Jump to content

4.0 swap, XJ to YJ questions


mjeff87
 Share

Recommended Posts

Didn't want to put this in Tech since it's not MJ related, but......

 

My non-wrenching neighbor just bribed me (with a case of Bud Light) to do an engine swap for him. What can I say, I like beer.

 

He's got a 93 YJ that his youngest son fubar'd the engine in (long story, but I'll confirm that you CAN kill a 4.0 if you try hard enough). He sourced a 95 XJ for parts close to here and wants to swap engines. I'm familiar with the XJ/MJ engine bay but have never been deep inside a YJ/TJ (although I own one..). Any differences between the long block between the two, or better yet, between the fully dressed engines? I'd like to do this as painlessly as possible and keep all of the accessories still bolted on if I could. Any tips on pulling an engine out of a SWB Jeep? I know the differences between the tranny X-member and the belly pan between the two, but not much else. How hard is it to pull the front clip on a YJ? Would I need to transfer anything over from the dead YJ engine to the XJ one, like motor mounts or the like?

 

Jeff

Link to comment
Share on other sites

I'd bet you need to change the motor mounts out, and maybe the exhaust manifold. the rest of the brackets and accessories aren't identical either...you may need to swap all of that.

 

the biggest thing I can tell you to swap is the flexplate/flywheel. they ARE different and it won't run w/o changing them. (I made this mistake with a 95 xj to 93 motor swap...)

Link to comment
Share on other sites

yeah, I already figured the flexplate and CPS. Never thought about the exhaust though :mad:

 

Wade, I'll take the beer for now :D , I'm actually kinda bored at the moment with noting major to really work on. I've got drop brackets to install on the MJ, but that's not really exciting.

 

Come June, though, neighbor-guy will be helping me move into the new house...he just doesn't know that yet :chillin:

 

Jeff

Link to comment
Share on other sites

Not sure about on the YJ, but I know on the Cj there is one center bolt for the grille/radiator support. I would definately pull that, and maybe both fenders. I am pretty sure that none of the xj acces parts will work on the YJ. It it was me.. I would hang both engines on a set of stands and swap everything over.

Link to comment
Share on other sites

I didn't see anything about what type of tranny each has in it. If they are both manual, you are going to have to deal with one being an internal slave (the YJ) and the XJ being external...in which case you will have to swap the bellhousings and all related clucth parts as well.

 

The front clip is pretty eeasy to take off of the YJ although just removing the grill is usually enough to make the swap easy.

Link to comment
Share on other sites

I didn't see anything about what type of tranny each has in it. If they are both manual, you are going to have to deal with one being an internal slave (the YJ) and the XJ being external...in which case you will have to swap the bellhousings and all related clucth parts as well.

 

The front clip is pretty eeasy to take off of the YJ although just removing the grill is usually enough to make the swap easy.

 

if he's just dropping the motor...he doesn't have to worry about the transmission. just needs to put the YJ flexplate on it.

Link to comment
Share on other sites

I didn't see anything about what type of tranny each has in it. If they are both manual, you are going to have to deal with one being an internal slave (the YJ) and the XJ being external...in which case you will have to swap the bellhousings and all related clucth parts as well.

 

The front clip is pretty eeasy to take off of the YJ although just removing the grill is usually enough to make the swap easy.

 

if he's just dropping the motor...he doesn't have to worry about the transmission. just needs to put the YJ flexplate on it.

I don't see where it says that he is working with an AT or MT though. My advice only applies to a manual trans, in which case there is a lot more to consider ;)

 

Obviously the term "flexplate" being used would make you believe it is AT...but, I learned a long time ago not to ASSume :thumbsup:

Link to comment
Share on other sites

I don't see where it says that he is working with an AT or MT though. My advice only applies to a manual trans, in which case there is a lot more to consider ;)

 

Obviously the term "flexplate" being used would make you believe it is AT...but, I learned a long time ago not to ASSume :thumbsup:

 

ok. let's recap;

 

old motor is junk

new motor is good

trans doesn't need replacement (so far as we know)

 

why does the difference between external and internal bellhousing matter then? he will need to swap the flywheel/flexplate from the 92 onto the 95 to make it run and everything match up anyways, so the bellhousing and clutch slave need not be considered.

 

didn't meanto ASSume, just used deductive reasoning

 

-Pat

Link to comment
Share on other sites

  • 3 weeks later...

Pulled the donor 4.0 yesterday, in a gravel parking lot (not fun, took about 2 hours) :dunce:

 

Gonna pull his dead motor tomorrow, then stab the new one in hopefully on Wednesday night after work..

 

Image Not Found

Link to comment
Share on other sites

  • 2 weeks later...

swap plans got waylayed by a visit from the inlaws last week :ack:

 

Got the YJ and the "new" motor down to the garage, ready to go at 0600 tomorrow. Today's the wife's birthday and she already threatened divorce if I try to start on it tonight......

 

If anyone's around and wants to come turn a wrench or drink breakfast, c'mon down. Same place that I did my engine swap at. Gonna try to knock it all out tomorrow so I can take my wife out Sunday for dinner (and miss the nascar race).

 

Jeff

Link to comment
Share on other sites

While all y’all were getting’ yer panties in a bunch here :shake: , some of us were wrenching over the weekend (and drinking copious amounts of beer) ;)

 

Finally got started Saturday around 10 AM:

 

Image Not Found

 

The blowed-up 4.0 :ack: :

 

Image Not Found

 

Got the front clip off and got goin’:

 

Image Not Found

 

Dead soldier, out:

 

Image Not Found

 

New soldier, going in later that afternoon:

 

Image Not Found

 

Got it bolted in and called it a day:

 

Image Not Found

 

Went back down this morning and realized the water pump had to be swapped, did that, bolted everything else up and fired it up. It ran, surprisingly…. :yes:

 

Image Not Found

 

Had a tranny cooler line leak and a fuel line leak (at the tank), fixed both, and drove it home:

 

Image Not Found

 

Couple things I learned about the differences between a XJ/MJ and a YJ/TJ 4.0. The passenger motor mount brackets are the same but the driverside one is different (found that out the hard way), and the water pump snouts are different as well as the alternator/AC compressor brackets. Like Pat said too, the flexplate differs from a 93 to a 95 as well.

 

All in all, a pretty fun swap and a good way to spend a weekend :cheers:

 

Jeff

Link to comment
Share on other sites

Picked a good weekend to do the swap....it just started snowing when we pulled it out and drove it home. About a foot later, he's now taxi-ing his whole family to work and what not jamminz.gif

 

Image Not Found

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...