Building an ISG Rig: The 80-Series Diesel Land Cruiser

Introduction

There are a few things that are ubiquitous throughout the world, due to the perfect blend capability, affordability, and reliability. The AK47, jeans, and if you’re talking cars, the Land Cruiser. For 67 years, the Land Cruiser has been a staple of off-road travel throughout the world. Their hard earned legacy for utter reliability and capability have earned the Toyota 4×4 a pedigree from Australia to the Arctic, and everywhere in between.

The HDJ81 Land Cruiser was, in it’s day, the ultimate in both stock 4×4 capability and comfort. Notoriously overbuilt, there are endless examples of 80 Series Land Cruisers with 300,000 miles and beyond. Known for their reliability and their mechanical simplicity, the Cruiser became iconic in some of the world’s most harsh environments and the 80 series is a time-tested legend in Toyota’s most well known and longest lived vehicle line.

As a testament to their capability, the 80 diesel series placed first and second in the Dakar rally, unmodified in 1996, and again in ’98, cementing the HDJ80’s reputation as a tremendously reliable overland vehicle.

But why choose a vehicle that is between 21 and 28 years old? …and what is it that makes the Land Cruiser, well, a Land Cruiser?

Construction and Expectations

The 80-series Land Cruiser boasts frame-on-body construction, a solid front axle, a simple and efficient powerplant and drive train, and a center locking differential (with the option of triple locks). We’ll discuss what this means from a practical perspective.

We won’t focus much on other people’s wants, but here are the things we wanted from our vehicle (you may notice that this looks familiar):

• Durability
• Reliability
• Capability (off-road and on)
• Commonality (availability of parts)
• End user repairability
• Fuel Efficiency and the ability to make our own

To this end, the 80-Series Cruiser – specifically the diesel-powered HDJ – won.

So let’s look at those common traits, how they relate to our goals, and give a little history on what they mean:

1. Frame on Body Construction: The benefit of this is that over extreme and uneven terrain, the frame can flex in response to torsion without warping the body. In collisions, Frame on Body allows the frame to absorb most of the impact, leaving the body serviceable. However, unibody designs have been show to be safer, and fewer unibody collisions resulted in fatalities[1]. Unibody models also consume less fuel due to weight, so the frame-on-body is best suited for vehicles that will be spending time off-road or hauling. The frame construction itself is a fully boxed, super heavy duty frame meant to survive the harshest environments.
   
   
2. Solid Front Axle: Hard core off-roaders will argue until they’re blue in the face regarding Solid Front Axle’s vs Independent Front Suspension (IFS), and a good comparison can be found here. No doubt, the Solid Axle cruiser can be a bit squirrelly on-road, but off road, it handles like a dream. As to the “swapability” and toughness, the Solid Front Axle wins, and as a recent swap of some doomed Birfields (the SFA version of CV Joint).
   
   While the replacement took some time and tools, it was doable, and the mechanical simplicity was evident. Offroad, the solid front axle shows it’s not all “RTI”; it flexes well in response to even wildly irregular terrain and maintains the articulation necessary to keep good traction. So for me, the Solid Front Axle checks the durability, reliability, capability, and end user repairability boxes. IFS can be great, and it’s come a long way, but it’s not something a layman can learn to work on without dedicating a lot of time and effort.
   
   
3. Powerplant and Drivetrain: While the 1FZ-FE series of gas engines are excellent, the Diesel powerplant (in the 80 series, the 1HD-T and 1HD-TFE) is both more efficient and offers up a little more torque at lower RPMs than their gasoline powered brothers. The A442 series transmission is likewise a notoriously tough transmission.
   
   
4. Locking Differentials: A locking center differential can make a huge difference offroad, and reducing slippage. In a traditional AWD vehicle (all wheel drive) the majority of the energy generated by the engine is sent to the rear wheels, and the rest to the front; this means an AWD isn’t sending an equal amount to all 4 wheels. Under normal circumstances, that’s fine, but in tough terrain, it can be the difference between the vehicle gaining some purchase (and moving forward) or being stuck. Overland Bound did a great video on the topic which can be found here.
   
