Hi,
In brief, the X-Type only used six hardpoints in common with the Mk3 Mondeo floorpan. The wheelbase was 1.75" shorter and the track was wider, so even the FWD diesels don't have that much in common. The AWD variants, of which all 2.5 and 3.0 engines were used a floor pan with those same 6 hard points, but only 2 pressings were identical between the Mondeo and X-Type, namely the front strut towers. Electrically, the Jaguar is a full CANBUS set up, and uses modules and high speed network cables. Most of the important modules are coded to the car and need Jaguar IDS/WDS system to program - doing things like swapping an instrument binnacle over without having programmed the replacement first will lock out the immobiliser until a dealer can sort it out.
The engines share a "common" block. The crankshaft, conrods and pistons are the same as the equivalent capacity Ford engine. Both 2.5 and 3.0 share the same stroke as per Ford, the difference in capacity being achieved with a larger bore for the 3.0. The actual block castings are similar but not exactly. All the ancillaries are moved around compared to the Ford, and the block castings themselves have additional ribs for strengthening. I understand the mounting hardpoints are in the same locations, but Jaguar mounts are bespoke because the subframes are different.
The bellhousing flanges are the same, and they use Ford clutches with dual mass flywheels.
The cylinder heads are Mazda castings machined differently, with solid lifters and continuously variable valve timing on the inlet camshafts. Ignition is by individual coils mounted over each spark plug rather than coil packs as per the Cougar.
The inlet manifold is much larger and uses a dual chamber arrangement to provide a similar variable inlet tract length idea as the Ford's Inlet Manifold Running Control system, only it has 3 states of tune rather than 2, using mixing valves in the manifold to alter the effective plenum volume rather than secondary butterflies to block off 6 inlet valves as per the Ford. This manifold stands much higher than the Ford item, which trades off space requirement in favour of removing the multitude of 90deg bends in the Ford system.
Lastly, the exhaust manifolds are different, and the Cougar's main catalytic converter is deleted and the "pre cats" are enlarged and become the only catalysts, which are 2 brick affairs with upstream and downstream lambda measurement. Due to the amount of exhaust radiation under the bonnet, the manifolds are extensively heat shielded and the X-Type cooling system is more complicated to include an oil cooler.
To summarise:
It'll bolt up to a Ford gearbox (the manual X-Type uses a modified MTX-75 anyway)
It'll probably bolt into the engine bay, but may need fabricated mounts
The Cougar bonnet won't close by a long shot
You'll need a Jaguar Powertrain Control Module to run the engine, along with Jaguar looms and cooling system
You'll probably find the Jag PCM will only talk to a Jag instrument binnacle
You'll need a Jag accelerator pedal - it's a fly-by-wire throttle (but the good news is that with a Jag steering wheel, clock spring and brake/clutch pedal switches you can have Cruise Control)
You will need a new exhaust as the Y-pipe arrives at a different place to clear the AWD transfer case you won't be using. If you opt to use Ford manifolds and Y-pipe, you'll need to work out how to disable the PCM from looking for the downstream lambda measurement, or you'll have a permanent MIL illuminated and it'll be stuck in Restricted Performance mode
You may need the Jag radiator and cooling system, which may or may not prefer the Jag climate control with it
That's my old 2.5. The 3.0 is identical externally.
