There is a common joke in academic circles that pokes fun at professors who make broad statements about “real life,” but in fact have little relevant real world experience on the topic themselves.  Though I am not a college professor, and I have never done a diesel engine swap, I am unfortunately one of these people, as I sit here in my “ivory tower” explaining what I call Land Cruiser “Dieselology.”  Dieselology to me is sort of like a new hobby.  Somewhat of an extension of the same-old “keep learning as much as you possibly can about Land Cruisers,” but I think in this sense we’re taking it to a new level because there isn’t a whole lot of information about diesel swaps for Land Cruisers.  Thus, a whole lot of the information here could be construed as “hearsay” which unfortunately one could argue it is.  So take it with a grain of salt!

For me it all started when I acquired and eventually sold my HJ60, a factory diesel 60 series Land Cruiser.  It was 90% my dream truck, which I sprung over, eventually turbo charged, and installed air conditioning into.  However, in my quest to posses the perfect truck (as well as have the satisfaction that I’d put it together myself), I decided to sell my 60 in order to fund the installation of an engine into a rust free Cruiser that still had the efficiency of the 2H diesel, but with more power.  I’d found the altitude where I was living at the time (between Alta and Park City, Utah, 6-8,000 ft in elevation) made a big difference in the performance of the truck’s engine (more on this later).  In fact, there was so much loss in power that I actually assumed there was something wrong with the engine.  It took me two months and several hundred dollars in a diesel injector rebuild before I figured out that it was simply the altitude causing the problem, which is a common affliction with the naturally aspirated diesel.  Months later, after the vehicle was sold, the new owner asked me to install a turbo charger on the engine for him, and I realized I had made a mistake: instead of selling the truck, I should have turbo charged it, which eventually solved the lack of power problem.

That aside, one of the biggest factors that led me to sell my truck was the possibility of doing a diesel swap, which to me not only served as a challenge but seemed relatively cool in my eyes.  I looked forward to doing the research and eventually spending the now several months of daily chatting about diesel conversions (which is largely what led me to write this article). And while I know a diesel swap isn’t necessarily for everyone, I know it’s for me.  So I began accumulating more and more information about different swaps.  As it started getting larger and larger, I decided I would share the wealth of information and put it all on a web site, http://www.cisautoweb.com/dtlc, which now exceeds over 100 pages.

My focus here will be basic overviews of the following diesel engines: GM V8s: 6.2, 6.5T, & 5.7L; Isuzu 4BD1-T & 2T models; Cummins 6AT, 6BT, 4BT; the Mercedes Benz Turbo I-5; Mitsubishi 6DR5; Nissan SD-33; and Toyota 3B, 2H, 1HZ, and 1HD-T engines.  The choice of the engines discussed here represents both what I think are the best candidates as well as the most commonly discussed swaps, whether they are good candidates or not.  Ultimately each one of these engines will fit and work into a Land Cruiser but each offers its own advantages and drawbacks.  With each engine we are going to cover adapters, vibration, noise, power (in both horsepower and torque), as well as general design and suitability for each application.  (Unfortunately most of the information is geared towards North Americans but there is information relevant to others world wide, including our friends Down Under.)

Before I get into specifics I thought it would make sense to go over the diesel engine’s basic function to give you an idea of how they work. Diesel engines work similarly in conceptual design to gasoline engines. They are internal combustion, have timing, an ignition stage, etc., but they do in fact function quite a bit differently than gas engines.  This overview will explain the differences between a diesel and a gasoline engine.  

Gas engines mix a combination of gasoline and air, compress the two, and use a spark plug to ignite the mixture, which is how power is delivered.  Diesel engines take in air only, compress it to a much greater level than a gasoline stroke, and at just before top center of each stroke inject a tiny amount of fuel via a special diesel fuel injector into the engine.  Because of the heat and pressure of the compressed air, the fuel combusts completely on its own without the assistance of a device like a spark plug.  Though there are some significant disadvantages to a diesel engine over a gasoline engine, the biggest advantages are lower torque curves (otherwise called low end power, which is advantageous for a true 4x4) and increased fuel efficiency.  Because of the pressure and heat generated in a diesel’s compression strokes, diesel can actually burn many somewhat “raw” fuels like peanut oil or kerosene.  Diesels also emit significantly less greenhouse gas emissions, although they do create more smog.

