Engine Suggestions Please....

[jimmy21669]

So, I got my 1987 MJ, have done a 4WD swap, but I don't think I will ever be happy with the 2.5L/AX4 combo in it and plan on doing a drivetrain swap next summer.

 

I am torn between a lot of options....so I ask this:

 

What is your suggestion for a drivetrain swap to achieve the following:

 

Good torque

Good highway handling

decent mileage

COST (I am not a rich man, so it cannot be too wild)

Ease of install (I am not afraid of fab work, but I want easy wiring, simplicity of completion like a TBI system, I do NOT want carbureted).

 

The 4BT engine management simplicity does draw me, but it's finding one....

 

Then picking up an NV4500/Dana 300 to finish it off....I would expect the cost to get high.

 

I also have looked at the simplicity of a SBC with TBI, the availability and shear awesomeness of the Muncie tranny's (SM420/465)...the costs are much less, but I am concerned with too touchy a throttle, which the SM420 7.2:1 granny gear could help with.

 

SO, what are your thoughts? And don't just make a suggestion, if you can, tell me what you know about the swap.

 

Thanks

 

Jim

[mkbruin]

I'd go 4.0.

 

Simple install, many ready-made parts, good mileage.

 

4bt is a dream choice, but its a TALL engine.

 

5.0 or 350 are good, but you won't get the mileage as the 4.0, and erquires a lot more fab.

 

For simple swaps that meet your needs, 4.0 is the way to go.

 

 

 

Counterpoint: For the cost of the swap, you can go and buy a second, 4.0 MJ. So, if you are going to spend the $$$, go big with a V8 swap or just buy a second rig to torture yourself with thats factory 4.0.

[jimmy21669]

I'd go 4.0.

 

Simple install, many ready-made parts, good mileage.

 

4bt is a dream choice, but its a TALL engine.

 

5.0 or 350 are good, but you won't get the mileage as the 4.0, and erquires a lot more fab.

 

For simple swaps that meet your needs, 4.0 is the way to go.

 

 

I only lean away from the 4.0 because I would have to do enough mods anyway, why not go bigger and better?

[mkbruin]

I only lean away from the 4.0 because I would have to do enough mods anyway, why not go bigger and better?

 

 

Per your needs:

Good torque

Good highway handling

decent mileage

COST

Ease of install

 

4.0 fits the bill perfectly. But as I said in my counterpoint... for the cost of the swap you can buy a 4.0 MJ

[shelbyluvv]

Yep, 4.0L all the way.

 

If you want a true PIA do a MPI 5.2/9 Mopar engine out of a ZJ.

[foreman1063]

Good torque

Good highway handling

decent mileage

COST (I am not a rich man, so it cannot be too wild)

Ease of install (I am not afraid of fab work, but I want easy wiring, simplicity of completion like a TBI system, I do NOT want carbureted).

 

/\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\ /\

The definition of a 4.0L. That would be my choice.

[Oizarod115]

GM 5.3L from early 00s model gm truck

 

hell of a motor (and i dislike GM) seen plenty of them with 200+k and never many problems, water pumps about the only thing that goes out and its a super easy repair.

 

oh! and the benefit of chevys stand-a-lone engine management that makes engine wiring pretty simple since its mostly separate from cab wiring.

[Pete M]

gears, gears, and more gears.

[brdhntr]

i'd go with the 4.0 as well. the ease of the swap would outway any benefit from a sbc cubic inch issue in my book. if you look at a sbc, they don't put out as much as you may hope without some mods. making those mods in the swap you're considering will require alot of work to make them fit/work in you app. take a good look at the 4.0 and then check out the mods that can be made to get much more out of it. it will fit and hook up without a problem and get as much or more than a mild build on the sbc. the money you save from the fab work that will be required in the sbc could pay for alot of mods to a good 4.0. check into the mods that can be done on the 4.0 and i think you'll be happy with the output vs a sbc. add the weight issue to the front suspension in a sbc swap and you'll be happier with the 4.0.

