DarkHorse's 1HD-T 80 Series 'Tank'

Hey all,

Have been meaning to do this for a while... so finally got around to cross-posting from another forum. Bear with me...

I've had my 80 for a few years now, after making a rash purchase under ludicrous time pressure. Being a 25 y.o. vehicle with 380,000km under it's belt, it hasn't exactly been smooth sailing, but I am working on ironing as many of the neglected scheduled maintenance bugs out. The purpose of this thread really is to document that progress, and float ideas for future improvements. My pics and recollections are a bit all over the place, so apologies in advance for that!

So... the very beginning:

Having owned a couple of Vitaras that I had heavily modified, up to the limits of regulatory engineering approval in NSW, I decided to upsize. The hope was that with a bigger, stronger starting point I wouldn't need to modify it as heavily to get what I wanted - a do anything, go anywhere rig that I could take crawling, camping, touring... whatever. I backed myself into a bit of a corner with a scheduled week away, leaving it until the week before trying to get the last Vit registered, but then in my frantic searching this appeared.

I wanted a 1HD-T, having heard they were a better bet than a retro-turbo'd 1HZ, and the GXL trim options were a nice bonus, and it had to be manual. I would have much preferred barn-doors to the tailgate, but it was a small 'price' to pay. Had I had more time to properly research I would have looked for a 93+ model with the bigger brakes/tow rating, but figured I could upgrade those fairly easily. A much later 1HD-FT was always going to be out of my price range, as was a VX Sahara. This one had relatively low mileage for it's age, and presented pretty well. It also had most of my 'priority mods' already bolted onto it, including most of the ARB catalogue:
  • ARB Deluxe winch bar with Aldi 12,000 winch (wire rope was rusted, but that's an easy fix.)
  • Scrub bars and side steps
  • ARB Roof basket
  • ARB awning
  • Kaymar rear swing-away
  • Safari Snorkel
  • 2.5" exhaust
  • Polished sunnies with 33" BFG ATs (good tread, but several years old)
  • ARB airlockers in both diffs, with compressor mounted in the boot
  • Uniden UHF
  • Dual Batteries with a simple 'dumb' isolator
  • ERPS that had been disconnected, leaving the dissimilar metal pads to accellerate rust where they had been placed.
The interior was a little rough, but again not too bad for something that had been in use for a quarter of a century.

Mechanically, other than the snorkel and a 2.5" exhaust it was pretty much stock as far as I could tell. Motor ran smooth for an old oil-burner, pulled strongly, gearbox was a little whiney but shifted smoothly. There was a clunk and at least two distinct vibrations in the driveline and a fair amount of play in the steering, both of which showed up much clearer in the 500km each way drive a few days later than they did on the test drive!

For the first couple of years not much really happened to the old girl... I travel quite frequently for work, so progress was sort of limited to little bits and pieces that I could do in very limited home down time - swapped the old halogen driving lights for HIDs off the old Vitara, threw in a sub, couple of amps, and some 6" speakers in the back doors, new trailer plug, relocated the rear number plate after a warning from one of Sydney's finest, stripped out some of the hideous PO aftermarket wiring, including the ERPS. I also pulled the winch apart, cleaned everything out, put some Dyneema on in place of the steel, and re-wired to get the solenoid box into the engine bay out of harms way. I also transplanted an old set of diff breathers from the Vitara, and relocated the compressor to the engine bay as well.

Balancing tyres and wheel alignments had done nothing to improve the steering, handling, clunks or vibrations, so I got the front hubs rebuilt, complete with new late model spindles (longer splines to delay wear) and Trail Gear Cromo axles. I decided not to go part-time as I liked the all-paw handling (previous Subaru owner syndrome...)

I also got my hands on a set of front calipers from a 93+ model, and bought a full set of new rotors, pads, backing plates, and a rebuild kit for the handbrake, including BOSS dogbones (highly recommend.)

Throughout all of that there were a couple of issues. The second battery fried, taking the main out with it. This was the impetus for stripping out the battery isolator, replacing it with another Vitara veteran in the form of an ABR Sidewinder smart isolator with in-cab switching and guage:

A few long drives were enough to convince me that the stock seats had to be upgraded, so I bought a set of the adaptor plates for the late model Ford Falcon seats. After a lengthy nightmare in the second-hand market, involving purchasing a pair of seats, paying twice the purchase price to get them rebolstered and refurbed, only to realise they were from the wrong series of car, I finally found a slightly rough pair that would work.

These are supposed to be a pretty simple replacement - pull old Ford rails off, trim a little plastic, bolt the 80 rails on, and bolt them into the car. So I pulled the front seats out of the Cruiser...

