Made some more progress the past few days, most of which was made tonight. I tackled the dash and HVAC system (in my case, just HV lol). Dash removal was pretty straight forward actually. This write-up helped a lot: Dash removal - Jeep Cherokee Forum. I also opted to remove my steering column/wheel. I'm going to clean up the firewall a tad from where the MJ had a leaking clutch master cylinder at one point. Removing the steering column helps. I also pulled out all the internal wiring harnesses minus the two plugs that go to the B-pillar dome lights, fuel sender and tail lights. Next course of action is seeing whether or not I can get that donor XJ to fire up. Last time I know, it would turn over but failed to start. Think the fuel pump may be shot but we'll know soon. Anyway, the other bit I got done was welding in some bottom radiator supports that I cut out of some 3/16" steel plate. Overkill, I know, but its the only flat steel I had around. But enough of that, it's picture time!

 

very cool keep up the nice pics and write ups. i am going to do the 2.5 swap to a 4.0 on my Dads 88 Comanche. i have a 89 4.0 with engine harness and cpu.

 

I'll keep the pictures rolling... They do a little better job explaining what I've done than words lol.

 

The only way to keep people's interest in build threads, is posting photos. Keep up the hard work.

 

Today, I gave the firewall a heavy dose of the BFH of Thor. I beat on that thing for 30+ minutes. Wire wheeled it and bed lined it. I think I knocked it back in the correct area to fit the 4.0, judging by pictures on the interwebz and loose measurements anyway. If it's not right, then I'll just go with my original plan of cutting and rewelding. Phase 2 will begin as soon as I get my donor XJ from my parent's house to mine. I am also planning on picking up a NP242 transfercase on Thursday from a '92 XJ to mate to my AX-15.

 

Picked up some turbine rims today and a NP242 a few days ago. Going to paint the rims black and put some different meat on 'em.

 

Those are gonna look sweet, always loved the turbines

 

I can say with confidence that Phase II of "4.0L into an '86 MJ" is a go.

I spent the past couple of days diagnosing the no start condition on my donor XJ. Two things were wrong. First was the fuel pump was toast. Applying power did nothing more than make it hum as it was stuck and unable to turn. Pulled another pump assembly from a parts XJ I just happen to have laying around... Anyway, put that into a tub of gas and went to go start the old girl after about 3 years of sitting and... nothing. So, I moved on to the next likely culprit, the CPS. As per cruiser54's helpful tips and tricks guide, I tested it for AC signal and it failed miserably. 0.2 VAC was all it would generate, definitely a no start condition. So I swapped in one that I knew worked and viola, the beast lives! Stupid me had a "ruh-roh" moment... forgot to hook the transmission fluid lines back to the radiator and, well... pumped all the transmission fluid all over the radiator and engine... Oh, and all over me... But anyway. So now I can move on to ripping that sucker out and getting it mated with the rest of the drivetrain and my MJ.

Oh, I also got most of the final aspects of the radiator top support and hood latches done. Welded some nuts to the rails so I can bolt down the top support. Also spent an hour or so and wore out 5-6 drill bits getting those seized CPS bolts out of my bellhousing. Ended up drill all the way through the bolts. I'll have to tap them, but at least its out. W00T! Anyway, once I get the drivetrain mated, I can see where I'll need to place the tranny crossmember at. Everything else will just be wiring and dash swap stuff. Maybe I'll be done with it all by the end of the year.

 

Got some of the piddly little junk done on the MJ in the recent days, mainly with finalizing the hood latches and so on. Welded in a small strip of metal to give the bottom of the passenger side hood striker something to bolt to since it was just hanging in the headlight opening. The driver side one is on the edge of the headlight opening, but seems to be sturdy, so I may just leave it as is. Also pulled the hood from my donor XJ and got it mounted. Wanted to make sure that everything lines up correctly. Test fitted the front clip and it lines up beautifully as well.





