Detailed Review of the Legendary 12H-T engine.

Joined
Jul 29, 2021
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55
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Libreville, Gabon
Hi there...
Hope you are all doing fine!

I am looking for someone who can do or has done a detailed review video (preferably) or article (similar to this one ) about the 12H-T engine? There seems to be nowhere on Youtube (and on the whole web:frown:) where I can find a complete review of this masterpiece of Toyota's history. So, I am posting this request here and there on the web, hoping someone (kind enough ) experienced and knowledgeable about the 12H-T will just help. :)
Regards
 
Joined
Mar 3, 2012
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Adelaide, South Australia
The 2H is a superior engine. Just sayin', more driveable in the outback, more reliable, longer lasting, less parts, cheaper to rebuild, less fluff bolted to it, more tolerant to abuse.. Criteria varies. The 12HT is a prima donna.
 
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Joined
Jul 29, 2021
Messages
55
Location
Libreville, Gabon
The 2H is a superior engine. Just sayin', more driveable in the outback, more reliable, longer lasting, less parts, cheaper to rebuild, less fluff bolted to it, more tolerant to abuse.. Criteria varies. The 12HT is a prima donna.
Thanks for the quick feedback. I also think the same. I have a couple of 2H's and have seen their legendary reliability in action.

I like your calling the 12H-T a "Pima donna" :) (I also have one) and it deserves to be treated as such... that is, with all the respect and care due to "her" rank. Shouldn't she? :)
 
Joined
Nov 18, 2019
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BC. Canada
The 2H is a superior engine. Just sayin', more driveable in the outback, more reliable, longer lasting, less parts, cheaper to rebuild, less fluff bolted to it, more tolerant to abuse.. Criteria varies. The 12HT is a prima donna.
Does this apply to a turbo'd 2H? I love my 2H and all but the lack of power is really starting to bug me. How does the turbo 2h compare to a 12HT? I still think turbo 2H is the way to go because parts availability in Canada for the 12HT is quite difficult to source(compared to the 2H).
 
Joined
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Messages
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Location
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Does this apply to a turbo'd 2H? I love my 2H and all but the lack of power is really starting to bug me. How does the turbo 2h compare to a 12HT? I still think turbo 2H is the way to go because parts availability in Canada for the 12HT is quite difficult to source(compared to the 2H).

There's zero doubt that the turbo will reduce reliability but dramatically improve performance. Some people have a great outcome, some people spend a long time chasing cooling issues afterwards. I'm not a fan, but many people are. Even in Australia some 12HT parts are not easy to source (especially replacement heads), and a failed 12HT is a big issue to deal with - unlike a failed 2H given the huge availability of these engines.

The 2H lacks power, there's no doubt. Hills scare me when there's a truck behind me wanting to get somewhere. But I've never had any issue with the lack of power when on the track.

If you haven't already its worth baselining your 2H to make sure you're getting all the power possible including:
  • Checking the injector pump spill timing
  • Ensuring your injectors have a perfect spray pattern
  • Ensuring valve clearances are bang on
  • Keeping a clean air filter
  • Making sure the fuel screw wasn't set too low from factory or that it hasnt been set for a higher altitude than you're usually at (a bit of smoke under very heavy load is a good sign)
  • Fitting a set of headers
  • Making sure your exhaust is as free flowing as you can get away with
Then on your vehicle (stating the obvious to some degree):
  • Reducing unnecessary weight
  • Keeping your tyre pressures as high as you're comfortable with (at least on bitumen)
Driving style can really assist as well - the 2H needs to be driven a bit more aggressively than the 12HT in my opinion. .
  • Get down into lower gears a bit before its necessary on hills to keep the revs in a higher range
  • Get a good run up for hills or even mild slopes and hit them in 4th rather than 5th (in fact I rarely use 5th in my HJ60 and only have the 4 speed in my HJ47 tourer)
 
Last edited:
Joined
Jul 29, 2021
Messages
55
Location
Libreville, Gabon
There's zero doubt that the turbo will reduce reliability but dramatically improve performance. Some people have a great outcome, some people spend a long time chasing cooling issues afterwards. I'm not a fan, but many people are. Even in Australia some 12HT parts are not easy to source (especially replacement heads), and a failed 12HT is a big issue to deal with - unlike a failed 2H given the huge availability of these engines.

The 2H lacks power, there's no doubt. Hills scare me when there's a truck behind me wanting to get somewhere. But I've never had any issue with the lack of power when on the track.

If you haven't already its worth baselining your 2H to make sure you're getting all the power possible including:
  • Checking the injector pump spill timing
  • Ensuring your injectors have a perfect spray pattern
  • Ensuring valve clearances are bang on
  • Keeping a clean air filter
  • Making sure the fuel screw wasn't set too low from factory or that it hasnt been set for a higher altitude than you're usually at (a bit of smoke under very heavy load is a good sign)
  • Fitting a set of headers
  • Making sure your exhaust is as free flowing as you can get away with
Then on your vehicle (stating the obvious to some degree):
  • Reducing unnecessary weight
  • Keeping your tyre pressures as high as you're comfortable with (at least on bitumen)
Driving style can really assist as well - the 2H needs to be driven a bit more aggressively than the 12HT in my opinion. .
  • Get down into lower gears a bit before its necessary on hills to keep the revs in a higher range
  • Get a good run up for hills or even mild slopes and hit them in 4th rather than 5th (in fact I rarely use 5th in my HJ60 and only have the 4 speed in my HJ47 tourer)
You've said it all. Thanks for the great post!
As for me, I don't mind with the 2H lacking power as per today's standards. Someone summed it up nicely in another thread: "The 2H will take you anywhere provided you are patient". That"s all I need, as a tourer.
 

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