Thread: Which Defender to convert to 4BD1T?

G'day Andrew,
Welcome to the forum, and to the section where all us Isuzu nuts hang out.

I think you've pretty much answered your own question with the issue of the Td5 having electronics to deal with. The 300 would be the easiest option with most things being easily adaptable.
Having said that, if you can get a Td5 at a really good price, it wouldn't be too much hassle changing things to suit, such as an earlier dash and throttle pedal assembly.
I think the seats in both models are the same ??? so it would depend on the treatment of each individual car you look at as to the condition of the seats, or any other parts for that matter.

Is the transfer case adapter kit you're looking at the one in this thread >> Isuzu MSA Gearbox to LT230 << I hope to get one of these myself when I build my next vehicle.

Cheers, Murray

Hi Murray,
Thanks for the reply. You're right I did answer my own question that it would be a bit easier to start with a 300tdi. What I should have asked is "who has done a 4BD1T with MSA gear box(both from a truck) conversion to a defender and what are the main issues to deal with?" ie, What should I realisticly expect it to cost if I do all work myself?, what extras do I need, air cleaner, radiator, starter motor etc etc? What would you do different? Worth getting a 6 speed box? Is it all worth it? Power compared to a turbo 4.2 patrol or cruiser for comparison?

The other thing I was suprised to read was that you "only" get about 14L/100K fuel ecomomy loaded up on a trip. I have actually owned a factory Isuzu county (non turbo) years ago (yes I should have kept it!) and I averaged about 10L/100K which is about the same as others have said on this forum. I thought the turbo would make the motor run more efficient and not change fuel economy much? Mabey the truck motors are tuned a bit different to the landy isuzu? I just thought I could achieve about 10L/100K from a 4BD1T but mabey this is unrealistic? 5spd may help?

Anyway to answer your question, "YES" the adaptor kit I am thinking about is from this forum. I actually met up with Sheldon at christmas time and he was good enough to let me drive his county with his kit installed. It had the arse about gear pattern but it honestly wasn't an issue, having said that I would still buy his normal pattern version since he has made one! It shifted well and the gear ratios seemed spot on, a nice very low 1st gear and ideal revs crusing in 5th. He is a top bloke too and I wont hesitate to buy his kit when the time comes.

Cheers, Andrew.

Originally Posted by taylorslandy

The other thing I was suprised to read was that you "only" get about 14L/100K fuel ecomomy loaded up on a trip. I have actually owned a factory Isuzu county (non turbo) years ago (yes I should have kept it!) and I averaged about 10L/100K which is about the same as others have said on this forum. I thought the turbo would make the motor run more efficient and not change fuel economy much? Mabey the truck motors are tuned a bit different to the landy isuzu? I just thought I could achieve about 10L/100K from a 4BD1T but mabey this is unrealistic? 5spd may help?

The turbo just allows you to add more fuel (because it adds more air.. keeping the ratio sane) so the burn rate will always have to raise to get access to the benefits of the turbo.

Originally Posted by taylorslandy

Hi Murray,
Thanks for the reply. You're right I did answer my own question that it would be a bit easier to start with a 300tdi. What I should have asked is "who has done a 4BD1T with MSA gear box(both from a truck) conversion to a defender and what are the main issues to deal with?" ie, What should I realisticly expect it to cost if I do all work myself?, what extras do I need, air cleaner, radiator, starter motor etc etc? What would you do different? Worth getting a 6 speed box? Is it all worth it? Power compared to a turbo 4.2 patrol or cruiser for comparison?

The other thing I was suprised to read was that you "only" get about 14L/100K fuel ecomomy loaded up on a trip. I have actually owned a factory Isuzu county (non turbo) years ago (yes I should have kept it!) and I averaged about 10L/100K which is about the same as others have said on this forum. I thought the turbo would make the motor run more efficient and not change fuel economy much? Mabey the truck motors are tuned a bit different to the landy isuzu? I just thought I could achieve about 10L/100K from a 4BD1T but mabey this is unrealistic? 5spd may help?