Today’s diesels, like most gas engines, have electronic control units (ECU’s) to control power and emissions output through adjustments of engine timing and fuel mixture to yield the most power and least amount of unburned fuel (poorly burned fuel is what typically causes poor emissions).   This is why today’s gas and diesel engines are much better for the environment as well as more powerful than previous mechanically based designs.  However, as I know little about diesel electronic control systems, for the most part I plan to avoid the topic all together.  That said, if you know anything about the basics of fuel injection systems, then generally you’ll be “ok” with diesel systems as they do not substantially differ.  However, I would recommend if you are considering a diesel swap, that you avoid the electronically controlled engines because mechanical controlled engines (unlike modern gas engines) were produced through the mid to late 90’s in some applications.  So you can still get a very nice, modern diesel engine installed into your Cruiser, but avoid the hassle of an electronic control system.  My theory on why diesels were not electronically controlled until the mid to late 90’s is that they can be manipulated to be very powerful and efficient in their mechanical form.  Because I believe emissions regulations drive efficiency trends, and because diesels are inherently more efficient, addition of the electronic control system have not been made until recently.

The heart of the diesel engine is the injection pump.  This one device serves the purpose of all ignition parts (distributor, cap, rotor, wires, spark plugs), fuel parts (fuel pump, and carburetor) on a gas engine.  The pump pulls in fuel from the tank and, using a gear from the engine, determines (via the gas pedal) how much fuel each cylinder should receive and when.  There are two common types of mechanical pumps: rotary (which look a lot like an automotive distributor), and inline pumps.  Inline pumps are commonly considered more reliable but both are still widely used and produced.  Both models typically use engine fuel for lubrication, and are very reliable. Another advantage to these pumps is that they are almost 100% mechanical (in non-ECU controlled applications) with few electronic parts, and as such allow the engine to be submerged, with major water proofing considerations primarily done only at the air intake.

Important things to consider when doing a diesel swap:

When I start discussing each engine, I’m going to address them in terms of weight, noise, vibration, power, and RPM range.  If you have a gas engine, you should notice that generally none of these should be an issue for you.  Furthermore, there are other non-swap related factors.  How do diesels drive? You need to use gloves when refueling.  And gearing…  So, a diesel swap isn’t for everyone, and they must be well thought out.  Mark Whatley, Technical Editor for Toyota Trails, once stated on the LCML this relevant thought:
"I don't have anything against a well thought out engine swap. I don't think that I can argue real hard for or against one. So long as you understand the strengths and weaknesses of whatever powerplant you are contemplating installing, and you are honest with yourself about how you will be using the rig and what it will end up costing you." 

I think to be safe, you should probably own a diesel before you attempt a swap (or have a shop install one for you).  You will want to experience the smell, rattle, and noise of diesel.  They drive differently, and if you are expecting a V8 engine,  - don’t. What you actually want in this case is a V8, not a diesel.  But if you decide you like diesel, there’s no turning back.  For me it has to do with uniqueness, ability to use different fuels, increased efficiency, and the idea that my Cruiser may not be so bad for the environment.  I like the sound, I even like the smell.  I also think diesels are more suited to 4 wheel drive and 4 wheel drive vehicles in off-road situations because of their ability to produce low end torque. 

However, diesels also have their disadvantages, such as gearing. Due to the relatively low RPM band of the diesel, you have to pay close attention to gearing for your specific application.  If it’s a trailer queen, try to go low low low of course (assuming you want to crawl).  In this case the perfect option is the very robust SM465 4 speed transmission with a granny low gear, found in Chevy 4x4s from 1968 to 1988.  On the other hand, if you are building a daily driver that will have smaller than 33” tires, you will definitely need a 5th gear (5 speed trannies for Cruiser applications are expensive), and will need to have axle gearing that factors in your tire size.  With 4.11’s and 35’s, you can get away with a 4 speed transmission depending on the engine you use.  For Toyota diesel installations (covered towards end of article), it is a substantially different ball game.

Some diesels have torque and HP curves that aren’t too far removed from each other (like most Toyotas, and some of the GMs).  These are ideal for highway Cruisers as well as off-roaders.  But many diesels are designed for industrial truck applications and have astounding torque figures (torque is awesome in my opinion, quoting Enzo Ferrari, “horsepower sells cars, torque wins races”) but with relatively little HP.  So you can have a 130 HP truck (which is actually similar to a 2F) but with 300+ ft/lbs of torque.  In that I have little real world experience with high torque - low HP engines, I can only speculate they will still motor along nicely and feel quite powerful.   But they will still not be a gas V8.  If you live in the lowlands with only small hills, I think as long as your diesel engine has more than 250 ft/lbs of torque, it will be great on and off road with proper gearing.  But if live in more mountainous terrain I think you will need a higher horsepower engine.

Finally, as with any engine swap, there are lots of little things that are going to be needed -- the proper radiator, air & fuel filters, fuel separators, etc.  I would budget at least $4,000 in parts to do the swap correctly.

