If you've watched our 6.0L
or 6.4L Powerstroke videos, you probably get the impression that we
absolutely hate Navistar International, who's the engine builder behind those
aforementioned engines. And yes, those two engines are absolutely terrible but
you have to remember that Navistar International does a lot more than just building light duty
truck engines, and really, their best engine ever arguably is the DT466 and it's an absolutely
legendary diesel engine. So, in this video we're gonna take a deep dive into the International
DT466 and I'm going to show you what makes it such a legendary engine; the goods, the bads,
and everything else you need to know about it. To get this whole thing started, we have to
rewind the clock all the way back to 1967, which is when International began development
of their 300 and 400 engine series. Back then, International had multiple divisions and one of
them being the construction equipment division, and that division had its own engine division,
which was a little awkward because International had its own engine division based out of
indianapolis. With that in mind, the VP of the construction equipment division, Bill
Wallace, was the one who actually wanted a new line of in-house engines that were fully designed
and built by International. Reportedly, it was a big uphill battle, but Bill eventually convinced
them to develop a new line of engines by taking the idea higher up, as basically all International
divisions at that time needed an engine upgrade. So, what better time to develop a new line of
engines to cover multiple divisions of the company as a whole? With that in mind, that's how we ended
up with the 300 and 400 engine series. They shared the same basic structure and architecture, a lot
of the same parts, and they were built on the same tooling and nearly the same assembly lines. What
makes these two engine families so interesting, is that they both have engines with different
displacements and power levels within 300 and 400 series, but both engine series have their own
shared bore sizing. What I mean by this is that all 300 series engines have a bore of 3.875 inches
and all 400 series have a bore of 4.3 inches, with the largest of the 400 engine series coming
in with a 5.35 inch stroke, which is the DT466. Fast forward to 1971 and the initial plan for the
entire 300 line, the 414 and the 436, was to be mainly used by the AG division, in tractors
and combines. The DT466, on the other hand, was supposed to be used mostly in construction
equipment. Soon that changed, but let's not get ahead of ourselves here. The 414 and the 436
found immediate homes in the International tractor lines. The D414 debuted in the 966 tractor, and
the DT414 debuted in the 1066, and the DT436 in the 1466 and the 4166 four-wheel drive tractors.
It wasn't until 1973 that the DT466 appeared in the 4366 four-wheel drive tractor. All these
tractor engines had a history of excellent service and usability in the International Harvester
tractors and even a little bit past that on the AG side of International Harvester when it was
sold off and became Case International Harvester. Unfortunately, the aforementioned engines used
by the AG division didn't really draw in all that much attention outside of the tractor world,
as the naturally aspirated versions really didn't have much to offer beyond just simple tractors,
which is when the 466 was let loose to more than just tractors. After a very expensive tooling
investment, to the tune of around $500,000, the DT466 was now available to the truck market
and it became an option for the Fleetstar, then the Cargostar, the Paystar, and last the Loadstar.
