throwing that car sideways in a desperate attempt to keep up I remember the joy I felt.

No the easy way has few rewards and no thrills.. So I'll share my knowledge with others hoping they too get to find the rewards of doing the difficult. Find the rewards of mastering the challenge. Learn to live the life they've been given not simply ease through it..

Sorry lecture over

1988RedT2 wrote: Knew a doc back in the day that bought one of these new. He loved it when it wasn't in the shop. No major issues with the driveline, IIRC, but the "little" things that make a luxury GT car a luxury GT car were always breaking.

From your story I wonder why he owned it? Do you think he ever drove it at 10/10ths? Threw it into a corner knowing he'd need every last inch of pavement and his skill to catch it? Let that big torquey V12 pull him up to the car's top speed?

Any car can have soft leather and other luxury stuff. Yawn, been there done that.. A Jaguar really isn't about that.. It's about winning the 24 hours of LeMans 7 times. It's about diving into a corner and having those brakes let you get deeper then your competitor. And doing it with style and class.

Enzo Ferrari once said the Jaguar XK-E was the most beautiful car ever. I believe it was Brock Yates who called it the worlds greatest crumpet collector.. Those aren't things anybody has ever said about the normal transportation module. OK so during the labor troubles some of the factory workers failed to properly tighten all the ground wires and there were issues of reliability. But that's like complaining that a beautiful woman burnt the toast.

Today I learned the guy behind this

Actually won 8 years later in this.

Frenchyd makes me want to buy a Jag V12 with every post.

Chadeux wrote: In reply to justthatguy: And it's at that point I question how good the chassis actually is and start looking at Mustangs and F-bodies again.

Mustangs and F bodies? I know they are cheaper, And pushrods are things even little boys can play with. However they are like not dating a beautiful woman because she might not know how to change a flat tire.. Jaguar or Chevy- One is decent transportation and one will make demands of you.. One will be boring and one will not.

m4ff3w wrote: Frenchyd makes me want to buy a Jag V12 with every post.

I'm really sorry about that. I feel like a drug pusher, knowing that while there is a element of fun and excitement in what I'm selling but also aware of the potential for heartbreak..

I should issue a warning with each posting.. Caution speed is addictive and dangerous.. It can and probably will cause you to spend way too much time in the garage all greasy and tired.. As a result of wanting to go faster your golf game and even social life will suffer.. not to mention any bank balance you may have had..

In reply to Chadeux: I wish I could post pictures of him at LeMans..

m4ff3w wrote: Frenchyd makes me want to buy a Jag V12 with every post.

Not me. Makes me think he's a bit "off" and that he's drank way too much Jaaaaaaaag koolaid.

In reply to frenchyd:

I was saying that if you are getting rid of all the parts that make the inside of the car "nice" is the chassis really good enough to be worth the headache? My understanding is that it's basically the XKE's rear axle stuck under a much heavier car. The XJS in standard form doesn't seem like the "10/10ths" sort of car, and doesn't really show much potential for it unless you're building a tube frame car with the XJS skins draped over it.

m4ff3w wrote: Frenchyd makes me want to buy a Jag V12 with every post.

I think he has the longest average post length on grm forums.

Chadeux wrote: In reply to frenchyd: I was saying that if you are getting rid of all the parts that make the inside of the car "nice" is the chassis really good enough to be worth the headache? My understanding is that it's basically the XKE's rear axle stuck under a much heavier car. The XJS in standard form doesn't seem like the "10/10ths" sort of car, and doesn't really show much potential for it unless you're building a tube frame car with the XJS skins draped over it.

If you're turning an xjs into a race car its because you want a race car that looks like an xjs. It's undoubtedly handsome. I don't think it's anywhere near the top of the list for race car potential. Especially if getting it to 3000lbs requires carbon fiber hood and fenders.

In reply to Chadeux: It really depends on your goal.. I'm a racer so speed is critical to me. Weight is my enemy. If you value cruising then your priority will differ.

Strength wise the rear end is massively overbuilt. We racers tend to lighten it up and still it lives through all the demands we make of it..It has roller bearings in it to ensure smooth and friction free travel over rough roads where ordinary cars just use rubber bushings.. We racers toss those and use simple bronze bushings since the race track is smoother than public roads. We also deep six the rubber mounts designed to isolate the road from the occupants.

A tube frame is for safety in a crash, it doesn't make the car faster. The "skins" are cheap fiberglass (Or expensive carbon fiber) that can be quickly replaced in the event of contact on the race track. Yes a XJ-S can be driven 10/10ths even though in stock form it is too softly sprung and the power steering is over assisted.

That just makes it more of a challenge but plenty of showroom stock racers suffer from the same ills and are remarkably fast in spite of it.. The problem is few of those cars are capable of the level of performance the Jag XJ-S is .. so extracting 10/10s demands real skill and {rhymes with Falls}

frenchyd wrote: In reply to NOHOME: Why new crush washers? If they aren't leaking don't mess with them.. Take the little knurled knob off and remove the plastic cap. Take a folded over piece of 1000 grit emery paper about 2 inches long and slide it between the points. Add a few drops of oil on the rubbing point of the springs and replace the cap.. Jobs done. OK some cars put the pump where it's harder to get at then the firewall of my TD So add a few minutes for needed for Access. If a British car is your daily driver then yes maintenance will be endless if you want it to be pristine and flawless. But that very nature of human interaction is what endears these cars to their owners.. They have a sense of empowerment knowing the car that well. A bond you don't get with the mundane and ordinary but reliable transportation unit. I'll grant that some people seek the easy path through life. Others actually seek challenges. I'm guilty of that. Learning to fly an aircraft off and on an aircraft carrier was extremely hard But today 48 years later it's still a sweet memory.. Racing my home made vintage Jaguar race car against Sir Stirling Moss driving the factory prepared Aston Martin Took every bit of skill and mechanical knowledge but when I watch the video of myself throwing that car sideways in a desperate attempt to keep up I remember the joy I felt. No the easy way has few rewards and no thrills.. So I'll share my knowledge with others hoping they too get to find the rewards of doing the difficult. Find the rewards of mastering the challenge. Learn to live the life they've been given not simply ease through it.. Sorry lecture over

Cause if you don't use new washers, chances are the work hardened copper is going to give you a small leak that you will then try to tighten until you crack the fitting on the fuel pump. Only takes .5 seconds to hit the washers with a torch and anneal them then run them over some fine sandpaper so they actually seal.

I know what you are saying about challenges, been there got the dirty T shirt and have moved on to other things when it comes to Brit cars. SU carbs are cute, but big deal, once you know the theory, who really cares anymore? I no longer start fires by banging stones together either, even though I could. Never have understood the "Car Soul" or "Horse and rider" zen. Cars are just nuts and bolts following the laws of physics. I abhor maintenance; I will restore it to new from a pile of rust, but I won't wash it after it is done.

In my world, once I climb a mountain, I am pretty much done with mountain climbing; I'll go parachuting or something else. Actually, no I wont take up parachuting cause I tend to get things right the second time more often than not, so parachuting ain't my sport!