   The Diff-lock essentially pushes an equal amount of power to all the tires, increasing the odds that the vehicle will find some traction when not all the wheels are on the ground or able to get purchase.
   A quick video primer on how a differential locks works can be found here. To expand this capability even further, the Land Cruiser offers triple locks as well, both as a stock option and an aftermarket modification. The short version on differential lockers is that they reinforce success (sending power to tires with traction) whereas open differentials send power to the tires without traciton.
   
   
5. Mechanical/Electrical simplicity: Part of being end-user repairable is the lack of electronic warning systems. Instead of electric sensors and switches, the early 80-series cruisers (92 and earlier) used vacuum and analog switches, which are both long lasting and simple. The 1990 HDJ81VX has no onboard computer systems, which means that while it doesn’t feature the latest and greatest in terms of technology (such as the CRAWL mode on newer Land Cruisers and Tacomas), there’s less to go wrong and more control given to the driver. It also means you need to be a better driver to get the most from your rig.
   
   
6. Off-road Performance: In addition to a lengthy pedigree as an off-road sports vehicle, the 80-series Land Cruiser has an impressive showing in some of the most harsh and technical environments on earth. From Africa to Australia, the Land Cruiser is ubiquitous and known for its ability to perform. While not a purpose built rock crawler, the 80’s bona fides off road mean that even in tough terrain, you’ll be able to get where you need to go.
   
   

Disadvantages

Anyone who speaks only to the strengths of their chosen platform is either ill informed, is irrationally loyal, or is selling you something. The 80-series isn’t perfect, and we don’t talk about things until we’ve broken them, so here are a few of the disadvantages of owning an older Diesel 80-series that we’ve found.

1. Parts availability: There are not many Diesel Land Crusiers here. If you need engine parts, be ready to order from Australia, Japan, or Canada. That said, there are parts that interchange with the domestic FJ80, and apart from the wait and shipping charges, it’s not hard to order parts from overseas markets.
   
   
2. Cost: This is tied directly to parts availability. Not only is the Land Cruiser known for high quality, high price parts, but most of them aren’t available in the U.S. Market. Expect to pay for repairs or turn wrenches yourself.
   
   
3. Service: Service shops (and even some Toyota Dealerships) won’t touch it. Not only are there liability concerns, your VIN won’t work with their computers, which causes an instant, irreversible mental shutdown… so forget maintaining a service record with an official dealership. If you want to find competent people to help you, join the Toyota Land Cruiser Association and find a local chapter.
   
   
4. Age: It should go without saying that while the 80-series is a great vehicle, 21-28 years is nearly three times the “trouble free” lifespan on a normal vehicle, and at the tail end of the 25 year philosophy of the Cruiser. Parts get worn and break, so if you *do* opt for a Land Cruiser, budget in repairs.
   
   At time of this writing, we’ve rebuilt the steering gearbox, Birfields (after failure), Shocks (one of which was completely shot), Brakes/calipers, some lights and hoses, tires. It will need gaskets and seals on the engine, and a new Load sensing proportioning valve. It’ll be time to think about a new turbo system in the near future, and other parts will fail. Some people have a car payment, you’ll have repair bills.
   
   
5. Economy: Compared to newer diesels, the TLC’s modest 17-18 miles per gallon isn’t efficient. The petrol FJ’s 10-14 is even less so. It’s not an economy vehicle.
   
   
6. Acceleration and Braking: Anyone who owns an early 80-series Land Cruiser will tell you, they’re not meant to be fast off the starting line, and the brakes were woefully undersized. The 3F engine especially, but the 4400 pound SUV is powered by a straight 6. It’s not a rocket.
   
   As to the brakes, this can be fixed pretty easily by swapping them for a large rotors/brakes, and calipers, but it’s worth noting that stock, they’re poorly matched to the vehicle.