Also pulled the dash from my parts XJ as it is not cracked like my former dash... only thing is, it's gray and the rest of the interior is tan. So, either I'm going to spray the dash tan or change all the interior to gray, which I can do mostly with XJ trim.

Lastly, I got the drivetrain buttoned together. Went to Lowes to get some new nuts for the transfercase bolt studs. In case anyone is wondering, they're 3/8"-24. I also removed the original ignition cylinder from the steering column as I will be putting it into my donor XJ's column. I wanted to use it because I have the original keys (Jeep AMC logo branded) and that to me is pure awesomeness.




Anyway, I am trying to sell the former engine and drivetrain as it is still fully functional. If I can get that sold, I'll buy the various parts needed to finish this swap (clutch kit, external slave, 4.0 fuel pump, etc...).

 

Some progress has been made...

Got my donor XJ pulled over here about a week or so ago. Started the tear down by getting things separated from the engine so it can be pulled soon. Also pulled the various things needed to swap into the MJ. So far I've pulled the engine harness, dash harness, cruise control harness and vacuum motor, HVAC box, steering column and steering box.

On the MJ, I painted the engine bay satin black. Looks 200% better. Anyway, I've gotten the engine harness placed, relay center bracket fastened down, HVAC box installed and steering column installed. Next will be the steering box, cruise control harness, dash and dash harness. Also I will be swapping the coil springs as I am told the 2.5 and 4.0 use different spring weights. Anyway, time for pictures...

 

You've made some changes since the last time i saw this build. Keept it up!

But you have me curious to ask..?? What was the point behind laying a beatdown on the trans tunnel? Last i knew putting a 4.0 into an MJ didn't require any tunnel deformation... I did the 4.0 HO swap in my 87mj and i'm in the process of my 2nd swap in my 86 longbed MJ and have had no issues with it at all...

 

The '87+ firewalls don't require modification as they were the first year of the 4.0. The '86s may or may not, depending on how early or late in the year they were built. At least that's what I've been told on ComancheClub.com. Mine is an early '86 for sure, hence the BFH of Thor on the location mentioned. I was going to cut that section out and weld in the same area from my donor but my welding isn't great and I'm not going to see the bumpy section 99% of the time so, I'm not worried too much. Biggest need for that area to be moved back is to give clearance for the head and manifolds. Again, that's what I've been told on CC. It'll make changing out the CPS a little easier (I hope).

Question for you too... Why is the link to your build thread for your '86 MJ in your sig go to somebody's '86 XJ build?

 

Holy Eff, thanks for the heads up lmao. Its fixed now. I don't really know how that happened.


i guess time will tell how much room you will have around your tunnel. i'll be keeping an eyeball on it

 

Just read through some of your build and it seems you've pretty much got the same project going on with your '86 as I do. Be sure to pass on some helpful tips and tricks.

 

Phase III officially started today.

I've removed my 4.0 from my donor today, but unfortunately not without a few broken pieces/parts. Managed to snap the O2 sensor clean off, as well as snap the back of the starter solenoid off and I broke the barbed elbow for the return line on the power steering pump.

Minus that, removal went mostly well. Took longer than it did when I removed the 2.5 from the MJ, but I figured it would given the longer drivetrain. Got the AW4 separated just a few minutes ago and the Renix flywheel that I got a couple of months ago is now sitting comfortably bolted to the crankshaft.

I ordered my LuK clutch kit and pilot bushing yesterday from RockAuto. Should be here in a few days and then I can button my new drivetrain together. My biggest concern here is what to do about the automatic transmission control unit. I know you have to bypass the NSS so the ECU will allow it to start, but where I'm not so sure is whether or not I need to keep the TCU plugged in under the dash or if I can remove that entirely. Gotta research that...

Luckily, as far as the bits that I broke upon removal, I have an extra starter, O2 sensor and my old PS pump from when I did my stroker swap and had to convert to the HO PS pump for the '99+ intake mani. Still pisses me off though haha. Who's ready for me to shut up and just move on to the pictures? lol