Alright - this is the
Holy Grail of fuel economy and torque. Diesels
typically aren't your first choice for horsepower,
but if you want economy, power to tow and a
reliable, long-life engine, diesel's are for
You will have to live
with a noisier motor, exhaust smell and, in
some areas, it's harder to find the fuel. In
the end, though, it's worth it.
The biggest differences
between gasoline engines and diesels engines
gasoline engine intakes a mixture of gas and air,
compresses it and ignites the mixture with a spark.
A diesel engine takes in just air, compresses it and
then injects fuel into the compressed air. The heat
of the compressed air lights the fuel spontaneously.
gasoline engine compresses at a ratio of 8:1 to 12:1,
while a diesel engine compresses at a ratio of 14:1
to as high as 25:1. The higher compression ratio of
the diesel engine leads to better efficiency.
engines generally use either carburetion, in which
the air and fuel is mixed long before the air enters
the cylinder, or port fuel injection, in which the
fuel is injected just prior to the intake stroke (outside
the cylinder). Diesel engines use direct fuel injection
-- the diesel fuel is injected directly into the cylinder.
It's been just about 20 years
since Jeep last really offered a diesel in a Jeep.
Back in the mid-80's, the Cherokee came with the option
of an underpowered, but very economical, 4 cyl diesel.
with either the five speed manual, four speed manual
or three speed automatic, the diesel engine was the
Renault 2.1 Litre Turbo-Diesel. Most of the Diesel
Cherokees were sold in Canada and Europe. If you could
live with the lackluster acceleration that less than
100 hp provided, you'd be very happy with the 31+
MPG the motor provided in your 4WD SUV.
Today, it's easy to find a Jeep Liberty diesel - provided
you have a deep wallet and are patient. There's precious
few of these great trucks riding around right now.
Given the fickle public's aversion to diesels (created
by the crap products GM turned out in the early 80's),
Jeep was aiming low with production runs of well under
10,000 units allocated to Canada, for example.
Add in the fact that this option, the Liberty 2.8
CRD (Common Rail Diesel) is only avialable in the
up-line Limited model, and you have the reason for
that low number - exclusivity guaranteed. At almost
$40,000 Canadian, before taxes, etc., that's one mighty
If you were lucky, and lived in Europe, you'd have
a hand full of diesel motor options to choose from
- units designed for everything from top fuel economy
to top torque and towing. Alas, North America is slow
to this dance. At least, the manufacturers are...
ENGINE SWAP TIME
Let's say you want to be a bit different. Let's say
you want to swap that tired old 2.5 4 cyl in your
YJ for something different. Sure, you could drop a
5 litre in there, or maybe a Dodge 318. Lot's of power
and lots of fuel, too.
If you've got some money (more than a normal V8 swap,
less than stuffing a Hemi in a TJ), maybe you should
condsider a diesel for your swap. We don't mean go
out and find on of the old, ratty Renault 2.1 litre
units - you'd probably never find one anyway.
Look to newer technology. Borrow from the Suzuki
guys - VW's 1.9L TDI motor is the hot swap for Samaurias,
so why not in your MB, Willys or YJ? It's not going
to make it a drag machine, but it offers plenty of
torque for daily driving and offroading, plus it'll
still net you over 30 MPG.
Not convinced - how about this. The VW TDI's came
with 90 HP & 177 lb/ft of torque stock (the 1998
- 2003 models). With only a few cheap mods, these
motors can reliably put out 125 hp and 270 lb/ft of
torque - that's V8 territory for torque! Diesels are,
as many now know, easy to make power with. They're
built tough enough to handle it, too. AND, the low-rev
nature of them ensures the torque is available down
low, right where you want it.
At this point, though, you'll be pretty much on your
own. We know of no one who's done such a swap, so
everything would be custom. But, that's what building
your Jeep is all about anyway, right? If you've got
the skills, the time and the money, the parts are
avialable. This is definitely not for novices.
If you've just got to have one of the OEM motors
supplied to the European marketplace, start with these
guys - VM
Diesel Specialists. They're in the UK, but no
one knows Jeep diesels like they do.
Jeeps - Diesel
back in 1953, Mitsubishi secured the rights to produce
a branded version of the Willys.
they had a good thing going, production carried on
until 1998 for this version.
few changes, other than to the engine, were made during
The guys over at LuxuryImports.ca
are a wealth of knowledge on these, and other, diesel
rigs. Drop them a line and they'd be happy to get
you into a new-to-you Mitsubishi Jeep or Toyota Land
are the specs of the rig in the pic above. For a historical
overview, more model specs and driver's impressions,
some time here.
(1983 model year- J54)
Normally aspirated diesel
mm / 1420 mm
55 HP @ 3300rpm
ft/lbs @ 2200/rpm
Semi-elliptic leaf spring
Semi-elliptic leaf spring
specs the same, except engine is Turbo Diesel