You should be aware of these things if you consider the HDJ. One of the reasons that I chose the HDJ81 over a 70-series (arguably a more capable vehicle) is that the U.S. Market has the FJ80 – which do have many common parts. With all this said, owning a vehicle doesn’t free you from payments. You just don’t pay the bank, you pay the mechanic (or your buddies and a parts store). If you keep up with your Cruiser and adapt to it’s idiosyncrasies, however, you’ll have a very capable vehicle that can tackle difficult terrain with ease… and for years to come.

Capability

Until you’ve seen the difference, it’s hard to explain why the Land Cruiser is such a superior vehicle. When you ask people, you’ll hear answers like “Well, I dunno… they’re just way overbuilt”, or “they just build them better.”

The truth is, there are so many little nuances that it’s hard to come up with a neat way to package them. The turn radius, the torque, the departure and approach angles, the stock articulation and “flex”, and, for lack of a better word, the resilience of these vehicles is remarkable. Add in clocking differentials, frame-on-body, and an overbuilt frame and powerplant and you’ve got something that’ll get you where you want to go for years to come.

We try and be unbiased when reviewing things, but insofar as stock vehicles go, the Land Cruiser is widely considered to be one of the best “out of the box” go-anywhere vehicles made. That’s important to me because I’m not looking for a rock-crawler; my goal is to have a truck built around the ISG principle of being ready for emergencies by getting out for fun when times are good.

Is it Legal/Is it hard to drive on the wrong side?

Like almost everything I enjoy, one of the first questions people ask me about the HDJ is “Is it legal?”

The answer is yes: the United States domestic market didn’t get Diesel Toyotas due to something called the “Chicken Tax”, which places restrictions on certain vehicle types. Additionally, diesel emission standards for Diesel imports are notoriously skewed against foreign auto manufacturers. Before importing, they had to pass EPA emissions, and Federal Motor Vehicle Safety Standards (FMVSS), and most manufacturers realized pretty quick it was a way to cut competition out of the “Big 3’s” stranglehold on the domestic truck market. However, after 25 years, the EPA exempts vehicles from the testing, and the JDM (Japanese Domestic Market) Toyotas easily pass the FMVSS, making them legal to import and register.

As to driving on “the wrong side”, it’s only tough if you’re going through a drive up bank or a drive-through, or when passing on narrow roads. Be prepared to hit your wipers when you go to signal for a lane change, though.

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Modifications

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With “Overlanding” becoming increasingly popular in the United States, building a vehicle for touring can mean anything from a Subaru with a tent, or imported Defender 110’s with rooftop tents that cost upwards of $125,000. Our goal is, first and foremost, mechanical reliability, but once that’s been seen to, some modifications can really make your vehicle more capable to handle more difficult situations.

So what upgrades have been done to the ISG HDJ81VX?

Lift and Tires – Probably the single most effective up front modification you can make to your vehicle is a small lift and larger tires. A 2″ coil and shocks lift was done, along with adding some BFGoodrich KO2 all terrain tires. When lifting a vehicle, most can be safely raise 2″ before needing caster correction, double cardan driveshafts/joints, and other suspension related upgrades. 2″ will allow the vehicle some extra room to get over obstacles without killing safety, comfort, and on road stability, as well. The KO2’s are tough, durable, and aggressive. While not the most comfortable on-road, they hold up well to the beating the take on jagged rocks and debris fields.

Turbo, Intercooler, and Aneroid upgrade – probably the most important place to start is the Turbo. The CT26 that came stock in the HDJ81 was a bit tired and ended up dying on the way home from the San Juan’s. Even while billowing clouds of oil smoke, the diesel managed to get us 600 miles back home to the shop. Once there, we opted to upgrade several components at once; the turbo was replaced with a GTurbo Grunter, while we fitted a High Performance Diesel Intercooler, new aneroid pin, and stainless steel oil catch can. This package hasn’t been put to the dynamo yet, but the performance increase is noticeable on road and off, and the mileage went from 14-18 to over 20 miles per gallon.

