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4.2L to 4.0L Swap

4.2L to 4.0L Swap

CJ RIGGS

Jeeper
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Posts
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Location
Dallas
Vehicle(s)
'82 CJ7 Base Model
Engine: 4.0L ('99 Wrangler)
Tranny: T4
TC: D300
Rear Dif: AMC-20 Wide Track, 2:73 gears
Front Dif: D30
I pulled my AMC 258 i6 / 4.2l out to have it rebuilt. The block was trashed. I spent some time looking for a decent replacement with no luck. In the process, one of my gearhead buddies found a later model 4.0L (complete with computer) out of a rolled cherokee with 108,000 miles.
My question at the moment is, what else do I need to scavenge off of the Cherokee while it's still available?
 
What year is that late model Cherokee?
 
I'll find out the details when I pick it up. The buddy that pulled it is not the same person that let me know he got it. "It was a something Cherokee, I think late 90's" he said. lol
 
i ask because the later models wont work with your motor mounts. I would stick with an older one 89-95 work the best.
 
I swapped a 4.0L from a 96 cherokee into my 86 CJ 10 years ago. Great swap
 
I pulled my AMC 258 i6 / 4.2l out to have it rebuilt. The block was trashed. I spent some time looking for a decent replacement with no luck. In the process, one of my gearhead buddies found a later model 4.0L (complete with computer) out of a rolled cherokee with 108,000 miles.
My question at the moment is, what else do I need to scavenge off of the Cherokee while it's still available?

I had this swap done. Guy thought he knew how to do it. He didn't.

Big issue was he failed to install the second O2 sensor (if memory serves). This essentially caused the computer to modify the fuel mixture gradually until it functionally couldn't run.

At least this is how it was explained to me.

But, now, it runs great, and getting rid of that carb has been so nice!

Good luck!
 
I picked up the 4.0 over the weekend. When I talked to the guy that pulled it, he said it was out of a 1999 Wrangler. It came complete, including the alternator, power steering pump, A/C compressor. They were a little rough getting it out. I have vision of Alien punching a hole in a chest and yanking the heart out.
Most of the damage was superficial. Oil filter wacked, Oil pressure sensor broke, small hole in the oil pan and a chipped power steering pulley. But the worst find was a broken intake. The ear that is used bolt down the front was broke through to the port. I'm sure it was that way for the PO. You could see the grit and grime in the break.
Other than that, the inside looks clean.

Arosesdad: Thanks for the heads up.

coldair: I see what you mean on the mounts. I'm assuming there is an adaptation, if not, I can fab whatever I need.

rockhpr: I've heard nothing but good comments on the 4.0. Really looking forward to hearing it purr.

I remember back in the day, I ran dirt track for a spell. There was one racer in the super modified that ran l6. Sounded like a bumble bee buzzing around the track. He always placed in the top 10 with that thing. I know they can sing.

20181027_131723.webp
 
The 4.0 is a great motor I have had three Cherokees with them. I would love to swap one into my '84 CJ. It makes it a lot easier when you get one out of a Wrangler because you get the right fan setup the Cherokee had two fans.
 
FYI i used all my brackets and stuff off my california AMC 258 i6 / 4.2l bolted pretty much right on to the 4.0 motor only thing i had to modify was the 4.0 intake where my power steering pump mounts.
 

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