I hope nobody pukes on me.

I have a PRISTINE 90 Conv. with a BAD V12. Got it for DIRT. I could part it out and make 10 TIMES what I paid for it.

I want it FAST, RELIABLE, and AFFORDABLE.

I wanna put an LS1/T56 setup in it and JAGUAR SPECIALTIES looks like they do the best work.

Anybody death with them?

www.jaguarspecialties.com

 

Never dealt with them but Andrew has a good reputation as far as I can tell. I wouldn't hesistate.

Cheers
DD

 

Regardless of the "butchered it" factor I just couldn't live with an engine swapped Jag. It would be like going anywhere in a VW kit car and having people check you out or pulling up to the real car and knowing in your mind there is a dirty little secret under the hood and you don't have the real thing and aren't actually experiencing what it is like to own that car.

Either way if I was going to do an engine swap and didn't use the V12 i'd be more creative than an LS motor. I think a XJR supercharged 6 cylinder would be really cool.

OR put an AJv8 in it. I think that would be an acceptable replacement if you cant deal with the V12. Go grab an XJR/XKR and you'll have 400hp and still be driving a Jag.

 

That's where we DIFFER.

To ME, the restomod process is about making the best car possible.

The Supercharged Jag motor and the v12 BOTH pale in HP for $, AND technological advancement of an LS1.

MAYBE YOU'RE RICH.

I'm not, and from the Chevy swapped Jags I've seen, NOTHING MAKES MORE SENSE.

I'm ALSO not talkin' about a 350 from the 70's.

Jags are known for their BEAUTY, not their dependability, so why WOULDN'T you wanna pull up with a reliable, cost effective, docile easily maintainable 400 hp secret under the hood?

Unless of course you DIG being GOUGED for parts and service on a drivetrain that pales in comparison, and I'm no SUPER CHEVY DUDE. Unless you're join' to PEBBLE BEACH or sittin' on 400 pounds of hundred dollar bills, a Jag swap just doesn't make any sense.

 

Welcome to the forum geoffsxjs,

When you get a minute, please follow this link New Member Area - Intro a MUST - Jaguar Forums - Jaguar Enthusiasts Forum to the New Member Area - Intro a MUST forum and post some info about yourself and your vehicle for all members to see.

In return you'll get a proper welcome and some useful advice about posting to the forum.

Graham

 

Nobody can guarantee that it won't happen. And, besides, you've already anticipated it. It's only natural that, on a make-specific discussion board, you'll come across make-specific loyalists.

Chevy-into-Jag conversions have been controversial for as long as I can remember. I've observed and participated in many of the discussions (and outright flaming arguments!) over many years. I doubt that we'll ever see the end of them.

That said.....

In my experience the nastiest arguments occur when the pro-conversion guys go out of their way to be *hyper-critical* of Jaguars in general and Jaguar engines in particular. It's only natural that this doesn't sit well with many Jag lovers.....yet many pro-conversion guys fail to see it.

OTOH, V8 guys who *avoid* ballyhooing about how horrible, unreliable, archaic, poorly designed, miserable, stupid, and expensive Jaguar engines are usually get along well with the rest of the crowd.

Just my observations, shared with you on a 'For what it's worth' basis. You may or may not find them useful in the future.





Which makes perfectly good sense to me. I've always felt that the easiest way to make an old Jaguar faster was to go with the Chev V8 swap.

And a V8 swap certainly can be affordable relative to the enormous cost of overhauling a Jag V12. Some of the V8 guys can comment of how much they actually spent. I reckon the amount varies quite a bit. Some guys really spend a lot of money.....well above and beyond a 'basic conversion'....and end up with a really impressive result.

As for reliable, well, that's gonna depend on numerous factors....not the least of which is the quality of the conversion

Cheers
DD

 

I agree with what Doug has shared about this. If you are willing to spend the time and money putting whatever fits your needs and price point then more power to you. I would just say that respect is earned and coming onto a Jag forum and going off about Jaguar reliability is not a good way to earn respect.

If you spend enough time with any marque you will find that all cars have positives and negatives depending on the year, make and model. There is no exception to this and because the XJS was built for 21 model years there are many XJS owners who have different opinions on which engine/transmission/headlight/taillight/interior options etc. were the best to them personally. Every one of us on here have our opinions and personal likes and dislikes but we share these with respect.

