Newer 4.0 Swap

[Rebelfish]

Hey guys, I'm new to the forum, Just kinda been reading old posts and finding myself aimlessly lost looking at pics of what I'd like my comanche to look like. I bought my 87 Comanche for $200 in August but moved to a new house and just got all settled in by October. I'm just starting to really work on it. It had the 2.5L with 4 speed manual, still new to Comanches so forgive me for not knowing anything. I've been Dealing with my 2000 Wrangler for the past 2 years. The comanche has been sitting for 3 years now and its 2wd and in pretty bad shape. I'm in the process of swapping a 350 into my wrangler because the 4.0 isn't cutting it on power and I'm not ready to do any major engine work at only 85K on it. My question is how hard would it be to swap my (00) 4.0 into my 87 Comanche? I've noticed the crossmember can be moved back and that all the mounts, engine and tranny are essentially the same. The only thing I'm thinking will be a real pain is all the emissions and computer stuff. I've done motor swaps before on race cars and in a couple wranglers but I'm just learning about the Comanche. Has anyone really done this? I'd like to swap most of my Wrangler stuff into the Comanche, I know my D30 is the same as the straight axle in the front. I have Chevy axles ready to go until my TJ. I just want the Comache to be my DD.

 

Thanks for any help.

Brenton

 

 

Here it is.

[BLHTAZ]

It should not be a big deal for you as you have all of hte wiring & computer with it so you can just swap all of that over to the MJ.

 

A 350 chevy swap is not much of a power gain over a 4.0L unless it is built or is an LS1 or similar. The 4.0L actually provides more torque and is a tougher more dependable engine. I would spend the money on stroking the 4.0L long before going through the V-8 conversion :idea: . I have just never understood why people think V-8's are such a great thing to do to a Jeep, but to each his own..."It's a Jeep thing" :thumbsup:

[Pete M]

The Wrangler parts will be in different locations than a comparable 00 XJ. It could be anywhere from a small headache, to a rip-your-hair-out headache to adapt it all. Pretty much everything in your truck is incompatible with a 4.0L.

[Rebelfish]

The V-8 is being built for my wrangler as a project. My roomate can't make rent so he's just giving me all these 350 parts that he bought new for his truck. The goal is at least 450 HP with around the same torque or more. The 4.0 just won't hold out for the driveline and tires in store for the wrangler. Its getting full width axles and all the goodies needed for a trail rig. I wanted the comanche as a DD for gas purposes plus its always nice having a truck bed. I figured the computer stuff would be the biggest pain in the rear but its the whole 4.0 driveline, front and rear axle. I've pretty much gutted the Comanche down to nothing under the hood. But would the interior be a whole different story? It doesn't have airbags or the same gauges really.

[mfpdm]

It's about time you started posting. :D

 

Just ribbing ya.

 

If your making your TJ a trail rig only, you should pull the dash and all and adapt it to the MJ. I know the 97+ XJ conversion has been done, but I don't think anyone has successfully done the TJ conversion yet. I could be wrong. Anyhow, that way you don't have to worry about trying to wire the gauge cluster in the MJ to match the electronics from the TJ. It would take some work but it would make a unique MJ with the DD dependability that your looking for.

 

And if that idea killed the plans for you coming over and getting some parts, forget I mentioned it. :D

 

:cheers:

[Rebelfish]

It's about time you started posting. :D

 

Just ribbing ya.

 

If your making your TJ a trail rig only, you should pull the dash and all and adapt it to the MJ. I know the 97+ XJ conversion has been done, but I don't think anyone has successfully done the TJ conversion yet. I could be wrong. Anyhow, that way you don't have to worry about trying to wire the gauge cluster in the MJ to match the electronics from the TJ. It would take some work but it would make a unique MJ with the DD dependability that your looking for.

 

And if that idea killed the plans for you coming over and getting some parts, forget I mentioned it. :D

 

:cheers:

 

Don't worry I'll still come over and get the parts. Probably tomorrow since I have nothing more to do with this 350 pull. I'm pretty sure I can make something work with the Comanche and the TJ wireharness. As long as I have a GIANT peice of cardboard to draw the wiring diagram on I'm fine.

[mjeff87]

I just got done swapping a Renix 4.0 into my '87 2.5 MJ. Using a 4.0 Renix (MJ) underhood harness, it was plug-and-play almost 100%. I'd imagine you could probably use a late model 4.0 XJ underhood harness and interior harness and that would save you about 90% of the wiring headaches. You'd still have issues with the gauge cluster and the back half lighting, but the majority of the driveline (i.e. get it to run stuff) would be taken care of.

 

Jeff

 

edit: and welcome to the club, fellow Virginian :cheers:

[Rebelfish]

I figured I would just end up using the XJ harness if its the same. And I can always change the gauge cluster and put in some custom autometers or something if I get really frustrated. But I wanna get it running first before I start interior work

[Eagle]

The V-8 is being built for my wrangler as a project. My roomate can't make rent so he's just giving me all these 350 parts that he bought new for his truck. The goal is at least 450 HP with around the same torque or more. The 4.0 just won't hold out for the driveline and tires in store for the wrangler. Its getting full width axles and all the goodies needed for a trail rig. I wanted the comanche as a DD for gas purposes plus its always nice having a truck bed. I figured the computer stuff would be the biggest pain in the rear but its the whole 4.0 driveline, front and rear axle. I've pretty much gutted the Comanche down to nothing under the hood. But would the interior be a whole different story? It doesn't have airbags or the same gauges really.

You wanna explain why you need 450 horsepower for a trail rig -- a vehicle that crawls along at less than 10 MPH at under 1200 RPM 95% of the time?

 

If you want to throw money at an engine, by all means have fun throwing, but IMHO you should at least have some sense of where the project is going. Horsepower in a trail rig is wasted. You can build great trail rigs on the Jeep 2.5L engine. It's only on the highway that engine doesn't measure up.

[Sugarfoot]

So let me get this straight, you did buy the 2.5 Comanche as a daily driver and for the gas mileage? Tune it up and leave it alone. If it's not broke don't fix it. Get familiar with the truck, you've only had it for less than 4 months.

[Rebelfish]

The reason I need the hp is for all the mud bogs I attend. As for rocks the closest rocks are 3.5 hrs away but mud is about 20 minutes. The 4.0 doesn't put out enough power or torque for what I need it for

 

 

And the 2.5 motor was cracked along the side on the block, no compressin on any cylinders and it had a blown head gasket. Its not worth rebuilding to me.