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Looking For Advice -Wisdom On 2.8 /4.0 Swap


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Hello all was hopeing to gain some insite for an upcoming project I have researched the forum and read as much as I can find on the topic but thought there might be a few tips or tricks or things to look out for. So I have an 86 comanche lwb 4x4 2.8 5speed motor is locked up . I also have a 93 cherokee 4.0 auto 4x4 ho. Have decided to do compleate swap. Engine trans interior the hole 9 yrds. I'm aware of the firewall issue and figure on cuting what ii need from the 93 as well as core support hood exc. Guess my biggest concern is wireing and dash anf all that goes into that. Any help or suggestions are appreciated. Starting on floor boards this week front clip motor and tranny removed. Hopeing to have in primer and running by spring. Thanks so much for the forum anf the info.

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The biggest concern for swapping in the 4.0 will be the firewall and wiring. Later 86s may have the firewall change in preparation for the next model year. You'll need most of the XJ's wiring that pertains to the front half. If I were you I would convert the entire truck up to the 91+ wiring to make everything match up. There's quite a few wiring differences between the 86 and later models that might be problems for you.

 

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After comparing the options of 2.8-4.0 swap I went with a 2.8. Took a 2.8 from a '93 S10 and downgraded it to '86 MJ specs. Maybe it doesn't have the power of a 4.0 but it has enough for my purpose and wasn't near as much work and rtrouble.

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Yeah it does seem like its going to be a whole lota work. In 1989 I bought a 86 mj 4x4 it had the 2.8 with auto trans I lifed it 4 inchs and ran 31 10.5 15 mudders and it wouldnt hardly get out of its own way and gas millage was horrid I loved that truck tho was in a horrific accident where a guy ran a stop sigh and I t boned going about 45 shoved bumper and everything back around the frame horns but drove it home it was quite unreal anyway I was never happy with that motor combo and have had a number of cherokees since and the 4.0 speaks for itself. I'm building this truck for my son he is now 13 so guess we better get started and would like the reliabilty of the 4.0

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Do a Magnum V8 swap, less work honestly. The wiring is about the same. Why not?

Thats what I plan on doing. Was orignally looking at putting a 4.0 in my 86 to replace the 2.8 but seemed like a lot of work. Can put in a 5.9 for equal or less work and have more power, so why not?

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Well for one thing I have the 4.0 ho donner and another its for a 16 yr old lol

I'm building mine for my son as well. He'll be 16 next August. Get them deeply involved in the project, make them buy some parts with their allowance, teach them the value of the truck. They will respect it more in the end. My truck happens to be one of the very first MJs ever built. It didn't stop me from building it the way I wanted it. Enjoy the time with your kid building the truck. Those are memories they'll cherish forever!

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Get them deeply involved in the project, make them buy some parts with their allowance, teach them the value of the truck. They will respect it more in the end.

 

And there is the true wisdom you were looking for. Doing that just about guarantees they won't see the vehicle as a throw away, or something they could neglect or take risks with while driving. Usually ensures the vehicles lasts much longer rather than turning into a salvage title like 80% of the mustangs and stuff I see for sale around here that were teenagers first vehicles... or worse of course. Just about nothing we hate more than to see an MJ declared totaled in a wreck around here.

 

Cherokees are a lot easier to come by, make that their first vehicle and fix the MJ up. Taking the time to do things right with him helping out, buying parts and stuff like Shelbyluvv said, then give that to him once he's driven the XJ for awhile and learned to respect the MJ.

 

Just my 

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What do you do for motor mounts for a V8, though?

Stock ZJ mounts bolt right in with a couple new holes being drilled. I had to make some drop brackets to lower the engine 1 1/2" or so. Look through the Black Betty build in the projects section for some pics.

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What do you do for motor mounts for a V8, though?

Stock ZJ mounts bolt right in with a couple new holes being drilled. I had to make some drop brackets to lower the engine 1 1/2" or so. Look through the Black Betty build in the projects section for some pics.

Wonder if thats the same for the 5.9?

Probably end up having to make my own...i want to add a couple more horses before i put it in anyway...

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What do you do for motor mounts for a V8, though?

Stock ZJ mounts bolt right in with a couple new holes being drilled. I had to make some drop brackets to lower the engine 1 1/2" or so. Look through the Black Betty build in the projects section for some pics.

Wonder if thats the same for the 5.9?

Probably end up having to make my own...i want to add a couple more horses before i put it in anyway...

The 5.2 and 5.9 have the same mounts. It's the same block. Get a nice running ZJ as a donor. Then let the wrenches fly.

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What do you do for motor mounts for a V8, though?

Stock ZJ mounts bolt right in with a couple new holes being drilled. I had to make some drop brackets to lower the engine 1 1/2" or so. Look through the Black Betty build in the projects section for some pics.
Wonder if thats the same for the 5.9?

Probably end up having to make my own...i want to add a couple more horses before i put it in anyway...

The 5.2 and 5.9 have the same mounts. It's the same block. Get a nice running ZJ as a donor. Then let the wrenches fly.
Actually been leaning towards a ram with a 4x4 5spd because id prefer a standard over an auto, and to date ive seen one 5.9 zj on craigslist. any big benifits to using a zj donor over a ram?
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What do you do for motor mounts for a V8, though?

Stock ZJ mounts bolt right in with a couple new holes being drilled. I had to make some drop brackets to lower the engine 1 1/2" or so. Look through the Black Betty build in the projects section for some pics.
Wonder if thats the same for the 5.9?

Probably end up having to make my own...i want to add a couple more horses before i put it in anyway...

The 5.2 and 5.9 have the same mounts. It's the same block. Get a nice running ZJ as a donor. Then let the wrenches fly.
Actually been leaning towards a ram with a 4x4 5spd because id prefer a standard over an auto, and to date ive seen one 5.9 zj on craigslist. any big benifits to using a zj donor over a ram?

 

Harness wires might be a little longer, making placement easier.  But I'm just going off of suspicion on that one.  Other than that, their pretty identical.  Valve covers might have the Ram logo on it.

 

What about a 4.7 HO from a WJ?  Anyone ever done that?

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Bragging rights, I can see.  However, the 4.7 HO puts down 265 hp / 330 lb·ft of torque.  The 5.9 Magnum puts down 245 hp / 345 lb·ft of torque.  This is assuming the information I found on the vastness and erroneous prone interwebz is correct.

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What is the weight difference between the 2 engines? That's another consideration to take into account... 

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Bragging rights, I can see.  However, the 4.7 HO puts down 265 hp / 330 lb·ft of torque.  The 5.9 Magnum puts down 245 hp / 345 lb·ft of torque.  This is assuming the information I found on the vastness and erroneous prone interwebz is correct.

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What is the weight difference between the 2 engines? That's another consideration to take into account... 

 

 

Its also good to consider the 5.9l will still be running when the 4.7l is sitting in the scrap pile.

 

These are valid points.  As far as weight, I'm not sure on either.

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Also important that ive been balls deep in a 5.9 and a 97 5.9 ram is my substitute dd while the mj is down. plus i want to add some horses to the 5.9 and stick with a manual trans. autos are lazy horsepower robbing slushboxes.

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