Builds OL'BETSY ZX: 1991 HZJ77 (1 Viewer)

[JDM Journeys]

Thanks fellas. That feedback helps a lot. I'll check out the sender's anyways, and just received my 'stat etc so I'll be doing that soon.

Meanwhile... First fuel returns are in! 11.8L/100kms, and that is not adjusted for odo accuracy, so likely a little better than that. This was mixed driving, suburban/highway, but mostly the latter, on 33x1250 ATs at around 3000 feet.

And yes. My metric and standard is mixed together in a mish mash. Lol. Such is life in Canada.

I'd call that pretty good economy so far?

 

[janyyc]

Re: your fuel economy, that’s about the same as I get with my HZJ78.

 

[JDM Journeys]

Re: your fuel economy, that’s about the same as I get with my HZJ78.

A 77 with a roof rack and fat old 33s should be around the same as a nice troopy, right?

I got to do a shakedown run yesterday. A buddy and I went on an overnight adventure into the back country. Many things worked well, others need adjusting, exactly the way any shakedown should go, right?

First off, I need to turn back the fuel. It got more noticeable as I increased in altitude (maxed out at around 1600 meters, which is about 3300 feet or so) but even at 1100m where I spend most of my time, I can lay down black smoke at will. Anytime I floor it, I can see it out the left mirror. And once up to speed, under load, ie hill etc, I can ease the throttle up to a certain point, and have a clear exhaust, but as soon as I give a little too much at one time, she spouts, and with a corresponding change in the sound of the valve train, to more of a clatter. I've driven small JDM diesels for a long time as I've said previously, and through the rockies as well as on the flats, so I'm in tune with what is normal, what lugging is, and what it can do. My opinion is this is overfueling. I've also come to the conclusion that I really like this platform, and if I'm going to keep it long term, I'm going to need some forced induction. Not right away, but in a couple of years when I get everything else where I want it. But for now... need to get it running optimally. I also need an EGT gauge, although my left rear view mirror is working pretty well for now. I'm going to run a few tests after backing off the fuel, once I figure out which one it is.

Is an OEM high altitude compensator something that is retrofittable I wonder, or not worth the effort? I guess a turbo is somewhat of an HAC isn't it.

Anyways, back to the shakedown. One thing I didn't mention, is I was towing. Yes, I know. These things can't tow in the rockies, etc etc. Sure they can. If an ILTIS can tow my trailer, then so can my truck. Best guess is just under a thousand pounds fully laden. "Like it isn't even there" until the steepest of hills. Then every single gram makes a difference.

And a pic from my buddy for good measure, the first bit of "wheeling" for this rig. LOL

Just getting started, but at least its out of the garage, and getting dirty...

 

[JDM Journeys]

One more for the setup...

My next mod (if you can call it that) is to make a baseplate for the rear cargo area, rear seats in situ. Then I have the freedom to tie down/bolt on whatever/wherever.

This is my first 4 door (for off highway adventuring) in 7 years or so, and its funny how often I forget about the accesibility of the rearward (passenger) doors. I didn't take my dog this time around, so when I got there and opened the back door, there was NOTHING in the back seat. Hahahah. Going to be some adjusting on my part. Over the years I got used to packing lean. Now I have a trailer AND a long wheelbase. Oh boy...

 

[OGBeno]

Rotary pumps are modular. So you can install lots of different accessory bits to it (AC idle up, HAC, BC, tach pickup, etc.)

 

[JDM Journeys]

Rotary pumps are modular. So you can install lots of different accessory bits to it (AC idle up, HAC, BC, tach pickup, etc.)

I'd love to hear firsthand experience from someone who's retrofitted an HAC to a rig that didn't already have it. Wonder if it would make much difference? I'm at 1100m normally... But all roads west put me into 1600m+ territory. Yes, boost is the obvious answer, but that's a ways off...

 

[OGBeno]

I would not boost a 1HZ. That's not what that engine was made for.

HAC fits on the top of the IP.

 

[GTSSportCoupe]

I would not boost a 1HZ. That's not what that engine was made for.

HAC fits on the top of the IP.

I can't agree more. If you want a turbo, swap out for a 1HDT. It's a bolt in upgrade. Sell your 1HZ to recover your money. Probably won't cost that much more than a full turbo kit would.

