XJS ( X27 ) 1975 - 1996 3.6 4.0 5.3 6.0

350 Chevy engines to replace V12

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  #121  
Old 10-21-2020, 09:25 PM
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Originally Posted by Robert S
If I just want to go as fast as possible for as little money as possible,
For me, the justification for a Jag engine swap would be easier access to a lot more power.

Nowadays, though, I think I'm more inclined to just go out and buy a car that already has the level of power/performance that I'm after. Boring, I know, I know,

Cheers
DD
 
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  #122  
Old 10-22-2020, 04:16 AM
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Originally Posted by Robert S
My thoughts after reading the whole thread. You buy a V12 XJS because:

A. You want an XJS. One or more things about the car does something for you. It may be the styling. It may be the interior. It may be the V12 engine. It may be the overall driving experience.

If I simply wanted a nice V8 car, I could have bought a Corvette. Or a Camaro. Or a Mustang.

I can understand why some people might do a V8 in an XJS, but I would never do it. M120 swap, unlikely as hell, but just a bit possible.
I fall into category A. I love the look of the XJ-S but not the headaches of the V12. A 4 litre XJS is a rare and expensive thing but to me would be very desirable.
A Corvette, Camaro, Mustang or any late 60's/ early 70's two door Chrysler would be nice but in Australia and probably any country outside of the Americas they are a far more expensive option. Having said that the XJS is nowhere near the cheapest Jaguar in Aus but it is one of the cheapest coupe's.
 
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  #123  
Old 10-22-2020, 08:25 AM
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Originally Posted by Robert S
The M70 BMW engine is roughly similar in terms of performance to a Jag V12..
LOL... I have a M70 powered BMW and a Jag 6.0 V12. They are in different leagues all together. Keep in mind the M70 was the basis for the V12 found in the McClaren F1, The BMW M70 is far more high strung and will rev to 6000 and make power and feels like it wants to keep going. It also makes more torque down low than the 6.0 XJS despite being just 5.0L. The long intake runners, amazing long collector exhaust system and dual ignition, dual fuel pumps and dual computers enable a very broad progressive power curve. It's also bullet proof, engine failures are unheard of. They do suffer from timing chain stretch which takes them out of time a bit and leads to a humming type of vibration in higher mileage cars. I have a higher mileage car and was able to tune some of this out by advancing the the ignition timing on one bank of the engine.

The Jag V12 is more sedate and far quieter and smoother if it's running right. The two engine are emblematic of their brand focus at the time. The BMW V12 has it's focus on performance and the Jaguar on refinement. Both engines hit their marks for the time.

Here is a good article on V12 sedans during their heyday.
https://www.caranddriver.com/reviews...mparison-test/


They both have some similarities too. Both were highly reliable in their final years only to be replaced by unreliable, problematic and lesser V8's that made about the same power with about the same smoothness due to advances in balancing and engine management.
 

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  #124  
Old 10-22-2020, 03:57 PM
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back in the day when i was able to do engine swaps,and had money, this V12 Audi DIESEL twin turb. was on my want mind!
Audi had an available V12 of 6L, all aluminum that only was available in Europe,in Q7 cars. stock factory specs 600hp at 5000 rpm, ungodly expensive!
some tests were done that with just a reprogram engine management, and free flow exhausts, bumped it to 750hp at 1200FT lbs, at just 2200rpm!
engine never had to be opened up! and weight was only 30Lbs more than a Jag V12!
i was at a race at Road America in 2007(last time Audi Diesel V12 car allowed to race at IMSA events). V12 car was banned permently!
WHY? you should have seen PENSKE cars being passed on the front straights, comin off the 1st corner Audi left everything behind! TORQUE!
ahh well never say never!
ron

 

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  #125  
Old 10-24-2020, 06:51 AM
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I also fall into category A. I just love the style and the lines, not a fan of the bumpers - but a body kit gives me the look I like. Engine under the hood - what ever it takes to keep them from being scrapped.

