P38 with a jap diesel

Hi good people,

First time poster here. First I want to apologize if I'm beating a dead horse with this topic, but I really could use some input. I know the general sentiment is to stay away from swapping engine in the p38 because of all the electrickery involved.

But here's the thing - I have the opportunity to get hold of a nice 1998 dse P38 with a dead engine. I was thinking of swapping the engine for an indirect injection japanese turbo diesel. Did some research and found out this has been done with the mitsubishi 4m40 and toyota 1KZ, which would be my engine of choice.

Before anybody lashes on me, let me say that spare parts for the bmw 2.5 are not easy to come across where I live (Africa) and they would cost a fortune anyway. Finding a second hand, well maintained engine, would prove equally as difficult and expensive. Japanese lumps on the other hand are a dime a dozen, plus they are usually reliable and easy to find spare parts for.

I know that fitting any other engine to the range rover gearbox would be a nightmare. What about swapping the gearbox too? I think that's what they did for this swap.

Now my biggest concern is about the BeCM. I can't for the life of me find any successful documented swap with an explanation of what to do with the BeCM .. In the link I posted above they did not mention any electric issues so I assume they managed to keep the BeCM working... Same with what I was able to find about the 4m40 swaps (even though it seems like the p38 gearbox was not changed for these swaps).

But how does the BeCM communicate with the new engine's ECU? I suppose it does not, and they have kept the old ECU to communicate with the BeCM (without running the engine anymore) telling it everything is fine so that the BeCM could continue to work normally, and used the new ECU to run the engine...

Whaddya good people think? Any input would be much appreciated

Just leave the M51 engine ECU in place is one way of keeping the BECM in line, probably plus a few sensors. You are right the ZF4HP22 would not take a more powerfull engine, however the ZF4HP24 as fitted to the 4.6 V8 would and it should not be too difficult to mate it to another engine.
Do let us know how you get on.
:welcome2:

:welcome2:

Errrrrr - errrrmmmmmm - I have no clue - interested to know the outcome though....

Just a word to the wise - the BeCM is tempermental enough with the factory unit - you could face alsorts of headaches with a third party engine....

Not sure about how it would react to being left plugged into the original EDC yet it is being told by various other things that the car is moving yet it thinks the engine is off!!!

Still as I said intrigued to find out the result - all I can say is good luck....!!

Saint.V8 said:

:welcome2:

Errrrrr - errrrmmmmmm - I have no clue - interested to know the outcome though....

Just a word to the wise - the BeCM is tempermental enough with the factory unit - you could face alsorts of headaches with a third party engine....

Not sure about how it would react to being left plugged into the original EDC yet it is being told by various other things that the car is moving yet it thinks the engine is off!!!

Still as I said intrigued to find out the result - all I can say is good luck....!!

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The ECU trick has been done.

Datatek said:

The ECU trick has been done.

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Fair Cop.....

Thanks for the welcome and the quick replies, Datatek and Saint.V8 :5bseeya:

Datatek said:

Just leave the M51 engine ECU in place is one way of keeping the BECM in line, probably plus a few sensors. You are right the ZF4HP22 would not take a more powerfull engine, however the ZF4HP24 as fitted to the 4.6 V8 would and it should not be too difficult to mate it to another engine.
Do let us know how you get on.
:welcome2:

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Well I went through the ZF4HP22 specs and it looks like it wont take more torque than it already does with the bmw unit, so that might need changing too. The ZF4HP24 would surely do the trick as you suggested but I would need to be very lucky to find a spare one, let alone a spare one in good condition.

I was thinking of keeping the 1KZ's gearbox and changing the gearbox panel inside the car too.. Checked the old beast with my mechanics today, they seem confident they can get through with swapping both the engine and the gearbox. Now, not that I don't trust them, they've done a couple of 1KZ swaps for me before - both very clean jobs - but I think they're underestimating the electronics here. Not sure if they've ever dealt with electronics as complex as the p38's..

So yeah, I'm trying to gather as much info as possible about the BeCM and stuff before we proceed with the swap. Such a bummer that the previous successful swaps were not documented, like at all...

ShotmaKer said:

Thanks for the welcome and the quick replies, Datatek and Saint.V8 :5bseeya:



Well I went through the ZF4HP22 specs and it looks like it wont take more torque than it already does with the bmw unit, so that might need changing too. The ZF4HP24 would surely do the trick as you suggested but I would need to be very lucky to find a spare one, let alone a spare one in good condition.

I was thinking to keep the 1KZ's gearbox and changing the gearbox panel inside the car too.. Checked the old beast with my mechanics today, they seem confident they can get through with swapping both the engine and the gearbox. Now, not that I don't trust them, they've done a couple of 1KZ swaps for me before - both very clean jobs - but I think they're underestimating the electrics here. Not sure if they've ever dealt with electrics as complex as the p38's..

So yeah, I'm trying to gather as much info as possible about the BeCM and stuff before we proceed with the swap. Such a bummer that the previous successful swaps were not documented at all...

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Did they not have the 4.6 version of the P38 out there? It would be easier IMO to use the HP24 as there would be less frigging to do with the electronics.

Both the P38's we've had in that had had a conversion had the 2.8 m40 Mits engine in. They left the ZF24 in and engine ecu. Both seemed to be an easy conversion with very little additional pipework.

Datatek said:

Did they not have the 4.6 version of the P38 out there? It would be easier IMO to use the HP24 as there would be less frigging to do with the electronics.