Different Applications of Diesel Engines:

Because diesels are found in a wide range of applications, there are a great number of engines available, but only a few that are best suited to the Land Cruiser.  There are two ways you can look at this equation, and a lot of it depends on what you plan to do with the vehicle.  With each description of an engine below, you have to use your own judgment to choose whether or not this engine is good for you.  If you are building a rock crawler with 42” tires that will see little 50+ mph driving, then generally any of these engines will do, with the biggest concern being how much power you want and how much noise you can handle.  If you want an all around daily driver then you are going have to pay close attention to all aspects discussed and also keep a close eye on your budget.  Unfortunately, generally stated: the more suited the engine to the Land Cruiser as a daily driver, the more expensive the engine.  And the cost of the engine is just the beginning of the cost of the conversion.

General Motors V8 Diesels
 
Unfortunately, in the GM V8 category there is a lot of hearsay to sort out.  GM’s legendary lemon of an engine is the 5.7L GM diesel that is derived from the highly respected GM 350 gasoline engine.  However, in the diesel application this block simply didn’t work and many of these engines won’t make it past 30,000 miles when most diesels, when properly maintained, will go 400,000 miles.  Personally I think this engine struck a big blow against the world of diesels in American passenger cars and pickups, and we’re only now seeing this reversed.  Following the disastrous 5.7L, GM introduced the 6.2L naturally aspirated diesel and the 6.5L naturally aspirated and turbo diesels.  Both of these have mixed reviews as well, but people commonly replace them when they have a simple fuel pump problem and therefore a good running engine can often be had for cheap.  I don’t have a heck of a lot of experience with these engines, but I have seen both 6.2 naturally aspirated and 6.5L turbo models in FJ40’s.  They both have the same bolt pattern as the 350, which is a big bonus.  They also use the same approximate motor mounts and weigh about the same as a 2F, which is significantly heavier than a gas 350.  Both the 6.2 and 6.5 have relatively low horsepower to torque ratio, meaning HP is greater while torque is lower, making the engine more ideal for daily driving.  HP is typically from 150 to 200, with torque in the 250-300 range, making them great candidates for highway driving.  They are also not excessively noisy or rattly.  The 6.2 is a simple engine, mechanically controlled, and though naturally aspirated, even at 10,000 feet will still outpower a 2F engine.  The 6.5L-Turbo is almost too much engine for a Cruiser using the stock drivetrain, but if you primarily do highway driving with little hardcore wheeling I think you’ll be fine.  The 6.5L-Turbo is also electronically controlled while the 6.5L naturally aspirated is not.  The 6.5L would also be an excellent choice for a Cruiser using stock drivetrain.  There are rumors of the new Duramax diesels being installed into Cruisers in Australia (I’m told Marks might be making an adapter) but I think this engine has way too much power for any Cruiser using stock axles, and probably so even with upgraded axles.  This engine is built by Isuzu (who is majority owned by GM), and though it has a uniquely American V8 diesel design (something about a V8 just sells better I guess), it retains Isuzu’s reputation as superior diesel engine builders.

Cummins Engines

  There are three Cummins engines that I think would be acceptable in a Land Cruiser application: the 6AT, 4BT, and 6BT, and their modern electronic versions.

 The Cummins 6AT is an awesome power plant and goes well in a Cruiser.  It is a little heavier and about 1” longer and deeper than a 2F, with the required transmission adapter about 1.5-2” longer.  This makes it a little more difficult to install into a Cruiser, but it can easily fit into all FJ40, 55, and 60 models.  I’ve now heard of two FJ55s that have them, and the one I’ve driven, which belongs Royal Rose (who has contributed to Trails frequently) is awesome. There is another one in California, the owner of which speculates that in order to get a 6AT to fit into a 40, you are going to need some body lift and a significant suspension lift.  In a 60 it would probably fit fine with suspension lift only, however you will most likely need to tweak the steering system.  (For more information on steering issues and how to counteract them, see my web site http://www.cisautoweb.com). Generally this engine rattles right along but it is not particularly loud and does not vibrate heavily.  It is indirect injected, and the design is originally by Onan.  Cummins bought Onan sometime in the mid 80’s and made significant improvements, so if you buy one, make sure you get the Cummins version.  One good thing I think is that all Cummins engines use metric hardware and parts so you won’t need a whole set of new wrenches.  The approximate power output of the 6AT is right around that of a 2F engine, except that low end torque is well delivered even from idle low and simply letting out the clutch can be a bone jarring experience if not done correctly.  It also has a higher RPM curve, closer to that of a 2F engine so you can run it at 3000 RPM’s if need be.  But at higher RPMS you will start to experience significant vibration so you will probably still need a 5th gear with the 6AT.   The 6AT does not have an actual "Chevy" pattern at the back of the block, but rather is designed to accept an adapter to mate it to different trannies. The Chevy pattern is one of the adapters it can be 
purchased with so it can be mated to a SM465 4 speed or a NV4500 5 speed.  These engines originally came in smaller late 80’s UPS trucks and generally have a good reputation.  However, when going up big hills with this engine, like a 2F, it can start to struggle.  Approximate fuel mileage in a wagon when properly tuned is around 20-25 mpg.

