Defender 4BD1T Conversion

[C H T]

Justin C suggested that I should put up a post about my Defender to which I recently fitted an Isuzu 4BD1T (very late Factoryturbo). The conversion was carried out by British Off Road who did an excellent job. The engine instalation looks and drives like a first class factory instalation. The engine was sourced from DNA truck parts in Minto - highly recomended also - and great to deal with.
1. The engine instalation.
I used a very rusty Isuzu County as the donor vehicle for all the Landrover specific parts - Bell housing (LT85), sandwhich plate, starter motor, aircleaner brackets, engine mounts (engine and chassis), radiator, header tank etc. I managed to obtain the Landrover Australia spacer to go between the twin oil filter hosing and the engine block, and made a spacer to fit between the oil line and the oil cooler - (gives clearance for the front tail shaft). The county chassis engine mounts were welded to the Def chassis in the relevant position. A brand new genuine LR Donaldson aircleaner housing was sourced from ULR in Melbourne. I retained the factory 4BD1T thermostat housing, and modified the Turbo cross over pipe. We had to remove the steel underbonnet stiffeners and replaced them with aluminium flat bar in order to give clearance.
2. Gearbox.
We used the R380 that was behind the 300 Tdi - it has the larger layshaft bearings - mated to an LT85 bell housing. apart from some initial alignment problems - see below - the installation has run over 11000kms now and trouble free. A 1.2:1 Disco transfer case was fitted, which with the R380 and 235/85 R 16s gives 2255 rpm at 100 kph and just over 2400 at 110. We have used a 6x6 clutch pressure plate and a custom soft centre clutch from NPC in Brisbane (great service) - no gearbox rattle at idle (upped to 800rpm).
3. Problems
1. Bell housing/gearbox alignment.
KLR did the initial mods to the bell housing, but didn't quite get the alignment right (about 1.5mm out). Brad very quickly offered to rectify the problem at their expense but time constraints meant that BOR sorted the problem in house. No complaints from me about KLR.
2. Rear main seal leaking. There was a very small groove in the seal surface on the crank shaft. After three changes of seal in as many months we fitted an Isuzu factory wear ring (like a very thick speedi sleeve) and over size seal which seems to have fixed the problem completely.
3. Oil out of the engine breather.
The engine was poking a fair amount of oil out of the engine breather. I cut the top off the oil separator and found that the small "mushroom valve" was well past its use by date allowing significant quantities of oil to surge up the oil drain line connected to the sump. The valve was replaced with an identical one from a Holly Carb kit. Problem solved.
4. Was it worth it?
Absolutely!!!! the vehicle does a lot of bush/remote area/long distance work fully loaded summer and winter, and while the 300 Tdi did a fantastic job, it simply wasn't big enough and therefore was working hard all the time. The Isuzu has transformed the vehicle it is quieter and smoother than the 300 Tdi - yes really!, noticeably faster on the hills and when towing, and much better in the bush - particularly in very steep country.
5. Before I forget.
Boost increased to 11psi with the fuel screw wound out just under half a turn (approx) Fuel economy so far 18.5 to 23.86 mpg.

As for the rest of the vehicle I have owned it from new: it was the very last 300 Tdi 110 wagon sold in Australia according to LR, Maxi drives front and rear, aux fuel, ARB B/bar and warn 10000lb winch etc etc.

Christopher

[justinc]

