Opinions on most reliable LC Diesel engines.

[John in Utah]

Thank you for the info. Would you go with a 1FZFE or a 1HDT here in Utah? Just your opinion?

Can’t speak to the newer cruisers but my little 3B has gotten me anywhere I’ve pointed it here in Utah. Over Soldier summit to Moab in 4th gear, point of the mtn no problem. An NA BJ60 might struggle but for the most part the Wasatch front is pretty flat. IMO a gasser is more driveable but when it comes to cool factor there’s no contest

 

[Indyteecee]

Can’t speak to the newer cruisers but my little 3B has gotten me anywhere I’ve pointed it here in Utah. Over Soldier summit to Moab in 4th gear, point of the mtn no problem. An NA BJ60 might struggle but for the most part the Wasatch front is pretty flat. IMO a gasser is more driveable but when it comes to cool factor there’s no contest

You drove a 3B all the way down to moab?

 

[John in Utah]

You drove a 3B all the way down to moab?

... and to Bluff, Logan, Hanksville, you name it I take that thing anywhere

 

[Indyteecee]

The 1HZ doesn't really have a weak point if driven with common sense
The 1HD T has had problems with big end bearings and ACSD , search for it, there are dozens of posts. But they can also achieve very high klms with good owners.

Have any opinions on the 12HT? I know this isn’t an 80 Series Motor but I’m still curious.

 

[roscoFJ73]

Its a good strong long lasting engine, but they are all pre 1990. Many have done over 500000klms. Some parts are unobtainable. Like the older B and H engines, they have the vacuum pump on the alternator.
There are work arounds for most problems.They are not much cheaper than a used 1HD T.
But if I came across a good one at the right price I might say yes.

 

[Indyteecee]

Its a good strong long lasting engine, but they are all pre 1990. Many have done over 500000klms. Some parts are unobtainable. Like the older B and H engines, they have the vacuum pump on the alternator.
There are work arounds for most problems.They are not much cheaper than a used 1HD T.
But if I came across a good one at the right price I might say yes.

The problem I’m having is that as I look around this site, I seem to see a lot of people having a lot a problems with the 1HDT. Not just big end bearings.

 

[VX 12HT]

Yep fuelling issues have a look amount of threads with 1hdt with the problem, i experienced this first hand i bought mine new back in the day 1992
I remember when i was at the toyota dealership i had the auto which smoothed it out a bit and couple of people with manuals said it was even more pronounced. I was a known problem with them,unfortunately mine had the beb problems as well. When running right brilliant. 12ht's fantastic no timing belt to change access to water pump with no timing belt in the way as well, just getting old as Rosco said a lot with very high kms everything wears out eventually.

The timing belt thing is not a reliability thing 1hz have them as well just did not have one to do on the 12ht so less expense. I think toyota never made enough money for parts off the 12ht so they thought lets change too a timing belt set up for the next gen motors to make some money. It just so happened my beb went at 100,000km at the same time my timing belt needed changing on the 1hdt. Now the fe motors out the 100 series give me that one any day.....

 

[roscoFJ73]

The problem I’m having is that as I look around this site, I seem to see a lot of people having a lot a problems with the 1HDT. Not just big end bearings.

Its a forum where owners come to tell you about their problem and ask advice on how to fix it, so you tend to hear bad things.
And there are many more 1HD T than 12HT in this world

This is my take on how things are.

1 Many of the imported 1HD T from Japan have higher or unknown klms on them.
2 Some owners think its normal to drive a diesel flat out most of the time.
3 In North America there are a limited amount of workshops where you can find someone who can diagnose a problem and repair it correctly the first time. Most owners can handle the odd hiccup but when they have had the vehicle 18 months and its spent 7 months getting fixed and had quite a few thousand dollars poured into it because the shop isnt quite up to speed, its a depressing experience.
In countries like Australia where Toyota dealerships and other workshops are well versed at dealing with 1HD T and diesel engines, there is no debate on reliability.Things tend to get fixed right the first time.

I don't believe the timing belt is a reliability issue. Its a proven concept right across the Toyota range. Some timing belts have gone 3 times past the service interval with little visible wear. I think there would be quite few 1HZ that haven't have a belt change in living memory.
Rotary injector pumps tend to wear out quicker than inline pumps , they have less parts and are designed to operate at higher rpm.
They are cheaper to manufacture and the diesel world is not returning to inline pumps, so get used to them.
Turning up the fuel and driving them hard also wears the injector pump out faster.
But most are still doing 350000klms without problems

There are things on the 1HDT that were a big plus over the 12HT.
1The power steering pump is built into the engine.
2 Same with the vacuum pump and it almost never wears out.
3 The 1HD T has a simple 1 wire solenoid shut down that almost never goes wrong.
4 A 1HD T has more torque at the top end. The 12HT comes in a rush and dies off after 80-90kph
5 Crankshafts, cams, cyl heads and injector pumps are easily obtainable new for a 1HD T, not so for a 12HT.

