yj 2.5l swap with a 4.6l stroker...... =]

[NorCalChris]

I am in the process of building 4.6l stoker. Its designed to run off the early obd 1 jeep ecu. There is this yj I might get. Its a 2.5l.....(gay i know). I want to put my stroker into a yj. As far as swapping a 4.0 into a 2.5 wrangler, what all is involved? I know I need a 4.0 and tranny combo, ecu, harness, and im gonna assume different engine mounts, but is there anything I should know about? Is the firewall in a different location on the 2.5 then the 4.0 wranglers? Does anyone know of any threads on any forums where someone has documented this?
I joined wrangler forums today, and so far I am completly pissed off I wasted my time. From browsing the site, it seems like not too many people know what the hell they are talking about. I searched, and everyone who has asked the same question gets a few respones all saying "swap a v8" or "sell the wrangler". I'm not gonna swap a V8 in and if there was yj with a 4.0 id definitely choose it, but this one seems to just work for everyone.

 

[VAhasnoWAVES]

the 4.2 liter that came in the YJs is physically bigger so the 4.0 will fit. but your going to be completely rewiring the jeep. i dont know of any motor mounts for this swap, so they may be custom as well. so will your exhaust. harder has been done.

ill give you another answer you dont want to hear... forget the 4.0, do a cummins 4bt. :laugh3:

you should ask a mod to move this to the advanced fab section, you may get more responses.

 

[NorCalChris]

The 4.0 also came in the yjs. Thats my issue. It seems like this swap is just too much work to do. Its not hard work,but its not simple. Buying a yj with a 4.0 makes it easy. All I have to do is swap in my stroker, play with my fuel presure and ignition timing and there I am on to fabbing. it looks like I might be headed that way now. mods. if you want to move it feel free to do so.

 

[VAhasnoWAVES]

oh, i failed to remember. though the YJ manuel i have does have 3 engines listed. one of which is the 4.0.:doh:

would be EASIER to grab a junked YJ with a 4.0 and steal its harness than fit one from a cherokee. or you could just snag the axels from the 2.5L for the 4.10s and then search for another YJ.

 

[NorCalChris]

I want a rig that is simple, and reliable. This is what I want to do with a YJ.
4.6 stroker, manual trans, locked and shafted Dana 44's, 5.28's, 35's, caged tied into rock fenders and body armor. Where I wheel, that would be fine. That's what I want, that's what I'm going to build. Someday. I decided, it's not going to be today. haha

 

[joe_peters]

I guess I'm not seeing the difficulty with such a swap. The YJ came with a 4.0, so that means there are off the shelf engine brackets and mounts. The crossmember could be an issue, but that would be simple to fab. The only thing you would need to do for wiring is the engine management--ECU/PCM, harness, all the sensors you already have. Everything else should be fairly simple.

I say go for it.

 

[NorCalChris]

I just gaduated from school. I need reliable transportation, and my jeep is very reliable. new engine, all new engine mangagement sensors, great tires, and I like it. the yj has an old and tired 2.5l that cuts out. gets worse gas mileage then my 4.0, needs work and really dont have time for this project just yet. i kinda jumped on it with out doing any reasearch. its not that the swap is hard, its the lack of my time and money to do a project right now.

 

[kastein]

iirc in either the yj or the tj, the engine mounts are in fact different and are welded to the frame... you can swap between them yes, but you're better off swapping your running (sorta) 2.5 yj for a 4.0 or 4.2 yj and then putting in the stroker. Unless you want to be welding stuff that is.

 

[leftlanetruckin]

Here are results from 30 seconds on Google..
http://www.google.com/search?hl=en&...hts=&as_occt=any&cr=&as_nlo=&as_nhi=&safe=off

Quick summary:
Motor mounts will need to be cut off and new ones welded on.
Crossmembers were real close if not the same IIRC.
Wiring is wiring, but I have heard of folks just adding the wires for the 2 extra injectors to their harness' and plugging them into the ecm (same plug for the 2.5 ecm and 4.0 ecm IIRC)
MPI 2.5 fuel pump will run a 4.0 just fine.
No differences in firewall etc between a 91 up 2.5 and 4.0 (dont know about the tbi 2.5's and 4.2's)
Oh yeah, a SBC or 4.3 is easier to fit in the YJ's engine bay:yap:
Martin

 

[kastein]

Here are results from 30 seconds on Google..
http://www.google.com/search?hl=en&...hts=&as_occt=any&cr=&as_nlo=&as_nhi=&safe=off

Quick summary:
Motor mounts will need to be cut off and new ones welded on.
Crossmembers were real close if not the same IIRC.
Wiring is wiring, but I have heard of folks just adding the wires for the 2 extra injectors to their harness' and plugging them into the ecm (same plug for the 2.5 ecm and 4.0 ecm IIRC)
MPI 2.5 fuel pump will run a 4.0 just fine.
No differences in firewall etc between a 91 up 2.5 and 4.0 (dont know about the tbi 2.5's and 4.2's)
Oh yeah, a SBC or 4.3 is easier to fit in the YJ's engine bay:yap:
Martin

this is a REAL important point! If your pump is for ANYTHING other than mpfi it needs to be swapped out. A carbed setup will probably have a mechanical pump or a very low pressure electrical pump, and a TBI setup will have a ~14.5psi electrical pump. Neither will drive a 6cyl MPFI setup.

He's going from RENIX or OBD-I (or carbed, not sure which) to OBD-II so the wiring harnesses and sensors will all be changing, so some of that doesn't really apply, but the rest is good solid info :thumbup: