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robert
Dodge Dakota
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3/24/2005
13:34:18

Subject: 1990 engine swap 4.0?
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In a recent 4wheel drive magazine they discuss engine swaps, and I noticed the 1997 jeep 4.0 engine: HP 181@ 4,600 rpm and 222lbs of torque@ 2,800 rpm specs are: 19 1/2 width and 31 inches in length , and it looks like it will fit into my 1990 dodge dakota 4x4, my question is will it bolt up to my exsisting 5 speed manual?
what else do I need to do?
wiring,computer??? need help!!!!



93dak4x4
Dodge Dakota
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3/24/2005
13:51:31

RE: 1990 engine swap 4.0?
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it should actually bolt up to your manual. the stock 5 sp in the wrangler was the ax15 and thats the same trans they used in the dakota. so theoretically it should work. however, you will have to change the computer and wiring harness because the 4.0 will have a completely different harness and i dont know if your motor mounts will require fabrication or not. all in all it will be difficult and its more worth your time to put in the 5.2



daddio
Dodge Dakota
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3/24/2005
13:58:47

RE: 1990 engine swap 4.0?
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have you checked the height? that straight 6 i am sure stands taller than a V.



mhall02
Dodge Dakota
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3/24/2005
14:37:09

RE: 1990 engine swap 4.0?
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Actually the 1990 5-speed, if its the same as my '91, is a NV-2500. The 2000 Jeep Cherokee linked to either a AX-15 or NV-3500 5 speed. I know this because I have the 2000 Jeep Chereokee and a Chrysler Service Manual for it. I wish my Dakota had that 4.0 inline six, its got a ton more power than my putzy pre-Magnum 3.9 V-6. The 2000 4.0 is rated at 190 hp, not bad for an old school AMC designed straight six.



93dak4x4
Dodge Dakota
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3/24/2005
18:49:37

RE: 1990 engine swap 4.0?
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ever drive one of those old amc 4.2L straight sixes? those things had all kinds of low end torque but no top end power at all, the 4.0 is a big difference. but it would probably do better in the dakota then the 3.9



robert
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3/24/2005
19:30:40

RE: 1990 engine swap 4.0?
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thank you for the information so far.
I have a np2500 5 speed manual trans.
I would like to put the newer 4.0 in it!
I was wondering if anyone has tried this before.
I know that the 4.0 is street and trail worthy and proven, and it is a better engine than the 3.9



robert
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3/24/2005
19:33:46

RE: 1990 engine swap 4.0?
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oops! I ment the NV2500 trans...which a just had rebuilt along with the 231 transfercase....slowly putting my GEN1 back to life....



olscout
Dodge Dakota
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3/24/2005
20:39:45

RE: 1990 engine swap 4.0?
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I can talk a little about the 4.0 vs. the 3.9 from some recent experience. I've got a 92 Dakota longbed 2wd, A500 automatic. I'm replacing it with an 89 Jeep Comanche Sport Truck, 4.0 four wheel drive with four speed automatic trans (from what I have heard/read, not a Chrysler trans, an Aisin/Warner model). The 4.0 has 152,000 on it, the Dakota 122,000 with a fresh timing chain and valve job. On the EXACT same drive of about 150 miles, the Dakota 2wd got 18 mpg, the Jeep 4wd pulled 21. The 4.0 has a TON more bottom end than the 3.9...no comparison there. I would guess it does run out of steam a little towards the top end, but how often do you get into the top end of the RPM band unless you're street racing Mustangs? (not that there is anything wrong with that as long as you win!). For TRUCK use, which is what I'm using mine for, the Jeep is going to be a much better vehicle- four wheel drive and better fuel milage to boot, with a sacrifice of some interior room. I agree with the guys that said Chrysler should have cut their losses and used the 4.0 in the Dakota, heck, even in the Ram and vans in place of the 3.9! The 4.0 I have is 'pre-high output'- I think mine is about 170 hp, the high outputs (beginning in 91 or 92) had a bigger throttle body and more 'fly by wire' controls, and put out 190 hp. The 4.0 is a very dependable engine- the top mechanic at my local Dodge/Jeep dealer (who has been working on Mopar stuff for over 25 years, and Jeep since they got the franchise a few years after the takeover) said he'd take the 4.0 over the 3.9 any day, 'they last forever' in his words. The 4.0 has issues, such as blowing oil into the air filter and air filter housing, which there are fixes for on the Jeep sites...just as the 3.9 has issues. Most can be solved, and the 4.0 is just as much a 'high mile' motor as the 3.9, maybe more so. I think it was probably a victim of the 'not designed here' syndrome by Chrysler...they got it in the takeover, and damned if a Mopar vehicle would show up with an AMC/Jeep designed engine, that would be a slap in the face to the Chrysler engineering department.
Now that I've wasted a lot of space writing that, unless I had a wrecked Cherokee or Comanche with a low mileage, super condition HO 4.0 sitting there so I could rob all of the engine controls and computer and entire driveline to go in a Dakota, I think it would be too much work for the return you'd get on a swap. Like the other guys have said, if you want V8 power, do the 318/5.2 or even 360 route. It would be easier and have more power. But the 4.0 would work great if you took the time to do the swap right.



robert
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3/24/2005
20:54:16

RE: 1990 engine swap 4.0?
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Thank you for the information, I wanted more power with less weight!
plus I have found that there are alot more options for aftermarket power buildups for the 4.0, I know that the v-8 has alot too, but you also have less of an area to work with, with the v-8 crammed in there, plus I like a challenge.
I am going to run headders, a larger throttle body, msd ignition, and a super chip to boot.
I found a 1997 jeep, 4.0 that was rearended and totaled(in the rear only) with 22,000 original miles, the owner bought it back from the ins company, and has been in his garage since.
I think this will rejuvenate my dakota w/198,000 miles and still running strong, w/ no leaks, still lots of power, a daily driver to boot, and strong compression, your right about the high miles of the 3.9 they do last, and I am glad to hear the same about the 4.0's as well...



93dak4x4
Dodge Dakota
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3/24/2005
23:42:15

RE: 1990 engine swap 4.0?
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i am almost willing to say that the 4.0 will take up more space length wise then the 5.2. the 5.2 is about 5 inches longer then the 3.9. and technically you have two extra cylinders of length with the straight 6. also the 4.0 ltr block is quite heavy. they are cast iron like the rest and weigh probably about the same as the 5.2



robert
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3/26/2005
22:37:24

RE: 1990 engine swap 4.0?
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here are some spec's I found in the march issue of 4wheel drive magazine volume 21 #4 page 69.
the dodge 318 weigh's 550lbs with out headers,tbi,pulleys ect, just the basic block, and only has 220 hp stock? and is only 1 1/2 inches shorter than the 4.0
here are the 318 5.2L spec's
width 25 inches
length 29 1/2 inches
height 27 inches
hp 220 @4,400rpm
torque 300 @ 2,800rpm

The 4.0 HO spec's:
width 19 1/2 inches (smaller than the 5.2)
length 31 inches (complete w/pulleys)
height 27 1/2 inches (1/2 taller than 5.2)
weight 398lbs. (152 lbs lighter than the 5.2)
with the new 4.0 head from jeeps R us Made by Hesco, drops an additional 30lbs off of the engine weight and adds on a ton of HP and Torque thoughout the rpm Band.
But with all this in mind, and I am going to do it.
Does anyone know for sure if the 1997 jeep 4.0 HO inline six will bolt up to my NP2500 manual 5 speed trans...




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