The LS1 V8 is a great engine and you are seeing it put into many older vehicles including older Fords. From what I have been told some of this has to do with the overall size of the small block Chevy V8 to horsepower. I think in the future you will see many more Ford 302 conversions as Ford is getting a lot more horsepower out of the newer 302's coming out but for now the LS1 seems very popular.

I wish you well getting the XJS back on the road. The XJS is a great platform to build on and makes a superb highway cruiser. I often forget how quite the XJS convertible is at highway speeds until I ride in another convertible of the same vintage. For it's time the XJS was hard to beat stock for high speed cruising as was demonstrated with the XJS winning the Cannonball coast to coast race back in the late 70's.

It will be nice to have 350+ HP in a XJS and still have room to get to everything like power steering hoses etc.. To me if you choose to modify a car like the XJS then what difference does it make what engine you choose to put in the car. I have always felt that Jaguar missed the mark when they did not offer the last XJS with the supercharged AJ16 option but to a XJS guy like myself it warms my heart to see the Jaguar super charged engine sitting in the XJS. Something about seeing " JAGUAR " in big red letters makes my heart beat a little faster-LOL!!!!

 

Wait until people start modifying these old cars with ELECTRIC motors... It's coming, and not too far away.

With the sizes of electric motors, you could do the swap and easily access everything you ever wanted under the hood! With the size of the XJS hood, you might make room for a set of golf clubs!

 

Maybe I am rich? Im a 22 year old brokeass college student that drives an XJS EVERYDAY.

We differ in that if we see a car and believe there is something fundamentally wrong with it I say I "don't like" the car and you think it is a good idea to get one anyway and "improve" the millions spent in engineering on that model.

the V12 is a very well built motor. If you think it is unreliable because of cooling or electronics or whatever you think, fix that one problem and drive the car. How is replacing an entire engine and trans cheaper and easier?

They have a "reputation" for being unreliable because of bad mechanics that can't perform proper repairs.


Where are you sourcing your parts from? Last time I was on eBay a USED LS1 with over 100k miles was $3k easy. A used AJV8 i about $1k. For $2k you could nab a supercharged version. If you want a LS motor making the same amount of power it would cost even more. I don't see how that is cheaper....

The other thing is Jags are not slow. Even a "dull" 6 cylinder sedan can get down the road just fine. If I were going to put the amount of money and work it takes into doing an entire engine and trans swap I would not choose a car that is already adequately powered. An XJS born in the 80s could go over 150mph......If I wanted "fast and reliable" I'd go buy a miata or MGB and put a big engine in it.

I don't know if you misunderstood, but I am not attacking you for wanting to do this, your post just came off as suggesting people who oppose XJS engine swaps lack validity in their stance.

 

Geoff says the engine is BAD. I interpret that as the engine having suffered an internal failure or some other sort of serious probem. Probably not an easy fix...not inexpensive one.

There ARE other alternatives, of course. A good used V12 shouldn't be expensive. Shoot, I got one for free...and it came with the entire car :-)

But it seems pretty clear that he wants a Chev V8.

Cheers
DD

 

Andrew from Jaguar specialties is a great guy. He is firm, fair and knowledgeable. He comes off a bit arrogant at times but dont let this deter you he is very knowledgeable and successful so perhaps this is to be expected. His Chevy conversion products are 2nd to none. I have personal first hand experience with him and his products.


As far as a conversion, if done right they are light years ahead of the V12. A stock The LT1 or LS conversion is just as smooth as the V12. I'd highly recommend a LT1 if cost is a factor. LS if money is no object. Manual would be great but for an auto the 4 speed transmission is the way to go, 700R4 for gen 1 SBC or 4L60e for LT1 or LS. You will need to change out the rear diff ratio to a 3:31 or 3:54 and doing this is much easier that what you read online.


On this forum there are a lot of Chevy conversion haters. They are just Jealous or rigid purist. Who wouldn't want a faster, more reliable, more economical XJs that handles better?

 

What is lightyears ahead about a pushrod engine vs an OHC engine lol?

