1HZ-T vs. 12H-T

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Combat Chuck

Combat Chuck

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I've been doing some looking around, and I've finally settled on an H-series motor as what I plan on swapping my SBC out for, but I'd like to hear more on the subject of these two motors.

According to the numbers, they're almost identical, same HP, nearly the same Kw output, the 1HZ's a little bigger (4.2 vs 3.9), but otherwise on paper, they seem very alike. That's where this post comes in, I'd like to hear people's personal accounts of these motors, what do they like, and dislike about the motors, their quirks and unique traits, fuel economy, reliability, any difficulties maintaining them.

Any replies would be greatly appreciated.
 
12H-T has no timing belt or pre-combustion chambers. Already has a turbo on it...Gbentink told me to swap mine out to a Supra CT-26 and I've got it running at around 15 psi max...awesome!

1HZ is a newer motor, quieter, seems to like higher RPM's compared to other Toyota diesels...drove a turboed one in a LC pickup that also liked to rev higher before the power kicked in, but he may have had the wrong turbo on it.

Either engine in your 40 is going to be great!
 
Combat Chuck said:
I've been doing some looking around, and I've finally settled on an H-series motor as what I plan on swapping my SBC out for, but I'd like to hear more on the subject of these two motors.

According to the numbers, they're almost identical, same HP, nearly the same Kw output, the 1HZ's a little bigger (4.2 vs 3.9), but otherwise on paper, they seem very alike. That's where this post comes in, I'd like to hear people's personal accounts of these motors, what do they like, and dislike about the motors, their quirks and unique traits, fuel economy, reliability, any difficulties maintaining them.

Any replies would be greatly appreciated.
Click to expand...

The 1HZ is a motor in production that will be made for a long time. With a turbo it kicks real ass.
The 12HT is great, but was not made in high numbers, so parts availability is a problem.
The 2H is a very nice combination with a turbo, but no where near a 1HZ-T in smoothness and power. and it is long out of production as well.

cheers,
Jan
 
Jan-78FJ40 said:
The 1HZ is a motor in production that will be made for a long time. With a turbo it kicks real ass.
The 12HT is great, but was not made in high numbers, so parts availability is a problem.
The 2H is a very nice combination with a turbo, but no where near a 1HZ-T in smoothness and power. and it is long out of production as well.

cheers,
Jan
Click to expand...
Thanks1 that's exactly what I was looking to hear. Parts availability is a huge concern of mine, and the reason why I shied away from a reasonable 3B offer. How about fuel mileage? any good info on that?
 
Combat Chuck said:
Thanks1 that's exactly what I was looking to hear. Parts availability is a huge concern of mine, and the reason why I shied away from a reasonable 3B offer. How about fuel mileage? any good info on that?
Click to expand...

mileage is pretty similar for all of them. If you are really nice you might get mid 20s, normal low 20s, if you kick the pedal down all the time you are down to 15.
cheers,
Jan
 
what is the price and availability of the 1HZ? where do I get one? is it like a half cut with ll the wiring and mounts and brackets?
 
Why are you not considering the 1HD-T?

There's no reason to choose the HZ over the HD.
 
Dougal said:
Why are you not considering the 1HD-T?

There's no reason to choose the HZ over the HD.
Click to expand...
Please elaborate.

I'm more familiar with the F series motors, and SBC's so if I overlooked anything, it has noting to do with preference, just misunderstanding the systems.
 
The 1HD T is a factory turbo version of the 1HZ sold from 90-95(may vary in different markets). It has direct injection and beefier pistons to cope with the added power.
But like all good toys it costs more $$$.
There is also the 1HD FT and the 1HD FTE,the latter being a 24 valve version

I owned a HJ61 with a 12HT and a 1HZ powered 73 series at the same time. The performance figures dont tell the full story.
The 12HT is much easier to get up to speed.
However the 1HZ can still get away nicely with a deft hand on the gearstick.

One thing I have always admired about the 1HZ ,is the lack of clutter around the engine block.
Things like the P/S pump and vacuum pump are built into the engine ,rather than being add ons(but still easy to remove/replace).
If you ever need to work on it on the side of the road you will be thankfull for the layout;)
 
Combat Chuck said:
Please elaborate.

I'm more familiar with the F series motors, and SBC's so if I overlooked anything, it has noting to do with preference, just misunderstanding the systems.
Click to expand...