 The Cummins 4BT puts out basically the same HP numbers as the 6AT, but with two less cylinders and 25% more torque.  This is the engine I became obsessed with before I found the Isuzu 4BD discussed further in the article.  There is a gentleman who runs one his Scout (tweaked to over 600 ft/lbs of torque), several people who run them in their military M37s, and a guy who runs one in his 55, all of whom I’ve spoken to about the engine.  This engine can be easily modified to be reliably tuned to run over 300 hp with over 750 ft/lbs of torque, but at the cost of massive noise and vibration.  Some people speculate it is not a road worthy engine at all but I say to each his own.  The Scout enthusiasts who first pioneered the swap are very fond of it while I’ve heard mixed reviews mostly from Cruiser owners who drive highly modified Cruisers in off-road only situations.  There has not been a whole lot of information about its use as a daily driver in a Cruiser.   For an off-road application I think it would be awesome even in stock form.  On the highway I’m not as confident, but I doubt it is an unbearably poor choice either.  In order to get it to fit into any Cruiser you need a somewhat long transmission with an elongated bell housing (otherwise you have to cut into firewall to fit the exhaust).  A NV4500 works perfectly but is an expensive transmission.  You will also need at least 4” of lift because the bottom of the oil pan and engine dip much lower than a Toyota engine.  Because of this I would recommend a spring over axle conversion.  Basically they are identical to the highly reputable 6BT found in Dodge trucks, but with two front cylinders missing.  They can use many of the aftermarket parts for the 6BT, hence the tweakability.  They are commonly found in large aluminum bread trucks from the late 80s and can occasionally be found used inexpensively, but are very expensive to have rebuilt.  They come in a wide variety of forms, ranging from earlier naturally aspirated versions (which I would definitely avoid), to the common turbocharged, 107 hp, ~250 ft/lbs version in the bread trucks.  There are also intercooler versions and the 4BTA aftercooler version, and  a later high-performance model using a high performance injection pump.  The commonly found bread truck version pump uses the Bosch VE rotary that every 100,000 miles or so will need a rebuild, primarily due to the loss of diesel fuel lubrication properties caused by recent environmental regulations that remove sulfur in fuel (which is bad for the environment).   The Bosch P1700 performance inline fuel pump is the one that allows the engine to be highly tweaked and is generally much more tolerant of poor lubrication properties.  But something about the excessive power also delivers incredibly excessive noise -- near deafening in fact.  Most B series Cummins engines (4BT, 6BT & variations) are governed at 2500 RPM’s so you’ll also need to pay very close attention to gearing.  In the late 90’s, Cummins redesigned the block to reduce noise and vibration and introduced the electronic engine and fuel control systems.  This fully electronic version was rebadged the ISB, as previous C series Cummins (think big rigs) became ISCs and so on.  The power output of the ISB’s is much greater, possibly too much for a Cruiser, with the lowest output of any ISB at over 400 ft/lbs, even the 4 cyl. versions.  I am not sure what the bolt pattern of the ISB’s are but both the 4BT and 6BT share the same bolt pattern as the 350 Chevy, sae #3.

Correction: Sae#3 and Chevy Patterns are NOT the same.  B series Cummins engines happen to be able to bolt to both variations.
(See Article Corrections Page)

The Cummins 6BT is generally the same engine as the 4BT but with two additional cylinders.  As explained by Rob Mullen, editor of the Land Cruiser FAQ, general Cummins “B” series (4BT, 6BT) folklore states (as well as any other pump-line-nozzle injection system) that the higher the power output, the higher the noise level.   As the engine receives more fuel input during the premixed combustion phase, a larger diesel "knock" is heard as that fuel rapidly combusts.  Therefore, generally if it’s louder, it’s more powerful.  This is why late model 24 valve Cummins 6BTs with 200 hp and 550 ft/lbs of torque are much louder than earlier 12 valve versions with 160 hp and 400 ft/lbs of torque using the same block and basic head design.  Whereas I once thought this engine featured too much size, weight, and power for a Land Cruiser, I’ve now changed my mind after seeing an FJ40 with a 6BT installed.  Generally for the 40 series I still think it is too much engine, but this vehicle is a rock crawler that uses Dana 60 axles and sits on 42” Swampers.  If you use the early 90’s, non-intercooler, 160 hp, 400 ft/lb version for primarily highway driving with some mild offroading, I think this engine would be fine in a Cruiser.  But later stock axles and a split Land Cruiser transfer case are a must.  This engine is huge, but without the intercooler surprisingly fits in an FJ60 or FJ40.  However, like the 4BT, you need to use a transmission with a longer bellhousing than a typical 4 speed (Toyota 4 speed, SM420, 465), otherwise you will have the same exhaust issues as it comes out very close to the firewall on the passenger side.  However, unlike the 4BT, it is generally a smoother revving, quieter engine that vibrates less, but all of these are still an issue.  And some believe the inline 6 is the perfect design for the diesel as they are more “naturally balanced.”  For this (and any diesel swap) you have to pay very close attention to how the engine is mounted or you will experience excessive vibration.  Though most B series Cummins engines have significant vibration dampeners, because there are marine applications, using a marine dampener can even more so reduce vibration. Very tough, diesel grade motor mounts are a must also.  Also like the 4BT, to get the 6BT into a Cruiser you also need at least a 4” lift.  With the 6BT, it is so heavy (905 lbs without flywheel or any accessories) that you must also have heavy duty front springs.  I would also make significant upgrades elsewhere in the drive train, probably retaining very few original Toyota parts.  Without them, I think a 6BT in a Cruiser that wheels would probably be a gamble.