Justin C suggested that I should put up a post about my Defender to which I recently fitted an Isuzu 4BD1T (very late Factoryturbo). The conversion was carried out by British Off Road who did an excellent job. The engine instalation looks and drives like a first class factory instalation. The engine was sourced from DNA truck parts in Minto - highly recomended also - and great to deal with.
1. The engine instalation.
I used a very rusty Isuzu County as the donor vehicle for all the Landrover specific parts - Bell housing (LT85), sandwhich plate, starter motor, aircleaner brackets, engine mounts (engine and chassis), radiator, header tank etc. I managed to obtain the Landrover Australia spacer to go between the twin oil filter hosing and the engine block, and made a spacer to fit between the oil line and the oil cooler - (gives clearance for the front tail shaft. The county chassis engine mounts were welded to the Def chassis in the relevant position. A brand new genuine LR Donaldson aircleaner housing was sourced from ULR in Melbourne. I retained the factory 4BD1T thermostat housing, and modified the Turbo cross over pipe. We had to remove the steel underbonnet stiffeners and replaced them with aluminium flat bar in order to give clearance.
2. Gearbox.
We used the R380 that was behind the 300 Tdi - it has the larger layshaft bearings - mated to an LT85 bell housing. apart from some initial alignment problems - see below - the installation has run over 11000kms now trouble free. A 1.2:1 Disco transfer case was fitted, which with the R380 and 235/85 R 16s gives 2255 rpm at 100 kph and just over 2400 at 110. We have used a 6x6 clutch pressure plate and a custom soft centre clutch from NPC in Brisbane (great service) - no gearbox rattle at idle (upped to 800rpm).
3. Problems
1. Bell housing/gearbox alignment.
KLR did the initial mods to the bell housing, but didn't quite get the alignment right (about 1.5mm out). Brad very quickly offered to rectify the problem at their expense but time constraints memant that BOR sorted the problem in house. No complaints from me about KLR.
2. Rear main seal leaking. There was a very small groove in the seal surface on the crank shaft. After three changes of seal in as many months we fitted an Isuzu factory wear ring (like a very thich speedi sleave) and over size seal which seams to have fixed the problem completely.
3. Oil out of the engine breather.
The engine was poking a fair amount of oil out of the engine breather. I cut the top off the oil separator and forind the the small "mushroom valve" was well past its use by date allowing significant quantities of oil to surge up the oil drain line connected to the sump. The valve was repalced with an identical one from a Holly Carb kit. Problem solved.
4. Was it worth it?
Absolutely!!!! the vehicle does a lot of bush/remote area/long distance work fully loaded summer and winter, and while the 300 Tdi did a fantastic job, it simply wasn't big enough and therefore was working hard all the time. The Isuzu has transformed the vehicle it is quieter and smpoother than the 300 Tdi - yes really!, noticeably faster on the hills and when towing, and much better in the bush - particularly in very steep country.
5. Before I forget.
Boost increased to 11psi with the fuel screw wound out just under half a turn (approx) Fuel economy so far 18.5 to 23.86 mpg.

As for the rest of the vehicle it was the very last 300 Tdi 110 wagon sold in Australia according to LR, Maxi drives front and rear, aux fuel, ARB B/bar and warn 10000lb winch etc etc.

Christopher

Thanks for the insight to all Christopher, And well done. It is a fantastic engine/ box for a 110. Have you thought of 255/85 tyres? At about 33 inches they give great salisbury clearance, excellent off road and that engine will easily push them.
Makes me want to buy a 110 again now...:D

JC

[C H T]

PS The conversion is fully complianced with an engineers certificate. All very straight forward.

[dobbo]

That sounds like a very nice Defender


Any pictures?

[C H T]

Justin I will be looking at tyre sizes when the time comes - the STTs are still less than half worn and performing brilliantly - Dobbo I am afraid no pictures at present but will see what I can do.

Christopher.

[Dougal]

Nice writeup. Being a very late model motor, do you have the non-wastegated turbo?

[C H T]

Nice writeup. Being a very late model motor, do you have the non-wastegated turbo?
Dougal
No the turbo is a wastegated Garrett. I understand that the order of turbo fitment to the 4BD1T is as follows:
1. Wastegated IHI. (not watercooled). Early 4BD1Ts including Australian army versions fitted to the 6 wheel-drives.
2. Non-wastegated watercooled Garrett. Later 4BD1Ts.
3 Wastegated watercooled Garrett as per my engine. Very late 4BD1Ts - mid nineteen nineties - mine is about 94 vvintage.

