4.0 MPI/Head on my 258

[ThisGuyUKnow]

I just purchased my first CJ7 a few weeks ago. I have been reading up and think I want to do the conversion in my title. I have never done anything like that before however. Just wanted to post here and see if anyone had done it and would be willing to give me a parts break down. I may have a line on a donor 2000 xj but it is an auto and my cj is a manual.. Not sure if that will make a diff in the conversion.... I am firguring on the CPS relocation kit to avoid having to mod the bellhousing or fly wheel. So i figured I might as well get the serpentine from the donor(can i retain my ac compressor if i do that?). What all parts do I exactly need besides the obvious ones to accomplish this project.

 

[elwood blues]

Hi ThisGuyUKnow, welcome to the site.

That's a nice looking CJ you picked up. I don't know of too many people on this site that have done a 4.0 head swap. From what I have read on other sites, it can be be a little tricky to get everything hooked up correctly, but once you get all of the wrinkles ironed out it's a rather reliable set-up. Let us know what you decide, and again welcome to the site.

 

[BrockGrimes]

One of my favorite links:
Tim Weavers 40 Head Article

I have more info listed in post #15:
http://www.jeep-cj.com/forums/f49/useful-info-thought-id-share-665/

 

[ThisGuyUKnow]

The build plan is:
1. I have the 4.0 head already set up ready to install. Has a three way valve job no other mods and is coming from a AMC 258 i6 / 4.2l from a member in another forum who did the head swap but is now going a diff direction. This part seems fairly straight forward and i am 98% that i have a good handle on it.

2. MPI from a donor 4.0.
This is where I start to get sketchy. I know i can get all the physical parts installed but I am not sure about the wiring. My buddy found a 2000xj for 500 bucks with front end damage. For 250 he said that I can have all the parts i want plus go 50/50 on the part out from the rest of the truck(he needs some parts for his xj). The good about this situation is that all the parts will come from one vehicle and if i forget something I can go back to the truck and pull it. The problems is that it is an OBII system and was originally Automatic and I can see a whole lot of potential headaches with the wiring since I have a manual and the OBII is more complicated. But for 250 maybe less when you consider the part out the headaches may be very well worth it.... Assuming that it is possible to get the OBII to see things my way. I
3. I want to go ahead and spend the $$ on the CPS relocation kit and it looks like the one that i saw was for a serpentine set up. This got me thinking since I go access to the donor is it possible to take all the serpentine components of a 4.0 and put them on the AMC 258 i6 / 4.2l with 4.0 head? If so can I retain the A/C compressor where it is(may have to buy a new one set up for serpentine but that is ok).

In the end I am hoping to have a AMC 258 i6 / 4.2l with the dependability of a modern engine. A boost in power from the FI should put me close to the modern 4.0s and put me in the vicinity of 15-18mpgs. Any help or resources would be great

 

[BrockGrimes]

See my post above.

 

[ThisGuyUKnow]

See my post above.

the link to the MPI wont open install

 

[BrockGrimes]

The 40 head article?

Check my other link post down adn post #15 there are a few more links, and there's one at the top of the page also.