Isuzu 4BD-1T & 2T

The Isuzu diesels are considered one of the best applications for a Cruiser but are also the engines with the least track record.  In my months of research I’ve heard of only three people who have them in their trucks, two of whom I’ve talked to, and to this day in each situation there are some details that still need to be resolved.  But this engine can be installed into a Cruiser.  Serious fans of this engine include former stories editor Henry Cubillan and Land Cruiser FAQ writer Rob Mullen, who calls it “the best diesel engine swap I’ve seen in a Cruiser.”

The 4BD’s are 4 cylinder diesels that were the diesel option instead of the Chevy V8 found in Isuzu NPR box trucks.  In the originally standard transmission configuration, the 4BD-1T produces 125 hp, and the automatic transmission version produced 135 hp.  Torque ranges from about 275 ft/lbs to about 350.  The added power is put into auto tranny versions to compensate for power lost in the transmission and the tranny’s gearing.  They are known for exceptional reliability, frequently going over 400,000 miles if properly maintained.  But you can also find cheap cores out there for $1000 or so, some that even still run, as well as good running used models as low as $2500.  They are direct injected and primarily mechanical in fuel operations in all 4BD-1T models.  This is why the 4BD-1T is an easier install.  Average alternator amperage (in this, as well as most industrial Cummins’) is above 100 amps.  I’m told there are some mechanical 4BD-2T models, but most are electronic. If you find either in a good running mechanical version, either would probably be a good candidate for transplant.

The Isuzu bolt pattern is actually a sae #3 bellhousing (same as the Cummins, Chevy 350, etc) but is rotated about 15-20 degrees so it either requires a “blank” that is redrilled or redrilling of your sae bellhousing (both of which, I’m told, are pheasable.  There is a rumored bellhousing adapter with the number WF 150015 stamped on the side that allows a standard GM bellhousing to be mated to the engine via the 1/4” thick adapter.  However, nowhere I’ve called has any information on this adapter even with use of the part number.  But there are also a number of other adapter options ranging from “blanks” that you drill yourself, to blank adapters that you can also drill yourself.  Of course, careful attention to mounting and strength are very important.  You don’t want your $8,000 diesel project to rattle apart.  Finally, in Australia this engine comes stock in Land Rover 130’s though I am not sure which transmission or adapter options are available. However, if the Rover and T-Case transmission setup is beefy this might be a viable option as most Rovers have similar offset and axle widths to FJ40 Land Cruisers, and 60 series axles are only 70 mm wider.

Some other relevant information, according to Henry Cubillan, former stories editor at Toyota Trails, and an American transplant Cruiserhead, the 4BD conversion is very popular in his native Venezuela.  Though Venezuela has their share of some very cool Cruisers, they never had factory diesel options, mostly because of cheap gasoline until recent years.  Henry is aware of 4BDs being mated to the factory 5 speed H55F’s, several of which he’s driven.  However, he’s not sure if they are redrilling the H55F bellhousing (same as F/2F/3F in Venezuela), which is what he thinks they are probably doing, or if they are using a “blank.”  However, he says he has several friends who have done this to their trucks and they “make it sound like the easiest conversion in the world.”

Because the Isuzu’s output is on the driver’s side, there is some interference with the stock steering under the hood.  Therefore you must either convert to Saginaw or find another option.  To discuss either the steering problem or the bellhousing problem, I have put together a page on my site (http://www.cisautoweb.com/dtlc) to display steering options which are unfortunately too complicated to describe here.  Finally, this engine is direct injected and though only 4 cylinders, like the Cummins 4BT, it’s still a fairly big engine at near 4.0 liters, the same volume as a 2H.  It is not abnormally loud but is not unbelievably quiet either, with a nice little rattle to it.  It is much smoother with a higher RPM band than a Cummins and I think would most likely be a great candidate in all situations for a Cruiser, FJ40 or wagon, though I’m told it produces significant noise in a 40.  However, you will need to use the strongest t-case from a 60 series Land Cruiser and I’ve heard it can chew apart ring and pinions on stock axles if wheeled hard.  

