'93 HDJ81 - Turbo Upgrades and More

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Joined
Mar 20, 2023
Threads
37
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363
Location
Eastern Idaho
This summer, I acquired a 1993 HDJ81. Relatively high mileage at time of purchase, approximately 400,000 kms. I have several early and mid-90s Hilux, but this is my first 80 series. My initial impressions of the rig are very positive. More roomy and powerful than my other trucks, rides nice, and is happy at 120km/hr on the highway (will easily do 80mph which is the highway speed limit in these parts). The fuel consumption, however, is less than ideal. I struggle to get 250 miles out of a tank. Fuel capacity seems to be around 25 gallons. Plenty of grey/black smoke on startup, some grey/black smoke on heavy acceleration, nothing I would deem unusual for a diesel. Truck appears to have the "cold weather" package, although is not marked "snow version" like some others. Heated seats, fuel heater, and the weird blind which can be pulled down over the radiator. Starts on the first crank so far every time, we have had a few close to zero degrees F days, but nothing deep in the negatives yet. No obvious blow-by.

I performed the following maintenance items after purchasing the rig. Everything appeared to be kept up on, aside from BEBs, which were close to delamination.

  • BEBs - ACL bearings & Conrod Bolts
  • Transmission Maintenance (A442F Electronic)
    • All four solenoids replaced
    • Strainer replaced
    • Drain & refill with Redline DT4 ATF
  • Front & Rear diff drain and refill with Amsoil SVG 75w90
  • Transfer case drain and refill with Amsoil SVG 75w90
  • Fuel filter & Petcock replaced
  • Timing belt
  • Water pump
  • Glow plugs
  • Engine air filter
  • Oil Change & Filter - Amsoil Signature Diesel 15W40
  • Grease all zerks (Driveshaft, spider joints, etc)
  • Fluid film undercarriage for wintertime
As of this weekend, I pulled my turbo. Replacing the old and tired toyota CT26, which now has 420,000kms, has been on my radar for a bit. The stock turbo is beginning to leak fairly significantly into the intake side, and I am noticing oil coating the intake side of the block. However, I do not have any noticeable oil consumption on the dipstick. There does not seem to be excessive crankcase pressure.

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I have read several threads on Mud about turbo kits; there are a plethora of options. But I am not sure if I have yet to come across my specific situation. I would like advice from those of you that have extensive experience in this area.

I am looking for a reliable setup which can bolt on to my stock exhaust and manifold with minimal or no modification. I would like to keep stock injectors and pump, although I understand I will need to tune my pump. Cost is a factor here; that being said, I would rather pay more for a reputable setup. I have looked at the PDI intercooler/airbox, but I do not know how important this really is. I would rather avoid the intercooler if it is not necessary. I have also considered having a local machine shop rebuild the stock turbo, I'm not sure if anyone has gone that route. I do a fair amount of towing, lots of highway driving, and I am almost exclusively at altitudes >5000ft.

Right now the Gturbo G300 green wheel seems like an attractive choice. I have ordered from HD Automotive in Australia in the past, but it looks like the kits can also be bought directly from Gturbo. Is there an American distributor? Kinugawa also seems like an "ok" option, but I am hesistant to put chinese/taiwanese parts on my rig.

Thoughts?
 
Only thing which was disturbed was the metal fuel lines from IP to injectors, the overflow bus, and of course the injectors themselves.

Fuel filter and gaskets recently replaced. The little plastic petcock/water separator are new also. Copper crush washers were replaced.

Something is definitely different/has gotten worse. The shudder when I let it coast in drive (slow speed no gas) was never there before either. Once it gets warm is idling between 700-800 which is fine.

I did damage the cyl 6 injector seat while removing old copper washer. But I don't think this is a compression issue. Still starts on first crank. And other 1HDTs with all kinds of scratches/marring on injector seats that ran fine.
 
I did damage the cyl 6 injector seat while removing old copper washer. But I don't think this is a compression issue. Still starts on first crank. And other 1HDTs with all kinds of scratches/marring on injector seats that ran fine.
easy way to tell whether or not the "scratches/marring" on the injector seats are contributing to the new issues you are having is to remove the injector and see if any "soot" is getting by and discoloring the injector post the seats/copper washers.

when replacing my injectors, I was advised to GENTLY tap on each injector clamp after seating/installing the injectors, during tightening and torqueing them
 
easy way to tell whether or not the "scratches/marring" on the injector seats are contributing to the new issues you are having is to remove the injector and see if any "soot" is getting by and discoloring the injector post the seats/copper washers.

when replacing my injectors, I was advised to GENTLY tap on each injector clamp after seating/installing the injectors, during tightening and torqueing them

Can't hurt. I'll pull cylinder 6 this weekend and take a peek. As for the tapping, interesting.
 