There's a reason why all of Toyota's heavy duty Landcruiser diesel's with OEM turbochargers are direct injection motors. There's also a reason why the indirect injection turbo 2LTE and 1KZTE in the light duty cruisers are prone to cylinder head problems. The pre-combustion chamber in the cylinder heads of the IDI diesels just looses too much heat into the coolant. More fuel/air in a turbo IDI diesel causes localized boiling in the cylinder head under high load. This causes hot spots with the metal eventually fatiguing and failing (cracking).

A turbo 1HZ would be fine for low loads in a run-about town truck. But if you work your truck towing up long grades etc, you'll wish you'd gone to a 1HDT.

 

[JDM Journeys]

That's the kind of feedback I need, borne through experience. Thanks guys.

I bought the 1hz for durability, and simplicity.

This is a hotly debated topic I know. But you guys don't feel the 1hz can be mildly boosted for altitude while retaining reliability? I'm used to going slow in my adventure rigs, I just don't like seeing so much black smoke out the tailpipe at higher altitudes, and figured some boost might help a more complete burn?

So my question remains... Would an HAC on top of the pump make an appreciable difference? I'm assuming it alters the fuel delivery amount based on atmo, to reduce overfueling. Wonder if I'd notice a difference? I feel like I'm not taking advantage of the (modest) available power because I'm backing out of the throttle to keep the egt's down.

 

[janyyc]

I presume it’s quite individual and you were also towing, but I’ve never seen a “cloud of black smoke” behind my Troopy… and you know, we do live in the same city
So I wouldn’t conclude it’s a lack of power or the altitude causing your problems.

 

[Loober]

This may not be something you want to hear...when I first got my 77, I was having similar black smoke issues, I tried everything possible, rebuilt injectors and pump, made sure no air is getting in, cleaned/replaced fuel lines, adjusted the pump all kinds of ways, nothing helped. Mine was turboed by the PO, I finally pulled the head and found the pre cup area was cracked screwing up the combustion and causing smoke and other things.

Reality is these trucks have had a long life, much of it unknown to us, who knows how hard it was driven or poorly maintained by its previous owners. Luckily yours has not be turbo'ed which reduces the liklelyhood of that kind of damage, but you never know. I would start with getting the injectors and pump rebuilt, make sure its timed correctly when getting it installed back. If that does not help, its likely more internal.

And I swapped an 1HDFT in mine after I found out about the head and never looked back, you think the truck is fun now, imagine 60 more hp with response/feel of a modern car.

Cheers

 

[GTSSportCoupe]

That's the kind of feedback I need, borne through experience. Thanks guys.

I bought the 1hz for durability, and simplicity.

This is a hotly debated topic I know. But you guys don't feel the 1hz can be mildly boosted for altitude while retaining reliability? I'm used to going slow in my adventure rigs, I just don't like seeing so much black smoke out the tailpipe at higher altitudes, and figured some boost might help a more complete burn?

So my question remains... Would an HAC on top of the pump make an appreciable difference? I'm assuming it alters the fuel delivery amount based on atmo, to reduce overfueling. Wonder if I'd notice a difference? I feel like I'm not taking advantage of the (modest) available power because I'm backing out of the throttle to keep the egt's down.

As injectors wear out, they do crack (open) at lower pressure. This effectively advances the timing, and means they're open for a longer time. This puts the system as a whole out of spec. Something like that could be happening with your motor if the injectors have never been serviced.

Ideally you would have the injectors rebuilt/replaced, and maybe have the injection pump tested/rebuilt also. But that is a big expense.

If the truck starts easy, your injection system may have more life in it, and you can do a bit of DIY tuning on the pump. Find the main fuel screw. Carefully note/mark/photograph the screw OEM position. Then turn it out a tiny bit and see what happens to your AFRs/smoke. Other folks who've messed with these pumps can probably provide more info, but I'd recommend only changing this screw by a tiny bit at a time like less than 1/8th turn.

You could also consider retarding the pump timing a touch too (if it's really knocking). Normally that is done with a dial gauge indicator. But with worn injectors the factory spec measured at the pump becomes less useful.

A friend of mine in our local club has a 1HZ with 3" stainless exhaust and a performance header. This actually helps the old 1HZ's flow a lot more air and make more power. More air will keep your AFR's down. His truck sounds fantastic too! So don't discount the improvement in performance that intake/exhaust modifications could make to your normally aspirated 1HZ.