 

by the way, i am a sbc man and have done a fair amountof mods to them. i have a suburban with a 350 and love it. i wouldn't put one in my jeep tho.

 

if you're really into a cool swap, just spend all the money on a supercharger and bolt it on for some fun.

 

just go with the 4.0 and enjoy. :thumbsup:

[jimmy21669]

I am starting to think about keeping the 2.5, but doing an AX15 swap using a Dakota bellhousing and building a 231 doubler, 8.8 4:10 rear and regearing the front to 4:10. I know a lot of TJ/YJ guys with Dana 30 4:10 sets laying around.

 

I have a freind works in a fab shop, so we can probably make the doubler.

 

The 2.5 is not so much what I worry about. It is the strength of the AX4/5 for serious wheeling. The AX15 will put up with ANYTHING a 2.5 can throw at it.

 

I am looking mostly for durability and reliability, and if I gear the HECK out of my drivetrain, and upgrade it, I think I can do fine with fewer mods and less money spent.

 

Also, the 2.5 has only 79k miles and lots of life left in it.

 

 

Final Drive Ratio: Up to 115.75 to 1 on 33's :drool: And I would be at 65 MPH in 5th at 2150 RPM.

 

Thoughts?

[1990 Pioneer 4x4]

4.0 and gear it appropriately.

 

What's up with the poll, hasn't been woring fow awhile? :dunno:

[Pete M]

our latest software update didn't go quite as smoothly as it should and the polls are one of the things that stopped functioning properly. :( hoping the next update will clear some stuff up.

 

 

TJ dana 30 gears will not work in MJ/XJ/YJ axles (low pinion vs high pinion). plus used gears are generally seen as a poor choice since trying to match up the old gear pattern is tough (meaning it could be pretty noisy).

 

unless you meant swapping in the entire axle, which will work. :thumbsup:

[mvusse]

I am starting to think about keeping the 2.5, but doing an AX15 swap using a Dakota bellhousing and building a 231 doubler, 8.8 4.10 rear and regearing the front to 4.10. I know a lot of TJ/YJ guys with Dana 30 4.10 sets laying around.

Did you get a high pinion 30, or low pinion? YJ gears work in high pinion 30 axles, TJs are low pinion. They do not interchange.

 

I have a freind works in a fab shop, so we can probably make the doubler.

Brett and Jeff? (JawzJPCustoms?)

[jimmy21669]

I am starting to think about keeping the 2.5, but doing an AX15 swap using a Dakota bellhousing and building a 231 doubler, 8.8 4.10 rear and regearing the front to 4.10. I know a lot of TJ/YJ guys with Dana 30 4.10 sets laying around.

Did you get a high pinion 30, or low pinion? YJ gears work in high pinion 30 axles, TJs are low pinion. They do not interchange.

 

I have a freind works in a fab shop, so we can probably make the doubler.

Brett and Jeff? (JawzJPCustoms?)

 

True enough on the D30...wasn't thinking.

 

And...no....

[johnj92131]

Sounds to me like you have nailed your best choice below - there is also a 4:1 transfer case out there. But you seem to have the low dollar way to solve your problem.

 

I am starting to think about keeping the 2.5, but doing an AX15 swap using a Dakota bellhousing and building a 231 doubler, 8.8 4.10 rear and regearing the front to 4.10. I know a lot of TJ/YJ guys with Dana 30 4.10 sets laying around.

 

I have a freind works in a fab shop, so we can probably make the doubler.

 

The 2.5 is not so much what I worry about. It is the strength of the AX4/5 for serious wheeling. The AX15 will put up with ANYTHING a 2.5 can throw at it.

 

I am looking mostly for durability and reliability, and if I gear the HECK out of my drivetrain, and upgrade it, I think I can do fine with fewer mods and less money spent.

 

Also, the 2.5 has only 79k miles and lots of life left in it.

 

 

Final Drive Ratio: Up to 115.75 to 1 on 33's :drool: And I would be at 65 MPH in 5th at 2150 RPM.

 

Thoughts?