So, update. This morning -6 degrees F. I plugged in the circulating heater and let it cook for about 45 minutes. It was working marvelously, pumping loads of hot coolant around (1500w heater). I jumped in the truck to start it, ran glow plugs 3 times, cranked it over, not even a splutter.

Now here's where things got interesting. I let the starter have it for a few seconds, and there was no smoke. Zero. Which means, no fuel. Popped the hood and sure enough the lift pump is soft. As I am operating the lift pump, I saw two drops of fuel roll off the ACSD arm on my pump.

My suspicion was correct all along- the hard starts and weird idle were air in the system. Pulled truck into the shop.

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Removed 12mm nut from ACSD arm, took of the arm and springs.

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It is difficult to tell in these pictures, but the ACSD shaft is the culprit. A significant amount of fuel has been escaping. It's been going on slowly for some time, judging by diesel sludge all over under the pump. I figured it was my power steering underneath but it was diesel all along.

The shaft has a tiny bit of play, if I push it to the side and pump the lift pump, I can hear the whistling sound of air entering and diesel dribbles/squirts out.

I ordered an ACSD delete plate from Dave at Back40 Imports. He is a few hours north of me up in Kalispell MT. So it will be here this week.

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I guess that all the work I did exacerbated the problem, and it got bad enough for me to finally notice. The super cold weather also pulls the ACSD arm, which in turn increases the leak. So when I park it for a few days in subzero weather, all fuel is leaking out of the lines and pump.

It seems like mystery solved!
 
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As suggested by @67azcruizr , I pulled cylinder 6 injector. Indeed it does look VERY sooty and gross above the copper washer but below rubber seal. 😥

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Cylinder 5 pulled, shown for comparison.

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What is my next move here... is there a way to seal/repair the injector seat without pulling a head.

I found this thread which discusses a few solutions like an epoxy. Has anyone tried this. What did you use to keep the cylinder clean.


Well, s***.
 
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As suggested by @67azcruizr , I pulled cylinder 6 injector. Indeed it does look VERY sooty and gross above the copper washer but below rubber seal. 😥

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Cylinder 5 pulled, shown for comparison.

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What is my next move here... is there a way to seal/repair the injector seat without pulling a head.

I found this thread which discusses a few solutions like an epoxy. Has anyone tried this. What did you use to keep the cylinder clean.


Well, s***.
probably, I've used this set Laser Tools 4597 Diesel Injector Seat Cutter Set - https://www.lasertools.co.uk/Product/4597/Diesel-Injector-Seat-Cutter-Set
with sucess on Mercedes, if the mesurements are right it should work on a 1hdt too.

take off the least amount of material you can. try to keep all the iron out of the cylinder by putting grease on the cutter, clean and regrease often when using.
 
So I boroscoped cylinder 5 and 6 today out of curiosity. Cylinder 6 piston initially looks HORRIBLE. However it is not damaged, swollen or cracked, but rather stained with awful looking rust colored and white stains.

cylinder 5. Later type piston bowl can be recognized by the "frills" on edges.
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Cylinder 6.
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The silvery blob is a drop of liquid reflecting boroscope light.

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As you can see the edges of the bowl are not chipped, melted or deformed but rather stained with crap.

Some penetrant oil did leak down into the piston when removing the washer, but I vacuumed it out with a shop vac + straw.

Anyone seen this before?
 
yea i don't think it's much to worry about, the pistons are just raw aluminum on this motor, id spend more time looking at the cyl walls that's much more important. Should be easy if you have the articulating camera, i use mine all the time.
 
Head is dropped off at a local machinist. The folks that normally do my engine work recommended him.

I will rebuild the head since I have it out. It's gonna be two weeks, probably more like 3. Machinist is going to recut my injector hole for cylinder 6 and either add a spacer or do 2.5/3.5mm increment so I can stack washers.

Also I'm taking the opportunity to send my injectors pump to Dave at Back40 Imports. Since I'm basically rebuilding the whole damn engine I might as well do the pump.

More to come.
 
