harris1986 Posted June 21, 2017 Share Posted June 21, 2017 I have a 86 2.8 and hate it, want to got to the 4.0 I6.. Tips, tricks and write-ups would be helpful ( how hard is this conversion? ) Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 21, 2017 Share Posted June 21, 2017 Quite a few have done it. You'll need a lot of parts from a donor jeep because the engine bay is smaller 84-86, 87 the bay was stretched to fit the 4.0 and all kinds of thing were rearranged like hood latch. Then their is the wiring and computers. You'll really need a good donor vehicle to get everything. The easiest solution is probably dropping a 3.4 v6 out of a 93-95 Camaro, essentially it's a 2.8 bored out to 3.4. Next would be to upgrade the fuel system to edelbrock intakes and Holley four barrel or as a few have done get the wiring harness and computers with the camaro engine and run the fuel injection and intake. But The 4.0 swap can be done. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 21, 2017 Share Posted June 21, 2017 http://comancheclub.com/topic/3253-the-legendary-28-to-40-swap-help-needed/ Here is one thread, plenty of others out there Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 22, 2017 Share Posted June 22, 2017 Just thinking here, would there be any benefit to a 2.5 swap? Same bolt pattern for transmission. don't know if I've ever heard of anybody doing this so it's probably not a good idea. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
harris1986 Posted June 22, 2017 Author Share Posted June 22, 2017 Looks like I need an XJ with a 4.0 however I'm also finding other Comanches in the area with 2.5 and 4.0 already in them. Now I'm torn on the build or just buy another rig Link to comment Share on other sites More sharing options...
omega_rugal Posted June 22, 2017 Share Posted June 22, 2017 Looks like I need an XJ with a 4.0 however I'm also finding other Comanches in the area with 2.5 and 4.0 already in them. Now I'm torn on the build or just buy another rig good luck finding a good MJ, XJs with fixable 4.0+AW4s are everywhere... Link to comment Share on other sites More sharing options...
harris1986 Posted June 22, 2017 Author Share Posted June 22, 2017 Looks like I need an XJ with a 4.0 however I'm also finding other Comanches in the area with 2.5 and 4.0 already in them. Now I'm torn on the build or just buy another rig good luck finding a good MJ, XJs with fixable 4.0+AW4s are everywhere... I'm in Oklahoma and have about 3 within 200 miles from me, maybe getting one in OKC - 89 with a rebuild 4.0 and 31k miles. Link to comment Share on other sites More sharing options...
Pete M Posted June 22, 2017 Share Posted June 22, 2017 should be some helpful info in here: http://comancheclub.com/topic/48710-diy-projects-writeups-master-search-index/ mid 90s 3.1/3.4 is still the easiest swap. a direct swap for you block (with the exception of the flywheel and fuel pump) and better in every way (better steel, better oiling passages, etc). plus the chevy fuel injection system is a stand alone unit and I'm told is an easy adaption. there's a writeup to that in the above link too. Link to comment Share on other sites More sharing options...
neohic Posted June 22, 2017 Share Posted June 22, 2017 I've got another option that I honestly think should be considered by anyone wanting to do a 4.0 swap... think 5.2. :D Granted, if your firewall allows for it then a 4.0 swap will be almost bolt in. If you figure motor/trans mounts, a 5.2 fits great in our engine bays! Think about this... doing a 4.0 swap means that you'll need to do something about your front core support to fit a proper radiator. Why not cut it to fit a somewhat more standard size radiator that'll get way better flow to it? Something else to think about is that there are millions of 4.0s out there but they're also getting harder to find low mileage donors. The 5.2s can be found in ZJs, Dakotas, Rams, Durangos... way more available, easier to find, and a better chance of finding lower mileage engines. Even more if you consider the 5.9s too! Cheap too! I picked up my donor vehicle for $300. Anyhow, I digress. This is probably a bit of a hijack/rant, but after my 5.2 swap I'd definitely consider it over a 4.0 especially in a '86 truck. Have a look through MY BUILD THREAD. Link to comment Share on other sites More sharing options...
Jeep Driver Posted June 23, 2017 Share Posted June 23, 2017 I like the way you installed your radiator, which one did you use? Efan or mech? Any problems with cooling? Do you have a forward pic? Link to comment Share on other sites More sharing options...
neohic Posted June 23, 2017 Share Posted June 23, 2017 I like the way you installed your radiator, which one did you use? Efan or mech? Any problems with cooling? Do you have a forward pic? My radiator came out of a Scout 800 with a Chevy 350 swapped in (why means it was cheap, used, and it was sitting around the shop) and I'm using the mechanical fan that came from the ZJ donor. I'd have more room if I went with an electric fan, but I really like the simplicity of a mechanical. I'm yet to see the temperature gauge go over 200 with this setup. Here's the best picture I've got off hand. It was before the lift, but it shows how tucked up my new front crossmember is. It hangs down about 1/2" lower than the stock stamped crossmember. I've got room though that I could've tucked it up higher... ah, well. My stock front bumper is temporary, but if I had decided to keep it and run the plastic lower valance then it would hide everything. Lots more pictures in my build thread too. :hijack: Link to comment Share on other sites More sharing options...
Jeep Driver Posted June 23, 2017 Share Posted June 23, 2017 Perfect, thank you. Good ideas here. :thumbsup: Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted June 23, 2017 Share Posted June 23, 2017 Awesome build! Wish I had thought of it years ago didn't think about 318 or 360 fitting in that engine bay since a 4.0 was difficult. Had a 318 until a few years ago I could of used. Btw for the 2.8 aside from being a fairly weak engine, clogged cats and bad transmissions / clutch can rob any remaining power. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
harris1986 Posted June 27, 2017 Author Share Posted June 27, 2017 Got an 89 running 4.0 XJ with 4x4 and 181K miles. Hope this will swap over to my 86 MJ easily, will also take the brakes and 4 inch lift kit Link to comment Share on other sites More sharing options...
Mj1986 Posted March 27, 2019 Share Posted March 27, 2019 Any recommendation in bererly starting my swap to 4.0 Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now