Hi Guys


has anyone in the team fitted a Jaguar V8 and manual gearbox (not a US lump) instead of the V12 engine & BorgWarner gearbox to a pre-HE chassis?


if so how difficult was this conversion and were you able to retain the original engine mounts & drivetrain behind the gearbox.


any information would be most welcome. Thank you in advance


have fun
BernardS

 

Hasn't been done to my knowledge.I don't think it matters much if its a PRE-HE, its still the same block and everything in the engine bay. The biggest pain with an AJv8 would be the electrical/computer systems. I think its a cooler idea than putting a stupid chevy 350 in for sure, so would getting a XJR inline 6, but i can just never see it as being less work than getting another v12 or repairing the current one. If you want to go fast, buy a different car.

You wouldn't retain the original engine mounts, you would make others. With the smaller engine you would want to take the opportunity to move the engine mounts further back.

You would have to make up a trans mount or modify the jaguar one and get a custom sized driveshaft.

Like I said, the most work I see would be in fabricating mounts and getting everything lined up, then setting up all the electronics and making them work with the existing gauges and switches in the car. There is also some thought to go into where everything ends up after it is bolted down, for maintenance, but its a good deal smaller than the v12.
I just see the v12 so close to the 300hp the ajv8 makes that I don't see any sense in it.

 

Bernard, IIRC the XK8 is based on the XJS pan which if true might tend to allow for this swap. I wouldn't think it impossible as I've seen every combo of engine in car that one could imagine. The Jaguar V-12 in a Midget was a bit much though!

 

Haven't seen that particular swap. Some folks have done the supercharged I6 though... check out this thread in the engines forum:

https://www.jaguarforums.com/forum/j...ged-xjs-56549/

Probably way cheaper to find a wrecked 6.0 V12 and then do a conversion for the transmission.

[edit] check out post 22

https://www.jaguarforums.com/forum/j...e2/#post440913

 

you know after thinking about it, a superchrged Jag V8 ,would make nice conversion.

lighter than V12 and smaller(more room to work on).

service parts more available, a lot of Ford parts would fit(1/2 price of Jag parts).

YUP, do it, keep posted!

 

That was my XJS from years ago..... Doing another right now using an XJR X308 as a donor, fitting everything, engine, gearbox, loom, modules the works....... Should be an interesting conversion

 

XKRacer, please document this conversion and post here - we would LOVE to follow along.

 

I could but the car will not look much like an XJS, everything is highly modified, the only recognizable part will be the buttresses and the rear lights..... Kind of.... It's quite hard to explain?

 

How the XJS looks right now...... Pretty rough but there's potential, I have removed the front of the car, never did like those large over hangs!

 

Wow... hats off (once again) to you guys with the skill and knowledge to pull off something like this.

Please, post the process!!! May not end up looking like an XJS, but it's based on one, so close enough.

Is this a build for yourself or a client? Do you have any sketches of what the finished product will look like, and what kind of power are you looking to extract from the V8?

 

You will have to squint a lot..... The car was converted to a Monaco years ago and is believed to of been No.1 which was owned by the Sultan of Brunei (debatable possibly).
I use to own one myself which as you have seen I started to play with but opted to put back to "normal" and sold a couple of years ago

I will be fitting one of my own front bumpers 2014 XK head lights, apart from that the body work is mainly Monaco although this is a 87 car I have converted it to facelift, pillarless doors, rear lights, trunk lid and quarter light windows



Originally a V12 which is a nightmare engine IMO, hard to work on, messy, rubbish electrics and costs a fortune to tune to any real power. I know some of my remarks are going to upset some, but there you go....

V12 went in the eBay bin and was sold, I still have the gearbox if anyone is interested, a full recon item with no miles put on it yet



I'm looking at getting around the 500 hp mark, not a problem to do really, don't need cats, I will make a nice induction kit, lower pulley, maybe upper as well with water/meth...

I am going to take a look at fitting the whole rear bed so I have the correct diff and outboard discs, shame really as it has a full recon bed on it with new brakes and an LSD, this too will be up for sale if I pull the swap off. Having the XJ bed gives me brake options as well, Brembos can be fitted for starters..... I have an LSD sitting on the shop floor I may use but might go a different route...... This is a customers car which he has given me free rein to a large degree which is good as I can make a really great looking car.

I shall be using a large proportion of the XJ interior, I have to shorten the dash 4", the centre console looks like it will fit, all the air con I can squeeze in, like I said previously I am planning on using as much as possible from the XJ however XK seats will be used and the seat modules seem to work on the XJ loom which is a bonus

As stated not much of an XJS left !.....

