Brain, where do you come up with the diesel having less fuel economy than a gasoline engine? I have run big block Ford engines in heavy service trucks and rarely got over 6 MPG. Now my service trucks are all diesel and even my old 94 F250 with the 7.3 IDI non-turbo gets 15 MPG while weighing better than 9K lbs. My 3500 Dodge/Cummins gets around 20 MPG while weighing over 20K lbs. It's true that diesel costs more, but it makes up for it by far in fuel economy.

 

I remember talking to a guy at the 1st F100 Supernationals I went to at least 12 years ago that had a "bread truck" diesel in his 56 F100 and got over 30 MPG. Of course back then diesel was about $.30 cheaper than regular unleaded. Now its $.20 more than premium. Do I need to start scouting bread trucks at my pull-a-part?

 

mech: mostly experience on the farm and over the road, a few articles I have read over the years (just googled, but not finding much besides this Don't Be Fueled: Gas vs. Diesel vs. Hybrid Power - MSN Autos - note they compare a 3.0 versus a 3.7, none of the specs are similar torque will always be different, but hp, displacement - nothing is similar ... they are comparing and apple and an orange and badmouthing the apple calling it red - not very professional in my opinion)

I pulled up fueleconomy.gov and tried to compare a similar HP f150 gas v diesel... I can't even get diesel stats other than benz...

The rule of thumb I was taught by farmer, mechanics, and diesel mechanics was this: diesel is a BYPRODUCT of gasoline production, it is a waste gas - hence the price is really cheap (true in the 80's). Diesel engines last longer, they simply just don't wear out. Diesel has less potential energy than gasoline, but has greater combustion expansion - I suppose that slight advantage is now lost because we aren't running GAS, we are running E10 - 10% ethanol (with real world efficiencies of 10% less efficient than pure gas). Diesels have a ton more torque - for those reasons tractors and OTR trucks all went with diesels.

The 15 minutes of research I did before replying doesn't really show anything contradictory other than NOW diesel is more expensive than gas and E10 - is turning into E15 now, and E85 could very well be mandated for all "gasoline" engines... it's a lot to ponder.

 

The thing I'm having to remember on this is it's not so much a gas verse diesel debate for what to use, it's a *This gas engine* verse *This diesel engine*. If I go diesel one diesel really stands out among the rest, the Cummins 5.9. It's a very different beast than the 6.2 Chevy runs (even though that thing gets amazing mileage, it doesn't get near the power) or the Powerstroke Ford uses.

And any gas engine will be something like a 351w/390/429/460. Nothing is going to be new by any stretch of the imagination. Just like I know a new Powerstroke puts out like 800lbs of torque, I won't be using one, it's about the engines that will be coming from a donor truck. If I find one it will be one of the older models that only put out like 400lbs, lol "only".

And it's going in a big 4x4, that makes a difference too. If it was a car the last thing I'd want is a diesel unless I needed to make 80mpg. In a truck it won't have you fly off the line like a gas engine, but you will be able to pull a house when you move. And a large 4x4 that can deal with slick snow or pull anyone else out is highly appealing around here. Not to mention diesel can be made to run off of many things that aren't diesel.

But so far a Cummins seems to be about 2-4 times as much money in my area. And I'm already stretching a dollar a thousand miles (and still trying to do even more than I need to right now, lol).

And the 272 I have in it now gets 5mpg. On a good day. When it's warm outside. I love the sound of it but it's far from practical.


So yep. I have a feeling it will be about whatever deal I can find. Found a couple good sets of axles on some donor trucks, might have to go that route and sell the rest off, but I have no place for anything... so that will be interesting. And by no place, I mean just that, lol.

 

This is probably another useless piece of info from me
but that 4 cyl cummins talked about earlier is like a 5.9 cummins with 2 cyl's cut off. on the b series cummins. they are aprox. 1 liter per cylinder so the 4 is a 3.9
and the 6 is a 5.9.
I just thought it was interesting....ok...i will....move along now...

