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Discussion Starter · #1 ·
Cherokee 4.0 in a CJ-7

I've got an 84 CJ-7 5 speed. I was going to have the original engine rebuilt and fixed up a bit. The place that is going to do it recommended dropping in the 4.0 out of a Cherokee they just bought for the tranny. He said I would have to buy an adapter but other than that they could swap it out. Gains of this that I can see would be fuel injection and a little added horsepower. How does this set up sound?
 

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depending on what your original engine was you could see loss of power and harder to work on with all the electric components on it.

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Blue 1981 CJ5 31" tires
*Damnit, anyone see where that door went?"
 

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The 4.0 litre from the XJ must be swapped as a complete unit to function correctly including the computer(s) and associated sensors. The 4.0 is fuel injected and needs all of sensors etc to run. You may also need to change the fuel pump to an electric pump to get the required fuel pressure if your CJ has a mechanical pump. One of the main reasons for swapping the 4.0 into a earlier Jeep in for the fuel injection which performs well at different altitudes and angles on the trail. As Jeepasaurus points out you could see a little less power as the 258 provides a bit more torque. The more computers and engine management systems that are added to an engine the more complex it becomes for backyard / trail fixes.

Rob Hogg
'90 XJ / '01 TJ
 

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Ya could keep the 258 and use a 4.0L HO head and computer/fuel injection/etc and stroke the 258...


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Phil M. - Kent, WA
95 XJ Sport w/Stuff
"Who cares about a list of crap, can you drive it?"
 

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Discussion Starter · #6 ·
Rgr, I'll talk these points out with the guys doing the work. I know he said he would be installing all the computers and sensors with the swap. I'll have to check on the fuel pump though. Would the loss in torque be a huge loss? I'm not trying to big dog my jeep at Rubicon. But I don't want a tinker toy either. Would it be better to go with nikon_jeeper's idea?
 

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Rhino, Rob Bryce may be able to further explain the idea I brought up...

If I understood correctly, you could use a 4.0L computer and the HO head...you could do a basic rebuild on the 258 and the 4.0L (242) head bolts right on...then you don't have to worry about adapters or power loss...and you'd be fuel injected.


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Phil M. - Kent, WA
95 XJ Sport w/Stuff
"Who cares about a list of crap, can you drive it?"
 

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Discussion Starter · #8 ·
Ok, I went to the shop last night and talk to the mech's, they said they are putting all the computers in along with new cords, hoses, pistons, total rebuild. I asked about putting the Fuel injection on the 258 they said it can be done but they've never done one. I don't want my jeep being the test pilot. The day after I pick it up Im driving 600 miles, then moving to Hawaii. So if theres any problems I'm screwed. I think i'll just stick with the full 4.0 swap, as long as I don't lose drastice power its all good. The 258 is stock now but I dont plan to leave the 4.0 stock, again nothing monster just a bit more, headers, exhaust stuff like that. He did say yes on the electric fuel pump and that he will be putting in all the sensors and computer stuff. Thanks for the help.
 

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Rhino, I think you made a wise decision based on your move. The 4.0 litre is a very common engine so getting someone to work on it should be no problem where ever you go. With the swapped head I would like to stay around the shop that did the work for a while to make sure there are no bugs. If you do find the power lacking there are lots of additions for the 4.0 to pick it up a notch.
For those interested in the 4.0 litre head swap I did find a couple of articles with details.
http://www.monsterslayer.com/jeep/40Head/40Head.htm http://homepage.mac.com/jefe/4to42.html

Rob Hogg
'90 XJ / '01 TJ

Happy New Years to all!
 

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Oh well yeah, in your situation that sounds like a great idea. I personally am a tinkering soul and love a constant challenge.
But...if I were moving I would just do the "go with what ya know" mentality, as you are. Good luck!!!


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Phil M. - Kent, WA
95 XJ Sport w/Stuff
"Who cares about a list of crap, can you drive it?"
 
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