Engine Family Comparison: 1HZ, 1HZ-T, 1HD-T, 1HD-FT (1 Viewer)

[Will Van]

Have you had them out to check?

The oiling issues on those motors are well established. Changing bearings doesn't stop the problem, it just resets the clock.

I'm confused. It was my understanding that the "BEB issue" was a series of years (1990 to 1994?) where Toyota used inferior bearing material between the crankshaft and connecting rods, and the factory bearings deteriorated prematurely. Supposedly swapping to ACL, Taiho, or updated Toyota bearings resolved the issue.

But it sounds like you are saying that the BEB issue was actually due to a faulty internal oiling design that supplies oil to the BEBs. And that the BEB oiling was redesigned between the 1HZ/1HD-T and the 1HD-FT generations. Is that correct? Can you elaborate on what Toyota redesigned? I thought the crankshaft was identical between 1HZ, 1HD-T, 1HD-FT, and 1HD-FTE?

 

[Dougal]

I'm confused. It was my understanding that the "BEB issue" was a series of years (1990 to 1994?) where Toyota used inferior bearing material between the crankshaft and connecting rods, and the factory bearings deteriorated prematurely. Supposedly swapping to ACL, Taiho, or updated Toyota bearings resolved the issue.

But it sounds like you are saying that the BEB issue was actually due to a faulty internal oiling design that supplies oil to the BEBs. And that the BEB oiling was redesigned between the 1HZ/1HD-T and the 1HD-FT generations. Is that correct? Can you elaborate on what Toyota redesigned? I thought the crankshaft was identical between 1HZ, 1HD-T, 1HD-FT, and 1HD-FTE?

That was the factory story but it's BS. It's a crank oiling problem that persists. The bearing shells were the innocent victims and should be scheduled replacement to prevent issues. It appears Australia had a combination of the best conditions to show up the issue. They drive in straight lines in hot conditions more than anyone else.

Yes the FT stopped the problem. There is even a research paper I found written by a team including a Toyota engineer about cavitation in the crank bearings of a 6 cylinder diesel.

 

[Will Van]

That was the factory story but it's BS. It's a crank oiling problem that persists. The bearing shells were the innocent victims and should be scheduled replacement to prevent issues. It appears Australia had a combination of the best conditions to show up the issue. They drive in straight lines in hot conditions more than anyone else.

Yes the FT stopped the problem. There is even a research paper I found written by a team including a Toyota engineer about cavitation in the crank bearings of a 6 cylinder diesel.

But aren’t 1HZ, 1HD-T, and 1HD-FT crankshafts the same?

 

[tmarx]

But aren’t 1HZ, 1HD-T, and 1HD-FT crankshafts the same?

For many years already the replacement blocks from the TOY factory has been the exact same for all the variants - my 1997 1HD-T has the FTE block with the provision for crank sensor which is only present in the FTE.

 

[Dougal]

But aren’t 1HZ, 1HD-T, and 1HD-FT crankshafts the same?

Crank is only one part of the bearing oiling system.

 

[KiwiDingo]

my 1997 1HD-T has the FTE block with the provision for crank sensor which is only present in the FTE.

Yep, spot on with them basically all being the same. I have a mate who's currently planning on using that crank angle sensor on his 1HDT to allow him to run the fancy FTE injector pump.

 

[Will Van]

Crank is only one part of the bearing oiling system.

What did they change to make the bearing oiling system better on the 1HD-FT? Could it be retroactively applied to the 1HZ/1HD-T?

 

[joekatana]

As someone who has had 12HT,1HZ,1HDT swapped 40 series I can say that the 1HZ has the best fit in a short 40. Yes I had plenty of fun with the 12HT and 1HDT swapped 40's back in the day but using the extra power that these had got me in sketchy situations where luckily I was young enough at the time and didn't know any better. This is a short wheelbase that has a 50 year old suspension design and the road manners of a tractor , cruising at 85 mph is probably not high on the list?