All these received the DT466 between January 1975 and the summer of 1976. As compared to some of
the other engines available in these platforms, such as the d150 the d170 and the d190,
the DT466 offered significantly more power, better fuel economy, more reliability, and best
of all it could easily be rebuilt in chassis, removing the need for fully removing the engine
for a rebuild. At that time, the medium duty truck market had been evolving towards diesels, but the
perfect engine, the engine that would eventually take over, hadn't been offered yet. Sure,
International had a few engines on this market including the D301, the D358, the DV462, and the
DV550, as well as others. And other companies, like Perkins, Cat, Cummins, and Detroit Diesel,
were also in this space. And don't get me wrong, all those companies had some great engines in
their own right, but International was about to completely take over the market by storm with the
DT466, which quickly became the engine to beat in the medium duty truck market. The original DT466
was built in 1977 and featured the AMBAC Model 100 rotary pump, but when the DT466b popped up shortly
after the introduction of the original engine, the original then became the DT466a. Throughout
the years, there were a ton of different changes to the DT466, with multiple power figures
throughout. Although there were a lot of changes, the easiest way to break it down is with four
generations of this engine, including the DT466 A and B from 1971 to 1981, the DT466c from 1982 to
1992, the DT466p from 1993 to 1995, and last the DT466e from 1995 to 2016. Throughout the near half
century run of this engine, many aspects actually stayed the same, including the super beefy heavy
cast iron deep skirt block. The crank case itself weighs a ridiculous 400 pounds with massive
bulkhead sections and main bearing surfaces. Interestingly enough, something that did change
throughout the years was the bore and stroke. Earlier versions of the DT466 used a
4.3 inch bore and a 5.35 inch stroke, while the later engines used a 4.59 inch bore
and a 4.68 stroke. We see this kind of trend with pretty much all modern engines using closer
bore to stroke ratio for a variety of reasons. One of the features that made this engine unique as
compared to other medium duty engines of the time, is the use of wet sleeve cylinder liners.
These ductile iron liners gave the DT466 a level of durability and service ability that
hadn't previously been seen on a medium duty truck engine. Instead, wet sleeves were typically
reserved for much larger engines, such as class 8 engines or even larger, because each bore uses
its own sleeve, the engine is repairable in the case that a piston explodes and damages the
cylinder or anything else damages the cylinder for that matter. This makes the in-frame rebuild
process even easier, which was one of the initial draws to this engine in the first place thanks to
its inline six configuration. Inside the engine, you'll find a massive 150 pound forged steel
crankshaft with induction hardened journals for improved wear resistance. The crank is bolted into
place by seven main bearings, which got bigger as the DT466 changed throughout the years. Bolted to
that beefy crankshaft, you'll find equally beefy connecting rods. Depending on the version that
you're looking at, you can see the OEM connecting rods hold up to over 1500 horsepower, which again,
shows how beefy and overbuilt this engine, is especially considering the factory power output
is about a seventh of that 1500 horsepower figure. On top of the block, we have another massive
component, which is the cylinder head, weighing in at a ridiculous 250 pounds. Depending
on the version of the engine, you'll either find two valves or four valves. Both versions feature
ductile iron rocker arms, hardened valve seats, and six bolts per cylinder. That being said, the
biggest weak point on the DT466 is actually found here, with the OEM head bolts being the weak
link of the entire engine. That being said, you generally won't see any head or head gasket issues
until you're north of a thousand horsepower. So, in stock form, it's really a non-issue. The
oldest versions of the DT466 come in around 1400 pounds when fully dressed but dry, with the
modern versions of this engine weighing even more thanks to emissions control systems, with some
models tipping the scales at over 1900 pounds, and really that's the overarching theme of
the DT466 as a whole: it's insanely heavy, typically a few hundred pounds heavier than
similar engines from International's competitors, while also being very underpowered. While
that's not great for performance, it's great for reliability and keeping the engine in one
piece when you do eventually crank the power up over four figures. Throughout its 45 year run,
this engine saw tons of changes, from mechanical injection to electronic injection, non-intercooled
to intercooled, and emissions-free to emissions plagued. That being said, it always used direct
injection, turbocharging, a strong and heavy-duty block, and a simple architecture. With that in
mind, let's quickly hop into each generation so I can explain what makes each one unique, starting
with the DT466b. This variant was rather obviously very similar to the DT466a, as they came out at
similar times and really they're just sub-variants of each other. One of the changes to the B engine
was a revised ring pack to reduce oil consumption as compared to the A engine. The compression
ratio was also increased from 15.5:1 to 16.3:1 to help bump up power a bit and help with cold
starts, which again, that's one of the overarching themes with the DT466, is that it's pretty
underpowered. The B engine also received wider main and rod bearings. We then eventually saw
another sub-variant pop up, which was the DTI466b, with the I standing for intercooled. Both the
DT466b and the DTI466b used the aforementioned AMBAC 100 injection pump and they had power
ratings ranging from 160 horsepower up to 210 horsepower. Fast forwarding up to 1982 and the
DT466c was introduced, and they made a number of improvements, including larger lifters,
an improved oiling system, and changing the injection pump to the Bosch MW. There was a
turbocharged version of this engine and then two intercooled turbocharged versions of this engine.
