Is there a consensus?

[Texafornian]

Is there any sort of consensus as to which diesel is the best swap for a GW? 4btl, 12V Cummins, 6btl Cummins, the VM Motori in the Grand Cherokee and Ram 1500? I want to plan for putting a diesel in my GW, eventually. Sadly, someone else will be doing the work, because I am disabled. So, I also don't want to do the most expensive swap. I seek ease of installation, decent fuel mileage, enough torque to easily handle mountain and desert trails, as well as drive to said trails. Not going to crawl any rocks unless forced to, in order to continue up the trail. I don't know that much about diesels, except they basically run off compression, last longer if cared for, get better mileage, have excellent torque to weight ratio, and use a more expensive fuel. 🤓 I'd like to read some opinions on this subject, if you don't mind. Thank you.

[Heavy_Metal_Thunder_81]

Cummins 4BT. Hands down easiest and most economical swap.

[joe]

I think you'll find most folks like the 4 and 6 cyl Cummins. I tend to agree also but that doesn't mean the other commonly avail dsls are bad. Cummins are generally the most expensive up front and the 4 cyl are hard to find. In their original platforms I've had great use and reliability with the GM 6.2's, Ford 6.9 and 7.3 powerstrokes. The 6.2's are probably the cheapest initial buy-in costs. I've never swapped one into a FSJ. Like the idea but could never justify the costs for my needs. What you mentioned knowing about dsls is true but there are costs involved. Any dsl swap is essentially custom work so having a shop do it will be "expensive". Dsls do run a long time if cared for but they do need maint with generally expensive parts. "Nothing" relating to dsls is cheap Gawd forbid if you have to buy an IP(injection pump $$$). I love dsls for those folks have have a real use for one. IMHO, just to get better gas mileage is not an economically viable plan unless you drive ALOT. To have a dsl swap done properly will be thousands by the time you're done. You'll have to figure out how many miles you'll have to drive before you even reach your break even cost let alone saving any money. Dsl's also like certain RPM's to work efficiently. Ones I've had seems their happy spot is about 2,200-2,500 RPM so generally stock FSJ Wag gearing is too high to maintain that range in normal use so leave some room in your budget for a possible axle gearing swap(both axles). Not trying to discourage your plan but it's easy to wrongly think I'll just drop in an old dsl and drive 300,000 maint free miles at 25 mpg. Keep doing your research and keeping track of related costs. Hate to see you have your car in a shop only partially done and you get a call. "You're out of budget." Having a shop do a dsl swap is not for the thin-of-wallet. Love'm but it's a serious investment so you have have figure out/decide on your overall "bang for the buck" factor.
Edit: On a side note: I'd personally go with a pre-computer controlled dsl.
Just "my" opinion.

[EKWagoneer]

Although I haven't done a diesel swap myself, and don't plan to, I think that the most popular swap is the 4bt swap, and the one I have seen the most. If you go that way, look in bread trucks and things like that for a 4bt.

Hope this helps.
Ely

[Mikel]

I love diesels, but there are modern V8s that with a properly matched drivetrain can give smooth and quiet power, with MPG that only diesels used to reach.

Going back to diesels, besides the ones mentioned, Isuzu used to make mechanical diesels like the 4BD1T that would be a very nice match for a FSJ.

Whatever path you decide to follow, I would run some quick numbers on paper, if fuel savings are your goal. It takes many tens of thousands of miles to break even on a diesel swap. You may find out that driving your truck as-is will be the most sensible option.

A good site to research diesel swaps is www.4btswaps.com They have sections for all common small diesel engines.

Good luck.

Here is mine:

[Texafornian]

Thank you everyone for your input. My end goal is to turn my GW into a long distance adventure vehicle. Gearing change and lockers already planned.

[jarhead_jeeper]

I converted a Quadra-trac Jeep CJ7 to a Chevy engine using mostly OEM parts. I had the the Jeep transmission internals swapped into a Chevy case. (The only real difference between the two turbo 400's is the output shaft.) Custom motor mounts and a conversion radiator were the only non stock parts.

If you were to go this route in a GW with the turbo 400 already in it a 6.2 or 6.5 diesel would be a very easy swap.

[blazer3664]

if fuel savings are your goal. It takes many tens of thousands of miles to break even on a diesel swap.

I agree with what is said there, but I never understood why some do a diesel swap to save $$ on fuel. Just never made sense to me for the reason you mentioned.
Even if you double your mileage, will you drive it often enough and far enough to make the ROI in a reasonable time frame?
Some will, but most wont get there before they sell or "retire" their rig.


Now for some, yes it would be about fuel mileage, but not to save $$.
For me its more about extending the range of my rig with the same # gallons of fuel.
..In that case, its like a lift or coil suspension, to each their own. If it fits your needs, go for it.

Even at that, I still have yet to justify the cost to myself................ diesels are $$ by the time its all done. Stopping off at the gas station is easy.........and at this point I dont go that far from civilization...........yet.

Just my 2 cents.

Jim

[GAPilot]

I have a Cherokee powered by a 93 5.9 Cummins. The engine fits nicely and only requires one power wire to run for the most part. My jeep has the entire running gear of a Dodge W250 swapped in (Chevy Dana 60 in front). The hardest part was changing over to the bigger springs for the rear Dana 70. The rig now gets 17MPG and can easily tow my 30ft boat with triple axle trailer. I added another gas tank to extend the range. The only complaints that I have is that it shakes too much at idle and the stock gas filler necks have to be spoon fed diesel. I often have to abandon gas stations because their diesel pumps have too much pressure and will not allow me to fill up.

[dndracing]

I have a Cherokee powered by a 93 5.9 Cummins. The engine fits nicely and only requires one power wire to run for the most part. My jeep has the entire running gear of a Dodge W250 swapped in (Chevy Dana 60 in front). The hardest part was changing over to the bigger springs for the rear Dana 70. The rig now gets 17MPG and can easily tow my 30ft boat with triple axle trailer. I added another gas tank to extend the range. The only complaints that I have is that it shakes too much at idle and the stock gas filler necks have to be spoon fed diesel. I often have to abandon gas stations because their diesel pumps have too much pressure and will not allow me to fill up.

Any pics, or a thread on this forum? I would love to see this build. I have a 1990 Dodge W250 Cummins 6BT donor truck and am currently shopping for a Cherokee to swap it in.

[GAPilot]

My truck is in the build thread under 79 Cummins powered Cherokee (pathkiller) http://www.ifsja.org/forums/vb/showthread.php?t=178081

[conehead]

You don't need to use the entire dodge drivetrain. All I used was the cummins 12V, transmission and transfer case. I kept the jeep axles and frame and it all fit and works well. I even fit an aftermarket intercooler behind the grille. http://s656.photobucket.com/user/pha...ehead/library/

[grand_wag_85]

I'm going a slightly different route with mine and using a Duramax. Seems they can get rebuilt cheap and the donor vehicles are a dime a dozen these days. Space wise they seem on par with the LS engines everybody is swapping.