Christopher

[Dougal]

Dougal
No the turbo is a wastegated Garrett. I understand that the order of turbo fitment to the 4BD1T is as follows:
1. Wastegated IHI. (not watercooled). Early 4BD1Ts including Australian army versions fitted to the 6 wheel-drives.
2. Non-wastegated watercooled Garrett. Later 4BD1Ts.
3 Wastegated watercooled Garrett as per my engine. Very late 4BD1Ts - mid nineteen nineties - mine is about 94 vvintage.

Christopher

Ahh very interesting. I have a 4BD2T turbo (in the parts bin) which is non-wastegated so assumed the last of the 1's would have had that too.

I'll wait patiently for pictures.:angel:

[C H T]

Ahh very interesting. I have a 4BD2T turbo (in the parts bin) which is non-wastegated so assumed the last of the 1's would have had that too.

I'll wait patiently for pictures.:angel:
I'm afraid the pictures may have to wait until the new year - no suitable camera available to take them yet!

[DRanged]

Well done mate. They are a superb package. Any info you could give me on your clutch set up would be great. I also run an R380 as well. PM any info if you like or post here.

Regards justin

[C H T]

Well done mate. They are a superb package. Any info you could give me on your clutch set up would be great. I also run an R380 as well. PM any info if you like or post here.

Regards justin
Justin

NPC Performance clutches built the custom soft centre clutch for me (07 3277 9403 - excellent service and very competitive pricing for the quality of product supplied). I supplied a sample - standard LT 85 clutch plate as a pattern. They used an Exedy plate suitably modified. They also supply aftermarket pressure plates with significantly higher clamping pressure than the 6x6 pressure plate that I have used.

Christopher

[Sabre]

Hi Christopher, thanks for the post, I would like to do the same conversion on my 130, would it be possible to give me names and contacts of suppliers over there for motor,bell houseing ect. As I think the nessesary parts for the conversion may be hard to obtain over here in the West. If you would give me a contact number I would be more than happy to call you. My number is 08 9574 6184.
Thanks
Rob.
also

[billy64]

Justin C suggested that I should put up a post about my Defender to which I recently fitted an Isuzu 4BD1T (very late Factoryturbo). The conversion was carried out by British Off Road who did an excellent job. The engine instalation looks and drives like a first class factory instalation. The engine was sourced from DNA truck parts in Minto - highly recomended also - and great to deal with.
1. The engine instalation.
I used a very rusty Isuzu County as the donor vehicle for all the Landrover specific parts - Bell housing (LT85), sandwhich plate, starter motor, aircleaner brackets, engine mounts (engine and chassis), radiator, header tank etc. I managed to obtain the Landrover Australia spacer to go between the twin oil filter hosing and the engine block, and made a spacer to fit between the oil line and the oil cooler - (gives clearance for the front tail shaft). The county chassis engine mounts were welded to the Def chassis in the relevant position. A brand new genuine LR Donaldson aircleaner housing was sourced from ULR in Melbourne. I retained the factory 4BD1T thermostat housing, and modified the Turbo cross over pipe. We had to remove the steel underbonnet stiffeners and replaced them with aluminium flat bar in order to give clearance.
2. Gearbox.
We used the R380 that was behind the 300 Tdi - it has the larger layshaft bearings - mated to an LT85 bell housing. apart from some initial alignment problems - see below - the installation has run over 11000kms now and trouble free. A 1.2:1 Disco transfer case was fitted, which with the R380 and 235/85 R 16s gives 2255 rpm at 100 kph and just over 2400 at 110. We have used a 6x6 clutch pressure plate and a custom soft centre clutch from NPC in Brisbane (great service) - no gearbox rattle at idle (upped to 800rpm).
3. Problems
1. Bell housing/gearbox alignment.
KLR did the initial mods to the bell housing, but didn't quite get the alignment right (about 1.5mm out). Brad very quickly offered to rectify the problem at their expense but time constraints meant that BOR sorted the problem in house. No complaints from me about KLR.
2. Rear main seal leaking. There was a very small groove in the seal surface on the crank shaft. After three changes of seal in as many months we fitted an Isuzu factory wear ring (like a very thick speedi sleeve) and over size seal which seems to have fixed the problem completely.
3. Oil out of the engine breather.
The engine was poking a fair amount of oil out of the engine breather. I cut the top off the oil separator and found that the small "mushroom valve" was well past its use by date allowing significant quantities of oil to surge up the oil drain line connected to the sump. The valve was replaced with an identical one from a Holly Carb kit. Problem solved.
4. Was it worth it?
Absolutely!!!! the vehicle does a lot of bush/remote area/long distance work fully loaded summer and winter, and while the 300 Tdi did a fantastic job, it simply wasn't big enough and therefore was working hard all the time. The Isuzu has transformed the vehicle it is quieter and smoother than the 300 Tdi - yes really!, noticeably faster on the hills and when towing, and much better in the bush - particularly in very steep country.
5. Before I forget.
Boost increased to 11psi with the fuel screw wound out just under half a turn (approx) Fuel economy so far 18.5 to 23.86 mpg.

