I'm converting a chepo project vehicle from the 2.5L to a 4.0L that I got for a good price. I need to know how far to move the engine mounts forward. I hear its the same amount for a V8. Has anyone converted a 4 banger to an I6 or V8 before?

you will have to change the Engine, Trans, Transfer case also

the 2.5 uses the AX5 tranny and 21 spline X case (231)
the 4.0 uses the AX15 tranny and a 23 spline X case (231)

be sure to get the wiring harness, computer with the 4.0 also but be sure that the 4.0L computer you get does not have the Key microchip or you will need the key and chip reader in the seering columb... (PITA$$)

Brian

I plan on using a torqueflite 999 or 727 with the 4.0l which would mount to my engine. the 231 would also mount to the torque flite. Im aware of some shift linkage problems with 727 and 4.0 combo but im not worried about that yet. just need to know how far forward to move the engine mounts. Anyone with some suggestions on anything else that they think would be a good mod would be appreciated. it is an 89 YJ. Im putting a 14 bolt in the rear and a high pinion dana 44 in the front. Anyone aware of a junkyard upgrade for a disc conversion for a 14 bolt? thanks

So let me see, you are going to use a 14 bolt rear with a 44 front with a 4.0l. Ok, thats just excessive sir, you may need to hand over that 44 front to any friend of yours with a TJ. Oh, Wait....that has nothing to do with the engine. I bet we could figure out how far forward you need to move the mounts by measuring someones YJ or poss. TJ with a 4.0 in it. Mine for example would probably work fine...as long as it spaces from the radiator right....and your shifter stuff still clears who cares.

My two cents.:beer:

who cares is the shifter clears, i'll just cut a new hole! as for the fuel tank, i plan on a 15 or 22 gallon fuel cell and mounting it flush with the bottom of the frame rails and just opening up the sheet metal in the back. talk about clearance. i know no one talked about the fuel cell before, but I had to add in my idea. actually its your idea:flipoff2:

I am doing a simular conversion on my 94 Wrangler. I had a 2.5L and purchased a used 4.0L HO out of a rolled 95' Cherokee. I have the motor mounts measured at about 4" forward from original position. This depends on the block you have though. I can not swear that the mounts would be the exact same on a block from a wrangler, so you might want to check.

You basically want the rear of the engine to be in the same location as the original motor so the tranny shifter rod and the transfer case mounts will be in their original location. To do this measure from the rear of the 2.5L to the back of the motor mount. Then do the same measurement on the 4.0L and subtract the difference. This should give you the amount to move the mount on the frame.

I am probably at the same point in the conversion you are so maybe we can trade notes. Here is a link on my web page where I am posting pictures and information as I do the conversion. They might not help you at this point though.
2.5L to 4.0L Engine Swap (http://www.offroadoutlaws.com/TechTalk/40LEngineSwap/4L0EngineSwap.htm)

:D Ain't upgrades fun :D

Animal

wow I had forgotten about this post. I am currently looking for a 98 or so tranny and transfer case to mount to my 98 grand chero engine. My only current obstacle is money at the moment. It used to be the electrical side of things, which no longer scares me. I've learned a lot in the past few months. One is that you NEED the service manual from the year that your engine is comming from. Are you planning on using your existing wiring for the rest of your jeep? I am wondering because it is going to be a hulluva lot easier for me to rewire the whole thing. you should email me at thenodnarb@aol.com with your subject the same at the title of this post. we should talk about all the other aspects of this swap that we may have missed.

Originally posted by thenodnarb
who cares is the shifter clears, i'll just cut a new hole! as for the fuel tank, i plan on a 15 or 22 gallon fuel cell and mounting it flush with the bottom of the frame rails and just opening up the sheet metal in the back. talk about clearance. i know no one talked about the fuel cell before, but I had to add in my idea. actually its your idea:flipoff2:

I just did this swap a couple of months ago. if you are interested in getting the engine in the stock 4.0 location the only place I could get a good measurement and this was confirmed by the shop manager at a "good jeep dealership" (read mod frendly) was to measure the rear head bolt to the fire wall. the measurement was 1 5/8" to the center of the bolt. make sure you have the engine level when you do this too. and as far as floor clearance you will need to cutt one inch back from the shifter location.