4.0 engine swap

[97XJSP]

before i got into this OD madness, i was really into the newer jeeps. I have a 97 xj with a 4.0 and AX15. both seem to be nearly indestructable for wheeling, although it may have to do with the size of the vehicle. i would think at first glance though, that a newer fuel injected 4.0 would have to be better than a stock 230! maybe not the best choice in terms of a swap but i've thought about it before. I know at least a few guys that are running high HP strokers in front of the ax15 and aw4 and i haven't heard of many issues. there are even a few folks with XJ's and TJ's that have swapped in SBC's and mated them to the stock trannies with few problems. And not that i think it's a good idea but i towed a jeep comanche behind the XJ once. the trailer was close to 3k pounds, and the truck is probably close to an xj. with 33's i had no trouble pulling grades or stopping for that matter. i've swapped disc brakes on the rear but if you brake soon enough, it's not that bad. another thing to consider is that the pre-95 jeeps had single diaphram booster that were terrible. the newer ones have dual diaphram boosters that makes a world of difference. i'll probably never do it again, but it's not that bad in my opinion. i towed the 715 home behind my dads 2500 Cummins, dana 70/80 discs all around and trailer brakes. that drive was almost as stressful as the comanche!

Just for reference, here are some numbers i pulled from jeepforum.com
4.0L I6 EFI "Power Tech" - 177 hp @ 4750 rpm, 220 ft lb @ 4000 rpm - used 87-90

4.0L I6 MPI "Power Tech HO" (High Output) - 190 hp @ 4750 rpm, 220 ft lb @ 4,000 rpm - used in 91-95 and updated in 96-01 to 225 ft lb torque @ 3000 rpm (00-01 models use a distributorless ignition system)

AX5 - 3.93, 2.33, 1.45, 1.00, 0.85, 4.72(rev)
AX15 - 3.83, 2.33, 1.44, 1.00, 0.79, 4.22(rev)
NV3550 - 4.01, 2.32, 1.40, 1.00, 0.78, 3.55(rev)

AW4 - 2.804 1.531 1.000 0.753(OD) 2.393(rev)

AX15 ratios don't look too bad, not nearly as deep as the nv4500 or T98 though! another problem is that most came as 4wd with mated x-fer cases. i don't remember a lot of it but i think the wrangler rubicon 4:1 case is a direct swap. i believe the dodge fullsize t-case can also be swapped easily. just some food for thought i guess...

[phoenix]

I wonder if anyone has thought of using a 4.0 with an AX15 and the 231 T-case(any model) and then having the output of the 231 go to the divorced NP205 or 200. since the output on the 231 is on the driver side, you could easily use the front output to run your winch as a PTO. Obviously you will benefit from the dual transfer cases gears and having a ultra low crawl ratio. I don't know if the lenth would work out.

[97XJSP]

that would be pretty cool! having seen dual cases in an XJ, i would image that there is plenty of room under the 715. ever seen how short a TJ rear shaft is? very short! i know there are also full size chevy chains that are wider/stronger that swap right into the 231 as well. i think you could easily put togther a combo that could handle it...

[2ndA]

I'm just trying to imagine living with only 225 ft lbs of torque.

[97XJSP]

yeah, it's nothing like a bigger engine and it wouldn't necessarily be a huge gain over the tornado but it would probably be more reliable and pretty cool too. the 4.9 strokers are putting out about 315HP and almost 350ft/lbs on pump gas with 8.9 compression. not too shabby...

[defbob]

The 4.0L I6 would handle the truck alot better than the Tornado . I would try putting a 4.0L infront of a T176 and a Dana 300 in the truck. The 5.87 with the 2.6low would help out alot offroad.

I have an '04 Rubicon 5spd and I wish I could swap my drivetrain over, with the Rocktrac that is. But I still have payments on it

[In2Fords]

I have a 4.0 in my xj and a np435/np205 using all stock bolt on parts, beside the $5 pilot bushing anyway. I dont think it would be a great freeway commuter but have no doubt it would survive in a m715. with just a 4.0/435/205 sitting on 37"s it would have a crawl ratio of 77-1 and rpms of 2700 at 50 MPH it would do OK I would think? run the 205 thru the NP200 and it would give you a crawl ratio of 154-1, give you another pto drive beside teh 2-3 you would have on the 435/205 now swap those 37"s for some 42" tires and that brings your 50 mph rpms to 2356. if you wanted some real deep gearing I think there would be room to run a short adapter out of the 435 into a 203/205 doubler then into the NP200, triple low sounds fun if you had tires large enough to need it OR swapped to a set of D60's and only used 4.88 gearing. Doesnt sound like it would be much of a strech for it? you wouldnt get upto speed as fast as a TJ but it would get up to speed.

Anyway, my .02C

[Panther]

http://www.youtube.com/watch?v=faGiMltGJ2g

[randyscycle]

A few years back, I was on I-66 coming from Front Royal, Eastbound. There is a long grade and it isn't terribly steep, but it is gradual and will make any vehicle work a bit going up.

Anyway, traffic was fairly heavy and slow and I couldn't get around the travel trailer in front of me as it crept (25 MPH) up the grade. When I finally was able to pass it, I saw why. It was about a 30ft dual axle travel trailer attached to a Chevy Cavalier. I still remember thinking at the moment I wanted to get as far as possible from it before he killed someone on the downside of that grade.

Not long after that, in almost the same area, I saw a Ford Aerostar pulling a mega-huge travel trailer and just barely. I still can't understand why you'd do that.

[scallywaggler]

I have done this safely from Alberta to Cape Breton Island on the East Coast of Canada (cross country trip). I towed a car trailer with a (full size) Grand Marquis LS behind my 1976 F-100 without any saftey issues. Ford truck and 390 CID/C6 combination but trailer and car out weighed the truck. Good mechanical condition of truck, tyres and braking sytem are critical and watch your speed especially on the freeway. If necessary to reduce excessive swaying, reduce your speed to maintain control and use your flashers. It can safely be done, requires responsible/sensible driving.