I have sold several 1HZ's to customers for their 40's here on Mud and some of them have used them extensively and say it is the best swap for their 40 giving them perfect road manners with decent highway cruising , very good gas mileage and tons of fun wheeling and overlanding and no I am not saying this because I have a 1HZ in the classifieds

If we are talking about a 45 troopy that will have a constant load of an extra 2000# of overlanding stuff or frequently pulling a car hauler I would opt for any of the direct injected TD's but I think this is not the case here

If you are dead set on a 1HDT I can always sell the one in my crawler and install a 1HZ in it instead , I really don't feel that the turbo is adding that much when crawling around.

 

[OGBeno]

Probably worth posting this information as at least a baseline for some of the engines being discussed:

 

[Will Van]

Probably worth posting this information as at least a baseline for some of the engines being discussed:

View attachment 2217353View attachment 2217354

Thank you! Great read. You don't happen to have the equivalent documents for the 1HD-FT or 1HD-FTE?

 

[OGBeno]

This page is pretty much a condensation of the SAE paper Toyota did for technical introduction of the engine to the engineering community. Toyota generally does this with each engine introduction.

It’s a good link.

1HD-FTE Toyota engine

1HD-FTE Toyota engine: design attributes, power and torque outputs, technology and models with this engine

australiancar.reviews

 

[Will Van]

As someone who has had 12HT,1HZ,1HDT swapped 40 series I can say that the 1HZ has the best fit in a short 40. Yes I had plenty of fun with the 12HT and 1HDT swapped 40's back in the day but using the extra power that these had got me in sketchy situations where luckily I was young enough at the time and didn't know any better. This is a short wheelbase that has a 50 year old suspension design and the road manners of a tractor , cruising at 85 mph is probably not high on the list?

I have sold several 1HZ's to customers for their 40's here on Mud and some of them have used them extensively and say it is the best swap for their 40 giving them perfect road manners with decent highway cruising , very good gas mileage and tons of fun wheeling and overlanding and no I am not saying this because I have a 1HZ in the classifieds

If we are talking about a 45 troopy that will have a constant load of an extra 2000# of overlanding stuff or frequently pulling a car hauler I would opt for any of the direct injected TD's but I think this is not the case here

If you are dead set on a 1HDT I can always sell the one in my crawler and install a 1HZ in it instead , I really don't feel that the turbo is adding that much when crawling around.

You're absolutely correct. I have been thinking a lot about "What do I want to use the Cruiser for?". My plan had been to try to build a truck that I could take on a long road trip while towing a small 1,500 lb camper, stop at various national parks or destination trails along the way, and do some light to medium wheelin' in some spectacular scenery. Austin, TX to Ouray, CO or Moab, UT...3,000 miles in an FJ40.

A DI turbo-diesel is the best choice for such travel. Plenty of torque for wheelin', towing, and mountain passes. Great range. Mated to an H55F 5-speed transmission and the right diff/t-case gearing, it could scoot right along at 55 to 60mph with 20 to 25 mpg. Add a LRA main tank and auxiliary rear tank (50 gallons of diesel), you could go 1,000 miles on one fuel stop!

But I realized that it's important to have reasonable expectations on the limitations of the truck. As you said, it's a 40 year old truck with a short wheelbase, solid axle/leaf spring suspension, and high center of gravity. After a 3,000 mile road trip in an FJ40, I would hate myself. I would need a new spine. It would be exhausting.

I think it makes the most sense to wrap up my 2F fuel injection build, sell the Hilux, drive the snot out of the FJ40, and slowly build a 1HZ swap in the interim. If I eventually want to add a mild turbo kit to the 1HZ, I can do so down the road. If it blows up, great! I can swap to a 1HD-T, 1HD-FT, or 1HD-FTE.

But I also just like researching and studying Toyota engines. Especially diesels!