Winch – One of the most beneficial tools you can have for traversing uncertain terrain is a winch. Whether for recovering another vehicle that’s been stuck, moving debris from the road, or recovering your own vehicle, the winch is one of the foremost upgrades you can do to hedge against getting stuck. The rule of thumb is to double your vehicles weight to determine the rating of winch you should choose. Remember to consider the weight of any additions you’ve made. The discussion regarding synthetic/cable winch line continues; while we went with a WARN with cable, this will eventually be upgraded to synthetic, due in part to the safety aspects, and in part to the weight reduction.

Bullbar – part and parcel to installing a winch is generally an upgraded front bumper capable of supporting it. In this case, we went with an ARB bull bar style that protects the lights, as well as provides a mounting platform for the the WARN M8000/10000/12000 series.

Lighting – Upgrading to a new bumper often provides some opportunities to mount some additional trail lighting. In the case of the diesel, we didn’t want to go crazy with trail lights, but added some Hella 500 Black Magic lamps to the front to give a little better forward visibility in deer country.

Roofrack and Rooftop Tent – The Roofrack not only affords some extra storage space for touring, but allows for the mounting of a rooftop tent, which has been a great way for our family to get out and camp with a minimum of setup and takedown time. The rack was purchased from PFadventure, and is a Prinsu model made to mount to the gutter rail of the 80-series Land Cruiser. The tent goes up or folds down in about 5 minutes, and can be installed or removed in about 10. Often viewed as a vanity item, Rooftop tents can be pretty affordable, as people often buy them, use them a couple times and sell them at a loss – we got our with an annex, anti-condensation mat, mattress, and all the attending gear (rain fly, etc) for $1500, and we can sleep 3-4 in the tent, and another 1-2 in the annex on cots. The tent is a Tepui Kukenam.

Long Range Automotive auxiliary fuel tank – Perhaps the ‘favorite” modification is the 24 gallon LRA auxiliary fuel tank. Putting my onboard fuel capacity up to 49 gallons, this gives the Cruiser a range of almost 1000 miles – a bit more with a couple jerry cans. The aux tank includes a dual filler neck and pump so that you can refuel while on the move from your auxiliary. While very expensive, the chief limitation of the Land Cruiser is it’s poor economy and limited fuel reserve. With an auxiliary tank, you buy yourself plenty of time to find more fuel.

HAM/CB Radios – Trail or convoy communications are a vitally important component of moving in a group and not leaving someone stranded, or constantly having to run between vehicles. While HAM radio is superior in every way, it requires a license and not everyone is willing to devote the time to get their HRO permit. CB on the other hand is often cluttered, but remains open to the public. Having a layered approach allows you to use whichever radio system best fits the situation and company. In the case of the Diesel, we went with a Yaesu 8900R tri-band unit.

Raise Air Intake (RAI)/Snorkel – The snorkel is one of those modifications that people often confuse; they’re not simple for water crossings. The raised air intake allows the vehicle to pull air from higher up, allowing for cleaner air and more diffuse particulates to be introduced into the air system. While raising the air intake can prevent a vehicle from stalling while in a water crossing (given that other mods have also been made), the chief benefit is a cleaner air filter and cooler air.

Raised Differential Breathers – Differentials require breathers that vent air and prevent pressure from building up. When clogged or faced with water intrusion, you can quickly introduce some nastiness into the diffs, reducing their lifespan and requiring a change of gear fluid. Raised differential breathers keep water and debris from getting into the differentials during water crossings. The modification can easily be done using some 1/4″ tubing (on the cruiser, anyway), and a one way air valve, such as you might find on a lawnmower fuel filter. this allows air to travel one way while preventing intrusion of water.

Swing Out Rear Tire Carrier (Summit Cruisers) – The final modification is the addition of a swing out rear tire carrier, made by our friends at Summit Cruisers. This relocates the spare tire to the rear of the vehicle where it’s more accessible, and as importantly, frees up the space in the stock spare tire location which can then be used for an auxiliary fuel tank. Garrett’s design also allows for the mounting of a Hi-Lift jack behind the spare, which helps with organization.

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Why not a Tacoma or a gas/newer Land Cruiser?

