2.5L to 4.0L Conversion

Jeepz4Mee · #1 (**permalink**) 01-31-2008, 04:51 PM

I have finnally found a motor, however, the motor is from a 92' YJ and was modified to a carburated engine. The question at hand is do I buy the engine and then find an ECU and EFI, or do I just find a full package deal with an engine and everything? I told the guy I would buy it this weekend for $300 bucks. I know its a good deal since I plan on rebuilding the engine myself. Also, how hard would it be to install the engine with a carburator then replace the fuel system with a injection system?

yjdave · #2 (**permalink**) 01-31-2008, 05:40 PM

Get the whole thing. the ecu and wiring harness need to match(kinda) in years. where you located. I can get a running 95' w/harness/ecu for 200.00. why not look for a low mile total and get everything for under 1G.

Jeepz4Mee · #3 (**permalink**) 01-31-2008, 10:03 PM

What years should I look for and what kind of make can I use? I am looking for a 4.0 with the ax-15 tranny. So you think that a carburetor is not the way to go?

Bounty__Hunter · #4 (**permalink**) 01-31-2008, 11:54 PM

Why swap to the 4.0L? You end up with another 4.0L jeep with a hacked up engine bay. Do something unique, something that can make more power, is cheaper, and has a larger aftermarket following. Like the 4.3L Vortec or SBC.

Jeepz4Mee · #5 (**permalink**) 02-01-2008, 10:35 AM

The reason for the 4.0 conversion is that I want more power, and at the same time, have it not be a very tough conversion. They made a YJ with a 4.0, so I was thinking that the parts that I do have, such as tcase and differential, will not have to be replaced or modified. Also, I wanted to have it inexpensive (under $1500) for the conversion, and since there are a lot of grand cherokees and wranglers out there with that engine in it, I thought that this would be an easy engine to find. If you think that this is a bad choice please tell me.

Bounty__Hunter · #6 (**permalink**) 02-01-2008, 10:15 PM

It's not as easy a swap as you may think. You still need to cut the motor mount perches from the frame and move them forward for the 4.0L, and change the input shaft on the transfer case to match the output of the tranny behind the 4.0L. You will need a new engine harness as well, custom or from a 4.0L donor. These are all things you need regardless of swapping a 4.0L, 4.3L, or 5.7L. You're choice isn't necessarily a bad one, just not much easier than swapping in better engines. Something to chew on.

KingJMc · #7 (**permalink**) 06-04-2008, 07:41 PM

I'm a new member due to searching the web for people w/2.5L to 4.0L conversion experience and found Jeepz.com.

I read your post and wanted to know how your conversion worked out. Did you complete the conversion?

How did you resolve the motor mount problem?

I’m in the process of converting my 2.5L (blown motor) to a 4.0L and ran into the motor mount problem. I searched around for motor mount conversion kits (brackets) and only found 350 chevy/buick motor mount kits.

It does not look like anyone makes motor mount conversion kits 2.5L to 4.0L?

I’m guessing the only option is to cut and weld?

I have a ’95 Jeep Wrangler YJ and the donor motor came out of a ’93 Jeep Cherokee.

How did you resolve the motor mount problem?

Thanks.