3 notch head gasket. (Red circle)

From the factory, they were assembled with either 1,2,3,4,5 notch gaskets.
Replacement oem gaskets are available as 1, 3, 5 notch gaskets. Same with aftermarket.

Best to measure the piston protrusion height to the block deck at all pistons and determine which gasket thickness you need.
 
A little update, I spent about five weeks waiting on the machine shop to fix the screwed up injector seat on cylinder 6. They did a great job - ended up cutting the seat down about 1/8 inch, then made a spacer and pressed it in to raise up the injector seat to the original height. I was very pleased with the results, injector hole in cylinder 6 was indistinguishable from the others, and now providing a nice flat sealing surface for the injector washer.

Originally, I was planning on rebuilding my head, since I had it out, and I ordered a full new valvetrain while I was waiting. But the head looked to be in incredibly good shape. Hard to believe it has 420,000km on it. I ended up cleaning everything up and putting it back together as is. Used a new three-notch head gasket, new head bolts, and replaced a few miscellaneous parts while I was at it.I also got my rebuilt injection pump back from Back40, and installed it.

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Truck has been back together for a week now, and overall seems to be doing very well. The Arashi Dynamics turbo is working out great, I have left my fuel screw at the factory setting, and am running the turbo with a 16psi wastegate. Green boost light comes on about 1200rpm, orange boost light comes on under heavy acceleration about 2500rpm. While cruising on the highway, unless going up a steep grade, boost light remains green. Noticeably less exhaust smoke, before I was chugging out some black and grey unburnt fuel at several parts of the rev range, now I am definitely running cleaner, hardly any smoke except the characteristic puff right when I start up. It seems like the rig is running the best that it ever has during my ownership.

I also noticed an increase in MPG, although not as much as I was hoping. I was solidly under 15mpg before undertaking all the maintenance. Now with the turbo, rebuilt injectors, rebuilt IP, I measured the the fuel economy on two long highway trips, each over 250 miles. I was getting between 16.5 and 19.5 mpg, driving about 130-140km/hr both ways. Yeah.. I was hauling ass. :oops: Truck is running 33"BFG KO2s, I measured the mileage using phone GPS (more accurate than odometer) and diesel fill from the pump. I have heard people are getting like 22+ mpg out of their 1HD-Ts. I have also thought that maybe the ECT transmission shift mode effects MPG. Or maybe the manual trans gets better fuel economy. I'm not sure. The heavy wheels/tires and big ARB bumper probably don't help.

I've also noticed that my idle seems a little rough. I think since deleting the ACSD, I might have to adjust the idle screw and A/C idle up. With my 3L on the Hilux, after removing ACSD, I had to mess around with the idle to get it running right.

A bit sluggish on initial acceleration after a cold start as well.

Overall, very pleased. I am not planning to do much else with the HDJ81 for a bit. I've got a turbo to install on the Hilux, and a second 80 series waiting to get some love.
 
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I did my first valve job this weekend on the 1hd-t. Luckily my 3L valve tool is the exact same SST #09248-04011, which works for both. I've previously mentioned the poor gas mileage earlier in this thread... well, that is all making sense now. Gillett diesel tested the injectors yesterday, and they need new nozzle tips (no surprise there).

The truck has been sitting several nights in the shop, so it was definitely a "cold" reading. Once I got the wood stove going, I did my clearances at room temperature. Not one, or two, but EVERY SINGLE valve clearance was out of spec. All the exhaust valves were too tight measuring between 0.23-0.28mm. Intake valves were all too tight as well, aside from cylinder 6 intake, which was too loose... weird.

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As I went along, I thought maybe something was up with my feeler gauges. I had a second set, so I double checked everything. Both sets of feelers returned the same reading. I did the same process when measuring shim thickness, I doubled checked the readings from my Starett calipers with my Mitutoyo calipers. Measured clearance is shown in blue pen, shim thickness in black.

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Ordered a bunch of new shims, and now we wait.


please fix typo, "SST# 09248-04011", should read 09248-64011
 
I have heard people are getting like 22+ mpg out of their 1HD-Ts.
Don't believe them...:rofl:

Never met a 1HD-T that gets better than about 19mpg (which was mine with fresh injectors, pump, Gturbo red wheel, intake, exhaust etc and driving fairly conservatively)
Had a guy who said his 1HD-FTE in an 80 got about 22mpg but I suspect this was mainly due to the driving style where he barely touched the throttle.
 

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