So im heavily considering picking up a non rusted out comanche with a good drive train. My plan is to put a small lift and some 33s at first, just to get back out on the trails. I will probably end up putting dana 44s and some 35s under it at some point, but that is about the biggest i will go this time around.

So i want to use the 4.0L until it tires out, but i wouldnt mind throwing a 4bt in it, not only for the torque but for the mileage, heck i would probably get better mileage in a comanche with a 4bt than i would driving my 08 dodge 3500!!!

The reason im posting is i dont know if the unibody that the cherokee uses, i believe the comanches are unibody as well, can handle the weight of a 4bt or not. I think it would be awesome to put a 4bt with a nv4500 or nv5600 behind it. Can the frame, or lack there of, handle the weight of that kind of setup?

You are correct, MJ's are unibody

it's been done before. This gus stuck a 4bt in there and an NV4500


YouTube - 4BTA Cummins Jeep Comanche (http://www.youtube.com/watch?v=KyS9A3jbwLM)

it's been done before. This gus stuck a 4bt in there and an NV4500


YouTube - 4BTA Cummins Jeep Comanche (http://www.youtube.com/watch?v=KyS9A3jbwLM)

awesome but that doesnt answer my question if stock its strong enough to handle the weight.

Can the frame, or lack there of, handle the weight of that kind of setup?

Not rusted and with strong motor mounts that spread the load... yes.

Not rusted and with strong motor mounts that spread the load... yes.

It will still fall apart like any other cherokee though, if it gets wheeled at all. :p

Only if you reinforce the crap out of the frame, otherwise the torque will destroy it in short order.

the MJ frame is fairly strong. to handle the torque, i would probably put on some frame stiffeners on the unibody portion.

here is the thread for that MJ in the video...
http://www.4btswaps.com/forum/showthread.php?585-4BTA-powered-92-Comanche-build-specs

i'd probably go with a mercedes OM617 over the 4bt in an MJ. lighter, cheaper, not so crazy tall, albeit more difficult transmission options.

The MJ frame is substantially beefier than the XJ frame, but only from the front LCA mounts back. I would do these:

http://www.hdoffroadengineering.com/collections/frontpage/products/xj-front-frame-stiffeners

up front before hanging a heavy diesel motor up there.

I would imagine the rest of the "frame" is beefy enough to take it. Might want to consider some sort of cradle or crossmember up front as well, provided there's enough room.

You can fit 33's on 3 inches and cut fenders, but might want to go a bit higher to clear the oil sump on a 4BT.

It will still fall apart like any other cherokee though, if it gets wheeled at all. :p

ya that was another question i have, i had some friends who have destroyed cherokees wheeling them but then you have guys who have wheeled their stuff for years. Are there any tips or trips to making the frames last on these things?

ya that was another question i have, i had some friends who have destroyed cherokees wheeling them but then you have guys who have wheeled their stuff for years. Are there any tips or trips to making the frames last on these things?

Yes, the frame stiffeners I posted earlier.

Bear in mind that the MJ frame is way beefier than the XJ frame. It's two inches taller and has a shit ton of reinforcements to the cab underneath. It's also double the thickness.

Belive me, I've beat the shit out of my MJ.

YouTube - Nate Wheeling Lions Den July 2010.wmv (http://www.youtube.com/watch?v=gTn5Fmr3Nvo)

Yes, that's my typical wheeling style. Now you know why I don't have any body behind the cab. Thus far the "frame" and chassis have been just fine, except for the rockers, but that's more to do with rust and bashing them than anything else.

've bent the front JCR bumper on both sides and the front frame horns are just fine. I have no dobt that a XJ frame subjected to my driving style would have serious dents all underneath, mine are still straight, they are capable of taking some abuse, and of supporting the weight of my truck on pointy rocks.

Yes, the frame stiffeners I posted earlier.

Bear in mind that the MJ frame is way beefier than the XJ frame. It's two inches taller and has a shit ton of reinforcements to the cab underneath. It's also double the thickness.

Belive me, I've beat the shit out of my MJ.

YouTube - Nate Wheeling Lions Den July 2010.wmv (http://www.youtube.com/watch?v=gTn5Fmr3Nvo)

Yes, that's my typical wheeling style. Now you know why I don't have any body behind the cab. Thus far the "frame" and chassis have been just fine, except for the rockers, but that's more to do with rust and bashing them than anything else.

've bent the front JCR bumper on both sides and the front frame horns are just fine. I have no dobt that a XJ frame subjected to my driving style would have serious dents all underneath, mine are still straight, they are capable of taking some abuse, and of supporting the weight of my truck on pointy rocks.

Awesome, thanks for the info. This is exactly what im looking for, as i will probably wheel the 4.0L thats in the mj for a couple season until i can get the funds together for a engine swap, and because well if the 4.0L is in good shape i probably will have little motivation to replace it until it starts wheezing.

edit: the whole reason im considering a diesel swap is the mileage and the fact that the turbo compensates for altitude, which is important up here in the rockies. My yjs injected 4.2L could barley turn the 38 boggers i had on it about 12000 feet even with 5.13s in the diffs

what year did the ax15 start showing up? Im hoping to find one with a 4.0/ax15/231 combo, seems to be the best starting drivetrain.

late 89 early 90 they started popin up

To give you an idea, what a tall a$$ motor the 4bt is...

http://www.no-bling.com/galleries/goat_Truck/lowres_6-17-09%20013.jpg

http://www.no-bling.com/galleries/goat_Truck/10-7-09%20002%20(Medium).jpg

i am going a similar route , i was trying to find a cummins for my mj , but i ended up finding a SD33 tf727 combo from a cj10a . the SD33 is nearly the same size as a 4.0L and came out of a jeep to boot . it makes less power but its designed to run forever . you can also turbo it with bolt on parts from a old scout ..

Parts for that diesel are spendy. Its almost the same as the diesel engine used in international vehicles. I had a 10a but it was missing some parts. Got rid of it. Awesome if you found one complete.