mpace6a Posted August 17, 2012 Share Posted August 17, 2012 So, I've been trying to put together a long term plan for my comanche, and being as it is an 86 with the 2.8, my main focus is a bigger engine. i've thought about doing a sbc or something similar, because all the work to make a 4.0 fit is worth more than a 4.0. So I'm trying to find out more info on swapping a cummins 4bt (3.9 liter I4) into a comanche, mated with an nv4500 5spd. i've only seen one case of it being in a comanche, and that was 2 videos on youtube of a yellow mj. anyone know where to find specifics? all i can find is mercedes swaps. Link to comment Share on other sites More sharing options...
Automan2164 Posted August 17, 2012 Share Posted August 17, 2012 ... i've only seen one case of it being in a comanche, and that was 2 videos on youtube of a yellow mj... He's a member here, 4BTMJ. I don't know if he ever did a build. Rob Link to comment Share on other sites More sharing options...
mpace6a Posted August 17, 2012 Author Share Posted August 17, 2012 ... i've only seen one case of it being in a comanche, and that was 2 videos on youtube of a yellow mj... He's a member here, 4BTMJ. I don't know if he ever did a build. Rob yea, thats what his tag on youtube was too. i've been trying the 4btswap forums, but nothing so far other than om617s into xj's Link to comment Share on other sites More sharing options...
simmonsm Posted August 18, 2012 Share Posted August 18, 2012 Hey I am also looking into a 4bt with nv4500 for my comanche, going to be very expensive but great fuel mileage and the power would be sick. there is a very detailed thread on 4btswaps.com on that yellow comanche on 4btswaps, http://www.4btswaps.com/forum/showthrea ... uild-specs Link to comment Share on other sites More sharing options...
HKB3 Posted August 18, 2012 Share Posted August 18, 2012 The 4bt is not a good choice for a MJ do to it's weight, also it "shakes" too much for a unibody. Oh and they ain't cheap Link to comment Share on other sites More sharing options...
mpace6a Posted August 18, 2012 Author Share Posted August 18, 2012 The 4bt is not a good choice for a MJ do to it's weight, also it "shakes" too much for a unibody. Oh and they ain't cheap i knew about the weight and cost, usually around 2500. Hadn't heard about the shaking though. wouldnt that be fixed with frame stiffeners though? Hey I am also looking into a 4bt with nv4500 for my comanche, going to be very expensive but great fuel mileage and the power would be sick. there is a very detailed thread on 4btswaps.com on that yellow comanche on 4btswaps, http://www.4btswaps.com/forum/showthrea ... uild-specs awesome fuel mileage, i've read about guys in full size pickups getting mid thirties, so in our trucks it should be in the forties, given the weight difference Link to comment Share on other sites More sharing options...
Automan2164 Posted August 18, 2012 Share Posted August 18, 2012 Or you could just find a 2.1L. In town with a little highway, last tank was 28.9 miles to the gallon and I still have to work the bugs out. Power wise, it's like any other 4 cyl though. Rob Link to comment Share on other sites More sharing options...
dasbulliwagen Posted August 18, 2012 Share Posted August 18, 2012 because all the work to make a 4.0 fit is worth more than a 4.0. Before I say anything else, please know I'm not trying to be an azz here, just trying to make sure you know what youre getting into in the nicest way possible..... You say that swapping in a 4.0 is too much, but you think that finding a 4BT will be OK? This doesnt make sense. All the work that will be needed to make a 4bt work in a Comanche is going to far above harder than swapping a 4.0 in. The frame stiffening, the lift kit to clear the oil pan, the custom made wiring harness and guage package, the custom made fuel system, custom mounts for the trans and engine, custom driveshafts.... it goes on and on. Unless you have full free access to a machine and fab shop, youll have $10,000 into this thing by the time you get it roadworthy. A 4.0 swap is easier because all you need is a running driving cherokee donor, and you swap it all over. The 86 may or may not need minor firewall massaging to clear the back of the engine, and everything Ive read about that says that its easy to do, and no big deal. If you find a 4.0 Wagoneer donor, you may not even need to modify the rear lights harness. I'm not saying that the diesel wouldnt be cool, just that for most people this swap is expensive and impractical. Please, think long and hard before attempting this. Link to comment Share on other sites More sharing options...
mpace6a Posted August 18, 2012 Author Share Posted August 18, 2012 the 4.0 swap takes more than just the firewall, not alot, but it requires changing the headlight buckets, front core support. If I'm doing everything it takes to put a 4.0 in, i'd rather go further than just a 4.0 is what i meant. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted August 18, 2012 Share Posted August 18, 2012 I forgot to mention the core support. If youre in for all it takes, I say go for it. I love seeing them like that, even considered it myself for a little while.... until I found out what a used 4BT cost!! Good luck! Start a build thread so we can all drool! Link to comment Share on other sites More sharing options...
simmonsm Posted August 18, 2012 Share Posted August 18, 2012 I'd love to see another comanche with the 4bt, my ultimate goal is to have a 4bt into my 87' with my 97+ conversion and about a 6 to 7 inch lift, the 4bt is my only justification for long arms and 35s LOL, as others have said its going to be expensive but you also don't have to go as in depth with mods on the 4bt and keep it semi stock and a little cheaper, as 4btmj said he dosnt have stiffeners but has some extensive stiffening from both of his bumpers, also I wouldn't expect more than 20-25 mpg without some tuning and turbo mods, I think 4btmj said he gets about 28 mpg mixed and he has a laundry list of mods and also is sporting twins now, still though, CTD 97' Comanche would be the ultimate rig for me Link to comment Share on other sites More sharing options...
mpace6a Posted August 18, 2012 Author Share Posted August 18, 2012 well if i can end up doing it, it won't be until after a year or so in the navy, so i can actually afford a 4bt, but right now I'm going through alot of crap just trying to go to bootcamp. but worst case scenario is i can't afford it, in which case a 318 is goin in Link to comment Share on other sites More sharing options...
cweemanrun Posted August 29, 2012 Share Posted August 29, 2012 I have a 4bt in mine works great but remember lots of Fab to make it fit and money I'm looking at around 7k right now and you will need min of 6-8" of lift . The weight difference between the two wasn't bad only settled my front springs about an half inch Link to comment Share on other sites More sharing options...
mpace6a Posted August 30, 2012 Author Share Posted August 30, 2012 I have a 4bt in mine works great but remember lots of Fab to make it fit and money I'm looking at around 7k right now and you will need min of 6-8" of lift . The weight difference between the two wasn't bad only settled my front springs about an half inch I was estimating around 10k to get it going...less is always better. What transmission/axles are you running? Link to comment Share on other sites More sharing options...
cweemanrun Posted August 30, 2012 Share Posted August 30, 2012 I'm running the turbo 400 and an np205 flipped set up with twin stick and right now I have the 30 and 35 but will be putting a Dana 44 for the front and a ford 8.8 for the rear. Link to comment Share on other sites More sharing options...
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