1HDT or 1HZ (1 Viewer)

[umpqua]

Subject vehicle - 1988 FJ 62. Original 3FE approaching 300,000 miles. H55 manual trans. Engine burns little oil and seems as strong as ever.

I've read through the diesel section and have tried to educate myself as best I can. I'm considering a diesel conversion and I have a "very" good mechanic that will do the swap. We seem to be able to find a 1HZ that he says he can turbo. In the back of my mind for whatever reason I think that the 1HDT would be a better engine. Maybe because that was his original suggestion but I've been unable to locate a 1HDT.

My priorities in order of importance are 1. Dependability, 2. Fuel Economy and 2a. Performance. I plan to drive this truck to S America at some point so parts availability will be important.

My mechanic thinks he can fab an adapter so that the diesel will work with the H55.

I've been a member of MUD for a while and I really appreciate the community. I would be thankful for any insight you can provide. Can you please share your thoughts?

 

[umpqua]

and....does anyone have a source for either of these engines?

 

[roscoFJ73]

The 1HD T will be a better choice than a turboed 1HZ ,but they can be hard to find. You can change the input shaft and bell housing and the H55F will bolt up to your diesel.

What kind of checks has he done on the 1HZ? These can get expensive to rebuild if the engine and injection pump are both worn out.

 

[roscoFJ73]

There is a MUD vendor named George(I forget his MUD handle) who sells an engine mount kit for 1HZ conversions

 

[umpqua]

Haven't seen the 1HZ yet. My mechanic will take a look before I commit to anything. From what I think I know, Toyota never offered a turbo on a 1HZ. Makes me wonder why......

 

[serenity]

Haven't seen the 1HZ yet. My mechanic will take a look before I commit to anything. From what I think I know, Toyota never offered a turbo on a 1HZ. Makes me wonder why......

Now there's a can of worms! Who has a link the thread on the factory turbo 1hz?

Being a 1hz owner I would say wait and find a good 1hd-t if you are going to the expense of a swap and want long term dependability.

 

[AussieHJCruza]

Apparently there was a factory turbo 1HZ, but having driven a turbo 1HZ and now now 1HD-T, go the 1HD-T. IMHO, more reliable turboed if maintained properly, better fuel economy and more power potential.

 

[ERNRAM]

 

[PNWScooby]

The overwhelming answer im sure will be 1HDT if you can find one. Or if you have the time to wait until you find one. You wont hear many complaints about the 1HZ i dont think except for lack of on road power and no one is bummed on having one I wouldn't think. But 9.9 times out of 10 if the choice is given people are gonna pick 1HDT. A 1HDT is a slightly beefed up 1HZ with a factory turbo. Which obviously makes it more reliable than a aftermarket turbo charged 1HZ.

I feel like I just said the same thing 5 different ways...but you get the point haha

 

[umpqua]

I appreciate the comments so far. Fortunately I don't have to do any thing. Doing nothing is always a viable option.

Hopefully someone will come along and ask if I've tried such and such a place for Toyota diesel engines. I haven't looked as hard as I should have but may receive a bonus soon at work.......

 

[AussieHJCruza]

The 1HD-T is a direct injection engine, which are more efficient, and seem to take turbocharging better than an indirect injection engine like a 1HZ, the IDI design puts a lot more heat into the head and therefore the cooling system which presents difficulties when working hard. They also have stronger conrods and IIRC a crank girdle which which the 1HZ doesn't have. The lower compression ratio and larger fuel pump elements make them more suitable to be wound up straight out of the box.

 

[umpqua]

Aussie, I assume you are in OZ. Any leads on where a 1HDT could be had. PM me?

 

[mudgudgeon]

2. Fuel Economy and 2a. Performance.

these two requirements do not fit with 1HZ


add a turbo to a 1HZ and dependability becomes somewhat questionable too

 

[mudgudgeon]

A 1HDT is a slightly beefed up 1HZ with a factory turbo.

this is a bit of an over-simplification.

they are essential built on the same block and bottom end. Different head(1hd-t is direct injected), pistons, IP, injectors, conrods, and turbo.
You can build a 1hd-t clone on a 1HZ block, but the 1hd-t is a bit more than a beefed up 1hz.

 

[ERNRAM]

Based on my torque curves above, if you want performance.....then 1HDT is the winner. A 1HZ with a turbo is next, but in the 1500-2500rpm range, still fall behind the 1HDT

 

[umpqua]

I will check back for further comments. I really do appreciate the input. You're helping with the decision. I got a price from an exporter on a 1HDT. Around $5,700 USD without freight. Seems like a ton of money but maybe that's what the market dictates.

 

[Gun Runner 5]

If performance is your ultimate goal just drop in a Cummins and call it a day.

 

[colby1979]

My choice would be the non-turboed 1hz as parts availability will be better for the long haul.

 

[ERNRAM]

Have you talked to Joe in Dallas? He brings in these from Europe in a shipping crate

 

[gerg]

If you keep that h55f you will kill it with a 1hdt
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