 

Yep, be a good choice for a half ton daily driver. I'd like the extra 2 cylinders for this build though, lol

 

Since you are wanting to build a 4X4 and power it with diesel, why not look for an older Dodge 3500 4X4? It will have the Dana 80 rear-end and Dana 60 front, and if you get later than (I think) 01, it will have 4 wheel disc brakes and hydro-boost. They are out there and can be bought at a reasonable price. The trucks seem to fall apart around 200K and the drive train is good for probably 200K more.

 

Hey Stephen,
Since we are taking an open mind about the different engine options - let's talk Toyota diesels for a second. Here is a link to a guy's page on swapping diesels into gas engine toyota trucks - evidently Toyota made diesel trucks for the U.S. market for 4 or 5 years in the 80's & even longer in Canada. If you are talking about putting Dodge diesels into the truck I don't see Toyota as much of stretch past that.

Toyota Truck Diesel Conversion FAQ and Guide

Ben in Austin

 

I have been keeping my eye open for an older dodge. Problem is they run for about $5000 around here, where as I can buy a donor truck with the axles I want in it for about $850 (or just some axles for about $700) and a powertrain from $300-$2000 depending on what I find. If I can find a good deal on one it is optimal, the problem right now is it's more money I don't have to spend on it for parts I'll just be looking to get rid of, and I have no idea where to put the extra parts in the mean time. lol I can't exactly leave an axle-less truck on the street around here :\

The Toyota diesels look neat, but I can't imagine trying to find parts for them. The Cummins has a draw to it that other diesels don't. And the Cummins is a Cummins, not a Dodge, it's just what Dodge uses. They've gone into Fords as well (so I just learned, lol) and many other things. I think they are the popular choice because they make a lot of torque and have very few parts and are much simpler than other diesels out there. But swapping to one means other parts. I believe your fuel lines have to be different, or at least can't have rubber in them. And I'm not sure I can just use my old gas tank.

I should re-title this thread "How to stretch a dollar 400 miles and some how manage to afford doing everything you want to to your truck", course that's way too long to catch on...

 

In that price range you are going to have to look much older and probably not going to find a Cummins. Here's a link to an early IDI for sale on here. https://www.ford-trucks.com/forums/1...sel-6-9-a.html

 

lol this whole situation is a "can't afford it, but it will work out anyways" sort of build. I have an '89 Bronco that I will probably end up using for some trade. I need to find some extremely good deals, but thats been this whole trucks story, lol. Playing hard ball is half the fun. Having money is like using a cheat code, lol.

Got to love the irony, can't afford crap, want expensive and particular parts. lol. If I was going to use a Dana 44 up front this whole thing would be a lot easier, but I want a Dana 60, and they are only found in 1 tons. Still... some how they're popping up.


The even harder part is finding them close to me, not 500 miles away. I don't have a truck to pick parts up. And I'm basically in the middle of no where. Yet it's working out already, lol, usually it takes several months for me to find any parts in the states around me, yet I found the parts I was looking for in my town in a day, or rather they found me. Go figure.

Should be fun, if only I could have gotten to it before winter started to come.

 

I was wrong earlier, the second gen Dodge 2500s also have Dana 60 front and Dana 80 rear when it is Cummins powered.

 

Well that's good to know. Thanks

 

Ok, not to drag this up but I think i finally have my answer;

the 5.9 Cummins


Good mileage, highly reliable, minimal parts, doesn't use glow plugs (winter issue here), easy fit without having to move steering parts or 4x4 parts ect, About 400lbs of torque which is uneffected up in the mountains (5% loss over 30% gas engine power loss), goes for about 300k miles, exhaust options to not sound or look like some of the towns red-necks, lol

Now... to find one I can afford, as well as hopefully the axles I need. Maybe I'll luck out and find a really good donor with minimal extra parts I don't need...because where on earth am I going to put a truck without any axles or a powertrain. lol


Thanks for the help guys, that seemed to have taken forever to figure out.

 

I like your logic, and while I argued against diesel I do have to say it sounds like you really thought this one out and have a good decision for the right reasons. Very glad you posted a followup, I'm itchin for closure one some other folk's questions.

I do understand that diesel acts like e85 when put into a previously gas system - a bit of a detergent effect, it breaks anything crusty loose and sends it into the system... Only final thoughts, get you an inline $5 filter first in the fuel system and carry a spare with you for the first 10k miles.