Found this on u-tube (put on line 5 days), it is a XJ12, not XJS, low mileage car that needed tinkering to get her firing on 12.
Bit heavy going for me, but still interesting

Cheers
Steve

 
  #126  
Old 10-24-2020, 09:24 AM
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The simplest and cheapest approach is to fix whatever minor problem is keeping the V12 from running properly. I realize it’s scary looking at all that plumbing and wires. But figuring it out is actually a lot simpler than re-engineering what was originally there.
Professional engine swappers want $20,000 to get a Chevy 350 installed and sorted? That tells me it’s not as simple as they make it sound.
Yes there are a lot of rubber hoses that need to be unhooked from one end and replaced with a new hose and connected to the other end.
In the years since it last ran sensors may have deteriorated but there are clues which tell you which one.
I was 14 years old when I did that to a Cadillac I bought that had an engine fire and burned all the wires. The red with the white stripe I found where it was good and traced it through the bad to where it was good again. It only took me a weekend to get to the part where I started the car.
Think of it like putting a picture puzzle together. Patience and some knowledge makes it go quickly and pleasantly.
Here’s the reward. A non running engine makes the car worth scrap prices. $500 or so. But once you get it running. It’s now worth at least $3500 maybe a whole lot more. Kind of a nice wY to earn $3000 isn’t it?
 
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  #127  
Old 10-24-2020, 10:20 AM
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Originally Posted by Mguar
The simplest and cheapest approach is to fix whatever minor problem is keeping the V12 from running properly. I realize it’s scary looking at all that plumbing and wires. But figuring it out is actually a lot simpler than re-engineering what was originally there.
Professional engine swappers want $20,000 to get a Chevy 350 installed and sorted? That tells me it’s not as simple as they make it sound.

Decades ago lumping a Jag was indeed relatively inexpensive. The main idea was to simply get the car back on the road for less money than repairing a dead Jaguar engine. The early swaps were generally quite rudimentary...and it showed. A basic, low-performance carburated V8 and automatic trans. Nothing special. Workmanship and attention to detail was not high on the priority list. Sometimes not on the list at all

Fast forward 30 years and see how things have changed. A great many of the lumped Jags are now beautifully engineered and executed...and the lumping is just one part of a resto-mod process which includes full cosmetic restoration and other upgrades. Many of the lumped Jags nowadays are really, really nice cars. It's no longer about getting the car back on the road as cheaply and quickly as possible.

$20,000 ? Nowadays that really isn't all that much in the hobby car world. For a lot of people that's no big deal. You gotta remember that there are lots of car guys spending $150k-200k or more on "resto mod" and "pro touring" Camaros and Mustangs.

As a V12 lover I'm sometimes saddened when I see an owner give up on a Jag engine too quickly. I'm quite sure some V8 swaps are the result of not knowing (and not wanting to know) how to get one running properly. But an engine swap their choice .....and may it ever be thus. If they are happy and proud of the end result then it's a "win" as far as I'm concerned. That's what the car hobby is all about.

Me? I'll be honest, I take a bit of pride in having a sweet running Jag V12 as a daily driver. I view it as an accomplishment. There was a learning curve, sure, but that's where I decided to put my effort even though others thought that effort would be better utilized on a different path. This doesn't make me better than the next guy. I'm just the oddball, that's all. And that's OK with me

If it all came down to nothing but least expensive, most practical, and easiest choices....well....none of us would even be here. We'd all be driving 10 year old Toyota Camrys.

Cheers
DD

 
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  #128  
Old 10-24-2020, 11:13 AM
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While I agree anyone can do anything to their car. You’re also right in that much of it was through lack of knowledge or understanding.
I collected 50 V12’s before I ran out of time. Many of them were pulled due to trivial issues like cracks in vacuum hoses or disconnected wires. Out of those 50 only two had honest mechanical defects that would have required rebuilding. That’s junked engines. 2 out of 50 junked engines.
 
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  #129  
Old 10-25-2020, 05:04 AM
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Originally Posted by Mguar
The simplest and cheapest approach is to fix whatever minor problem is keeping the V12 from running properly. I realize it’s scary looking at all that plumbing and wires. But figuring it out is actually a lot simpler than re-engineering what was originally there.
My V12 came out because the previous owner replaced the head gaskets but never finished wiring or plumbing the car back up. I was sold a "complete car" but when I got home I found some things were obviously missing. The seller was going to freight them to me but never did.

So I had a jigsaw puzzle that I knew was missing pieces but did not have a clue as to how many were missing. The workshop manuals I have are extremely low on detail about said plumbing, my 1992 parts car is nothing like the 1978 model under the bonnet and I could not find anyone local who had one tht I could go and see and take photo's of.