Both good engines, both have their pros and cons.

 

[umpqua]

I change the connecting rod bearings in every truck, never had a problem, although I have seen them fail in other people's trucks where they haven't been changed. I removed the ACSD on mine but none of my trucks have had any problems. Just regular maintenance so far on 50,000km in the last 18 months. A 20+ year old truck is as reliable as you make it with preventive maintenance and frequent inspection.

ACSD= Cold Start?

 

[roscoFJ73]

Advance Cold Start Device.
It should be called the Cold Start Timing Advance Emissions Device.

 

[Indyteecee]

Advance Cold Start Device.
It should be called the Cold Start Timing Advance Emissions Device.

At this time I’m now considering all different types of cruisers. 60,70 and 80 Series. I’m just trying to find the one that will fit my needs over here in the US. What engine is in your rig? 1HZ or 13bt?

 

[VX 12HT]

Going back to your original reliability question i would say go for the 1hz with better parts availability. The timing belt thing as said its fine just a service item you need to do every 100,000kms.

 

[umpqua]

Bought a troopy and removed/sold the 3Bi. Went in with the 1HDT as I wanted more power and didn't want to turbo any engine that didn't come from Toyota that way.

Following the recommendations from others on Mud the BEB's were serviced, cold start removed, timing belt changed, rebuilt injectors, water pump. Probably other pm's that I forgot. I have yet to drive the truck as it's still with the mechanic. Having driven 500 interstate miles with the 3b troopy on the way home I knew I wanted more power and the 1HDT should deliver it. Plus, I already had purchased the 1HDT. A lot of back and forth from previous threads but others have good feelings about the engine. I'm sure that the 1HZ is great as well and probably wouldn't go wrong with either. Personal preference as again I didn't want to turbo an engine that didn't come from the factory that way.

 

[Gun Runner 5]

I see a reoccurring theme in all of these type of discussions.

Yank out that old 1HZ and replace it with a 1HDT. The last time I checked the 1HZ is still somewhat rare in the U.S. while the 1HDT is even more rare. Although both can be sourced with some effort, I've yet to see either one sitting on a shelf at NAPA?

 

[Indyteecee]

Bought a troopy and removed/sold the 3Bi. Went in with the 1HDT as I wanted more power and didn't want to turbo any engine that didn't come from Toyota that way.

Following the recommendations from others on Mud the BEB's were serviced, cold start removed, timing belt changed, rebuilt injectors, water pump. Probably other pm's that I forgot. I have yet to drive the truck as it's still with the mechanic. Having driven 500 interstate miles with the 3b troopy on the way home I knew I wanted more power and the 1HDT should deliver it. Plus, I already had purchased the 1HDT. A lot of back and forth from previous threads but others have good feelings about the engine. I'm sure that the 1HZ is great as well and probably wouldn't go wrong with either. Personal preference as again I didn't want to turbo an engine that didn't come from the factory that way.

I’m interested hear your opinion once you’ve had the truck back for a while.

 

[mudgudgeon]

The problem I’m having is that as I look around this site, I seem to see a lot of people having a lot a problems with the 1HDT. Not just big end bearings.

Rosco had done good points above.

The big end bearing issue with 1HD-T is hit and miss. Many would still be on the original 25year old BEBs. An oil sample analysis from time to time would help identify it ahead of a failure.

I've drove a 12HT 60 series daily for about 6 months years ago, love every minute of it, and is responsible for an obsession with diesel landcruiser. I've owned a 1HD-T powered 80, and loved it too.

If this question was asked on lcool.org/forum which is an Aussie based cruiser forum where diesels are common, you'd get the same answer.
1HD-T, or more modern 1HD-FTE both have legendary status and still command a big premium for second hand prices. Both are capable of some impressive power if you choose to gives turbo's etc.
HZ also has a reputation for reliability and strength, but also as being a bit sluggish.

 

[Indyteecee]

Rosco had done good points above.
I've drove a 12HT 60 series daily for about 6 months years ago, love every minute of it

Just curious, if you loved every minute of it, then why only 6 months? Did you sell it?

 

[mudgudgeon]

Just curious, if you loved every minute of it, then why only 6 months? Did you sell it?

It belonged to my uncle, and was on loan.
My dopey cousin rolled it on a beach, and it got drowned when the tide came up before it could be recovered.

 

[Indyteecee]

It belonged to my uncle, and was on loan.
My dopey cousin rolled it on a beach, and it got drowned when the tide came up before it could be recovered.

Sad. I’ve taken a 12ht 60 into consideration as well. If by some miracle I can find one in decent condition for a reasonable price considering they’re all 30+ years old now.

 

[Mookies]

Advance Cold Start Device.
It should be called the Cold Start Timing Advance Emissions Device.

More like the "Supposedly good idea for about 5 years then leaking and leaving metal shavings inside the injection pump Assembly"