TJ 2.5 to 4.0 swap question... - Page 2 -
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post #16 of 21 Old 08-01-2010, 08:34 PM
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Originally Posted by davidchancey View Post
I've also done the swap. Very easy swap I thought. It's alot easier if you use the same year parts. Was also cheaper than regearing. Got the whole swap done for $200 including price of motor.

Exactly! My net out of pocket was $30!

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post #17 of 21 Old 08-01-2010, 09:55 PM
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I would do a 4.0 swap. Like someone else said, it's hard to beat its low end torque. I also find it hard to believe it is the same amount of work to swap in a V8 then a 4.0. I would get a 4.0 with its wiring, then stroke it, then swap it in. Really the biggest mod is the engine mounts.

I can't wait until I have the money to rebuild and stroke my 4.0.
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post #18 of 21 Old 08-01-2010, 10:19 PM
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Originally Posted by Shrek View Post
...Having said all that, the 4.0 is a superior TRAIL engine over the V8. Most V8s won't give you the torque at 600-1000 rpm like the 4.0 when your crawling around. On the street or in the mud the V8 would be a panic but for a trail Jeep, the 4.0 is pretty hard to beat.
I have a small displacement V8 in my TJ and it makes more torque at 1,200 RPM than the 4.0 does at its peak.

Almost any V8 will make more low end torque than the 4.0 I6. I'm not sure why some people believe otherwise.
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post #19 of 21 Old 08-02-2010, 06:29 AM Thread Starter
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The motor mounts aren't gonna really be an issue for me. We were gonna either weld up the 4.0 mounts, or fab up a custom mount with some scraps. As far as the electronics go, I'm gonna be making it carb'd so we're gonna wire a custom bare bones set anyhow. Though if the 4.0 will truly plug and play, I may just leave things injected. My biggest concern at this stage is finding parts that will mate up properly. I'm planning on a custom trans. mount as well and am gonna be tucking as high as possible to gain belly clearance.

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post #20 of 21 Old 08-02-2010, 10:24 AM
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Regarding wire harness mod. I paid for it to be done. So you guys are saying it is unnecessary? Am looking into it.
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post #21 of 21 Old 08-02-2010, 10:58 AM
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Originally Posted by gensysmike View Post
Regarding wire harness mod. I paid for it to be done. So you guys are saying it is unnecessary? Am looking into it.
I swapped a 2002 4.0 TJ engine, computer and engine harness into my 2001, 2.5-equipped TJ. There were no modifications required to either the 2001 body harness or the 2002 engine harness. I unplugged the 2.5 engine harness and plugged in the 4.0 engine harness. It is necessary to swap computers, but again, no modifications whatsoever to any wiring.
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