The 1HD-T is the replacement for the 12H-T. Same package as the 1HZ but direct injection and factory turbocharged.
Better fuel economy, more power, easier starting etc.

It seems strange to consider the 12HT and the 1HZ but not the 1HD-T.
 
IMO i'd pick 12h-t just for the sake of beefier build (gear-driven cams, direct injection) and if i remember right there also were some crankshaft bearing issues in the 1HZ...

About parts, you can get pretty much everything from the aussie wonderland..
 
I mentioned the 1HD-T in one of your other threads...I think it's the way to go.

Rosco...IIRC BOTH the 1HD-FT and the 1HD-FTE are 24V, the latter having complicated electronic control crap to deal with. Sheldon put a 1HD-FT into his FZJ80, and I think it's probably the best in the HD series engine to swap in, but are very rare to come along.

Sheldon has driven my FJ80 with the 12H-T/A440f full time case combo, and he feels it has just as much if not more get up and go as his FZJ80 with the 1HD-FT/5spd and part time case combo. The 12H-T is no slouch, and it is a very robust engine. I'm very happy with it, but if it wasn't the 12H-T then it would have definitely been the 1HD-T.

BTW...if you're in the US, any Toyota diesel engine that you go with will be more complicated to get parts for. There's always excellent guys like Dave S. in Japan (Japan 4x4), Canadian outfits like G&S, etc. etc. to source parts from.
 
i did similar research, i had a 2h, i just finally decided on a 12ht. mainly because of it's simplicity and cost was a factor for me, but i think it was the simplicity that made me finally decided on a 12ht. i am still not regretting it. i am now thinking of putting an intercooler and a bigger blade on the turbo, all of that for 1,400. dollars.

i considered another H engine but i was told i will need to replace the main bearing, then it will be a great engine after doing that, i can not remember which one, but the cost was much more.

good luck, which ever you decide i know it will be a good one.
 
after driving and driving in mates 2h turbo's and same in mates turbod 1hz's the seem to have heaps more power for driving on and off road, drive a lot better and smoother

the 2h are slow tractor motors the hz's are cream
 
Clint79 said:
after driving and driving in mates 2h turbo's and same in mates turbod 1hz's the seem to have heaps more power for driving on and off road, drive a lot better and smoother

the 2h are slow tractor motors the hz's are cream
Click to expand...

I thought it was about 12h vs hz, you know, 2h is totally different thing...
 
First .. the 1HZ it's comparable to the 12H-T ( seen only factory Toyota numbers .. ) the 1HZ-T ( aftermarket turbo ) will make much more powa than 12H-T ( again almost stoc both )

Then there is many places that the 1HD-T was sold from 92 to 2001 in the 100 series ( example here .. )

If I need to choose an engine for a great engine .. will be a 12H-T for sure .. but If I need to choose and engine coz I need to use and abuse as a Toyota enginie will be 1HZ-T sure ..

The 1HD-T it's another complete animal .. but maybe it's my impresion but are not that tough as 1HZ is ..
 
Tapage said:
If I need to choose an engine for a great engine .. will be a 12H-T for sure .. but If I need to choose and engine coz I need to use and abuse as a Toyota enginie will be 1HZ-T sure ..

The 1HD-T it's another complete animal .. but maybe it's my impresion but are not that tough as 1HZ is ..
Click to expand...

I really don't get this.
Overseas the turbocharged 1HZ does not have a reputation for reliability, in fact people will dissuade you from turbocharging them.

Just because an engine is dead reliable in NA form doesn't mean it's going to be dead reliable with 15psi thrown down it. Especially when it's a high compression idi engine.

Anyone want to put a 1HZ turbocharged against Gbentnik's 12HT?
 
Dougal said:
I really don't get this.

Anyone want to put a 1HZ turbocharged against Gbentnik's 12HT?
Click to expand...

actually if the 12H-T it's 8PSI factory boosted .. and with this boost make the same amount of powa that makes the 1HZ NA .. why if you buy a 1HZ and turboed it .. need to go 15 PSI ..?

If where me .. and get a nice ( or new ) 1HZ and love the reliability .. will push it as same as 12H-T is .. and will probably end with better numbers anycase .. 8PSI ..

If I get a 1HZ for fun .. mmmm .. not .. I will stick with the 12H-T or jump to 1HD-T engine .. :D

In the same line diferent scenario I push my 2H-T to 14 PSI just for fun .. coz it's my fun Cruiser ..
 
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