Mercedes Benz I-5 Diesels

There are several models of Mercedes Benz diesels that have been proven successful and reliable for swaps into FJ40’s.  However, the most powerful of which, a mid 80’s inline 5 cylinder from a 300TD or TD wagon is probably the best bet for a Cruiser swap.  Luke Porter of www.4x4labs.com and Alan Lungi of www.rockbuggysupply.com (who also runs a Cummins 4BT in his FJ55) have been experimenting with this engine.  It is unusually smooth, quiet, and light, and can be souped up to over 200 horsepower (but at the cost of longevity).  If left in stock form (at around 115 horsepower) this engine will run forever.  However, torque is limited and the redline is very high at about 4500 RPM’s.  All of this is understandable considering the engine comes from a car.  It can easily travel at 3000 to 3500 RPM’s, however, making it a great candidate for an FJ40.  Alan and Luke are both working on adapters for the engine in order to mate it to the stock 4 speed, as well as a number of GM transmissions.  There is also a company in South Africa that is rumored to produce these adapters and hopefully they will be available Stateside shortly.

Mitsubishi 6DR5 and Nissan SD-33

The Nissan SD-33 came in Scouts and is another possible candidate.  It came in both naturally aspirated and turbocharged versions and is in plentiful supply mainly due to higher performance swaps done by Scout owners.  The reason I put these two engines together is because I consider them to be similar, though in reality the Mitsubishi 6DR5’s hp and torque curves are almost identical to the 2H, while the SD-33 (even turbocharged) produces about 150 HP but only about 160 ft/lbs of torque.  In fact they are also very similar to a Toyota 2H in size and weight, so if you are considering a particularly expensive 2H swap, I would actually recommend one of these because they are cheaper, more plentiful, 12 volt, and with almost identical characteristics.  The Mitsubishi is nearly identical to the 2H in every respect -- it even has an almost identical Nippon Denso injection pump, and is approximately the same size, weight, and sports a similar power band.  The 6DR5 was a factory option from the late 70’s and early 80’s Dodge trucks and came originally naturally aspirated.  However, many were turbocharged due to the sluggishness of the engine in such a large truck.  This turbo charger also fits a 2H engine, and in fact I got mine from Royal Rose’s Mitsubishi 6DR5 (covered in the October 2002 issue of Toyota Trails).  They also have the same exhaust flange pattern.  However, the Scout uses a commonly American bolt pattern while the Mitsubishi actually uses the Land Cruiser bolt pattern!  For more information on the characteristics of these engines, see the 2H section in Toyota engines below.

Toyota Diesels

Ah yes, the mythical Toyota diesel.  In the great white north they were blessed with a limited number of 40, 60 and 70 series Toyota diesels that we never had in the States.  Elsewhere in the world, as these engines became somewhat obsolete, Toyota produced the 1HZ and 1HD Laser series diesel engines (which are awesome).  The B series diesels all share the same block and are 4 cylinder, while the H series diesel are all 6 cylinder, and share similar blocks.  I was lucky enough to own a naturally aspirated 2H engine in my HJ60.  With stock tires, it’s 24 volt system (24 volt is awesome, I think all vehicles should be 24 volt), it performed beautifully on the flats and hills, very seldom losing momentum.  I even towed a 40 series from Vermont to Chicago with the HJ60, and generally it was an impressive engine in typical 80’s Japanese fashion, just barely suited to the vehicle power-wise.  

However, the reality is that the 2H engine, the more powerful of the factory diesels from Canada, has only a modest 107 hp and 177 ft/lbs of torque, significantly less than even a good running 2F.  Because both the 2H and the 3B are indirect injected (considered typically an earlier design, but well proven and still manufactured), the fuel economy of the 2H and 3B is still good, but not amazing compared to some modern direct injected equivalents that can get substantially better mileage.  The 2H typically gets in the area of 20-25 mpg, and a 3B typically gets around 25-30 mpg.  Adding a turbocharger not only increases power but can increase your fuel efficiency if tuned for such, and in both situations brings the power of the vehicle up to about that of a 2F found in late FJ40’s, FJ55’s and FJ60’s, with little compromise in reliability and engine longevity.  However, you can also adjust the fuel flow for more or less power.  Some people (including some in Australia where Toyota diesel engines are much more common) have their 2H and 3B engines screaming out massive amounts of power with turbochargers, but at the cost of longevity.  Diesels, unlike gas engines, are typically well suited for turbochargers right out of the factory, whether they originally had them or not.  Some diesels have their longevity compromised by adding significant boost pressures (as is rumored for most naturally aspirated Toyota diesels) but some will run just as long if not longer.  