Anyway to answer your question, "YES" the adaptor kit I am thinking about is from this forum. I actually met up with Sheldon at christmas time and he was good enough to let me drive his county with his kit installed. It had the arse about gear pattern but it honestly wasn't an issue, having said that I would still buy his normal pattern version since he has made one! It shifted well and the gear ratios seemed spot on, a nice very low 1st gear and ideal revs crusing in 5th. He is a top bloke too and I wont hesitate to buy his kit when the time comes.

Cheers, Andrew.

Regarding your questions......

Cost of a conversion is quite variable depending on the condition and cost of your engine, gearbox etc, etc.
My conversion, for example, cost ~$8000 including $4500 for a whole damaged truck with a rebuilt engine and gearbox, but that's just one example.

You will need a radiator, either a County Isuzu one, or a V8 rad can have the outlets swapped.

Air cleaner. I'd recommend you get the standard twin element Donaldson filter, although you might have to do some mods to the outlets if running a turbo.

You'll need to get a 12 volt starter and alternator if you want to avoid the hassles of running a 24 volt system. Mine still has the 24 volt glow plugs, but they're not hooked up because you never need to pre heat a 4BD1 anyway.

Is it all worth it ? In my opinion, definitely.

Power compared to other engines ? Someone who has direct experience with Toyotas etc might be better qualified to answer that one than me.

Regarding fuel economy......... I'm running 15psi and I've turned up the fuel, so 10L/100k is out of the question for me, but there's no reason you can't run a more conservative setup to suit your needs. Before my diesel conversion, I had a 4.2L petrol V8 in the County, so to be honest I don't really care how much fuel the Isuzu is using as it will always be heaps more economical.

Cheers, Murray

Originally Posted by flagg

The turbo just allows you to add more fuel (because it adds more air.. keeping the ratio sane) so the burn rate will always have to raise to get access to the benefits of the turbo.

Thanks for the reply. I am aware that with a turbo more fuel is added with the extra air to produce a bigger bang. But although there is more fuel added I thought it actually makes your engine run more efficient therefore giving more power for the engine size. But I supose that because there is more power on tap we like to use it which feeds even more fuel in which makes the fuel economy suffer. But hey at least you get some bang for your buck! 14L/100k is still respectable for a loaded vehicle on a trip.

And thanks Murray for the guide on how much it will cost. Sounds like you found a bargain at only 4500 for the truck. So about another 3500 to fit and finish the conversion, not to mention countless hours I guess!

Cheers, Andrew

cheak out ARDs i think a post 96 110 may have problems with the paper work, but i doint realy know just what i have read here and there

taylorslandy - you in stanley tas?

i'm guessing this will have what you need and it's just down the road.

Isuzu 86 NKR short 5 ton | Heavy, Farming & Agriculture Equipment | Gumtree Australia West Tamar - Beaconsfield

Originally Posted by taylorslandy

The other thing I was suprised to read was that you "only" get about 14L/100K fuel ecomomy loaded up on a trip. I have actually owned a factory Isuzu county (non turbo) years ago (yes I should have kept it!) and I averaged about 10L/100K which is about the same as others have said on this forum. I thought the turbo would make the motor run more efficient and not change fuel economy much? Mabey the truck motors are tuned a bit different to the landy isuzu? I just thought I could achieve about 10L/100K from a 4BD1T but mabey this is unrealistic? 5spd may help?

I have a genuine landy 4BD1(+T). The best economy I have received was ~9.5 L/100, but usually get 11-15 l/100 - depending on how I drive...

The worst ever was when sitting at 120-130 km/h into a VERY strong headwind while towing a 5m boat about 400km east of Adelaide. I could just about watch the fuel needle sink. About 26 L/100 from memory. With an NA engine under the above conditions I would have been sitting on ~80 km/h and using less fuel.