As for the rest of the vehicle I have owned it from new: it was the very last 300 Tdi 110 wagon sold in Australia according to LR, Maxi drives front and rear, aux fuel, ARB B/bar and warn 10000lb winch etc etc.

Christopher

How did they do you engine mounts? New welded to the chassis or extended the 300TDi mounts? also have you done any towing? if so how has the R380 Handling it?

[C H T]

The engine mounts were cut off a rusty Isuzu County chassis and welded onto the Defeneder Chassis - you could use the mounts off the Stage one donor vheicle. I have done some towing (upto 2.8 tons) with no problems at all. The vehicle has travelled approx 18000 kms since the conversion and is performing brilliantly. The R380 seems to be standing up without oany problems.

Christopher

[bushbuddies]

hi I have a 1995 300tdi defender and am looking at the same conversion . You said that you put a 4bd1t out of a truck into your defender. Did you have to change the sump or will it fit in ok. Any other info that will be helpful as I want to upgrade my defender in the near future.

[Disco44]

I had one of the originals.Series 3 stage 1 3.9D.What a machine only thing was the weight of the front end which made for a change of in driving in soft sand.All in all a good package but my 4 speed LT95 needed an overdrive which I fitted...my was naturally aspirated not turbo and hills used to kill it.

[C H T]

Bushbuddies

The truck sump fits without any problems - pm me your phone number - I would be happy to discuss the conversion eith you. I am in Rockhampton regularly and would be happy for you to have a look at my vehicle. It has now done almost 90000ks since the conversion - most of the mileage in the outback - and is going brilliantly. The result was well worth the effort and cost

Christopher

[andrew e]

Bushbuddies

The truck sump fits without any problems - pm me your phone number - I would be happy to discuss the conversion eith you. I am in Rockhampton regularly and would be happy for you to have a look at my vehicle. It has now done almost 90000ks since the conversion - most of the mileage in the outback - and is going brilliantly. The result was well worth the effort and cost

Christopher

gee thats some kms. is there taxi sign on your roof? :D

[flagg]

2. Gearbox.
A 1.2:1 Disco transfer case was fitted, which with the R380 and 235/85 R 16s gives 2255 rpm at 100 kph and just over 2400 at 110. We have used a 6x6 clutch pressure plate and a custom soft centre clutch from NPC in Brisbane (great service) - no gearbox rattle at idle (upped to 800rpm).


Hi Christopher,

I have an shiny R380 on my floor ready for this conversion! At this stage I'm going to leave my current LT230 as it is.. but as its a county one it is 1:1.4. If I've worked it out correctly the disco box is higher overall speed on the output - an extra overdrive.

Did you drive yours with the 1.4 in there at all? Would an N/A Isuzu be able to pull it reasonably?

Thanks - your help has been fantastic :)