After 6 years of it sitting there looking sad and inactive I decided that n engine swap would have it sorted. I'm not going the V8 route if I can help it. I'm going with a DOHC 4 litre inline 6 Ford Barra engine. At 261.5HP it is only 34HP short of the V12's 295.025HP but being ~200Kg lighter the power to weight will likely be better. These engines came factory turbocharged too and they started at 322HP and went up from there to 426HP (these are factory figures) but their torque spread made them one of the best engines ever made.

https://drivetribe.com/p/why-do-aust...RaaOfXhIldmbfw

 
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  #130  
Old 10-26-2020, 01:25 PM
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I'm lumping a V12 XJS. I have no issue with the Jag V12 but I prefer it be an LS in there. Why? simply because I want to and it'll be fun. I'm not emotionally attached to the prestige of car brands etc. I absolutely love Mercedes W108's and I love the engines they came with, but I have a buddy who put a LS in his and I cant dislike it because it so cool. I'm a hobbyist and I have a broad interest in cars. I don't think the XJS does anything particularly better than other cars in the same era to be honest.

Also, my favorite V12 is the M120 Mercedes. Its a mint engine plagued by the bio-degradable wiring and computers everywhere. I will swap an M120 into a car one day, and I'll use a stand-alone ECU too.

Now to all the purist/elitist who talk down to people who do engine swaps as if they're dumb, it might be time for yall to take a step back. Or just continue to yell at clouds lol.
 
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  #131  
Old 10-26-2020, 04:38 PM
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Originally Posted by Pirublues

Now to all the purist/elitist who talk down to people who do engine swaps as if they're dumb, it might be time for yall to take a step back. Or just continue to yell at clouds lol.
As the quality of conversions goes up I suspect the level of respect will follow along accordingly. But remember, a lot of lumps are not so well executed .....so sometimes there's not really any justification for purists to step back.

To illustrate:




In the first example, well, it would be pretty ballsy to expect (much less insist) that anyone "step back"

The second example.....an entirely different story !

Cheers
DD

 
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  #132  
Old 10-26-2020, 04:40 PM
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Originally Posted by Pirublues
I'm lumping a V12 XJS. I have no issue with the Jag V12 but I prefer it be an LS in there. Why? simply because I want to and it'll be fun.
That works for me !

Cheers
DD
 
  #133  
Old 10-26-2020, 04:48 PM
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Originally Posted by Doug
As the quality of conversions goes up I suspect the level of respect will follow along accordingly. But remember, a lot of lumps are not so well executed .....so sometimes there's not really any justification for purists to step back.
I've never seen one of the high dollar well done conversions, but I've seen plenty of the low to mid-dollar conversion, and they ranged from "farmers backyard" to "indifferent shop" levels of quality. In all cases there was a system that didn't work, that would have worked with the original v12 - it was either the climate control, cruise, speedometer, trip computer or all of them that didn't work. Interior finishes were often rudimentary to be generous. I don't think any of them could have passed an emissions test, or a structural examination of the welding.

There is a great reason to step back - step away from the poor car that was hacked apart!
 
  #134  
Old 10-26-2020, 05:32 PM
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Originally Posted by Pirublues
Now to all the purist/elitist who talk down to people who do engine swaps as if they're dumb, it might be time for yall to take a step back. Or just continue to yell at clouds lol.
I actually applaud engine swaps. I think it's a win/win situation, both for the purists and the lumpers.

The individual doing the swap is getting what he personally wants, and has the right to do whatever they want to their car. It's theirs and they should make any modification that makes them happy. I've seen a couple of impressive conversions, and there is ample non-running or poor running inventories of XJS's out there.

For the purists, our original cars get more valuable every time another XJS gets lumped. The long production run and huge import numbers to the US hurts the XJS' valuation as a classic car here, and the more the herd gets culled by wrecking yards or other means, the higher prices are going to go. It's kind of a George Bailey moment, 'every time a lump sings, an XJS gets its wings.'

win/win

 
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  #135  
Old 10-27-2020, 03:53 AM
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Originally Posted by Mac Allan

For the purists, our original cars get more valuable every time another XJS gets lumped. The long production run and huge import numbers to the US hurts the XJS' valuation as a classic car here, and the more the herd gets culled by wrecking yards or other means, the higher prices are going to go. It's kind of a George Bailey moment, 'every time a lump sings, an XJS gets its wings.'

win/win
Is that a win? You want one it is going to cost you a shed load more. You want parts for the one that you have its going to cost you a shed load more.

I got out of Ford Capri's because rusty and or bent panels were starting to cost an arm and a leg as were most Capri specific parts.
 