This is a great question that I get from time to time. The answer is three parts, and it needs to be prefaced with:

This HDJ80 isn’t the best option for everyone. The gas 80-series and 100/200 series are very functional, if you’re not afraid of electronic systems, and don’t mind a gas engine.

When it comes down to it, here are my distilled reasons:

1. At present, no diesel Toyota is offered in the U.S. market. Diesel’s are legendary for three things: Their relative efficiency, their torque, and their ability to burn unconventional fuels. As part of my overall plan, I want a vehicle that I can make fuel for. I can’t improvise petrol, no matter how hard I try. The long-term reliability of these engines is exceptional, and a friend of mine makes diesel in his garage for the equivalent of about $0.70/gallon. This is a goal for a later article.
   
   
2. Mechanical Simplicity and Durability: It’s simple and even a lay person can learn some basics in terms of repairs and maintenance.The HDJ80 was particularly appealing because it shares some common parts with the FJ80, which is available on the American market, unlike the 70-series (which is considered by many to be the “best” Land Cruiser).
   
   
3. Exceptional off-road capability, with good aftermarket support.

The 80-series was widely considered to be the last “true” Land Cruiser… the epitome of off-road capability and comfort. The problem is they’ve been discovered. A triple locked 80-series can cost up to $15,000 with high miles, where as a model with Center Diff Locks will still cost around $5000. In short, the ship is sailing on the 80-series as the price point to miles ratio is starting surpass the capable, newer 100-series… which can often be found for $10,000 or under with much less abuse.

Considerations

If you do go after the 80-series, it’s going to need some love. On the gas models, expect the common leak spots:  here’s a few things to look for:

• – A *trustworthy* importer.
• – The Big End Bearings; there was an issue with the metallurgy in the Diesel 80 series. Some got quality BEBs, and others didn’t. Left unaddressed, they can cause catastrophic failure.
• – Steering pump and Gearbox leaks: these are common leak spots as the seals tend to go bad after 25 years.
• – Oil in and around the turbo
• – Excessive crankcase pressure (coming out of the valve cover, usually)
• – Wiring and electrical gremlins; for whatever reason Japanese import vehicles tend to come with a ton of aftermarket electronics.
• – Consumable parts such as shocks, brakes, and bulbs, as well as fluids.
• – Turbo
• -Pinion Seals on the driveshafts/diffs
• -Tie-rod ends, knuckle condition, and knuckle nuts! These can all lead to death wobble or worse, catastrophic axle failure.

Conclusion

There are some excellent competitors from a variety of manufacturers and for most people, the best choice would probably *not* be a vehicle nearing 30 years old. Some of it will come down to “Do you want a bed or a cargo bay?” or “what size vehicle do I want?” With that said, the HDJ80 or FJ/FZJ80 is a great vehicle with a ton of potential, and that with a little love, will be on the road and trail for decades to come.

If you want to look into owning a JDM Land Cruiser, we strongly advise people to check with Steve Jackson of Land Cruisers Direct. We worked with 3 importers when we settled on an HDJ, and of them, Steve was the only one who was transparent, helpful, and detail oriented about all the nuance of owning a JDM diesel.

Thanks for reading, and if you enjoyed this, be sure to watch for upcoming articles on the modifications and repair work we’ve done (and continue to do) to the ISG HDJ81VX.

Cheers,
Aaron

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If you’d like to see some of the adventures we’ve taken the HDJ81VX on, check out the following videos, we hope you enjoy them.

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Sources:

[1] https://www.ncbi.nlm.nih.gov/pubmed/24821629

[2]Four Wheeler Network, “Frontend Feud”
http://www.fourwheeler.com/how-to/suspension-brakes/1308-frontend-feud-ifs-vs-solid-axle/

[3] Toyota Motorsports, “Land Cruiser Gallery: Motor Sports”, 1995-2018. Recovered from web: http://www.toyota-global.com/showroom/vehicle_heritage/landcruiser/gallery/dakar_rally_95-01.html, 7/30/2018