Petrol to diesel engine conversion

[gjm 3258]

Anyone got any guidelines or gotchas for doing this? I've been offered a free Range Rover P38 V8 with a blown headgasket - possibly more problems. I'd like to convert it to diesel.

Obviously there's all sorts of EMS stuff to sort, but other than that and appropriate fuel pumps, is there anything in particular I need to be aware of? Can I continue to use the same fuel tank, for instance?

[kiwi535 538]

can use the fuel tank jst clean the tank out well

[allan 295]

any help https://en.wikipedia.org/wiki/Range_Rover_(P38A) 

[aja540i 1906]

Are you going to use the motor from the 320d? 

Don't "forget" to change the fuel type on the registration, otherwise you won't be able to pay your RUCs!

[gjm 3258]

2 hours ago, allan said:

any help https://en.wikipedia.org/wiki/Range_Rover_(P38A) 

Thanks.

2 hours ago, aja540i said:

Are you going to use the motor from the 320d? 

Don't "forget" to change the fuel type on the registration, otherwise you won't be able to pay your RUCs!

Gosh. Now that would be terrible! 

Not what I was planning though... This is - might be - something not specifically BMW related. 

[lord_jagganath 421]

Mercedes?  or shock a japanese unit? KZs are pretty common to swap in. 

[coop 261]

I think the over rated 1KZ would be cracking heads on a monthly basis having to haul around a 2.5 tonne Range Rover. 

 

Complexities around the P38 might make it easier and cheaper to keep it as a parts car and find a standard 2.5dse, or the later L322 with the BMW td6, or even a td5 Disco. 

Also I think diesel and V8 gearing are different of the top of my head... the V8 Range rovers will do 70 in 1st and around 120 in 2nd. 

[gjm 3258]

The questions do involve the possibility of repowering a Range Rover.
I've been offered one with a blown head gasket (4.0, GEMS engine) which probably means other issues.

The idea had been to possibly swap in a Mercedes diesel, or possibly an early BMW M57. However, the BECM (Body Electrical Control Module) in the Range Rover makes this very difficult, so I'm going to junk that idea, and settle for useful parts from the donor instead. The BECM ties into everything and messing with it can cause any number of issues, ranging from fuel pump to electric windows. (They junked it in the P38 successor, the L322.)

Edited December 2, 2018 by gjm

[lord_jagganath 421]

if you are a sucker for pain, there is the option of entirely rewiring the thing... that would become a 4 year project...

[gjm 3258]

23 minutes ago, lord_jagganath said:

if you are a sucker for pain, there is the option of entirely rewiring the thing... that would become a 4 year project...

I have enough pain sorting the P38 with 12 months WoF that I have! Someone has gone to a lot of trouble to make sure that the air suspension won't work without being manually inflated with an offboard compressor - it really would have been much simpler, easier and faster to have just fixed the problems it had, instead of butchering wiring, air lines, removing the compressor, blocking the valve block, bypassing relays...

[Eagle 1662]

Haha wtf. Why wouldn't you just convert to coil springs. Only major problems my fathers had was air suspension (gone now) and heater core o-rings leaking (2nd time). BMW engine and transmission are the best parts and still solid at 230,000km

Edited December 2, 2018 by Eagle

[gjm 3258]

32 minutes ago, Eagle said:

Haha wtf. Why wouldn't you just convert to coil springs. Only major problems my fathers had was air suspension (gone now) and heater core o-rings leaking (2nd time). BMW engine and transmission are the best parts and still solid at 230,000km

The one I have here is a 4.6 V8. (BMW EMS. )

Heaven knows what a previous owner was thinking with the bodges they put in place. Probably had someone quote them $000s to sort $50 problems, and so took a long route to not fixing things.

Replacing air with steel suspension needs a cert, which is enough to put a lot of people off.

[Eagle 1662]

Seen quite a few without certs so it down to the WOF inspector i guess  

[kiwi535 538]

1 hour ago, Eagle said:

Haha wtf. Why wouldn't you just convert to coil springs. Only major problems my fathers had was air suspension (gone now) and heater core o-rings leaking (2nd time). BMW engine and transmission are the best parts and still solid at 230,000km

for the same reason they had air suspension in the first place Lower ride for the ride,higher ride for off road .Apart from the silly sized wheels and tyres they have they are very good off road,one of very few to be good at both

[Olaf 3318]

what's the Mercedes diesel in the Ssang Yung Musso?  OM606?  Wonder if they're reasonably priced and available?

[Eagle 1662]

23 minutes ago, kiwi535 said:

for the same reason they had air suspension in the first place Lower ride for the ride,higher ride for off road .Apart from the silly sized wheels and tyres they have they are very good off road,one of very few to be good at both

Yeah the benefits of air suspension are given. My comment was aimed at the butchery of which appears to have distorted the system. Nothing worse than people attempting half ass fixes.

[kiwi535 538]

8 minutes ago, Eagle said:

Yeah the benefits of air suspension are given. My comment was aimed at the butchery of which appears to have distorted the system. Nothing worse than people attempting half ass fixes.

sorry my mistake i though you were deriding the option to spend the money and repair it back to working order

[gjm 3258]

As said by others, the P38 EAS (Electronic Air Suspension) is a good system.

It's not actually all that complex either, but it is very misunderstood and unscrupulous (uncaring, ignorant) repairers play on this. Simplicity does lean towards springs and shocks (and there are good conversions available) but these will never have the active element of EAS, or provide for multiple, selectable ride heights, either automatically or based on operator choice.

A lot of people don't realise the P38 had genuinely active suspension which would detect lean in corners, and increase pressure to the 'low' side of the vehicle, giving it a flatter cornering attitude. It also automatically lowered above a certain speed for safer, more secure higher speed driving, and could be lifted by several inches for off road use.

[coop 261]

You'll also find amongst Land Rover enthusiasts, P38s are more desirable with the EAS in the vehicle and working than ripped out for coils. For obvious reasons. Coupled with the four wheel traction control, they are were more capable off road then nearly anything else from the 1990s.

I think these are becoming more collectable amongst LR enthuiasts, not to the level of the RR Classic but enough to save or not butcher good examples.

I had one converted to coils, and it had a better ride quality than one with EAS. 

My only issue with them is the transfer case - controlled electronically by the BCM and the transmissions own ECM, with no real mechanical locker, so if you break an axle etc in the bush you're really buggered. No doubt another obstacle you'd need to navigate around with a re power.

[Eagle 1662]

Yep they are not a bad car for their day but have many potential flaws. EAS is great when its working but doesn't seem to last very long before something fails. The HVAC system is pretty troublesome also. 

Don't have high regards for the rover engines and even though the M51 isnt a bad engine for its time its just a bit under powered in P38 coupled with the turbo lag 

Only reason i my father never sold his is they generally seemed to be worthless these days (had from new $80,000 in 1998). I can see a good diesel example possibly fetching a reasonable price but im sure the market for them is relativity small.

[E30 325i Rag-Top 2958]

Would you need to change the fuel pump in the tank, and possibly the tank as well? Not sure if the engine you are looking at putting in has common-rail injection (i'm guessing it is..) which could require a more beefy lift pump to get the required pressures up to the start of the CR system, especially with diesel viscosity v petrol. Plus the fuel return tends to be at a reasonable pressure so could over-pressurise the tank - German engineers would normally make one part number for both so it's over-engineered for the petrol system, the tank venting could be slightly different though?