It's done! 3.0-liter turbo-diesel FJ60 from TLC

[Carlyle]

That is a great set up, congrats!

 

[charlieaarons]

What about taller tires instead of a gearing change? 8.25R16 is narrow (~9") so it will probably fit. Someone may make 35-10.5R16. And there's even 9.00R16 XZL at 36.4"; might not fit a spring under 60 even with lifted springs.
The tires on it look fairly short, maybe 32", so 8.25s (34.0") would drop rpm at 65 ~200 rpm.

Charlie

 

[DesertRose]

Awesome! Glad you got it back and took it off road immediately! Sorry I wasn't there to see the sile on your face when you left!!

So sorry we missed you - it was the only week I could have come over, and of course you weren't there!

Great job, it's an amazing build. Performance on and off highway is nothing short of perfect, IMO. The thing does anything I asked it to, and with ease, and wanting to do more - never reached its limits.

The mileage will be back up in the 25+ where we expected it once I do the re-gearing and let the engine break in. This is only a few thousand miles into it, and only my first tank of diesel, too (and with a 40 gallon tank, this is getting VERY tough to test the mileage!).

And yes, grinning ear to ear!

 

[Jonathan Hanson]

We wanted to stick with a modest (31 inches tall) tire size to reduce unsprung weight and rotating mass, and a narrow tread for reduced rolling resistance, thus the 235/85/16s on 7-inch rims. Also, a heavier tire/wheel combination is a pain to lift up on to an ARB or Kaymar rear rack.

I think the highway mileage will take a significant jump with the stock 3.70 gears, which will drop the engine speed by 250 rpm. I expect the low range ratio will still be more than adequately slow for our needs, which includes little rock crawling. If not, we can install a set of the Marks low range gears from Australia.

 

[DesertRose]

It's been fun to watch this story unfold, but man, 21-22 isn't that great (to me). I guess I was hoping for more like 25-27.

We'll get there for sure - there is no reason it won't once we sort out a few things and the engine breaks in. And I stop trying to drag race.

 

[Hltoppr]

Wow....let me wipe the drool off my shirt. You guys are not good on my retirement savings....

Can't wait to see it in person!

-H-

 

[charlieaarons]

We wanted to stick with a modest (31 inches tall) tire size to reduce unsprung weight and rotating mass, and a narrow tread for reduced rolling resistance, thus the 235/85/16s on 7-inch rims. Also, a heavier tire/wheel combination is a pain to lift up on to an ARB or Kaymar rear rack.

I think the highway mileage will take a significant jump with the stock 3.70 gears, which will drop the engine speed by 250 rpm. I expect the low range ratio will still be more than adequately slow for our needs, which includes little rock crawling. If not, we can install a set of the Marks low range gears from Australia.

Be aware that Mark's gears have either a built in underdrive or overdrive (1.08 or 0.92) in high range depending on which ones are put in. So the 0.92 version would be close to switching to 3.70s. That, with a very mild tire size change (~1") would get you right where 3.70s would.

Charlie

 

[lowenbrau]

Speaking of break in, has the manufacturer recommended specific lubricants for this? I have a buddy who considered it a mistake to use synthetic oil to break in his 1HZ Toyota diesel after he rebuilt it with chromoly rings. He figures it took more than 60,000km to seat the rings. Perhaps dyno oil (with plenty of changes) is the right thing for a while.

 

[ChuckB]

I'm SOOO jealous!! Can't wait to see the articles.

 

[tdesanto]

:26_34_3: and

:clapsmile

Can't wait to see it in person soon.

 

[Jonathan Hanson]

I'm pretty sure Marks has a gear set that lowers the low range without affecting high range.

Yep, here it is:

Marks

We are sticking with conventional oil for now, with plans to switch to synthetic later, perhaps at around the 10,000 mile point.

 

[dieselcruiserhead]

congrats!

Also I would recommend checking with Kurt Williams as he installed a couple of the mark's sets and has good info on them.

Nice old school/LCML-ish post:
The first gear of the H55F is I think about 4.9:1 so actually pretty damn low despite how well that transmission shifts/drives. This alone is far greater than 4.88's in the diffs for example. With that tire size I would put money that it will wheel just fine even with the 3.73s... I owned a stock HJ60 with that gearing and little/no complaints and/or perfectly tolerable off road, even getting up to 33s -- for what it's worth!

Bummer that you have to swap diffs. What I would do is acquire a set of stock FJ60 diffs, sell your existing diffs complete for maximum efficiency, and install your new diffs with ARBs or selected diffs as a replacement. Best bang for buck, lowest down time, easiest/least labor intensive...

 

[overLand_Cruiser]

I recently went from 3.73's to 4.11's when I installed my locking axles. With 33x12.5 MTs I am pretty close to being back to stock final drive (~1.04 overdrive factor by my calculations). I am running a 1HZ/H55F I haven't not seen my mileage affected too much, I still average about 21-22mpg with a 50/50 drive cycle. I do suspect it has affected my top end, but the only trip I have taken it on with extended highway driving since swapping axles I had it packed to the roof with tools and cruiser parts and I averaged 22mpg, down from 25mpg that I used to get on the highway unloaded. I do appreciate the grunt the gears have provided, but with a turbo you'll have all the grunt you need, so the 3.73's would probably be ideal for highway economy.

 

[Jonathan Hanson]

I agree with you, Andre, that it's unlikely we'll need lower gearing. Not a huge deal to swap the R&Ps; I'll pull the carriers and have my nephew set them up; he's a whiz at it.

 

[DesertRose]

I recently went from 3.73's to 4.11's when I installed my locking axles. With 33x12.5 MTs I am pretty close to being back to stock final drive (~1.04 overdrive factor by my calculations). I am running a 1HZ/H55F I haven't not seen my mileage affected too much, I still average about 21-22mpg with a 50/50 drive cycle. I do suspect it has affected my top end, but the only trip I have taken it on with extended highway driving since swapping axles I had it packed to the roof with tools and cruiser parts and I averaged 22mpg, down from 25mpg that I used to get on the highway unloaded. I do appreciate the grunt the gears have provided, but with a turbo you'll have all the grunt you need, so the 3.73's would probably be ideal for highway economy.

Great information, thank you!