Engine and Trans swap LJ78 (1 Viewer)

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alabama
I have a 1991 prado (LJ78) and am looking to replace my 2LTE.

I have a heavy rig modified for extreme off-roading and overlanding. This has blown up both my engine and transmission. From my research the 1KZ-TE with mechanical injection pump is the best and easiest swap. But I am also looking to swap the turbo with the CT20B. With this added power I am afraid it will be too much for the transmission (A343F) but the only kind of easy swap that is stronger is the R151F. But this means going from auto to manual which is a lot of work.

Does anyone have any suggestions on engine or transmission ideas for this rig?
 
When you say heavy rig and extreme offroading, how heavy and extreme are we talking here? Blowing up a 2L-TE doesn't take much, but I'd be surprised if your A343f would have been destroyed by any 2L-TE without a lot of abuse. That transmission is pretty robust, it was used behind a bunch of diesels and gas V8's in various platforms. I wouldn't say an R151f is stronger than an A343f.

A mechanical 1KZ-T would be a simple swap when coupled with an R151f, but more difficult if you want to keep an automatic since the engine ECU also controls the transmission. While better than a 2L-TE, the 1KZ is still not the pinnacle of robustness and would still require an intercooler, tuning, and a sympathetic right foot to make it last in that application.

I've put a VW 1.9TDI in my LJ78, but wouldn't recommend that for extreme use. I wheel mine and do a lot of highway travel, but am generally pretty careful about not letting it run too hot (slowing down for hills and headwinds, for example). Other options for US-spec diesels would include the VW 2.0 TDI's (Pumpe-Deuse or CR), Jeep Liberty 2.8 CRD, the Mercedes OM617, OM602, or OM647 inline-5 engines or the Cummins R2.8. Non-US diesels would include the Toyota 1KD, any of the VW V6 TDI's, and probably many other engines. Pretty much any of those options apart from the OM617, R2.8, VW 4-cylinder TDI and possibly 2.8 CRD would require custom adapter plates, and they would all necessitate custom wiring harnesses, tuning, etc. Some people have been able to shoehorn an inline-6 into a Prado engine bay, too, but that looks really tight.

For gas engines, a 5VZ-FE would be a good fit in the engine bay, and while bigger the 1UZ fits ok too and would provide better power.

With any non-Toyota engine you'd be better off swapping to a manual transmission, the simplest option being an R151f or R150f with a LandCruiser style transfer adapter.
 
I have a 1991 prado (LJ78) and am looking to replace my 2LTE.

I have a heavy rig modified for extreme off-roading and overlanding. This has blown up both my engine and transmission. From my research the 1KZ-TE with mechanical injection pump is the best and easiest swap. But I am also looking to swap the turbo with the CT20B. With this added power I am afraid it will be too much for the transmission (A343F) but the only kind of easy swap that is stronger is the R151F. But this means going from auto to manual which is a lot of work.

Does anyone have any suggestions on engine or transmission ideas for this rig?
A340,341,343. they are not weak transmission. tire size is the killer for those automatics. bear in mind, if you use 35" thats bout the limit. bigger than that.
it depends how soon it will die.
 
When you say heavy rig and extreme offroading, how heavy and extreme are we talking here? Blowing up a 2L-TE doesn't take much, but I'd be surprised if your A343f would have been destroyed by any 2L-TE without a lot of abuse. That transmission is pretty robust, it was used behind a bunch of diesels and gas V8's in various platforms. I wouldn't say an R151f is stronger than an A343f.

A mechanical 1KZ-T would be a simple swap when coupled with an R151f, but more difficult if you want to keep an automatic since the engine ECU also controls the transmission. While better than a 2L-TE, the 1KZ is still not the pinnacle of robustness and would still require an intercooler, tuning, and a sympathetic right foot to make it last in that application.

I've put a VW 1.9TDI in my LJ78, but wouldn't recommend that for extreme use. I wheel mine and do a lot of highway travel, but am generally pretty careful about not letting it run too hot (slowing down for hills and headwinds, for example). Other options for US-spec diesels would include the VW 2.0 TDI's (Pumpe-Deuse or CR), Jeep Liberty 2.8 CRD, the Mercedes OM617, OM602, or OM647 inline-5 engines or the Cummins R2.8. Non-US diesels would include the Toyota 1KD, any of the VW V6 TDI's, and probably many other engines. Pretty much any of those options apart from the OM617, R2.8, VW 4-cylinder TDI and possibly 2.8 CRD would require custom adapter plates, and they would all necessitate custom wiring harnesses, tuning, etc. Some people have been able to shoehorn an inline-6 into a Prado engine bay, too, but that looks really tight.

For gas engines, a 5VZ-FE would be a good fit in the engine bay, and while bigger the 1UZ fits ok too and would provide better power.

With any non-Toyota engine you'd be better off swapping to a manual transmission, the simplest option being an R151f or R150f with a LandCruiser style transfer adapter.
For wheeling I have done a few double blacks and my eventual goal is to do the hardest trail in every country in the Americas. The truck has 35s, rock sliders, snorkel, dual locked, lift, etc. With it fully loaded I come out to around 5750 pounds.

The engine swap is more because the 2LTE I have has always been a lemon and plagued with issues like cracked cylinder head and rusted out cooling system. I am fine with going 50mph max and make enough torque for wheeling but all of this on the transmission is just too much. And I would hate to do all the work to switch it to a manual if it’s barely stronger.

I have tossed around the idea of either a Mercedes diesel or the new Cummins but again it’s more of transmission issue than anything, especially if I swap to the KZ.

And yes intercooler and everything I will do. If I stick with the A343f is there any year that is stronger or anything that should be done to it to help it survive?
 
A340,341,343. they are not weak transmission. tire size is the killer for those automatics. bear in mind, if you use 35" thats bout the limit. bigger than that.
it depends how soon it will die.
Yeah I have 35s but do not plan to go any bigger but can not get away with smaller tires for the trails I do.
 
If you are thinking to swap engines. M57 or om605. Transmission will be Zf8hp. The best of the best combo. Cons is money is the factor. 1kd is good as I’m using, but the electrical is no joke at all.
 

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