Ah crap. Oh well, time to pop the welding cherry on the old girl:

Not my prettiest work, but the old rusted sheet metal wasn't exactly co-operative. There's enough solid metal in there now that I'm not worried about flying through the windscreen any time soon. Of course the corresponding bolt on the passenger side was the same. Gotta love symmetry.

End product happiness:

...and even happier:

While I was stuffing around with the interior I thought I'd throw some LEDs into the instrument cluster, which was that classic old, dim, green that I relate to cars three decades ago. Again, should be a relatively simple swap... except that nothing is that easy. Getting the cluster out is painful enough, let alone having to do it several times to plug back in and check polarity on every. single. lamp. I also managed to short something, resulting in a section of the circuit tracer vaporising. A very ghetto little jump lead of wire soldered down solved that well enough. I got everything plugged up as it should be, including sub tank guage and heater control unit, only for every one of the main backlights to develop disco syndrome a few days later. I still haven't resolved this. The face I think says it all:

Then at some point a year or so ago things started going really bad.

On the way back from a weekend up to the Central Coast (400ish km) it blew a hole in the rubber coolant hose for the turbo, dropping all it's coolant and sending temps through the roof. I managed to limp it into a caravan park on the highway, where the staff were nothing short of amazing in helping out. Within two hours I had a substitute hose scavenged from a Hilux wreck, and was back on the road.

Skip forward a month of overseas work, and I was back on a trip down to Canberra (300ish km) when the heat guage shot upwards again. This time any water poured into the radiator came gushing out somewhere at the rear of the engine - heater hose as it turned out. Unfortunately I didn't have a convenient caravan park to turn into this time, and being a Sunday afternoon, two hours south of Sydney, I was lucky to find a tow-truck that could come and get me, and a workshop in Bowral that was open that I could leave the car at for diagnosis.

The head was taken off the motor and sent away for scanning, the report coming back with a crack between cylinders five and six. Then followed a saga of waiting on deliveries, communication, deciding against rebuilding the bottom end as well, the mechanic ending up in hospital (unrelated, but inconvenient!) driving down to collect the car supposedly finished only to find it not boosting, smoking heavily, and well down on power, taking it back and waiting again.

Six months and six grand later I had the old girl back with a shiny new head, radiator, and all soft hoses renewed. I hoped I could put all that behind me...
Since then it has all been a succession of little stuff... and not so little stuff:

New boots! 33" Cooper STT Pro. Pretty impressed so far, and getting rid of the old BFGs cleared up at least some of the high speed vibes. They bag out and hook up pretty well:

Keen eyes might notice the addition of a couple of cheap LED bars on the front of the car. These are more Vitara refugees, and as part of the wiring and switching of these I decided to get the very dim factory headlights onto fresh wiring direct from the battery via relays. This turned into quite a process, but I'm glad I did it.

Here are some mock-ups of the relay array:

The from-scratch centre console that will house the light switches and in-cab winch control, power distro, and dual battery control:

...and some of the nightmare wiring:

Aaaaaand onto the current debacle!

I'd been noticing an increasing waft of exhaust smell inside the cabin, and the engine bay looking more and more sooty:

I replaced the steering column bush in the firewall, which was utterly flogged out, but the waft continued. When I got around to pulling the manifold off, I discovered this:

The corner that has no gasket left was also lacking a nut on the stud to hold it down. Not sure which might have caused which, but I was swearing quite loudly in the direction of Bowral anyway.

Oven cleaner is pretty awesome stuff... just keep it away from aluminium or alloys in the engine bay!
While I had the manifold, heat shields, airbox lid and cross-over pipe off I decided to throw some paint at them just to make everything look a bit more schmick, and to facilitate easier cleaning in the future:

I also bought a cheap SAAS Boost/EGT guage, so drilled the pilot hole for that in the manifold and heat shield:

Of course, looking at that I then had to take the valve cover and timing cover off and get a bit creative.

Stuck waiting for the gasket and new manifold studs and nuts that Aus Post lost, I got a bit carried away and did a little bit of superficial porting and polishing on the exhaust side. The gasket holes are 37mm, while the ports on the head and the manifold are only 31, so plenty of material can be shaved. I'm not expecting any major improvement, but figured I might as well while it was all apart, and the manifold in particular will have to benefit at least somewhat from the smoother passages. Good excuse to buy myself a new die grinder too, which also came in handy for scrubbing the crappy looking surface of the head.

Anyhoo, yesterday and today was *finally* reassembly. Got stuck for a little while on the front inner manifold to turbo stud. Turns out I just needed to look at it from the front of the car instead of the position I spent most of the day in:

"Get a bigger car" they said.
"It'll be so much easier to work on" they said.
My ribs are still aching.

(Random foreground inclusion of a GFB boost Tee I discovered when pulling all this apart. Good to know!)

