New 1993 HDJ81 Owner, First Things to Do? (1 Viewer)

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Apr 9, 2019
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Denver, CO
Hi All,

Whelp, I just got a HDJ81 and for me, it's a first for LCs and diesels. It's stock as of now, but I'm looking to make a list of the changes I'd like to make. I'd like to take care of important things first and it's been suggested I get an EGT gauge/pyrometer to monitor those temps and avoid overheating. Sounds reasonable to me. Is there any other things that I should do first to help the reliability/safety of the engine and/or drivetrain before I get into non-essential things like roof racks and sleeping platforms?

I'm pouring over all sorts of info and falling into a bit of a rabbit hole. Snorkels, boost gauges, roof racks, tires, 24v->12v conversions...

I really appreciate any tips and am stoked to start this journey.

-Stu

1959552
 
Hi there nice rig. First on the list should be to check the big end bearings, no shortage of info on here for that. 24-12v converters aren't really necessary as the rig is 12v just like the FJ80's. The only thing that's 24v is the starter. Some kind of controller switches the batteries from parallel to series just to start the beast. Have no idea how it works but if it fails I'll have to learn fast.
 
Nice truck!

Change the BEB's, and further to the point above, ONLY connect accessories to the driver's side (RHD) battery, as the left side battery sees 24V when starting.

There's lots of threads in this section on what maintenance to look into with HDJ81's, happy reading!
 
  • ACSD delete
  • replace BEBs (connecting rod bearings, big end bearings)
    • although there is information on this forum (not sure if I would rely on it unless its backed by Toyota documentation) that post 08/93 (wrong date?), non-red "Turbo" on intake pipe, manufactured 1hdts have had a BEB root cause finding and failure mitigation completed by Toyota
    • i just completed this last month, took me 5 hours with plastigaging.
 
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it's been suggested I get an EGT gauge/pyrometer to monitor those temps and avoid overheating.

While this certainly wont hurt , you can drive them safely by dropping back a gear when the engine is working hard on hills, towing etc.
Watch for the colour of smoke your engine makes especially for changes in colour and the amount of smoke. Rebuilt injectors are always a good policy. A poor spray pattern or weak injector springs saps power and adds heat to engine combustion.
A secondary temperature gauge to monitor coolant temps is always good policy and if it has an alarm, all the better.
 
I was kinda wondering how'd I'd do it next weekend without an EGT, as I need to go over a 12k' pass. What if it's an automatic, lol?
 
I was kinda wondering how'd I'd do it next weekend without an EGT, as I need to go over a 12k' pass. What if it's an automatic, lol?

You can downshift an automatic. Keep the revs high = keep the load low(er), better for the engine and the trans than lugging.
 

Its still an engine designed for a turbo ,so the pistons are a bit tougher than NA pistons and they also have a slightly lower compression ratio. As Ian said just take it easy.
At higher RPMs in a lower gear for the same speed, you have more air flowing into the engine for the same amount of fuel, this helps (a lot) to keep the combustion chamber cooler.
 
Lol, I forgot AT's do have a low gear...

Thanks for the advice, your explanation really helps.
 
Don't allow the tyranny to shift on it's own while traveling uphill. The gear hunting creates heat....
I find it you can maintain speed and rpm things are good. You need to change gears if rpms decrease and or speed drops.
I am currently driving a 3b so heat monitoring is essential.
The important thing is not to lug the engine by trying to maintain speed while rpms drop.
 
High load on the engine is when the EGT's really climb, avoid those situations if possible.
 
Don't allow the tyranny to shift on it's own while traveling uphill. The gear hunting creates heat....
I find it you can maintain speed and rpm things are good. You need to change gears if rpms decrease and or speed drops.
I am currently driving a 3b so heat monitoring is essential.
The important thing is not to lug the engine by trying to maintain speed while rpms drop.

See, this is helpful in actually helping me *feel* how to drive it.

How important is coolant temperature when considering EGT temps? My guess is it is, but to a much less degree (and often too late).

Thanks for your help, this is good stuff.
 
See, this is helpful in actually helping me *feel* how to drive it.

How important is coolant temperature when considering EGT temps? My guess is it is, but to a much less degree (and often too late).

Thanks for your help, this is good stuff.

Coolant temp is linked, but remotely, as it is MUCH slower to climb that EGT's, and therefore useless to drive by. Get yourself an EGT and boost gauge, it's really eye opening to see what's happening vs. what you expect was happening, and will change your driving style with these trucks.

Trans temp gauge is nice to have as well, but you'll likely find that once you change your driving style it's much less of an issue and that's not the gauge you'll watch going forward. Add an external trans cooler and keep it from hunting gears and it's usually just fine unless you're towing.

Upping the boost from 9-10 stock to 14-15psi really wakes these engines up, and helps keep them cooler as well.
 
I've been looking at gauges lately and don't haven't really found one I like yet. I'd like to get one with EGT & boost on the same dial (separate probes), with an alarm when EGT reaches a set temp, preferably not $400.
 
I've been looking at gauges lately and don't haven't really found one I like yet. I'd like to get one with EGT & boost on the same dial (separate probes), with an alarm when EGT reaches a set temp, preferably not $400.

Redarc has a 2in1 gauage for boost and EGT, I'm not sure of the price though, or about the alarm.
 
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Those are really nice. Look good, customizable, good reviews, alarms, etc. Proud of them tho', it's $315 'merican.

EDIT: I found this. No alarm, but has EGT, Boost, and (AT) temp gauge: 3in1 Black Face EGT w/ Digital Boost & Temp Gauge

I ran this for 5 years or so. Nothing wrong with the functionality, but trying to read the digital numbers on the bright sunny summer days is a total PITA. The digits are barely visible which is really annoying when you are trying to keep a close eye on your EGT's or running close to the upper limit.

I've switched to running separate gauges. More clutter, and it's not all in the same spot, but I can clearly see every reading no matter the lighting conditions.

I should clarify that mine had boost as the analog and EGT and trans temp as the digital. Analog for the EGT might actually be better and ok since once you set your boost, it doesn't really fluctuate unless you have other issues happening.
 
I should clarify that mine had boost as the analog and EGT and trans temp as the digital. Analog for the EGT might actually be better and ok since once you set your boost, it doesn't really fluctuate unless you have other issues happening.

Analogue EGT seems like the way to go on this, that's the one you pay closer attention to. If you can put boost on an alarm then you don't need to watch it as much.
 
I have that glowshift gauge, boost analog and egt, tranny digital. It is a little hard to see the digital readout. If I were doing it again I'd go analog egt.
 
I think I'll go with the one I linked. It's a helluva lot cheaper than the RedArc ones and has the analogue EGT that's been suggested would be better (makes sense). I don't plan on towing much, so I don't think the digital AT temp would be a deal breaker. Good conversation folks :)
 

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