2.5 to 4.0 engine swap

RickyOchen

RickyOchen

New Member
Joined
Dec 10, 2021
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5
Location
Medina, Ohio
I am considering swapping the engine to a 4.0, and had a few questions for the gurus on here.

I found a couple of gems on FB marketplace that are too good to pass up. From reading on here I see the 97-99 TJ year is what I would be looking for which I found a 4.0 w/32rh Auto 109k all wiring w/ecm. The other engine I found is a 2000 with just the engine, wiring & ecm I would need to get a new tranny for this setup which is my least fav option here though for the price I could still be under budget.

My question's on this would be what would I need to get to make this fit in my '97. I read mixed comments on radiator and accessories including the AC. Also what year 4.0's I can use. It's a Jeep so AC is def not something I even use though mine does work, lol. Now I do know I will need an exhaust, motor mounts and a different drive shaft?

Any help would be appreciated, I am getting everything ready so when I drop the ball on this all I need to do is drop it off to my mechanic and he'll handle the rest.

Thanks in advance.
 
I’m sure it can be done. Why not sell yours and buy a 4.0? Not sure that swap is worth the effort when it can be bought?
 
I bought his for my son and I will be honest fell in love with it, lol

I want to keep fixing it up and I REALLY want that AMC 4.0!!!

you do make a really good point though, maybe I am done with his and I buy my toy now hahahah
 
RickyOchen said:
I bought his for my son and I will be honest fell in love with it, lol

I want to keep fixing it up and I REALLY want that AMC 4.0!!!

you do make a really good point though, maybe I am done with his and I buy my toy now hahahah
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If you enjoy the process and the project have at it. It could be a fun build. I just think for the couple thousand you will spend completing this you could sell your Jeep and add that project money and have a factory installed power plant.
 
Figure about 3500 to do it. Lots of odds and ends add up if you get a motor missing accessories like acc brackets and power steering lines that don't transfer over from one to the other. motor mount brackets, etc.

The used 4.0 may be of 'unknown' quality. I had to rebuild most of mine.

The added injector wiring was fairly easy once you get the pins you need.

Need a transmission. Hopefully it mates to your existing transfer case (differences in input gears)

Might need driveshafts? My front was too short after in my YJ.

All-in-all, id just not do it again and buy a nice 4.0 model.
 
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For the time/effort/expense/headache you could of had a V-8. Honestly depending on the year it's a lot easier to swap a Dodge magnum 5.2 or 5.9 V-8 into your Jeep and you'll be a lot happier. Gets about the same MPG as the 4.0 but has more power.
You can run either a automatic or manual transmission. The wiring is fairly easy and the Dodge PCM talks to the Jeep dash so you don't need a custom dash.
 
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707kevin said:
Figure about 3500 to do it. Lots of odds and ends add up if you get a motor missing accessories like acc brackets and power steering lines that don't transfer over from one to the other. motor mount brackets, etc.

The used 4.0 may be of 'unknown' quality. I had to rebuild most of mine.

The added injector wiring was fairly easy once you get the pins you need.

Need a transmission. Hopefully it mates to your existing transfer case (differences in input gears)

Might need driveshafts? My front was too short after in my YJ.

All-in-all, id just not do it again and buy a nice 4.0 model.
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Yeah I see what you’re saying, I found a complete setup with tranny for 1.1k the engine has 109k and I did hear it run. What made me start thinking about a swap though staying with the original power train would make sense and since it’s my sons too I will probably hold off after thinking more. I’m thinking about getting a ‘05 LJ for myself and call it a day, lol. Thanks for the input man appreciate it
 
Wildman said:
For the time/effort/expense/headache you could of had a V-8. Honestly depending on the year it's a lot easier to swap a Dodge magnum 5.2 or 5.9 V-8 into your Jeep and you'll be a lot happier. Gets about the same MPG as the 4.0 but has more power.
You can run either a automatic or manual transmission. The wiring is fairly easy and the Dodge PCM talks to the Jeep dash so you don't need a custom dash.
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What my original plan was, I’d prefer a V8 lol I was even thinking diesel for awhile, there’s a guy around town has a YJ dropped a VW diesel in it rather cheap. Pretty sick…I’ll prob keep the stock power plant till it does then go the V8 route. We plan on keeping the TJ forever!!! I’ve been looking at getting a LJ, not a fan of 4dr jeeps and JL’s are too much. Thanks for the info, appreciate ya
 
RickyOchen said:
What my original plan was, I’d prefer a V8 lol I was even thinking diesel for awhile, there’s a guy around town has a YJ dropped a VW diesel in it rather cheap. Pretty sick…I’ll prob keep the stock power plant till it does then go the V8 route. We plan on keeping the TJ forever!!! I’ve been looking at getting a LJ, not a fan of 4dr jeeps and JL’s are too much. Thanks for the info, appreciate ya
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There are a few people on here who have Dodge V-8's swapped into their TJ's
I have a 1997 I bought in 2002 that I swapped a V-8 into in 2006. And I'm doing a complete rebuild of the whole rig right now. But with a Dodge 5.2 it had enough power bit burned the same amount of fuel as friends with 4.0's.
I'm working on a writeup on how to do the wiring and should have it done here soon.

Try to find a complete rig if you have the space for it. If you're going to go automatic look for a Jeep Grand Cherokee with a V-8 as they have the starter on the passenger side where the Dodge has the starter on the drivers side. But getting a complete rig saves you money in the long run because you aren't having to buy all the little items. A lot of people find rigs that were in a wreck or at a auction and I know a couple of guys who did the swap for under $500 after selling off parts from their donor rig.

Here is a good thread over on the JeepForum about doing the Dodge magnum V-8 swap.

https://tinyurl.com/38795wcc
 
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