 

[Greg_B]

This is a good discussion and as such I've linked it to the 1HD-T 1HD-FT 1HD-FTE and 1HZ thread. While no "proof" of why the BEB pitting is present has been provided, the discussion and information on this family of engines is valuable. Another thread (where oiling is discussed as well) which has a great discussion hitting a variety of points is located here.

Cheers
gb

 

[GTSSportCoupe]

The oiling issues on those motors are well established. Changing bearings doesn't stop the problem, it just resets the clock.

1HZ has the same oiling system as 1HDT does it not? But no bearing issues with the 1HZ.

I always assumed the pressure wave of the first direct injection revision was a little harsh and contributed to BEB premature wear. Looking at the damaged bearing shells that come out of the motors, it seems the damage is concentrated on the upper shell. As you say though, maybe more oil flow is all that was needed.

Toyota revised the injectors and piston bowl design a couple years into the 1HDT. Did the bearing issue not improve around the same time?

I know from past gasser Toyota experience, the bottom ends with oil squirters seem more prone to BEB damage. I wonder if the oil flow at idle is marginal for the extra requirement of the squirters?

 

[Greg_B]

The idea of the thread compiling all info as folks change out their bearings - bearings photos with pump/block numbers - is to try and get some rough idea to the question of "is there a change post 08/92 when they changed the injection and bowl" (as well as larger fuel supply line). Not enough time has gone by yet and it will likely take years even with good participation.

Much more rare for 1HZ, however there are sporadic comments on line and I have seen one set of BEB's from a 1HZ that showed pitting. I think that engine was turbo charged while in Japan but have no proof.

gb

1HZ has the same oiling system as 1HDT does it not? But no bearing issues with the 1HZ.

I always assumed the pressure wave of the first direct injection revision was a little harsh and contributed to BEB premature wear. Looking at the damaged bearing shells that come out of the motors, it seems the damage is concentrated on the upper shell. As you say though, maybe more oil flow is all that was needed.

Toyota revised the injectors and piston bowl design a couple years into the 1HDT. Did the bearing issue not improve around the same time?

I know from past gasser Toyota experience, the bottom ends with oil squirters seem more prone to BEB damage. I wonder if the oil flow at idle is marginal for the extra requirement of the squirters?

 

[Will Van]

The oiling issues on those motors are well established.

Disagree. The degradation of BEBs in some 1H-series of motors is well established.

It's a crank oiling problem that persists.

It is speculation that the cause of BEB degradation is due to a crank oiling problem. "Crank Oiling Problem" is a very broad explanation for BEB degradation.

There is even a research paper I found written by a team including a Toyota engineer about cavitation in the crank bearings of a 6 cylinder diesel.

Is this the research paper you are referring to? That's a very interesting research paper and might be helpful to solving the BEB degradation. But I think it's important to keep in mind that the research paper:

• Is testing a generic inline 6 diesel engine with at least 7 main bearings. No specific mention of 1HZ, 1HZ-T, 1HD-T, 1HD-FT, 1HD-FTE, or any Toyota Diesel engine is made.
• Is discussing and testing the main journals of a diesel crankshaft. Not the BEBs.
• Is NOT testing for degradation of bearings due to cavitation or degradation for any other reason.
• Is testing for noise above 5kHz in the main bearings.
• The paper explains that the cause of the noise is from:
  • (1) the cavitation of oil on the bearing surface; and
  • (2) vibration of the main journal.
• The paper concludes that the noise can be prevented by adding grooves to the bearing surface, preventing the cavitation from reaching the edge of the bearing and causing the 5kHZ noise.
• Cavitation erosion is occurring during the tests, but the paper makes no mention for preventing cavitation/erosion on bearings of any type.
• A Toyota engineer was on the team.

I also reviewed this article on the 1HD-FTE. Toyota added grooves to the main bores of the FTE to transfer grooves into the bearing surface of the main bearings, presumably to reduce noise. There is no mention of BEBs or big end conrod modifications.

Crank is only one part of the bearing oiling system.