Lower firewall-end was also a right pain to get a torque wrench onto, but I got there... one click at a time.
So, for the sake of a kind of before and after look:



Pic also shows: compressor on the driver's side firewall, diff breathers on the firewall near the intake manifold, winch solenoid box next to the fuel pump, etc.

Naturally now other bits are annoying me - the little bracket that holds the throttle cable (no biggy) and the intake manifold and rusty part of the head under the fuel rails (kind of biggy) ...and in hindsight I could easily have done the relief detail of the airbox lid in red, so that can go on the 'later' list. Otherwise I'm quite happy with the look - especially in a lo-res photo that fuzzes out my crappy painting!

Here is the EGT sensor plumbed in. I read some bad reviews about the sensor being fragile and susceptible to water, so I was extra careful handling it, and put some heat-shrink on that first section. I have also run it through some convo tubing, together with the boost tee for the guage feed just before the switches mounted on the side of the airbox. From there they will run together in convo tubing through the gland in the corner of the firewall next to the brake booster and into the cabin.

I think that's about it up to date now... so what about the future? I have a few things that need doing as priorities, and then a loooong wishlist, some of it more realistic than others. I simply don't have money to spend on the rig at the moment, so that sort of determines what will get done and what will have to wait.

Immediate priorities:
  • Catch can
  • Weld up chassis cracking
  • Finish centre console and gauge install
  • Install Turbo Timer
  • Find source of leak into driver's footwell when it rains (suspect snorkel mounting on pillar.)
  • Replace all driveshaft unis (still chasing vibes, and just because I have no idea how old they are.)
Realistic wishlist:
  • Major service with C.E.M products
  • Intercooler (Aeroflow do a cheap 600x300x75?) and a good excuse to practise my tig welding.
  • Full 3" exhaust
  • Tune fuel pump and up boost to 14ish PSI/650* EGTs
  • 1FZ airbox lid
  • Paint flares, inner arches and bullbar with Raptor liner
  • Replace steering wheel
  • Get crappy mis-matched spare out from under the car, and mount the reasonable BFG on a suitable rim
  • Dynamat EVERYWHERE
Tell 'im 'e's dreaming:
  • GTurbo
  • Fuel pump and injector rebuild
  • Intake manifold enlargement
  • Dynamat the crap out of everything
  • Rear bar
  • Long range tank
  • Drawers and fridge slide
  • Rebuild steering box with later pin and pitman
  • LED headlights
  • Respray... at least bonnet
  • Rust repair - there is a hole in the rear window surround, and I suspect one in the windscreen surround somewhere too. I've also found a small hole in the passenger footwell.
There is bound to be heaps more that escapes me right now, and more still that will crop up as the car gets used, but that's sort of the direction I'm heading with it for now.

Oh, and I did one more thing that I love:

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Great stuff. They can be alot of work the older trucks but usually once the key is turned and she roars to life the smile on your dial grows wider and you realize its all worth it.
Nice truck.
Gtrubo here we come... ha

Great write up mate and very nice kit you have going there!
Yeah... one day. It's not a priority at the moment, and the price tag keeps it in the 'one day' category for now.


Great stuff. They can be alot of work the older trucks but usually once the key is turned and she roars to life the smile on your dial grows wider and you realize its all worth it.
Nice truck.
Absolutely. I like the mechanical 'simplicity' of older cars and the ability to work on them without having an electronics engineering degree. I'm well aware that it is going to be a constant project, but I'm confident I can get it and keep it at a standard that I'll be happy with. It's comfortable enough and powerful enough for me as is, which are the main attractions of newer machinery.

I had that smile today - have installed a turbo timer and got all the wiring for the boost/EGT guage sorted. That warm fuzzy feeling when it fires up, there's no more exhaust leak, the guage does its little dance then reads the manifold temp rising, boost needle moves with a little rev, and the turbo timer flashes and keeps the motor running for it's intended 30sec when the key is turned off. Now gotta get everything put back together and find time to go for a drive. Pump tuning is the next little exercise. Lots to learn there.


Well-Known Member
Got to love building a old 4by up. Always full of surprises and entertainment...
I have been through the same, new and tweaked engine which included nearly everything under the engine bay, rebuilt brakes, diffs, drive shafts and transfer case. Its now done nearly 200,000 km of touring and hard 4wding and still going strong so hang in there its all worth it.
Got to love building a old 4by up. Always full of surprises and entertainment...
I have been through the same, new and tweaked engine which included nearly everything under the engine bay, rebuilt brakes, diffs, drive shafts and transfer case. Its now done nearly 200,000 km of touring and hard 4wding and still going strong so hang in there its all worth it.
Fingers crossed I'm through the worst of it...

Back atcha. Have seen your name pop up on MUD, where I am spending a lot of time reading up.

Nice buld story mate, really enjoyed reading it.
Glad you enjoyed!