Generally, speaking of all Toyota diesels that were placed in Land Cruisers in markets throughout the world, they are all very smooth, quiet, with horsepower to torque figures very comparable to 6 cylinder gasoline counterparts – a relatively low ratio compared to the commercial diesels discussed previously.  For example, a 1HZ naturally aspirated diesel has around 135 hp and 230 ft/lbs of torque, just like a 2F.  I would say it’s safe to say that in most Toyota diesel applications since 1983 or so, Toyota has made an attempt to take all common negative aspects of industrial and commercial diesels (roughness, noise, smell, vibration) out of their diesels, providing a relatively pleasant driving experience (in comparison to a Cummins, for example) and hardly noticeable compared to even a FJ60.  They feature little difficulty starting in winter conditions, even without the use of a block heater, and if there is no turbo, you do not need to wait to allow it to cool down.  If I were someone considering a swap and had the money to spend on it, I would take the most expensive option and would likely choose a Toyota diesel in a Cruiser, for wheeling, driving, or whatever.  I had the pleasure of driving an FJ80 that had been converted to diesel using a 1HD-T engine, with an astonishing 420,000 miles on it.   It was simply an awesome truck.  It moved quickly on the highway, got great fuel mileage, and was generally a very nice, powerful, and great condition truck, even with all of the miles.  And of course it makes me jealous of the Australians because they have these in factory specifications, with lockers, a part time 4wd system, and 5 speed transmissions!

The following paragraph has numerous errors which are explained on a Article Correction Page.

The Canadian 3B and 2H engines are the naturally aspirated engines that were available in Canada.  The 3B is a 4 cylinder power plant which outputs approximately 97HP and 160 ft/lbs of torque.  These engines are extremely well built and are known to last well over 400,000 miles with no problems.  There is an earlier version and a later version, the 3B-II (found in BJ60’s and BJ70’s), and the early 3B (“3B-I”) which was in Canadian BJ-42s.  The 3B-II is considered better suited for turbo charging (on a 3B-I you have to make fairly involved oil passage changes to turbo charge it).  When considering a swap, the features of the 3B-II are the best and I would avoid use of a 3B-I.  Though they share the same bolt pattern as a 2F or 2H, 3B versions of the same Land Cruiser transmissions used in F and H series Cruiser require a longer bellhousing with a different flywheel and a longer, coarser splined input shaft.  BJ-42s came with the famous H41 4 speed tranny, which is basically identical to a US spec H42 transmission, but with a lower first gear at approximately 5 to 1 (versus the H42’s, 3.5 to 1).  This difference is actually quite noticeable offroad, a greater difference than dropping your axle gears from 3.73 to 4.88, for example.  

In 1983 Toyota began equipping Canadian 3B powered Cruisers with the H55F 5 speed transmission, also coupled to the split transfer case.  This transmission also has a low first gear, but with an added 5th gear.  It also has a higher transfer case low range ratio of about 2:1, like an HJ60.  This model also represents the introduction of the 3B-II engine.  The 3B-II H55F was available in both the BJ60 wagon and the BJ70 (1985-ish replacement for the famous 40 series).  In 1986 Toyota decided to replace the 3B with a slightly more powerful 6 cyl, the 2H engine, the second version of the original “H” 6 cyl. diesel found throughout the world.  This engine produced a modest 107 hp and 177 ft/lbs of torque, and was only available for two years before Toyota introduced the FJ62 for two years and then dropped Land Cruiser entirely from the Canadian market.  The 2H can also be turbo charged fairly easily, but lacks a staple factory turbo charged diesel addition: piston skirt oil sprays that cool the bottom of each piston to counteract the heat created by turbo charging.  The naturally aspirated 3B does, however, feature piston skirt cooling.  However, 2H engines can run just as well with turbos without the cooling feature.  The 2H shares identical bolt pattern, size, and approximate weight of a 2F, however, in Canada they were 24 volt and need extensive modification to be run in a 12 volt truck.  (As a bit of an aside, 24 volt is awesome and very powerful.  On a steep grade at Moab I actually ran out of fuel once and used the 24 volt starter to get me up and over about 40 feet of very tough obstacles, without phasing the dual battery setup).   H55F transmissions from a 2H will bolt directly into a 10/85 and later FJ60.  However, you have to make some adjustments because the HJ60 has some of the creature comforts of an FJ62 (push button/vacuum actuated 4H) versus the FJ60’s manual shifter.  Both the 3B and 2H were available in factory turbo charged versions, the 13B-T, the 14B-T, and the 12H-T.  These are also considered very reliable engines and put out near the power of a 2F.

