A Jag is a Jag. You have to love whatever you do to it or you will not enjoy it anymore.

I personally would NEVER invest that kind of time, to defile a classic Jag. (Now you can define classic) As a former Jag Mechanic from the early 70's, (BMC San Francisco), it would break my heart if I woke up one day and a shiny new small block chevy were inhabiting the bay of my 1979 XJ12L.

2 pennies is all i got.

 

I have been trying to find out more dimensional information concerning ALL the differences between the XK6, AJ6 and AJ16 engines. Do you by chance know if this information can be found? (More details than the more common published general information: Alum. versus steel blocks. AJ blocks mounted at angle versus vertical for XK6 blocks, Intake and exhausts on opposite side, head differences, how trans mounts, front timing cover...)

Thanks.

 

This is a guy on the Facebook XJC group named Arnoud Bordewijk from NL. He's already transplanted a 4.0 straight 6 using a donor. He'd certainly have the info you need. On FB he posted a link to the details. See below.

Welcome to Jag-lovers - Members Photo Viewing Page

 

The AJ6 and AJ16 are essentially the same engine with quite a few detail differences that made the AJ16 much better in most respects. Dimensions are therefore the same, and I would think equal in length to the V12, as the AJ6 was based on the V12 and designed for manufacture on the same machinery. However the only real way to find out is to go and measure one up and compare it to your old assembly. The main thing is the engine-transmission assembly is mounted to the body by three mounts, two at the front and one at the back of the gearbox, (the XJ assembly also had a small engine steady mount at the top rear of the engine too)

As the AJ6 was never fitted into a Series 3 shell one must compare the position of the AJ6 mounts to that of your old XK engine/transmission assembly to see what modifications might be needed. There will be room in the engine bay, no doubt of that, as Jaguar got a V12 in ! Getting all the plumbing right, plus the electronics and other ancillaries is an art that can only be acquired by trying it !

Having looked at Arnoud's pictures, I had forgotten that the AJ6/16 engines have the inlet and exhaust sides of the cylinder head transposed to that of the XK.

 

the ultimate engine transplant for Jag XJ12L, would be in my opinion, an AUDI V12 Diesel,

smooth as silk, quieter than a Jag V12, get 28-32MPG(US gallon), Now power, so much more than anyone could realisticly use, specs, same weight as a Jag V12, 4 Quad cams, 4 valves per cylinder, twin turbocharged, bolted to a GM 6 speed auto, from a cadillac Escalade.

factory rated at 500hp, 750 torque, full torque at 1750rpm carried to 3500rpm , max rpm 4500. big sedans and heavy cars need torque down low not at some screaming rpm.

of course you would need a rear axle ratio change, but while you are at it(no one has mentioned it) the rear cage would require some serious mounting improvements. pic enclosed!

any one who has tried to really make a stop light accleration run has literally RIPPED the complete rear end out of a Jag XJ series.

not many of the engines mentioned have enough torque, so with a low powered engine it just might work!

and if factory power wasnt enough, a simple reprogram of just the ECU computor, could raise power to 650hp, and enough torque to spin the planet backwards,850 torque.

all that without taking the engine apart just stock.

and i never said it would be cheap!!!!

 

I was wondering about the possibility of taking an AJ6/AJ16 bottom end. Crank, rods, pistons and then fitting a series 3 head with a custom timing chain, cover, and pan. I am interested in creating a hybrid engine where I keep the intake and exhaust on the same sides as a series 3 engine.

Just a thought.

 

A complete non-starter; there are no commonalities at all between the XJ and AJ engines.

 

well the pictures say it all for me. The 12 will become a coffee table base or more than likely a wine rack. You can't give them away.


As for reliability, who knows. Your going to spend a bundle, no matter the path.


Hopefully your grin will be a mile wide and you'll be eight miles high when you punch the throttle of your dreams.

 

Actually, you can.

I pal of mine gave me his Ser III V12 VDP. Body is shot; engine is an absolute sweetheart. Runs like a watch and doesn't even leak oil.

The car has zero market value as it stands but he didn't want to simply send it to the scrapyard....so he gave me the whole thing lock, stock, and barrel.

I have plans

Cheers
DD

 

I reckon that we all look forward to hearing about them Doug.

 

In a nutshell I'll be turning a Ser III XJ6 (yet to be purchased) into a Ser III XJ12.

With any luck I'll be in a position to start the project in a few months.

It'll be a lot of fun.

Cheers
DD

 

Doug, sounds like a good plan, pretty straight forward conversion, VDP nice car.

course finding a good body in the salt & snow belts, may take some time, depends on your luck!


skillet; i have a great piece of thick brown see thru glass table top, 4' by 2' oval shaped, for your V12 base, great conversation piece,for sale for anyone interested, PM me.

 

It has to be said that use of an engine made in the hundreds of thousands like these US manufacturers V8s is bound to be cheaper than a Jaguar engine made in only thousands per year. Costs of components is going to be cheaper and these engines are very reliable, no doubt of that.

If it keeps the car on the road, OK, and I am aware of the problems the XK 4.2 engine suffered from, having experience them myself. Of course in the UK the US V8s are not in plentiful supply, (almost nil, in fact). So the cars go to scrap yards.