I can hear Steve furiously typing from here!
The problem is we don't have many small capacity, lightweight diesels in Australia. What we do have is generally set up for FWD.
IMO for a mechanical turbo diesel all we can really look at is the Peugeot XUD9 from the 405 SRDT. You can buy adapters for these to vitara gearbox from a mob in the UK. These were also the factory fitted diesel in European Sierras built by Santana. The motors aren't particularly hard to find, they're cheap and they last forever.
An LJ is going to be particularly hard to do. The gearing is far to low so you'd have to look at swapping at least the transfercase to something else. The centred front diff means you likely wont have enough vertical height to clear the bigger diesel but at least the engine bay is quite long. Due to the narrow chassis rails you'll need to fit quite a bit of bumpstop spacing to clear an offset diff pumpkin which you would have to run with any transfer case conversion.
One of the bigger problems with LJs and engine conversions is the steering box wont clear the bellhousing so you need to convert to a conventional front mounted steering box.
You'll also have to cut out the gearbox and transfer crossmember and almost certainly replace all the mechanicals. As much as I'd love to see a well done deisel LJ81 they would be one of the hardest vehicles to convert. You'll be left with little more than 2 chassis rails and the body from the LJ.
(FWIW one we built in 85 is still going strong BTW)