The 1HZ and 1HD-T engines (and variations).  

The 1HZ engine is now considered the staple of Australia and much of the third world.  Here in North America we only saw them in very rare Canadian mine trucks for a short period of time.  Though naturally aspirated, with 12 valves and indirect injected, these engines are tried and trued, and are still manufactured.  They produce almost identical power to the 2F, and in fact are very similar in size and weight. However, they seem to be less phased by altitude than the 2H.  Like the 1HD-T, the 1HZ exhaust exits at the rear passenger side (unlike a 2H), making it ideal for US swaps.  1HZ’s and 1HD-T’s are both found in Australia and Japan most commonly, and if you opt to have one imported you can obtain parts through Specter Off-Road (sor.com), and either SOR or the aforementioned regions would be the most likely source from which to purchase one.  In Australia, all vehicles are 12 volt; in Japan they have 12 and 24 volt, so make sure you get the 12 volt if putting one into a 12 volt truck.  Both are also mechanical -- the 1HZ remains completely mechanical while the 1HD-T has been replaced with the even more powerful, electronic, 24 valve 1HD-FTE.  Both have timing belts that must be replaced every 60,000 miles or so, and both can be swapped even into modern Cruisers.  The 1HD-T puts out about the same amount of power as a 3F engine, but tweaking can easily be done to the turbo’s waste gate to allow the engine to be much more powerful.  

However, there is a known problem with the 1HD-T’s main bearing retainer that affects engines.  This can allow for some possible problems when importing, particularly in a non-Stateside junker when claiming the engine is “rebuilt.”  If not addressed it can cause the engine to blow up (see my web site for more information).  Transmission wise, early 1HZ’s used the standard H55F transmission while at some point they were switched to the H151F 5 speed transmission which shares the same bolt patterns a US spec. 1FZ gasoline engine, found in FZJ-80’s from ‘93-‘97.  All 1HD engines and their variants must use the H151F transmission or an automatic with identical bolt pattern.  If you want to avoid the hassle of importation and have money to burn, you can also simply buy one of these engines from Specter. There are also a slew of other non-USA diesels, the P series, the 2L-T found in 70 series throughout Europe as well as North American mini trucks, the K series, and others.  However, these will not be addressed here -- see Rob Mullen’s FAQ for more information at http://www.birfield.com, when the new version is published.  In the meantime, see the last published version at http://www.off-road.com.    

Other General Swap Information

With a diesel swap there are several other things that must be addressed.  If swapping one into a fuel injected truck, you must remove the high pressure fuel pump as most mechanical diesels rely completely on the injection pump to bring in fuel, or have a small very low psi “pusher” pump.  You must also use good fuel filters (in some cases the housing of which is built into the engine) with a very good fuel separator -- I recommend Racor brand filters and separators (see my website for more information).  Also, because modern brake systems are vacuum assisted, and because diesels do not produce needed vacuum to assist the brakes, you must rely on an auxiliary device.  You can use electronic systems but these are bulky.  Also recommended are belt driven vacuum pumps, which can be found from other brands of diesels (like a Mercedes Benz).  Toyota’s solution in 3B and 2H applications is to use an alternator that also serves as the vacuum pump, which also has an oil feed and return line for the pump’s lubrication.  Swapping in one of these alternators is a viable option but on average they only produce about 30 amps.  You also need a small vacuum storage tank but otherwise your standard master cylinder and brake components will be fine.  (Again, there is more about this on my web site.)

Because diesels do create a significant amount of noise, some much more so than others, you do have to consider this when installing it into your truck.  If you are building a daily driver, you should pay very close attention to noise.  On my web site there are several links to good suppliers for noise suppression devices.  However, if planning to drive your truck in normal routine, and the engine is noisy from the start, I wouldn’t even consider it in a FJ40 that will have a hard top.  And if you do, then I would make sure I do a good amount of sound proofing in the firewall and floor of the vehicle.  For an FJ55, it would be the same situation except that I think a 55 would be significantly better for noise.  60 series and 80’s have carpeting and a thicker headliner that I think would be better suited to sound deadening, but you may also have to address some soundproofing.  I have heard a little sound proofing in a 60 goes a long way.  

My final point is that a diesel swap can be done and could be very exciting.  However, you have to realize what it will cost, how long it will take you, and what you will get out of it.  Consider that these factors will take a decent amount of work and quite a lot of money.  If you are having a shop do the work, I wouldn’t be a bit surprised to see costs as much as $15,000 –a lot, considering it’s only a re-power into your same old truck.  But it can be done creatively and make for a lot of fun in the process.  Good luck!

If you have questions on any of this material, feel free to email me at andre@collegeinternetsolutions.com, I’d be glad to answer any of your questions.