HJ61 12HT -> HJ75 transplant.

[User Name]

Hey guys
(little intro you could skip)
I've been lurking for a little while and thought it time to sign up and ask a couple questions. I know some/all have been asked before in some way but I haven't read (or been able to dig up) the exact info I need in an easy to follow sense.

My experience level to keep in mind- Have had 3 different projects in the past. 1974 Ford XC ute, 1986 Ford XF panelvan, 1968 Ford XT wagon. One of the projects had quite extensive body work done with some mechanicals, whilst the others were mainly swapping panels, playing a little with motors etc. In short though, I've never rebuilt a motor completely, never transplanted a motor myself and done mechanical/driveline swaps, this is also my first diesel and first 4x4. I have no institutionalised engineering/mechanical qualifications so I apologies in advance if my phrasings aren't quite right, it's just how I get it out of my head, please correct me if I'm wrong!
I'm eager to listen and learn though, and if you tell me what something is and what it does, it'll most likely stick.

So to the point, I just picked up a rolled HJ61 with 12HT/5 Speed to transplant the drivetrain and rear diff out of into my HJ75 Troopcarrier.

Questions I have;

1. Can I find a good (free) source of information/manual on the electrics and mechanics of the 12HT/2H motors online?

2. The 12HT has about 400k on the clock, it idles smooth. There is no blow by when checking at the oil cap. It has got diesel that has been sitting in the tank for a good 8 months and I have no idea when the last oil change was done (though black, it's 'clean'). It idles fine, but if I try to hold revs (whilst in neutral/stationary) to 2k it begins to flutter and then drops revs and splutters and/or dies. I will be changing oil and fuel tomorrow, however what else could this be? Fuel pump/filter?

3. I am building an 'expedition' troopcarrier that needs to take me all over Australia at the least, and in the long term all the way around the world. From what I've mentioned, would you recommend I rebuild any part of the motor in particular? Or should I just do it anyway? I am wanting to take it apart to replace pistons and bottom end bearing, will look at the injectors as well, is there anything else I should seriously consider? I would like a rock solid, reliable motor, that can go for many more miles without any major servicing. This is why I picked the 12HT!

4. I hope to run the motor on both diesel and SVO/WVO. I'll start a seperate thread in regards to setting up a expedition vehicle capable of doing this on the road, however is there anything extra I should be considering motor wise while it's apart? I know from lurking there is one member who runs a modified 12HT on SVO/WVO (apologies, name escapes me, possibly Tim?), but would love to chat or get some info there.

5. The gearbox and transfer that came with the HJ61 differ from the 75. The 61 has an electronic/magnetic (I think?) L4 engaging mechanism, whilst the 75 is all manual/stick. Is it going to be easily transfered (pun?) across to the 75, or if possible am I better off keeping the 75 setup? Are either of these setups considered more durable/preferable?
I do like the idea of less electrics, however...

6. The transfer in the 75 is possibly damaged, so I am considering using the HJ61 transfer, the gearbox in the 75 though is in better condition than the HJ61 gearbox, can the box and transfers be mixed and matched? If not I'll be looking to recondition/rebuild the setup which is most preferred for reliability.

7. Lastly on the powerplant section (at least what I can think of..), is there anything I need to consider in the swap between 12HT and 2H? Whilst I have read about the swap, I have not seen a thread of someone doing one. Will I need to bring particular parts from the 61's engine bay across to make the 12HT run in the 75?

8. In regards to diffs, I have been told the 60 series will fit under the 70 series easily. How easy? Is this bolt out and bolt in? Do I need anything else before I jack the car up to take them out? What is the procedure for taking a diff out of a vehicle?
Also, will I be able to put the 70 diff under the 70 so I can easily get rid of it on a trailer?

That's about it! I know that's a lot of questions, but any help will really be appreciated, even been pointed in the direction of other threads covering these particular topics (I've read so many that I've lost track).

Peace!

 

[Juggla18]

G'day Username,
So many questions. I am doing the same as you, 12ht into 75, and have a mate who has also put the auto from a 61 into the 75.
I run my various trucks on veg. Very easy.
This is my first time on a forum, so not sure how it goes. If you are in Sydney, contact me and I'll show you the veg setup I've got in my troopy.
As I understand it, the 2 motors, 2h and 12ht blocks are the same, so will bolt in easily. The one thing willbe whether the 12ht is 12 or 24 v.
Good luck.