True. But how do we prevent BEB degradation? Is it due to cavitation erosion? Should we increase the oil pressure? Add aftermarket BEBs with grooves or chamfers? Reduce running clearance? Run harder bearings? Switch to 1HD-FT conrods?

 

[Loober]

The idea of using a 40 for long distance driving and having it be a comfortable and relatively safe feeling experiencing especially towing something is misguided regardless of the engine. The short wheel base presents all kinds of problems, I know there are folks that use them for those purposes but doesn't mean its ideal or anywhere close to it. If you are looking for that to be your main use, spending time and money on a drivetrain would be better suited for another model of land cruiser, like a 60. Having gone down that road with a 40, spending all kinds of money to over come the short wheel base woes, finally cut my losses and went to a longer wheel base rig.

 

[FJBen]

This is a short wheelbase that has a 50 year old suspension design and the road manners of a tractor , cruising at 85 mph is probably not high on the list?

have you met @wngrog?

Either way I agree with you. I’ve had built fuel injected 350s, stock 6s, N/A diesels, 1fz, 3FE and now a 13BT and have enjoyed this one the most
in terms of engine.
I can turn that up a little bit I enjoy it.

@Will Van
As for a 40 for a long trip rig, you had better be committed. I’m not saying you can’t do it or shouldn’t, but it’s definitely not the best suited for that. The 40 is my favorite land cruiser.
it would be epic to pull a small trailer, attack the road and enjoy it in a classic 40 with upgrades, so I’m pulling for y


Unsolicited biased opinion here:
I can tell you my “new FJ40” BJ74 is waaay better of a highway long haul rig than any 40 I’ve driven.
It’s basically everything you want minus being a LHD 40.
factory direct injected turbo diesel, 5 speed, lockers, full floating axles, removable top/soft top, 20mpg, cruises quite comfortably and quietly down the highway with good heat/ac

 

[Will Van]

have you met @wngrog?

Either way I agree with you. I’ve had built fuel injected 350s, stock 6s, N/A diesels, 1fz, 3FE and now a 13BT and have enjoyed this one the most
in terms of engine.
I can turn that up a little bit I enjoy it.

@Will Van
As for a 40 for a long trip rig, you had better be committed. I’m not saying you can’t do it or shouldn’t, but it’s definitely not the best suited for that. The 40 is my favorite land cruiser.
it would be epic to pull a small trailer, attack the road and enjoy it in a classic 40 with upgrades, so I’m pulling for y


Unsolicited biased opinion here:
I can tell you my “new FJ40” BJ74 is waaay better of a highway long haul rig than any 40 I’ve driven.
It’s basically everything you want minus being a LHD 40.
factory direct injected turbo diesel, 5 speed, lockers, full floating axles, removable top/soft top, 20mpg, cruises quite comfortably and quietly down the highway with good heat/ac

LHD HZJ75 Pickup with a 5-speed would be killer!

 

[Will Van]

The idea of using a 40 for long distance driving and having it be a comfortable and relatively safe feeling experiencing especially towing something is misguided regardless of the engine. The short wheel base presents all kinds of problems, I know there are folks that use them for those purposes but doesn't mean its ideal or anywhere close to it. If you are looking for that to be your main use, spending time and money on a drivetrain would be better suited for another model of land cruiser, like a 60. Having gone down that road with a 40, spending all kinds of money to over come the short wheel base woes, finally cut my losses and went to a longer wheel base rig.

Ok, ok, the road trip idea is not realistic. I would probably do it once, and then never again. I have a 2019 Tacoma TRD Off Road that is better suited for the whole experience. But a great family friend who recently passed away introduced me to Land Cruisers. He had a Sky Blue 1960s model that was immaculate. He would tell me stories about piling his family into the Land Cruiser FJ40 (6 of them!), hooking up their pop-top camper, and driving all around the United States on adventures. I can't help but think, "Hell, if he could do it in 1971, why can't I do it now?" Is it ideal, safe, or comfortable? Of course not. But that's not really the point.

Either way, a Toyota turbo diesel would be cool in a 40!