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jeep 4.0 swap


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Just wondering if anyone ever swaped in a 4.0 in a z I drove a HO yesterday and was totally impressed with the power and torque for a stock jeep it really pulled. header, cam, and or a turbo would make them run. They should be plentiful in the wrecking yards too. overdrive auto of 5 speed manuals are plenty tough and good ratios in the 2x4 cherokees

anyway just a thought not going to swap my v-8 to go back to a six

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Just wondering if anyone ever swaped in a 4.0 in a z I drove a HO yesterday and was totally impressed with the power and torque for a stock jeep it really pulled. header' date=' cam, and or a turbo would make them run. They should be plentiful in the wrecking yards too. overdrive auto of 5 speed manuals are plenty tough and good ratios in the 2x4 cherokees

anyway just a thought not going to swap my v-8 to go back to a six[/quote']

 

You know I've thought about this plenty!! A year ago I had a 92 XJ with the 4.0L with a 6.5" lift and 33" muds. It had gobs of torque, and I didn't have to regear witht the big tires.. it pulled damn hard. There are several stroker kits available for this engine. There has been plenty of discussion about forced induction on these motors, and a lot of people didn't think it was a good option because of the high compression. You could definitely build a great running N/A engine out of one though. My XJ had 155,000 on the odometer and it ran like a monster. Started instantly everytime even in cold weather..

 

I even hydro locked it once BAD crossing a river.. I sucked the water out of the intake with the radiator spill over house, and it fired right up :) Tough as nails.

 

Phyte

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as Long as I can remember any time anyone talked about jeeps they always say get the 4.0 models They don't have the problems that other amc motors have heard that they are the same motor as in the old 60's ramblers they used to race against the v-8 crowd in factory racing

any way they do have alot of performance mods in the aftermarket.

a cherokee frame and a lift seems like it might fit under a z pretty good

almost like my 510 wagon on a cj5 frame(only had to shorten it 1.75 inches.

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as Long as I can remember any time anyone talked about jeeps they always say get the 4.0 models They don't have the problems that other amc motors have heard that they are the same motor as in the old 60's ramblers they used to race against the v-8 crowd in factory racing

any way they do have alot of performance mods in the aftermarket.

a cherokee frame and a lift seems like it might fit under a z pretty good

almost like my 510 wagon on a cj5 frame(only had to shorten it 1.75 inches.

 

Looks like you can stroke them to 4.7L for not a lot of money. Just need a crank out of a 258cu and the rods. Here's a really good article on how to do it. The worse part of it is the front of the crank needed a 1/4 spacer for the balancer.. thats it!

 

http://www.rockcrawler.com/techreports/stroker40/index.asp

 

Phyte

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I still have my old 89 cherokee 4.0. The this is 15 years old and it still starts right up in -30 celcius and still pulls hard. I have done a good bit of maintance on it over the year as motors go there are pretty easy to work on too. You would difinetely need a sportier cam tho and I am not sure of their rev cababilities. (My jeep has no tach and now that I think about it I am curious as to its redline?).

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Im not sure about the 4L FI motor, but my buddys 4.2 is a dog. Doesnt like to rev past 4000 at all. And even at that rpm (which is SCREAMING in his old YJ) it is pretty gutless. Lots of low end grunt though. He rebuilt his 4.2 last year, and can sqwak the rear tires (31X10.5) taking off, but still runs out of steam at about 4000.

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I had a 4.2 in a YJ and it pulled ok, not great but ok. The fuel injected motor in my ’93 is much faster. My lady’s ‘97 4.0 is faster still, but this could be from a gear change. These cars have always gotten us home.

I have thought about this swap as well. It doesn’t have the under the hood WOW factor...unless you win. It would be nice to see one done.

How about one under boost?

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Guest Nic-Rebel450CA

I've never had much desire for the thought of making a Z into a tree stump puller. :roll:

 

Anything can fit if you make it. The real question is "why"?

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Anything can fit if you make it. The real question is "why"?

 

Economics.

My first Z swap motor was from a taxi. It was a free 318. I had no desire to drive passengers about, but I still took the time to make one fit.

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Guest brianglawson
header, cam, and or a turbo would make them run.

 

just so you know you cant put headers on a turbo motor its the turbo manifold :D:D

as far as a jeep swap goes i wouldnt do it, light cars benefit alot from fast revving motors, a z is a light car, a jeep revs slow...2 and 2 together it wouldnt suit me

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  • 6 months later...
Guest angryAJmonotone

It would be an interesting swap, i have an '88 yj, with the 258 (4.2l), the old 258s dont offer much past 3500ish, but if im not mistaken the 4.0 will rev to around 6. There are also a few supercharger kits available for the 4.0, with performance getting up to around 300 hp, and alot more torque. There is also a stroker kit (as previously mentioned) for the 4.0, brings it up to a 4.7 i think. As for being slow revving, i think thats largely just a flywheel issue, when i did my tranny swap on my jeep, my flywheel was very very heavy, and it had 2 seperate sets of teeth (i was told this was to support hand crank starters, but i really have no clue), im sure that with a new flywheel you could get a bit more rev out of these motors.

 

 

Here is a link to a site about all jeep motors:

 

http://www.jeeptech.com/engine/amc242.html

 

Another option would also be the 258. Altough it doesnt make alot of power stock, you could swap in the head out of the 4.0, put a good cam (i think crower has a few good grinds for these motors), headers and either a weber carb, or convert to fuel injection (mopar makes a multiport fuel injection setup) , it would still be a very torquey motor, but could still pull hard at higher rpms.

 

The big question is if this swap would be worth the money, seems like you could get a good v8 setup for around the same price.

 

oh well

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Guest 73TPIZ

If anyone goes this route, remember '91 up. '90 down is 90% the same as newer, but whatever Jeep did to the other 10% feels like night and day.

Different intake for sure. Different cam? ECU? Head and Block look the same. But gobs more power.

 

I've had a '88, a '90, 2-'93's, a '96, and an '00, and the '91 up HO's haul a$$.

 

Talk about tough. I R&R'd a cylinder head on a friend of mine's '90 a few years ago due to warpage. It had 250K+ mi on it. I looked at the cylinders while the head was off a noticed mucho ring groove at the front and rear of 3 cylinders without much on the sides of same. As in 3 cylinders were egg shaped. Told him this, bolted the serviced head on, he drove it 40k mi more over the next 18 months on his mail route, sold it, new owner drove it 20k more on her route, then she wrecked it. All this and never noticed any oil smoke. I couldn't frigging believe it.

 

A kid at the local track sprays his 300k mi jeep with 100 shot of NOS and drives it home every week for the past year. Kicks every other SUV's arse. Unbelievable.

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