 

[cult45]

Hey man, welcome. There's a lot of info on here, so you should be able to find what you need. Search for 12H-T into HJ45/47 etc as it may contain the gems you're searching for. I'd also recommend documenting everything here as you go with pics so others can follow you should they decide to do the same.

1. There should be a FSM [Field Service Manual] here or online or from Toyota. There's a guy on here called lostmarbles who's full of the good oil on diesel Landcruisers. He may know where to source one. Also RoscoFJ73 chucked a 2H in his FJ73, so he may know more.

2. Sounds fuel related, but that's all I got I'm afraid.

3. A rebuild will be cheap insurance when you're crossing the Sahara..

4. Unsure. Maybe you could search/post in the Diesel Tech?

5. Generally all H55's are the same animal with a model specific tweaks, especially if they're both ADM trucks. Best to bust out the measuring tape and the camera and compare visually. I too prefer non-electronic, not that I can talk with my specced up BJ74, but yes I'd go mechanical everything where possible.

6. Pretty sure you can mix and match H55 parts. If you're going to build, go full mechanical.

7. The 2H and 12H-T share blocks, as Juggla18 has confirmed. So aside from finding room in the bay for all the turbo-model additions it should be relatively straightforward, the only hiccup being if the HJ61 is 24v. Even then, you can search for builds on here that have converted 24v stuff to 12v by sending the parts [alt, starter etc] to a good auto electrician. I think there's a HJ47 troopy in the 45 section that has a 1HZ that he converted to 12v. The best way to do the swap is to photograph the s*** out of the HJ61 and the HJ75, then keep both cars on hand for the swap.

8. Is there something wrong with your 75 diff? A visual check and measurements will confirm if it easy to swap. Check spring perch placement, width etc. FYI the centre's will be the same.

Good luck dude!

 

[NZCruisers]

5. The gearbox and transfer that came with the HJ61 differ from the 75. The 61 has an electronic/magnetic (I think?) L4 engaging mechanism, whilst the 75 is all manual/stick. Is it going to be easily transfered (pun?) across to the 75, or if possible am I better off keeping the 75 setup? Are either of these setups considered more durable/preferable?
I do like the idea of less electrics, however...

6. The transfer in the 75 is possibly damaged, so I am considering using the HJ61 transfer, the gearbox in the 75 though is in better condition than the HJ61 gearbox, can the box and transfers be mixed and matched? If not I'll be looking to recondition/rebuild the setup which is most preferred for reliability.

7. Lastly on the powerplant section (at least what I can think of..), is there anything I need to consider in the swap between 12HT and 2H? Whilst I have read about the swap, I have not seen a thread of someone doing one. Will I need to bring particular parts from the 61's engine bay across to make the 12HT run in the 75?

8. In regards to diffs, I have been told the 60 series will fit under the 70 series easily. How easy? Is this bolt out and bolt in? Do I need anything else before I jack the car up to take them out? What is the procedure for taking a diff out of a vehicle?
Also, will I be able to put the 70 diff under the 70 so I can easily get rid of it on a trailer?

First off , Welcome

Secondly , no 60 diffs do not fit under 70s easily at all. There spring mounts are different widths. To make them sit right it requires some competent fabrication skill. The long side of the axle being longer on the 60s than that on the 70s means the diff pumpkin sits in where the drivers side spring perch should want to be. Spring over or under it isn't a 2 min job to fab up a mount unlike the passenger side.

But the diffs/hubs etc should all interchange

Re the manual 4X4 shift between your 75 and the 61 , 61 uses vacuum to change. As long as you take the VSV valves along with the nessary piping and wiring you can make it work . Compared to your 75's manual shift , both are realiable enough

Don't quote me on this but I reckon your transfers between your 75 and the 61 should be the same and think the manual shift/vaccum shift should be unboltable so you can choose which option you want to go with

Lastly , good on you for picking 12HT for a tourer , great motor. You may want to read into the sensitive throttle issues , many people on here have put up solutions for the problem , it definately needs addressing for offroading

Good luck

 

[Elbee]

Any updates on this transplant?