KevinC506

To start off. This swap isn't worth it. No need to remind me.

There's a few reason why I've found myself doing this.
1) Motor has 99k and got it for a very low price
2) I work for Ironman4x4fab and we are making a swap kit.
3) Because I can and no one else really has

Lets start off with the basics so everyone is sort of on the same page.

The Block

99+ TJ and WJ 4.0 blocks have different engine mounting locations than XJ/ZJ and older TJ. Some bosses are shared on both and some non-existent altogether. The bolts in the pictures below represent where the brackets mount.

2000 XJ 4.0 Block.

Driver Side


Passenger Side




2006 TJ 4.0 Block

Driver Side


Passenger Side



The differences are small but prohibit the ability to mate to each others mounting brackets. What you can't see very clearly is the depths at which each boss resides. Specifically, the passenger side of the blocks, where they all sit at different depths. Driver sides are nearly the same except one boss on the XJ block is a hair deeper than the TJ block.

Here is the solution for the mounts. We took our regular XJ brackets and adapted them to fit the TJ block. Not only were bosses a bit difference, but the arm of the bracket that mates with the motor mount, actually sticks out farther than an XJ one.

Passenger comparison (TJ Left XJ Right)


New bracket



Wiring

This isn't as big of an issue, because we are all OBDII here, but still worth mentioning. The only things you will need to fix up front are some connections. For instance, the CKS is different. Both have the same wires just different connector that needs to be swapped over. You can either grab one from a TJ harness or order a new plug online or maybe at the parts store. All in all easy fix, just please use good wiring etiquette and do not use bag nasty crimps. Waterproof connections only

End of the day make the computer think it still has its original 4.0. I'm not too confident on what will and wont work in this category or what other differences there are in a newer year 4.0 compared to a 2000. Another one of those things I'll take as it comes. I don't anticipate much resistance here...get it? resistance? Ohms?

Accessories

Newer TJ and WJ 4.0's have their alternator, A/C compressor, and whatever else all backwards and up and down compared to us "normal" XJ people..With that, you have two options to make it all work.

1.) Keep the TJ setup. Not as hunky dory as it sounds. You're gonna have to run custom A/C lines and wiring to adapt to the XJ harness and setup. So you're still gonna have some work to do, but all in all probably less.

2.) Swap it all over from your XJ. This option was easy for me since the TJ motor didn't come with anything. Yes, I could source the parts needed, but whats the fun in that? After all I'm going against every logical and moral code from the arm chair mechanics sweating reading this right now.

This is where I'm at now. Motor brackets are off to be CNC'd and now its time to work on the other accessory mounts.

I'm making this post because I want this to be well documented and I don't see any other threads about people doing this. Again I wouldn't recommend this swap, unless you have a whole shop and lots of time. The cost to benefit ratio says sit back down and stop thinking these silly thoughts. Hopefully, when this is all done there will be a swap kit available to make this whole process easier. Getting harder and harder to find low mileage 4.0s and all this will do is open up the options a little bit.

Probably wont sell at all...but oh well. Just enjoying the fabrication challenge and to go against the grain.

Here's your disclaimer. I'm here to learn too. Any aforementioned information may be incorrect and I understand that. I will be updating information as necessary. By all means any input or questions is encouraged.

Im not here to promote Ironman4x4fab. This is just us working on a project and sharing our progress. We're people too.

Rojito

Interesting idea. I like it.

One quick question. Does the 06 4.0 have the same head issue as some of the 00-01 XJ 4.0s. I'm assuming Jeep fixed the problem by then.

KevinC506

No sir! That was fixed after 01. They made a stronger head there after which is desirable for us 00 and some 01 XJ owners.

Which is another point which I didn't mention. As we all may know already, heads are 4.0 interchangeable. So we dont have to worry about that if you had a TJ block with no head, doing a rebuild, or whatever.

Cane

people usually say that because someone thinks the swap will be to drop in the engine and everything will work 100%. you seem to know what you're doing so I'm sure it'll get somewhere!

KevinC506

lol thanks! Never really thought about that. When I grabbed the motor I laughed, not at the excitement of a new motor over the pile that I had, but what I was about to put myself through to make it work.

XJwonders

Another difference is that 05-06 throttle bodies are different and the idle control sensor is somewhat different or something. I'm sure that's nothing.

I'm interested in this type of swaps, like you mentioned, that ll open up a bit wider range of interchangeable blocks. Good start.

If anyone on the forum gives you problems, give me a heads up.

JeepMN

So if anyone gives this dude any problems what would you do exactly? Ban them? Because he has more knowledge than most about block swaps? Sorry to change the subject but...,

shooptube

I think he meant people saying that it was a waste of time, which it is not. I want to see if the alternator can be kept up top on the motor

Jeepin'_Aint_EZ

sweeeeeeet write-up. I'm interested to see where this goes.

Willys55

looks like you are off to a good start........


on a side note: if I stopped doing something because someone said it was a waste of time or stupid, I just moved forward with more tenacity than ever before.

KevinC506

Truer words were never said.

Going to start work on the Alternator and A/C brackets this week. So I will hopefully be able to share how that goes soon.

jon-d

Cool project!

OverlandZJ

I'd be eager to eliminate that 06 TJ dizzy.. are you familiar with "laughing monkey"?

See if you can figure a way to use the WJ style dizzy.

There's a large thread on JF about those.

KevinC506

To be perfectly honest with you, I have no idea what you are referring to. Please explain, I'm all about learning too lol.

KevinC506

Got the brackets today. They're monsters. Still need to weld the mounting bosses to the bracket, but bolted it up to show you how everything will be grabbing the block.

Passenger Side






Driver Side







So there's been a small change in plans for this operation. I orignally stated that we were gonna make brackets to fit the accessories from the XJ to fit the TJ block. This is now no longer the case. We have acquired another motor from an 05 TJ with all the bells and whistles for a seperate project other than this one. So, it only makes sense to use it since we've got it.

'05 TJ Motor



Will hopefully have the brackets fully made next week. Then I'll start the process of attaching all the accessories onto it from our donor motor. You maybe be wondering how are you gonna make that work? Well, its a lot easier than I previously thought now that I have it sitting in front of me. The Alternator sits literally above where it does on an XJ. So no modification to wiring. The A/C compressor is on the other side, so for some that's a problem and you will have to run A/C lines. Maybe if you grab the TJ lines it will be enough to make it work. However, I'm not running A/C (haven't for many years) So I will just be running the compressor as a place holder, maybe turn it into an OBA system down the line.

Those are the only real issues I foresee at the moment. Once I drop her in, I'll probably realize some pain in butt thing I didn't see before, but we'll cross that bridge when I get here.

On a side note picked up a new AW4 with 100k on the clock. So this whole drivetrain has been set back a 100k from where I currently was at lol.