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Old 10-27-2020, 06:13 AM
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Hello Jim - bit left field I realize.
Presuming you mean the 1970's Capri? Below is my 64 Consul Capri that my father brought me when I was six. Still sitting on the farm where it will stay until my parents retire.
When I was in my teens, I liked the American muscle cars, as I have gotten older, I have moved towards the English cars.
Got to love the challenge


Big old Austin behind the Capri is liked by my wife - but may be too far gone to save, time will tell

Cheers
Steve
 

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  #137  
Old 10-27-2020, 07:32 AM
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Originally Posted by Jim5_0
Is that a win? You want one it is going to cost you a shed load more. You want parts for the one that you have its going to cost you a shed load more.
Some of us can afford a shed load more... so yeah, it's a win. Once you lump a Jag it's no longer a Jag, It's a lump. Nothing wrong with that I have drooled over many lumps. Just saying. Nope, I'm not a purist, personally I am way ok with the other 239 1996 XJ12's being lumped making mine the only '96 V12's left. Lump away.
 
  #138  
Old 10-27-2020, 08:08 AM
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The reason a purist may need to step back has more to do with what other's do with their stuff causing said purist to be outraged or condescending. If someone does something harmless with their own possessions/money and it gets you to behave in that particular manner then yes, you need to step away. You can dislike something all you want but taking it that far is unhealthy. I only say that because I've seen it on this forum as well as others, when people don't like what was done to a car they become condescending and rude about it. A common toxic trait in our car community.
 
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  #139  
Old 10-27-2020, 09:16 AM
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Originally Posted by Pirublues
The reason a purist may need to step back has more to do with what other's do with their stuff causing said purist to be outraged or condescending. If someone does something harmless with their own possessions/money and it gets you to behave in that particular manner then yes, you need to step away. You can dislike something all you want but taking it that far is unhealthy. I only say that because I've seen it on this forum as well as others, when people don't like what was done to a car they become condescending and rude about it. A common toxic trait in our car community.

It's akin to sports...were loyalties can become toxic.

But in fairness we must also look at the role lumpers have played in creating this environment. Among them is a contingent who bring heat on themselves in particular and lumping in general. They go out of their way to gratuitously bash Jaguar designs, and exaggerate the faults, and then tout themselves as being better and smarter than purists because they've lumped their Jaguar. Then, when they're done bashing, act shocked and insulted that their opinions are met with disapproval.

Also in fairness I'll add that, IMO, this contingent seems to be slowly disappearing....but the fallout lingers on.

Personally, as justification for lumping, I'm heartened to hear your honest "Because I want to and it will be fun" as opposed to 103 other reasons and explanations that often come from lumpers....many of which are often not particularly convincing.

Cheers
DD
 
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  #140  
Old 10-27-2020, 01:26 PM
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Gotta love these debates! Of course everyone has and is entitled to their opinion, so I'll share mine.

I'm new to the Jaguar thing. Not brand fanatic to Jag or any brand for that matter, as you can see I've owned a variety and plan to do more in the future. My aim is to experience as many as I can. I call it like I see it, good and bad.

I've expressed my thoughts previously on my first 1000 miles in my 96 XJS 4.0. Coming up on the next 1000 soon. Some of you may look down on those with the 4.0, and that's ok I get it. I wanted a Jag. I'd like to experience a V12 one day perhaps, but I didn't want more trouble than I could handle, and with a shortage of V12 techs around I just feel like I spend more time on the road enjoying the car than working on it. In the end the risk vs reward wasn't worth it to me.

But I will say that I am a purist at heart. I'm not a fan of off-brand engines powering something they weren't designed or made for. I get the hot-rod mentality and do-it-because-I-can thinking, but it's just not what I'm in to. If ya got a Ford, put a Ford engine in it. This cram a SBC into whatever is just wrong IMHO. I have a brother in law mechanic, SBC diehard. Wanted to put one in my 911SC. That's heresy! The 911 driving dynamic and character is achieved by the boxer flat-6. Low center of gravity. Rev-happy. Power equal to the chassis. You change that, and it's no longer a 911. It's a Frankencarthingamajig.

I've owned V8s from Chevy, Dodge, Jeep, Range Rover. All of them were adequate. Most of them leaked a lot of oil and didn't like to rev much at all. The Chevy and Dodge engines were pretty crude actually. Now I know you can sweeten them all and custom build til your wallet busts. The Alfas I've owned would not have been the same car with any other engine. The twin-cam was legendary for a reason. It was the entire personality of the car. The engine, transmission and chassis are the car. Everything works together, as it was designed. Handling. Power. Sound. Revving. Shifting. Braking.

If you want a Jaguar, it needs to have a Jaguar engine, otherwise it's not a real Jaguar. It's something else. That's true of any brand, not just Jaguar.
 
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