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1986 4.0 swap


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This week marts the start of the engine swap on my 1986 MJ. Right now the jeep has a 2.5  in it with a ax4 transmission and a np231 transfer case. The old 4 banger is at its end with a rod knock and complete loss of power. 

 

Right now the jeep has 36 in super swampers with stock gearing a stock axles. I bough it last summer and have slowly found the good and bad 

 

Good :  Has spring over conversion done with pucks and new coils up front. Has a rustys track bar and brace combo. There is almost no rust minus 2 small hols in the floor pan and the passenger tail light area.

 

My plan is to start at the front with the engine and drive train and move my way to the back then to the inside.

 

1st. 1994 4.0 out of a grand cherokee and parts from a 1993 cherokee

2nd. built dana 44 axles ( its not a rock crawler so i don't think dana 60s a needed )

3rd. short bed conversion. right now its a long bed so i would like to buy a short bed a cut the long bed to the shackles for a better departure angle

4th. change from red to a olive green along with rust repairs

5th. and this point i will and new bumpers and a winch and any other work i missed on the outside

 

 

I don't want this to be a straight mud truck or rock crawler. I want to to be a reliable off road truck that i can go out and adventure in but not have to trailer it to trails. 

 

I am open to suggestions and advice but please be respectful, there are many different ways to do things and its up to the owner to decide how to do it . 

 

I will post pictures as soon as i have made some progress 

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In my experience, the weak point of hp d30 is the u joints. Even the larger ones.

 

They are the exact same u joints used on d44 axles. So you would be giving up ground clearance from the larger pumpkin, while still having the same weakest link.

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  • 3 weeks later...

i have completed a lot since my last post 

 

1994 zj engine is in now, for some reason when i used the engine mounts and frame brackets i ended up having to use the driver side frame bracket for everything to line up.

 

i didn't bang the fire wall back enough to have room to get the the transmission bolts so I'm just going to cut the fire wall from the inside to get to the bolts and then weld in a new piece of metal .

 

i have some electrical things to deal with like getting the new harness to work with the old steering column. 

 

the engine seems to sit a little high so the zj ac compressor is hitting the hood, guess i gotta swap that for a xj compressor. 

 

still need to get the radiator fitted in 

 

i have the new clutch so i can get the transmission in 

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i have completed a lot since my last post 

 

1994 zj engine is in now, for some reason when i used the engine mounts and frame brackets i ended up having to use the driver side frame bracket for everything to line up.

 

i didn't bang the fire wall back enough to have room to get the the transmission bolts so I'm just going to cut the fire wall from the inside to get to the bolts and then weld in a new piece of metal .

 

i have some electrical things to deal with like getting the new harness to work with the old steering column. 

 

the engine seems to sit a little high so the zj ac compressor is hitting the hood, guess i gotta swap that for a xj compressor. 

 

still need to get the radiator fitted in 

 

i have the new clutch so i can get the transmission in 

 

You'll have to swap over to XJ/MJ accessories and belt configuration to get everything to clear.  Also, as you noted, swapping the driver's side frame rail engine mount is necessary because the 2.5L's weight is distributed different since it's shorter.

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  • 2 months later...

Since the last post the project went from going good to a dead stop and then jumped to going amazing

 

I had a lot of trouble getting transmission in and basically took all of August off from working on it. But I took a whole day this Tuesday and everything just seemed to go together

 

List of things still have to do

 

Modify rear drive shaft (already cut to length just have to weld)

 

Get front drive shaft ( have one but for some reason the yoke on the transfer case is a different bolt style so I need a different one or different drive shaft)

 

Bend clutch line a bleed clutch

 

Wire up the rear lights

 

Fixed the fuel sending unit, it's not reading any fuel

 

Fix coolent temp gauge

 

Finish up the interior wiring so the courtesy lights work and so the stereo works

 

Weld exhaust on

 

Clean up engine bay ( make sure all the wiring and lines are not rubbing or going to melt)

 

Fit electric fan

 

Weld up transmission tunnel

 

Fix horns

 

Seems like a long list but the engine starts and runs great the rest should go easy

 

 

Pics will follow soon

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Since the last post the project went from going good to a dead stop and then jumped to going amazing

 

I had a lot of trouble getting transmission in and basically took all of August off from working on it. But I took a whole day this Tuesday and everything just seemed to go together

 

List of things still have to do

 

Modify rear drive shaft (already cut to length just have to weld)

 

Get front drive shaft ( have one but for some reason the yoke on the transfer case is a different bolt style so I need a different one or different drive shaft)

 

Bend clutch line a bleed clutch

 

Wire up the rear lights

 

Fixed the fuel sending unit, it's not reading any fuel

 

Fix coolent temp gauge

 

Finish up the interior wiring so the courtesy lights work and so the stereo works

 

Weld exhaust on

 

Clean up engine bay ( make sure all the wiring and lines are not rubbing or going to melt)

 

Fit electric fan

 

Weld up transmission tunnel

 

Fix horns

 

Seems like a long list but the engine starts and runs great the rest should go easy

 

 

Pics will follow soon

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  • 1 year later...

The ole 4.0 into the 86. Gotta love the modifying of the firewall for fit. When i did mine i was pretty gentle and delicate at first. After removing and installing the driveline as a whole unit prolly 6 or more times only to barely get my fingers between firewall and trans/engine I went full Hulk mode and cleared the hell out of it.

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