I don't think any of the people who hate seeing V8 conversions are jealous of the car making more power. I have another car that makes more power and is a lot faster. The XJS is what it is, it is an experience. To add to the "jealousy" part....like I said before if I wanted a super fast and efficient reliable engine swapped car and XJS is a horrible place to start. It weighs 2 tons FFS. If you are engine swapping an XJS and you aren't a bad mechanic then you are wasting a ton of money

Anytime I see a chevy 350 in a Jag it just lets me know the owner is a bad mechanic.

 

I wouldn't normally promote another forum here, but, I think you'll get a warmer reception over on the Jag-Lovers.org Lumps forum

Personally, I can't stand the idea of someone taking a thoroughbred, removing it's soul, and turning it into nothing more than a mongrel.

That's the problem with these cars currently being so devalued. It opens the door for heretics who have no respect for the marque. They buy the car cheap, and rather than man up, and learn to work on, and appreciate the nuances of the V12, they try to turn a low production exotic into a run-of-the-mill Camaro.

If you wanted a Chevy, you should have bought a Chevy. If you want a Jaguar, keep it a Jaguar, and discover what it's like to own a truly exceptional automobile.

 

That's painting with an awfully wide brush.

Over the years I've come across *some* cases where it was pretty clear the the owner just didn't want to be bothered with learning how to make a Jag engine run properly. No time, no interest, no curiosity....whatever. They did the V8 swap just because they were more comfortable with a Chevy V8. Not sure if I would describe them as 'bad mechanics', at least not in all cases. Let's just say that some guys enjoy the challenge of something different more than others.

In *most* cases the V8 swap is done because the Jag engine puked and it was more cost effective to swap in a V8. Some done by good mechanics, others done but butchers.

In *some other* cases the the V8 swap was done as part of other re-engineering. Usually the owner likes the Jag styling, and maybe the suspension.....but that's about it! These guys are usually prety darn good mechanics.


Cheers
DD

 

Lol...I used to think the same thing... push rod motors while not elegant as OHC are very strong performers on the street and are racetrack proven winners. For example...The corvette with it pushrod V8 make mores power, offers significantly better fuel economy. GM's pushrod V8 weighs less than the straight 6 motor in the BMW Z4. A few years a go Ford switch to overhead cam Chevrolet continued on with pushrods in the modern LS. The LS with it's pushrods won, LS motors dominate many forms of racing.

A stock block Buick V6 turbo pushrod motor dominated Indy until it was banned. Look it up. Pushrod V8's are compact and have a very low center of gravity, ideal for racing. Ford's GT40 beat Ferrari handily in the 60's with an Iron pushrod motor...Go figure.


That's a broad brush & close minded statement and I personally find it offensive. Many are prudent DIY'ers like my self and do good work. Fact is the V12 has many expensive problems that need solving. The first is fuel consumption. The V12 with it's 3 speed auto is a fuel consumption pig. Quite frankly the low mounted distributor is dangerous. Many V12's have caught fire from a simple and minor fuel leak...what's so sophisticated about that design? Repairing the V12 has simply become difficult, parts are expensive and availability is poor. Additionaly what do you get for all that complexity and expense...a slow car that can be trounced by V6 Camary's from the 90's

A modern GM pushrod engine and transmission weighs in at about 550Lbs, the V12 engine and trans package tips the scales at over 1000LBS. Whats so great about that?


As I see it differently. The underpowered complex V12 made a good car a bad car. If the XJS came with a simple pushrod Rover V8 it would have been a better selling car because as I remember back then people bough them for the great looks and put up with the V12. Today... The XJS V12's have very low resale values compared to other classic cars of their era. I believe if it had a simple and reliable V8 they would be worth more.

Its really bad form to consider those who want to upgrade their Jags as stupid or reprobates. When you do you only denigrate yourself.

 

There's a lot of Non Jag Parts on your car. Kind of hypocritical to say that considering the parts list on Jagzilla. You've modified you car the way you want... so allow others to do as they see fit without insult. It could be argued that 1/2 of the Jag powertrain (TH400) was Chevy anyway.

 

@ DOUG: Yeah, the engine was THRASHED, and I got the car for an embarrassingly low price. I couldn't pass it up.