Here is a picture of that screw. Again, just an idea, and be sure to do your own research on it.

 

[JDM Journeys]

This is great stuff fellas. Thanks so much.

So just to clarify, I'm not emitting black clouds. It's just under load and WOT and shows as a small black stream... It can be totally modulated with pedal position. I just know from experience how much the eg temps are rising when I'm seeing a black line out the exhaust.

Starts on like... half a turn of the motor. So compression in that regard would seem to be good.

I know egt gauge is absolute priority, and then I might turn the fuel back just a tiny bit and see if I can reduce the smoke just a little bit.

Headers and larger bore exhaust sounds like a good idea if it helps, and of course injectors are probably on borrowed time if they're original at 240k kms...

Still might look at the HAC as a possibility as well, for when I go much above my 1100m of home altitude.

Appreciate the opinions folks, and the PM's. Even when some views are diametrically opposed. There are many ways to solve problems, or create new ones. But knowing all your options means you can at least screw up with your eyes open.

 

[SNLC]

Turbo it but get the GTurbo kit and a big PDI intercooler. Also go 4” intake from air box to turbo, do a 3” exhaust. Advance the timing, get an EGT gauge, make sure you cooling system is tip top shape and drive it until it dies.

Might go 100,000ks or more before it dies, or it might not. A lot of money to do up a 1HZ right and even then like others have said, it is IDI. So perhaps sell the 1HZ as suggested and do a swap, it’s a relatively easy swap. Even then with a 1HDx you are probably going to want the upgrades if you want to tow and not be a slug in the mountains.

Cheers

 

[Gun Runner 5]

I believe it was Wayne Smith that often said “your right foot can MANAGE most of your issues”. **
** Perhaps not a direct quote but it was something like that.

 

[Gun Runner 5]

I kept my 77 Series normally aspirated for 5-6 months to get a feel for the engines overall health prior to making any changes. I had an EGT installed upon delivery from the importer. I was shocked at the EGT’s even on moderate inclines (the automatic transmission didn’t help). Kinda ironic, that after installing a Garrett turbo, A/W Intercooler and a 3“ exhaust I saw those temps drop by hundreds of degrees. There is no doubt that at least in my case the addition of a properly tuned turbo made the Cruiser far more driver friendly.
** Sorry for the temporary hijack.

 

[Blomdala]

Unfortunately I didn't have an EGT gauge installed before I added a turbo to my 1HZ, but my understanding was that the real killer for 1HZ was high EGT. So with some basic adjustments after reading about the injection pump, a 3 inch exhaust, and an 1hdfte turbo I feel like I'm able to keep my temps low, but also understand what is going on with my engine. Its higher mileage (310k km) but starts quickly hot or cold, I keep an eye out for smoke but its very clean, and towing my 2k# trailer I am able to keep the EGT below 900F. I really like what @Gun Runner 5 said, about the throttle pedal. When my temps go up from wind or hills, its up to me to keep the EGT in check if I want to ensure some longevity. I do need to work on an intercooler to keep things even lower.

I have gone back and forth about engine swaps as surely a 1HDT, FT, FTE would be a significant improvement. I can say that it makes me feel good that my lowly 1HZ is still in production today, and make me inclined to keep it in there. Ease of parts availability for any kind of repair is a big plus for me.

 

[JDM Journeys]

Well I have finally ordered what I should've had on hand before I bought the truck: an EGT gauge. Went with an Auber Instruments model, and it's even specced for 24v so no messing around with converting to 12v, switching bulbs, etc.

This one is the tiny digital model with a 1" x 2" fascia, so I'm going to see how it fits on top of the steering column. Barring that, I might be able to enlarge a switch blank to hide it in.

Either way... This will be a good monitor for how things are running before I start messing with injectors, IP, etc.

 

[JDM Journeys]

Just published a short story about driving impressions of my HZJ77 - a little fun and hyperbole within. If you're looking for serious journalism, you've come to the wrong place.

Driving Miss Betsy (Project Adventure, Part 5) - The Gearhead Project

FINALLY we get to drive it!

www.thegearheadproject.com

 

[Gun Runner 5]

@JDM Journeys .... “Now, fair warning: first gear is more like a hint, or an encouragement to go forward than it is any real forward momentum.”
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That momentum can be measured in inches or for you metric guys, millimeters.