Lets start with , I have a 57 Willys wagon with a rusty frame,

So doing some looking around I figure that I should be able to mount the Willys wagon onto a CJ8 frame with out too much problem.

Using an after market ( stronger than stock ) CJ8 frame, And most of the parts from a CJ7 that I stripped, I should be able to complete this project with out excesses expense

Now the problem, with fuel prices going up, I want to get a good MPG with this rig.

First thought rebuilding the 4.2 6 cylinder and keeping the all jeep drive train, but thinking a diesel is the way to go.

Price on a 4BT is just too much, So thinking of tiring to fit a 6BT as in Dodge Truck Diesel into the CJ8 frame and boxing the firewall on the Willys Wagon.

Thoughts on this build or are there other diesel engines that I should be considering?

Doesn't the 6BT weight around 1000lbs? If so might want to think about beefing up that CJ8 suspension and brakes.
Otherwise you'd have one sick rig dude.

There is a lot of good information here.

http://www.novak-adapt.com/knowledge/engines_general.htm

I know the 4.0 can be pretty thrifty when matched up to a manual transmission. My daughters '01 Cherokee gets 22 ish MPG cruising at 75 and isn't bad around town. The cam is small and the gears are long and it all works well together. If you want to run a carb I would guess its possible to convert. Plus the 4.0 is light, at least compared to a diesel which is an advantage off road and on. I've never done it but I understand the 4.0 head will fit a 4.2 which will give better breathing of the 4.0 plus extra torque.

I think I'd go in the archives and copy hotroddave's "super duper gas mileage 318" build and toss that in there...high compression, tight quench, very short solid cam and a t-quad...

I really can't see the 6bt getting that much better fuel mileage than a 4.0. Plus, the weight, size, and limited powerband of the diesel will make this a very unwieldy project, to say the least. The scrambler frame, aftermarket or not, really isn't up to snuff for that much weight. Engine compartment size and radiator size will be two other limitations. If you are really set on doing this, I would suggest a Wagoneer frame. Or an Isuzu turbo diesel. Or both.

it's not quite "mopar" but perhaps consider a Volkswagon 1.9 TDI?

There was someone who has swapped one into a later jeep with much sucess. Near 30mpg iirc.

http://www.jeepforum.com/forum/f12/3-0l-mercedes-turbo-diesel-into-1994-yj-835449/

This guy put an 80's mercedes 5cyl turbo diesel in his tj. Sounds like the hardest part was making the adapter plate to mate the motor to his ax-15 trans.

Hey we all want it all in our vehicles. The thought of a cheap trail rig thrown together and a 5.9 diesel just doesn't add up to me. Not unless you are climbing grippy terrian and hauling 4 tons!
Trails and MPG to me sounds like light and small. Something that can take an hour to go 2 miles and not make a dent in the fuel tank, and also doesn't require a mil-spec drivetrain.

How about outlining overall cost, type of trails and expected cargo and people loads?

Don't forget that the jeep is less aerodynamic than a brick!

On the highway, there is a mpg limit you will hit no matter how efficient a motor you have.

On the trails, bouncing over rocks, creeping around in 2-lo, and etc. I find that I give out long before the gas tank does.

My opinion, pick a motor, then gear it to match. It's not going to make too much of a difference in the long run.

PS: Going down hill from vail pass, I have to give it gas to keep up to the speed limit, thats pathetic aerodynamics

The 1984 Lincoln Mk coupes had an option for a BMW built diesel.

http://carscoop.blogspot.com/2010/10/rare-find-1984-lincoln-continental-with.html

I had a mining engineer friend who had one in a Mark VII coupe and he got 32 to 34 MPG consistently on frequent trips from Whitesburg KY to Lexington KY

I did that same trip many times in a 1984 Ford Thunderbird gasoline V6 and typically got 24 MPG.
My brother had a 1986 Mercury Cougar turbo 4 and would get 26 MPG on the same exact trip.

It would be a relatively rare car to find in a salvage yard, but about the right size for Jeep duty.

The air cooled Deutz diesel used for portable pumps is a great design, and I have read where it has been retro-fitted into trucks.

If you wanted to stay with a newer design
consider the Motori diesel in the Jeep Liberty
or a VW TDI, including a 5 cyl TDI

Tom ended up buying the PRICEY 4BT last night

He bought an entire Frito Lay truck

Yes, just about to buy a wrecked Dodge 4X4 Diesel for the engine and trans.

But the 4bt in the bread truck showed up on Craigslist yesterday. Should have it on Monday Night

And the bread truck was cheaper also

you should make some money back scrappin the body

I know that my 5.9 cummins in my 90, will go anywhere any of my other full size gasser friends trucks will go. It will wind in the mud with any bigblock for trail duty, and I can wheel a whole weekend on a few gallons of diesel. My buddy's with big blocks, and even small blocks, they are dumping gas in every night, sometimes even in the afternoon to finish the day.

After seeing mine work, and wheeling friend took his BBC out and will never go back. His tuned 5.9 cummins has never been a slouch to his BBC.

All that being said, I think a 5.9 is going to be a little much for the above said chassis. I think the 4 cylinder B will be sweet.

Michael

Way to go, Tom!
That has got to be better than a 6 for your use.
Don't plasmacut, that's blowing money on the ground! Haul it down whole.
Heck, you could sell sheets as "Official Moparts Lightweight Patch Panels"...
At least cut out the signage and Ebay it as vintage and rare!

Since Tom hasn't posted a pic of the Willys he bought off of me here you go....

Also, I decided to put a diesel in my Dodge M37 and suddenly he has to have one as well