TapyMJ Posted January 3, 2019 Share Posted January 3, 2019 Can someone give me the time frame they think it would take to swap a 2.5L to a 4.0L. they are both jeep motors and i have 2 jeeps i just want to put the bigger motor into the other one. thanks in advanced Link to comment Share on other sites More sharing options...
Pete M Posted January 7, 2019 Share Posted January 7, 2019 that would vary wildly with the owner's experience and how many hours they can give it each day. There are guys out there that have torn apart so many Jeeps that I'd wager they could do it in a long weekend. for the rest of us mere mortals, it'll take weeks. also, you'll be swapping just about EVERYTHING from one to the other, not just motors. wiring, trans, etc. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted January 7, 2019 Share Posted January 7, 2019 This swap isnt just the motor.... it is the motor, the trans, the engine harness, the dash harness, driveshafts, mounts, crossmembers and a dozen other things I can't think of. A complete donor with a side by side swap would be best, even then you may still need to modify the wiring and rear driveshaft depending upon donor vehicle. Link to comment Share on other sites More sharing options...
TapyMJ Posted January 9, 2019 Author Share Posted January 9, 2019 So i have an 86 jeep and an 88. The 86 has a 2.5L and the 88 has a 4.0L. so I'm going to swap the 2.5 to the 88 and the 4.0l to the 86 and both of them run. so i have a complete donor vehicle. just wondering. both have the same transmission in them I'm pretty sure. what do you guys think? Thanks Link to comment Share on other sites More sharing options...
JustEmptyEveryPocket Posted January 9, 2019 Share Posted January 9, 2019 I may be wrong on this, but the 86 firewall is not made to accommodate the 4.0L engine. So you would need some serious fab skills to make that work, not that it can't be done of course. Also I don't think the motors mated to the same transmission (assuming automatic?). If they are manuals then I know they are not the same transmission. Anything is possible with time and money. Just may not be the easiest or fastest. What is the final plan here? or the reason for the swap? Link to comment Share on other sites More sharing options...
Pete M Posted January 9, 2019 Share Posted January 9, 2019 the 4.0 and 2.5 do not share transmission bolt patterns. the firewall of the 86 has been clearanced by some guys with a large hammer. plus some of the late year 86s have the newer firewall already. it's the upper radiator mount and hood latch locations that are the real pain to swap. Link to comment Share on other sites More sharing options...
TapyMJ Posted January 10, 2019 Author Share Posted January 10, 2019 the reason for the swap?? hmmm?? well sentimental value tbh on my 86. its the jeep yellow comanche and i love the thing. just redid the interior on it and wanted something with more umf then that 2.5L any suggestions on what would be eaiser?? Link to comment Share on other sites More sharing options...
mjeff87 Posted January 10, 2019 Share Posted January 10, 2019 20 hours ago, JustEmptyEveryPocket said: I may be wrong on this, but the 86 firewall is not made to accommodate the 4.0L engine. So you would need some serious fab skills to make that work, not that it can't be done of course. Also I don't think the motors mated to the same transmission (assuming automatic?). If they are manuals then I know they are not the same transmission. Anything is possible with time and money. Just may not be the easiest or fastest. What is the final plan here? or the reason for the swap? Some 2.5's did have AW4's behind them, but they require a different bellhousing and torque convertor than the 4.0 version. But, I've always read (and seen) those to be limited to the 87-89/90 model years, although anything theoretically was possible to order way back then Link to comment Share on other sites More sharing options...
Pete M Posted January 10, 2019 Share Posted January 10, 2019 4 hours ago, TapyMJ said: the reason for the swap?? hmmm?? well sentimental value tbh on my 86. its the jeep yellow comanche and i love the thing. just redid the interior on it and wanted something with more umf then that 2.5L any suggestions on what would be eaiser?? gearing is your best bang for the buck. what size tires do you have? Link to comment Share on other sites More sharing options...
TapyMJ Posted January 11, 2019 Author Share Posted January 11, 2019 yea gearing would be a good idea. but i want more horsepower I like the gear idea though. its just stock tire size that i have. not planning on going any bigger at the moment. Link to comment Share on other sites More sharing options...
Pete M Posted January 11, 2019 Share Posted January 11, 2019 what gearing do you have now? if you skim through the epic tech forum, you'll find Mkyboy's supercharged 2.5L build. Link to comment Share on other sites More sharing options...
Swampy Posted July 6, 2019 Share Posted July 6, 2019 On 1/11/2019 at 10:16 AM, TapyMJ said: yea gearing would be a good idea. but i want more horsepower I like the gear idea though. its just stock tire size that i have. not planning on going any bigger at the moment. I have a 2.5 with 5.13s and 35s. It did great in every gear except 5th gear of the ax15. It doesn't like 5th gear not enough power. But that was before my wiring harness fried itself. I'm tempted to run d44s or something similar to get deeper gears in the axles 5.38s 5.71s 6.17s Link to comment Share on other sites More sharing options...
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