Greybush

hey guys im looking to get an 4bt cummins and install it into a 94 xj i was wondering if you guys knew what i would need to do to achieve this successfully

XJeepWerks

From what ive read, You'll need to start by framing your Xj. The unibody wont support a 4bt diesel.

hawaiian808

Haha, whew I made a list for this.
Its simple honestly just alot of time consuming custom work, you don't really have to frame it more like make a cross member that goes to the rails under the body, but if your serious ill make you a list

ProudXjOwner

ALOT of research and fab skills!

wiggles

This is something I'm interested in so I'd love to see this happen!

XJeepWerks

I know a 6bt Cummins is 1200lbs, so a 4bt probably isn't too far behind it. Far cry from our 519lb l6's.

hawaiian808

Ill make a list I've done the research myself for a different project, also noted if you so it right 25mpg is easy also a parts truck like a d250 will make everything easier


Ok so here we go!

Im going to start from parts then go to fab

You need a,
4bt
Nv4500 out of a d250 ram ( I Belive to many transmissions to remember them all)
All Accessories off a 6bt that u may want for your rig (alt, ac etc)
Dash cluster from d250 (diesel of course )
Fuel pump system similar to a fass, airdog, etc
A heavy duty radiator
Electric cooling fans (mechanical are far to big)


Then you will need

A cross member that ties both unibody rails together also motor mounts, 4bt plain I recall is about 7-800lbs
Front springs, ethire custom made or heavy duty ones from a jy
Custom transmission mounts
Custom transmission well (aka beat with a hammer)
Move the transfer case back
Make a dash out of a piece of sheet metal, mount all the gauges in it from the d250, and attach all sensors to 4bt, may need some aftermarket one,

The beauty of a 4bt is that it is mechanical, no ecu nothing, the dash will work of a 6bt some sensor holes are in different locations, hell if its going to be a trail only rig all you need is a fuel pump, the engine, and a cooling system, the beauty of older diesels!

Gee oh Dee

Moved to Advanced Tech.

Greybush

thanks for all the input guys i found an xj motorless for 200 bucks and ill strip that down and have to convert it over to a 4wd as well so replacing the power train is not a problem with me. As for that D250 tranny i would need the transfer case off it as well or am i going to need something other then that

hawaiian808

Here comes the fun part haha,

Most d250 and old f250 came with a granny first, so usuing a xj xfer case of your choice would make 4low so low you could scale mount everest in first with no throttle, sounds awesome till you have to shift to get any speed and anyone who has wheeled a stick knows that split second your off the throttle could make or break you, you could always gear the differentials higher to make up for it, but since this is unknown territory for that, it will be a learn as you go
It is simpler to keep the old xfer case because you will only need yo lengthen /shorten the stock shafts for your front and rear witch is cheaper, and one custom shaft with different size splines for the primary ( I am not to certain how you would mate the tranny to the xfer case but that seems the simplest)

but the d250 xfer case is geared accordingly so if you want to you
can use the transfer case but now you run into a big problem,
You will need to get custom shafts to go from the d250 spline count/size to your 8.25 and d30 axel size, not to much of a problem for a good 4x4 shop but still complicated
Then some custom linkage for your shifter select and she's done, I would imagine the d250 xfer case will hang low compared,

kansasxj

will the stock axles hold up the weight of a 4bt? will they handle the torque as long as you dont get stupid with the throttle?

hawaiian808

I imagine a moly front would work and a 8.25 would hold up

prerunner1982

Sounds like a lot of work if the goal was 25mpg... when I can get 23 out of my stock XJ. Though it would have a cool factor...

hawaiian808

Well im talking 25 with a pump and bigger turbo pushing near 190-200hp and 350-400ft lbs (fully built) but id you want super economy 30mpg is possible

cherokee90

Idk why everyone thinks it's going to rip the body apart. Let's see the 4bt weighs around 750 pounds, and the jeep i6 weighs 500ish add a winch and bumper on front of that and you around or over the weight of a bt4. Just make a crossmember for the motor mounts and I believe you will have more then enough strength for the new motor.