The air-to-air intercooled model was known as the DTA466c and the air-to-water model was known as
the DTI466C. By 1987, the DTA466c produced 240 horsepower and 609 pound-feet of torque. To help
keep the new increased power figure cool, the water pump was also upgraded as compared to the
earlier engines. That takes us up to 1993 where the DT466 yet again went under a transformation
following a few years of development. This time around, it was designated as the
DT466PLN NGD, which stood for pump line nozzle new generation diesel. Really, a lot of this was
kind of some marketing ploys, as the engine was still mechanically injected and pretty similar to
the previous engine, but that was soon to change. The NGD PLN engines had a high mounted pump and
a cast squared off valve cover, with notches for the injectors. They either used a Bosch P3000 or
P7100 injection pump, and depending who you ask, this is considered to be the best DT466 ever, as
the Bosch P7100 pump flows significantly more than previous injection pumps, which means that it's
much easier to crank up the fueling and ultimately crank up the power. This version of the DT466
was rated at 275 horsepower and 800 pound-feet of torque, which again, is still underpowered
given its engine size, but it's definitely a step in the right direction. But unfortunately, as
the story of pretty much every diesel engine goes, the EPA began to enforce stricter standards,
which required cleaner diesel engines and so International joined forces with Caterpillar in
the mid-90s to develop the hydraulic electric unit injector, also known as HEUI. As a result of their
development of this new unit electric injector came the DT466e that was introduced in may of 1995
and along with the new electric injection system came a new cylinder head. The bottom end also
featured all the same upgrades that we saw on the DT466p. Power for the new DT466e ranges
from 195 horsepower up to 250 horsepower, with the later Maxxforce engines reaching upwards
of 300 horsepower and even higher. Unfortunately, the introduction of the electronic injection
system was really the downfall of the DT466, as it was incredibly reliable before all the
electronics, but never reached that kind of reliability again with the electronic injection
system. That system is known for being very problematic and having a ton of little failing
points that can cause the engine to not run entirely. Ironically, the rest of the engine
is still just as good as ever. That strong and reliable base is still there, but the electronics
draped on top of it caused an immeasurable amount of problems in the long run. So, that's a brief
summary of the legendary story of the DT466 from Navistar International, and really, a lot of
people, like I said at the start, like to clown on the Navistar International name for creating
the 6.0L Powerstroke and the 6.4L Powerstroke, and while those engines are very terrible in
their own right, the DT466 represents what Navistar is capable of and what most diesel
engines, including modern diesel engines are capable of when they're not plagued with
electronics and emissions control systems thanks to the EPA. The DT466 really changed the medium
duty truck market forever and it's never been the same. It was arguably the best engine
ever in that market. It's super reliable, it's nearly bulletproof, it's super easy to work
on, it offers a decent amount of power, although it is underpowered given its weight, and it just
does the job simply well and it's not going to break on you. In fact, people love this engine so
much that you can still see it being used today, although not new, it is being used in a lot
of tractor pulling events, where the high horsepower versions of this engine, where people
are really cranking them up, those engines can see upwards of 4,000 horsepower at 300psi boost
pressure, and they're still holding together. Sure, that's not a stock engine, but it goes to
show just how strong the DT466 is. International produced over two million of these engines and
you can find them in a lot of different things, from box trucks, school bus trucks, construction
equipment, farm tractors, and a whole lot more. If you guys enjoyed this video, be sure
to smash the thumbs up button, get subscribed so you don't miss out on future videos, drop a
comment down below if you think there's anything I missed or anything you want to add, drop it
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