Okay, bear with me because I'm mapping this out in my mind, as I go.

While the Thor 4.0 V8 in my Disco 2 is "fine" mechanically, I do have a little knock when cold. Once it warms up, the knock is undetectable. I've been playing with various oil viscosity and modifiers, but that's a topic for another thread.

Being a BMW enthusiast, and a very big fan of the old M30 straight six, I would love to pull the V8 out and drop an M30B35 in it's place, but there doesn't seem to be enough space to deal with the M30's length. It would be an easy enough swap since I happen to have a 4HP22 mounted behind an M30 and it would be simple enough to change only the bell housing on the 4HP22 in the Disco. But, this is a dead end, unless I want to relocate radiators off to the sides like an old Audi 5000.

The 4HP24 was used behind the M70B50 V12 BMW, in the 750il, and the engine is short enough from bell housing to radiator, but it's far too complicated for what I want to do. Yes, it can be done, I've seen the youtube video, but personally I find no real benefit other than wow factor.

I also happen to have a 2001 Jaguar XJ8 with a 4.0 Liter V8 (AJ27 engine I believe) that has very low miles after being replaced due to a timing chain failure, shortly before the abysmal 5HP24 transmission died in keeping with the 5HP24 tradition.

I do not believe the 5HP24 transmission bell housing will work on the 4HP22 in the Disco 2 (Although it would be an epic win if it would), however after a little research, a 4HP24 was used behind the 1994-1997 Jaguar XJ8 with the AJ26 V8, and I believe the 4HP24 bell housing can be installed on a 4HP22.

My thinking along this path is to:
a. Verify that a 4HP24 bell housing can be swapped onto a 4HP22 transmission, then verify that the 4HP24 bell housing bolted to a Jaguar AJ26 V8 will also bolt to an AJ27 V8 (I'm about 90% certain it will).

b. Figure out if the Jaguar throttle body can be removed and replaced with something more simple like the one on the Thor 4.0.

c. Check to see if the various Jag sensors are even close to mimicking the Thor sensors

d. Check for potential clearance issues with the oil pan and exhaust manifolds.

Yes, there are many potential stumbling blocks, but my idea is to do this swap with as little ECU/TCU/BCM issues as possible so that essentially all the Rover computers simply think that it's just another Thor V8.

My goal here isn't really to gain horsepower (although the AJ27 has roughly 80-90 more horsepower than the Thor 4.0), I really simply want to use the Jag engine instead of scrapping the car because it has such a horrible transmission, and an engine with less than 30K miles.

As far as engine management is concerned, the Jag engine could benefit from being less complicated, and most of the components on both engines are Bosch. The Jag engine is a little heavier, and a little wider due to the dual cam configuration, but it looks like width isn't going to be that big of an issue in the Disco.

The Jag uses coil on plug ignition, but I should be able to swap the coil pack off the Thor V8 and not have to make any changes to the Rover ECU.

In the "Perfect World", this would be a dead simple swap, but that's why I came in here.

Anyone with much more experience with these issues is encouraged to contribute.

 

I like the way you think. Been considering the same thing with a Mercedes M113 v8. Make it happen. Would be nice to eleminate the old Buick 215 block

 

1. see if jag motor will bolt up. 2. Remove all of the sensors from jag motor and replace with land rovers. Swap over throttle body and IAC. Use rover coil and wires. Figure out trigger wheel for stock lr crank sensor. Use rover fuel injectors. Drive truck.

 

What this guy said...

 

That's the direction I was thinking, except that I don't believe the Jaguar motor will bolt to the front of the Rover 4HP22. The Rover 4.0 Thor and the Jag AJ motors (I don't imagine) are going to share a bell housing bolt pattern.

That's why I was digging around to find a suitable Jaguar bell housing.

I realize that Ford/Jaguar and Rover eventually joined forces in the later 2005+ LR3 with a 4.4 Liter AJ31 (I think) Jaguar motor, but the transmission doesn't have a removable bell housing and won't play nicely with the computers on the Disco 2.

The crank position sensor was another of my concerns, I'm going to need to investigate what type the Jag uses, and figure out what type the Rover uses and see if they're even mildly compatible.

I'm not going to rush into this, since the Jag is just killing the grass in the back yard, and the Disco 2 runs well for now.

I'm going to hunt around for a V8 Jag 4HP24 trans, and maybe a wrecked/damaged/engine blown Disco 2 and work on putting this together so I'll have time to check everything and fabricate mounts etc and when the time comes I'm hoping to have it plug n play.

Being able to put an AJ motor in a Disco would open up a pretty wide range of options, including the 4.2 and Supercharged variants. Not that the rest of the running gear would appreciate throwing 300+ horsepower at components designed for 180, but some interesting possibilities none the less.

 

Custom bellhouings are relatively cheap...