I REALLY didn't mean to start this up as a pissing contest.

Jags are WELL KNOWN for their dependability and trouble free, do it yourself, low cost maintenance.

MY BAD.

I don't know WHAT I was thinkin'.

MUSTA BUMPED MY HEAD.

Thanks for the advice and heads up on Andrew, ICS.

I think I'm on the right track now.

 

This is what I really do not understand about forums.

A person joins a forum called ""COOKINGVEGAN.COM"" where people go thru great pains to cook without any animal meat, and post a topic on how great it is to eat whole cows daily......and then expect to get a bouquet of flowers and their hair brushed by all members.

Do whatever you desire with your car. Put a lawn mower engine in it and paint it hot pink if you want to. As far as I know , no one is going to be taking you to the Supreme Court to prevent you from doing it; but just like you are entitled to manifest your opinion about Jaguar engines so are others entitled to manifest their distaste with what you are doing. Same thing when people visually heavily modify a car with aftermarket rims or body alterations such as hood scoops. They post pictures and everyone is supposed to be "nice" and give post a thumbs up emoticon and smiley face.....I guess part of being PC now is to go around validating and supporting any and every idea anyone has at any given time, lest you be branded as "mean" or "divisive".

As far as I know discussion does not entail patting each other on the head and placing gold stars on each other foreheads.

If your 6th or 7th post on a forum where people go thru great pains to keep their Jaguar engines running immaculately is about the superiority of the Chevy engine and and how much "sense" it makes to swap out the "unreliable" Jaguar engines, then common sense should tell you what's going to happen.

 

That's Ok, it happens all the time when this subject comes up




Well....actually..... in the hands of a good DIYer who takes the time to learn the tricks and quirks, an older Jag CAN be dependable, fairly trouble free, and low cost. I've been driving Jags since 1997 (three different cars) and have never been on the back of a tow truck!

You're starting off with a dead engine so naturally that's a different kettle of fish.

But, yeah, these will never be 'drive it and forget cars' no matter what engine is under the hood. A high level of owner involvement and comittment is needed. If you're willing to do an engine swap I'd say you're there.

Once you get it on the road many here can help sorting out the other issues...which I can virtually promise will exist.

It'll be worth it in the end because XJSs are great cars when they're sorted out

Cheers
DD

 

Hmmm...I don't see where I've replaced any major Jaguar brand parts.

When one of my 24 year old Bosch fuel injectors stopped working at 140+mph during a race against a Pontiac Firebird WS6, burning a hole in one piston, I too, could have ba$tardized my car, by slapping a GM LS motor in it, but, it would have ceased being a Jaguar at that point, and would, instead, have just been another mongrel roaming the streets. By the way, the Pontiac with the LS motor was getting ever smaller in my rear view mirror when the fuel injector let loose.

To summarize what I have done to my car since that tragic event, I replaced:

A "bad" Jaguar V12, with a Jaguar V12 that was built by a Jaguar racing team.
A Jaguar intake manifold and throttle body, with a Jaguar intake manifold and throttle body that has been painstakingly flow tested and modified by a former Jaguar engineer.
A General Motors brand automatic transmission, with a Richmond brand manual transmission, while adding a Jaguar clutch master cylinder in the process.
A Lucas brand ECU, and a Lucas brand ignition system, with a single Electromotive unit, which does both.
A Jaguar 2.88:1 differential, with a Jaguar 3.54:1 differential.

Adding to that, with the exception of the Jaguar clutch master cylinder (which was NOS sourced from a Jaguar parts vendor, and came in the green Jaguar box), all of the above parts were salvaged from a wrecked Jaguar XJS which was headed for the scrap heap.

You're right icsamerica, I'm clearly a hypocrite, who has mindlessly, and cold-heartedly ripped the Jaguar soul from my car. NOT

My other XJS is a bone stock, 24 year old daily driver which is on the road 6-7 days every week, is driven 99% of the time by my lead-footed teenage son, and sees more than 10,000 miles per year.

That tiny little fact kinda blows a big, gaping hole in anyone's theory that Jags are unreliable pieces of crap, that should have their engines replaced by a common cookie-cutter V8 at the first available opportunity.