 

Had to google the Monaco conversion, but yes - I remember seeing these in magazines and various books I've collected over the years.

Not my cup of tea, but I respect the skill it takes to pull off such a conversion.

Perhaps you should start a new thread for your build? What's your timeframe for completion? Thanks a million for sharing this information. Great stuff.

 

HI XKRacer,


thanks for picking up the tab and running with the Jaguar V8 conversion. I am certain that this will get a great audience.


for my part I will not go with the body conversion since my "76 XJS will partner our 84 HE. However I am at the moment endeavouring to source a low mileage XKS V8 and (hopefully) a manual gearbox. if you have access to a unit please let me know.


by the way what was the V12 worth on Ebay ? I will have available a pre-HE with a documented 132k miles on the engine. It is good running order with Crane ignition and used on a weekly basis in the current car.


My reason for change is due to the fact that we have a V12 in the collection and would like the convertible to be able to have a little more modern punch etc.


thank you for the photographs. will be great to see the progress as part of my learning curve.


have a great day
BernardS

 

Putting the body to oneside fundamentally the conversion can be as simple or complicated as you like........ The V12 went for £300 an absolute bargain for someone, got it out of my way!

If you want to go V8 but keep the look on the inside of the cabin you do not need to go as a drastic route as me....... Easiest gearbox to use is from a S Type diesel V6 2.7, bolts straight on to the V8 handles the power easy, you will have to make a flywheel, use the ring gear from the flexi plate off the V8 and get one turned up, use a standalone ECU plenty out there you could even get away with a megasquirt if you wanted to...... Prop is easy to sort and you are up and running, I would go the R engine might as well have the poke

 

Something I forgot to mention that is a bit of a pain...... The sump!

You will have to modify the bed, the pan or dry sump it, the supercharged engine sits high so as a minimum you would have to fit a straight 6 bonnet/hood or put a bulge in.....

 

some pix of my 1978 XJS roadster(Flint has seen them,and others). done back in 94-95, little ahead of the curve, but still viable in the car world.

i do like my version of the V12 ,no Lucas under the hood, all electronics are GM stuff,much more reliable.
is your car a LHD, is it legal in UK?

i have never seen a Jaguar S-type diesel in USA,much less procure a transmission. making up a flywheel,HMM! balancing, alignment,ETC?

i use a GM 700R4 auto. with overdrive, special light weight convertor(instant engine response) with a rear drive ratio 3.73-1.HD power lock.
rear trans mount chevy part $25. usd. custom cross member $10. also aluminum driveshaft.

had to stiffen the body,rear seat delete,(open top car),and front engine bay cross mount.

wide body rear fender flares, also helped to stiffen body. been thinking, i may shorten the rear overhang(kinda looks to long),IMO.

i use a standalone ECU since 1994, upgraded 2 times, much improvement in resolution and adjustments.

i do respect all types of engines and drive systems, been modifing cars for over 60yrs.

but there is something about a 12cylinder engine, that is Kool, maybe the bragging rights,talk the talk or just plain sound.

my custom exhaust exits all 12 cylinders from one outlet , and the sound is absolutely fantastic, especially above 4000rpm(at least thats what the guys say).

and yes, not for everyone, i do understand.

V12 is 100% custom overhauled, hi-pistons, performance cams, custom heads,etc.(still dont make expected power), but good enough for street work.

 

Pretty impressive.........

Lefthand drives are perfectly legal in the UK, this particular XJS was converted to lefthand drive, the customer wants it for either there Swiss or Italian houses I forget which but also to commute back to the UK


The S Type Diesel is a European thing and was not available in the US, balancing everything is simple enough a spigot bush lines everything up for the input shaft

Another benefit of the S Type box is the remote gear linkage makes things very simple

 

What is the heritage of the S-Type diesel?

Is it based on the Ford Duratec, aka 3.0L petrol?

 

I don't think it was but a joint effort by Ford and Jaguar, ford still use it also in a V8 version, it was designed in the UK at the Dagenham plant

 

Great, another person who comes on the Jaguar XJS forum and drags the Jaguar V-12 through the mud! You are right it is your opinion BUT there is NO validity to your posts to continue to drag the V-12 Jaguar down, serves no purpose at all, adds nothing and only serves to alienate some here (remember plenty here really, really like the engine, it's electrics and its ease in maintenance) hey, my opinion. Best of luck in your endeavor, it's interesting and commendable your using a Jaguar power plant, just don't see the need to keep thrashing the V-12. Cheers.