I just picked up a 4.0L motor complete w/ manifolds out of a 94 XJ. Has the injectors, trottle body ect. If I source a
engine harness and ecu from a manual XJ of near the same year, will this head bolt to my 4.2L block? Whitch pushrods should be used? Cam? ect. I can hardline the fuel system and run an inline 40psi fuel pump. What would be missing? I have an edelbrock performer 500cfm on an offenhauser intake right now and it needs to be rejetted as I nearly die from the exaust fumes (I bought it this way) I can install an o2. How can I make the crank sensor work? I have a source for a BA10 bellhousing in a 4.0L TBI XJ if nessessary.
Any thoughts?

It'll fit after a few mods. The 500 is too large for that engine.. If you put a new 390 on there you will be happy with the jeep. There is a lot of time and trouble included with the head change.. Including welding up some coolant passages. You may want to investigate quite a bit before starting.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

Padding that post count huh BJ <img src="/forums/images/graemlins/lol.gif" alt="" />
Oh trust me I know the 500 is too big, but like I said I bought it this way. Hence the FI possibilities. I do have the entire 4.0L motor, the bottom end just has low compression. I would be better to just build it and than install it instead of messing w/ the 4.2L. Probably could sell the 4.2L, Offenhauser intake, and the Carb and recoup most of my 4.0L swap costs. I was just hoping the 4.0L head would be a plug and play kind of deal...oh well.

Steps to buying and wheeling an old carbed YJ
step 1: Pull motor, peugot trans and small input xfercase.
Step 2: Pull weak axle assemblies
Step 3: Pull springs ect
Step 4: Replace it all w/ better stuff.
Step 5: Wheel it <img src="/forums/images/graemlins/shiner.gif" alt="" />

I've only owned this thing for a month and a half <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" /> <img src="/forums/images/graemlins/lol.gif" alt="" />

If you have both engines out you can change out the cranks and rebuild a monster engine in that ride.. Man I would go for it! I think it is a 4.6 fuelie when finished rebuilding.. The best of all worlds.
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

OH my Wyleone has the fever.... someone we know is working on a 4.0 head swap but is just going to carb it... I will be doing a 4.0 swap when I can clear a hole in the shop... and we will be stripping the other YJ soon... 4:10s for ya...

That happens??? <img src="/forums/images/graemlins/lol.gif" alt="" />

I keep thinking big but the 4.0L I have needs rebuild, the BA10 in it has a bad 3rd gear synchro, The rear is damaged from the previous owner got water in it and let it sit there till everything pitted. The diffs have 3.07 in them and I have 33" tires on it. I have to prioritize better and when the 4.0L core came up (no the 4.0L does not run) I started getting excited about getting a "Fuelie" (As Big Jim calls 'em) I'm not big on carbs but the rig wheels as you can tell from out trailrides section at FOR. So first things first, the hurt rear end must be swapped. They may be 30/35s but they will do till I get an AX15 in there to get rid of the hurt BA10. I already have an NP231 and I will SYE it and get rid of the xfer case drop. THEN I will swap to fuelie. I can build a Ford 8.8 later down the road to upgrade from the D35.

I keep having to remind myself repair whats broke then upgrade what is not. (Sounds like I need to put that in my sig)
BTW BigJim, that 4.6L fuelie sounds R E A L L Y good. Sounds like I have a new project to add to the list. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Yeah Wyle you have most of the parts at hand already. The thing should have the torque of a V-8 and not need all the adapters and mods of one. Go for it. If you were closeby I would put it together for you. Just for grins. <img src="/forums/images/graemlins/smile.gif" alt="" />
Big Jim <img src="/forums/images/graemlins/pfft.gif" alt="" />

heres some good ole write ups


http://novajeepers.com/images/Islander90/head/


http://www.off-road.com/jeep/new/40conv.html

http://www.rockcrawler.com/techreports/stroker40/index.asp

<img src="/forums/images/graemlins/cheers.gif" alt="" />

OOOOOOOOOOOOOOOOOOOO AHHHHHHHHHHHHHHHHHH I GOTTA BUILD ONE OF THOSE.it will be a hellova lot cheaper than going through hesco.one thing though the head bolts,i thought i read that one head had 1/2 dia while the other had7/16(thinking 4.2 had the 7/16. if that is the case which bolts do you use. if you use the 7/16 you will have space around the bolt and a smaller head so that is a possible problem.but if you use the 1/2 you will have to drill and tap the block.now as a reminder i dont remember which bolt was where or even which article i was reading(read so many lol) but if im wrong let me know before i do something i will regret later.

I'm gonna give it a shot. I have the head and exhaust manifold, just need to clean it up and get some gaskets. If the head looks flat, (I haven't checked yet) I'll probably just lap the valves and slap it on and see what happens. If it looks warped, I'll get it magnafunked and shaved and maybe a valve job. Maybe build that MPI stroker later when I get ready to retire the Cherokee! For now the MC2100 will do fine. We both have the 7/16 bolt hole blocks, Some kind of spacers for proper alignment (I've read 4 will do) and plugging the extra water jacket holes are the only issues I see. Your supposed to be able to use the same lifters, pushrods and even rockers as the 258. We'll see soon!<img src="/forums/images/graemlins/pfft.gif" alt="" /> <img src="/forums/images/graemlins/cheers.gif" alt="" />