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That would be best, and if I could get ahold of a HP24 gearbox I might even consider something more powerful than the 1KZ. Something like a toyota 1VD leaps to mind

Well, I've been looking out for a p38 for quite a while now and I've only seen about a dozen around. All where either DT or DSE.. Out of sheer curiosity, do you happen to know if there were many manual DSE? I think I've stumbled across a coulpe of manual DSEs while searching the forum.. Didn't the DT come standard with a manual gearbox, and the DSE with an auto?

I reckon a p38 with a manual gearbox might be a better basis for my project, but the DTs I've seen around were... errr... Let's say they were not as classy as the DSEs

RangeRoverBreakers said:

Both the P38's we've had in that had had a conversion had the 2.8 m40 Mits engine in. They left the ZF24 in and engine ecu. Both seemed to be an easy conversion with very little additional pipework.

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It was Tony Wigress of Stanton 4x4 that did the ones local to us,thankfully he has now retired !
It wasnt too difficult to sort out the electrics,the main things you need in place are the crank sensor,throttle position sensor, coolant and ambient air temp sensors.Not too hard,the main problem with the Mitsy engine was the sump rubbing the track rod.Also some of them broke drive plates repeatedly so he fitted two at a time.I think that was more of an alignment issue though.
There was another one around the Trowbridge area running a Mazda SL35t against a manual box.It was a very neat conversion and had plenty of go,but it was a little hard on clutches.

According to a fantastic book by James Taylor - Range Rover, The Second Generation (ISBN1-86126-633-5) no affliation, just a very good book!!

In the UK the very first DSE's did come in a manual form, then moved to Auto's for the rest of the run...

The interesting thing is, when BMW took over, they did with the Range Rover what they do with their BMW's - you buy a base car, then add bits to it from the options list - as an example I had a DSE but with Manual Seats, no Steering Wheel Audio Controls, but had Crusie Control, Leather, Auto, Hi Line Audio with Sub Woofer and CD Changer....

This guy used a 6.2L with a 4hp24:

Range Rover P38 diesel conversion - Expedition Portal

RangeRoverBreakers said:

Both the P38's we've had in that had had a conversion had the 2.8 m40 Mits engine in. They left the ZF24 in and engine ecu. Both seemed to be an easy conversion with very little additional pipework.

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eightinavee said:

It was Tony Wigress of Stanton 4x4 that did the ones local to us,thankfully he has now retired !
It wasnt too difficult to sort out the electrics,the main things you need in place are the crank sensor,throttle position sensor, coolant and ambient air temp sensors.Not too hard,the main problem with the Mitsy engine was the sump rubbing the track rod.Also some of them broke drive plates repeatedly so he fitted two at a time.I think that was more of an alignment issue though.
There was another one around the Trowbridge area running a Mazda SL35t against a manual box.It was a very neat conversion and had plenty of go,but it was a little hard on clutches.

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Cheers for this info. For all the talk about how difficult it is to do an engine swap on the p38, it seems like they did get on just fine with the 4m40.. I wonder if fitting the 1KZ will be as straight forward as with the Mitsy lump..

Eightinavee do you happen to know if it's the HP24 that had the drive plate issues with the Mitsy engine? I ask because the 1KZ is more torquey than the 4m40..

Saint.V8 said:

According to a fantastic book by James Taylor - Range Rover, The Second Generation (ISBN1-86126-633-5) no affliation, just a very good book!!

In the UK the very first DSE's did come in a manual form, then moved to Auto's for the rest of the run...

The interesting thing is, when BMW took over, they did with the Range Rover what they do with their BMW's - you buy a base car, then add bits to it from the options list - as an example I had a DSE but with Manual Seats, no Steering Wheel Audio Controls, but had Crusie Control, Leather, Auto, Hi Line Audio with Sub Woofer and CD Changer....

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Cheers Saint.V8 ! You're right, whenever I read about a manual DSE it seems to be one of the early ones.. Although I wonder if it's the same with LHD models

By the way, anyone knows if there's a specific reason why there seems to be no common rail diesel conversion for the p38?
I found a thread with a bloke who attempted to install the bmw M57 lump in his p38 but I don't think it turned out too well for him

ShotmaKer said:

By the way, anyone knows if there's a specific reason why there seems to be no common rail diesel conversion for the p38?
I found a thread with a bloke who attempted to install the bmw M57 lump in his p38 but I don't think it turned out too well for him

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There is a company over here that does a conversion to a later range rover engine, 3L I think, can't remember the name, symtek maybe, but its pricey

Edit- http://www.bodylogicuk.com/90265/info.php?p=11&cat=327170

There is a company doing a TdV6 conversion if you have a fat wallet.

They also do a m57 kit, about 3 grand, then you have to buy an engine and make it fit don't reckon you would get much change from 5 grand

Chrisfrain2007 said:

They also do a m57 kit, about 3 grand, then you have to buy an engine and make it fit don't reckon you would get much change from 5 grand

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With the TdV6 you need a gearbox as well as the engine, with secondhand parts I think it comes to about €8,500

It's on my list for when I win the Euro millions

Datatek said:

With the TdV6 you need a gearbox as well as the engine, with secondhand parts I think it comes to about €8,500

It's on my list for when I win the Euro millions

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Personally, I don't think I could , if I won the euro millions is have to get a overfinch 630r