Custom flywheel. Rover gears. Jag bolt pattern.

It'll hold, for about 6 minutes. But they will be the most entertaining 6 minutes of your life.

 

4hp22 and 24 are the same housing, but the 24 has places for electronics. Bell housings are interchangeable. I have a BMW M20 4hp22 BH on my RRC 4hp22 now.

I'm M70ing my RRC now, which previously was running an OBD1 M52.

M30B35 will fit, but the sump has to be dealt with.

The issue with the 24 is it's electronically controlled. You can drop the guts from a 24 into a 22, common upgrade when rebuilding. OR I've been toying with popping the valve body from the manual 22 into the 24, drilling and tapping for the kickdown cable (boss is there) and done.

The T-case should bolt up at the rear with the Rover output.

In for this. Jag v8 is pretty cool. I'm more of an M60 guy though....

 

Among the list of possible swap options I considered was the M60B40, since it is a motronic 4.0 liter. Of course finding one with good timing chain guides, that's a different story. I have an E39 540i 6-Speed, which is the M60B44, and I think it would be a great engine for the Disco, but I would have to locate one, and I think the "conversion" work would be higher. The M20 would be a step in the wrong direction (but that's just my opinion).

I recently sold my E34 with a turbocharged M50B25 Non Vanos, and knowing they outfitted some Discos in South Africa with M50s, makes me regret selling it, but I've been eyeing my wife's E36 328ic for it's buttery smooth 2.8

It's an overly tight fit if I wanna keep the AC, and I believe they only made one oil pan design for the M30 for it's entire run, and while a custom pan isn't completely out of the question, and there are a few places that make a dry sump for the M30, I don't want to reinvent the wheel.

I've read about upgrading the clutches and drums in a 4HP22 with the components from the 4HP24, and that may happen down the road a little further, but I'm hoping to use what I have, in as much as that's possible.

I've thought about that as well, and I'm hoping to avoid that if I can. At this point good used Rover 4HP22s are plenty cheap, and it's not like they were even used to their full lifetime potential. There are plenty of low mileage 4HP22 transmissions and transfer cases pulled from Discos that dropped a sleeve and were junked because of it.

Most of the signs point to a workable solution. I am a little concerned about the flexplate to torque converter connection. Of course, as long as a 4HP24 torque converter will slot correctly into a 4HP22 Rover front pump assembly, I won't have to worry about a thing, except for maybe the Crank Position sensor. The sensors are drastically different, and I'm suspecting that the one on the Jag is magnetic, like a hall effect sensor, where the one on the Rover is a pulse generator.

That could be a problem, but it might be easy enough to source a toothed wheel for the front crank pulley. Still, even with all of these issues, it doesn't seem like it would be as big of a task as an LS swap, while retaining 100% of the ECU functionality, as well as gauges, body control module, etc.

Of course, this whole plan might go sideways if an LR3 I found locally can be bought cheaply enough, because it's an SE V8 with the Jag 4.4 liter, and it needs an engine. The 4.0 in my XJ8 would quite literally be a direct bolt in swap for the 4.4 and while it wouldn't have as much power, it would be really simple. I would then need to source a new swap for the Disco 2, and at that point I might lean more toward a rebuilt M60B40. But I'm not counting on the LR3 being cheap.

 

Yah, mine was OBD1 M52, with M20 BH, TQ converter, and flex plate, all bolted into the Rover 4hp22.

I was so anemic.

The M6x will need a custom bellhousing. They never came with a 4hp variant trans. Is why I decided on M70. It literally bolts up, and isn't as terrible as people might have you think. It's a very popular engine for kit car guys.

 

There's a rumor (at least according to wikipedia), that a 4HP22 was used in some E34 530i behind the M60B30, again, I've never seen evidence of this, and can't speak to it's validity, but if that were the case, the 4.0 and the 4.4 would bolt to that bell housing. However the referenced E34 user manual does make mention of the 4HP22 behind both the European M30B30 and M60B30. That gives me a little hope, but it's wikipedia so it may have been edited by someone trying to win a bet.

I wouldn't think that having a custom bell housing made for the ZF would be that big of deal, considering it's so widely used, but I would really rather use existing products, not only to keep costs down, but to also make a swap that anyone can duplicate with the same components.

Depending on the variant of the M70, you're really talking about a power and torque range that seems a little bit overkill, but that's just my opinion, and it may not be for your application. I love the sound, power and "torque on demand" of the M70 and M73, and I even contemplated dropping one in one of my E34s, with a 6-Speed behind it, but the logistics of getting everything else to work was just too daunting for power that would be easier and cheaper to obtain by simply turbocharging my M30.

I'm still going to have to research the crank sensor issue, and I'm sure that mounts will have to be fabricated, but it still seems to be a workable solution.