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from 2.8 to 4.0


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ok so i have an 86 with a 2.8 mj, well i had bought my brother an 89 mj with a 4.0, the rust in it is really bad and rustin away the frame and kinda looks fixable but if not i get the 4.0 engine, would the 4.0 fit in the engine bay of an 86 mj without cuttin away at the fenders and would my AX15 (or AX5 if i ever convert to 4wd) handle the 4.0?

 

Redwolf

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1. You don't have an AX15. It was only used behind the 4.0L from mid-1989 on. You have an AX5 or possibly a T-5.

 

2. No cutting of fenders is necessary to fit a 4.0L into an '86, but cutting and/or reshaping of the firewall might be necessary. Of course, since you have the '89 donor vehicle, you could graft in the '89 firewall.

 

3. As to the XJ with the rusty frame -- the XJ is unibody. It doesn't have a frame.

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Yes, the 4.0 will fit in the '86 engine bay with a slight massaging of the fire wall and you'll have to do some fab work to fit the radiator.  The AX4/5 won't bolt to a 4.0, so your only reliable option is an AX15 (or NV3550) if you want to keep it a manual.

I know these hit mostly on 2.5L to 4.0L swaps, but there should be some relevant info here:
http://comancheclub.com/topic/39539-links-for-25l-to-40l-swap/

 

Also, here is my build thread when I started my swap.  I've got some pretty good pictures and details on how I fit the 4.0 radiator in the '86 model.  It's not a challenging as you would think.  I had never done something of this magnitude until I took on this project.  I drive my MJ almost every day.

http://www.cherokeeforum.com/f46/86-comanche-dd-159524/index4/#post2542580

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sorry had a brain-fart bought what trans i have and if the ax4 doesn't bolt up to the 4.0 what auto trans came with the 89 MJ elimanator? and Eagle, it's a donor MJ not XJ and it looks like a frame what's rustin (as seen in picture below)

 

Redwolf

 

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