So i've been thinking about switching out my 2.5L 4 Banger for a Cummins 4BT. I was just wondering if anyone had done this already with this engine or something similar that is a diesel. I was not sure where to begin. Any pointers?

reevesdieselyj (member name) did a diesel swap in his rig. i did a search for threads started by him, click me to check them out. he did a swap in a yj, but you might find some of his threads helpful to you. btw, welcome to the forum.

4bt swap into a TJ

You'll have better luck on this forum. We're a bunch of Daily driving 4.0L junkies that go out and beat on them on the weekends and ask for help on the forum to put 'em all back together again.

Keep us posted and start a build thread. I'd love to do this myself.

lots of things will need to be beefed up. basically anything that would have to be improved for a small block v8 will also have to be done for a 4bt.
now there are 2 different 4bts i have seen put into wranglers. one is the 3.9 and the other is the 3.3
the 3.9 is a bit on the heavy side, weighing something like 700 pounds i think. the 3.3 weighs about 550 i think.

another interesting thing to think about for a diesel motor is this

its not quite developed yet, but it could be pretty interesting.

yep...4bt weighs in at 780 fully dressed

4bt is a good swap

I am looking to do the same thing. How much HP and Torque does a cummins produce? And how the reliability.

yanmar makes marine diesel engines, 4cyl engines weigh 385 lbs
they also make tractor engines

4LHA-HTP 160
4LHA-DTP 200
4LHA-STP 240
4LHA-STP 240
Number of cylinder 4-inline 4-inline 4-inline
Output at crankshaft mhp/kW 154 / 113 240 - 177
Rated Speed rpm 3300 3300
Displacement L / cu in 3.455 3.455 / 211
Standard drive KMH50A
Weight with gear/drive Kg (lbs) 360 (794) 365 (805) 365 (805) 409 (902)
Environmental status c b,c

depends on what you do to them. mine has the ve pump and soon to upgrade to p-pump. mines doing 195 hp and 433 tq at the wheels. its a good engine and mileage is great

What transmission are you running?

the stock ax15 that came in the jeep

Wow, that keeps the cost of the conversion down. I have a million questions.
Stock clutch?
Transmission adapter?
What kind of milage do you get?
Build time?

I always thought that a cummins would make a good trail rig.

no the clutch is a 11 inch gm clutch and pressure plate. i used an adapter from (advance adapter) im getting about 26 to 28 mpg. it took about 7 wkds to do it when i had time. i posted a video on my ( my stainless dash) thread

What's next on the build list?

Jeeps never stop growing if you keep them long enough.

im building sliders for it now and doing some changes on my wheels...... and p-pump my engine soon

Hey I have toyed with this idea for my YJ. I was looking at putting the 5 speed manual from a dodge 2500 12v behind it. that is supposed to be a bolt up transmission and the t-case is supposed to be drivers drop right? I am concerned with driveshafts. I figure I will have to have custom ones made. and what axles are you running?

The NV4500 is pretty tall and long...can I get you a measurment if you'd like

I was afraid of it being to big, but measurements would be wonderful

ok gimme a sec, I'm gonna run back out to the shop and get um for ya...ole lady is vaccuming anyway and I am tired of hearing it

Ok here's what I came up with approx.

19" wide at the bellhousing
18" tall to the shifter collar
19" from the front of the bell housing to the rear of the tranny
33" total length (but I am using a 2wd to a divorced case)

That's not stock output. What upgrades have you done to it? Is that all from tweaking the pump or have you done other things?


I don't know if or when you plan on doing the swap but I'll be doing a 6BT swap this winter or this coming spring. I'm sure there will be a thread or 2 on the build.

Better budget a 60 front and some stought springs for that 1200# baby

Yup, already taken into consideration and plans are already in place. I bought a complete running 94 Dodge Ram so the Dana 60 front and Dana 70 rear are already in my possession. I'll use the Dodge springs up front until I can get my bank acct back up so I can build and stretch the suspension.

Howya gonna deal with that 3 piece front axle design problem?

Well I haven't given it a great deal of thought yet but I was considering just putting in a Posi-Lok like you would on a YJ's Dana 30 and using it that way. It is the same basic design only larger.

Or you could do like all the pullers do around here and get a longer inner for that side and delete all that stuff I don't think they are that pricey actually

BTW I am doing a compound turbo 12V in my current project. I have a guy out west that winds the coils to my specs and they are very affordable. PM me when you get to that point and I will hook you up with him

i put a set of pod injects, 366 gov spring,denny t fuel pin, hx35 turbo and turned the pump up

I'll look into it. Thanks. I guess it depends on which t-case I get. If I get something I can convert to twin stick or is already twin stick I could do that. If not I'd probably put in the Posi-Lok in case I want 2WD low range for what ever reason.

Nice. I don't know a whole lot about bumping up the HP on these engines yet but I was almost sure you had to do more than just tune the pump up. My 6BT will probably remain stock. So how do you like having over 400 ft/lbs in the Jeep?

the jeep is a blast to drive and the power compared to the 4.0 is huge. im looking at buying a p-pumped 4bt to replace what ive got now.