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-   -   Swap from 4.2 to 4.0 (http://www.wranglerforum.com/f218/swap-from-4-2-to-4-0-a-25200.html)

beasst95 01-14-2009 07:34 PM

Swap from 4.2 to 4.0
 
First of all I have been in this forum for a few months and every thing I came across has a lot of info. You guys in the forum have been very helpful, Thanks.
Second, I have a 89 YJ with 4.2, Carb, and Auto trans. As you guys know it's a pain. What are some things I may need for the swap. What year 4.0 and vehicle from, and other items. Once again thanks for the help.

payj90 01-14-2009 08:42 PM

why not jump right to a small block of some kind? i would suggest a 350 they are quite plentiful, and a few diffrent companys make the adaptors for the swap.

Fire Hart 01-14-2009 09:05 PM

I agree with Payj90

jpdocdave 01-14-2009 10:30 PM

maybe he wants to keep his jeep a jeep:flipoff:

4.0 is a great motor, and you'll love it compared to yours now. i'm putting a stroker built out of both motors in my 87.

i found a motor on ebay that had all the accessories, manifolds, sensors, wiring and computer, along with a radiator, and some other stuff. you'll need all that, accept the radiator.

if you want to go a cheaper route, look into the 4.0 head on the 4.2 block. you get the fuel injection basically, and your 4.2 block would stay in the jeep.

beasst95 01-15-2009 12:45 AM

What 4.0 jeep would I need to get it from? Would it be from any year and model? What about the heads, what would need for this if I would go the cheaper way.
Thanks guys.

jpdocdave 01-15-2009 05:06 PM

since you have a yj, i'd say any yj 4.0 91-95. now the head swap you could use any 4.0 head, do some searching cuz there's a more desirable casting number that i can't remember off hand.

beasst95 01-16-2009 01:00 AM

This sounds like you know your stuff, I will do some research and thanks a lot guys.

spazinweasel 01-16-2009 06:56 AM

i think 92 and up are the high output 4.0 i got mine out of a 95 cherokee you may also need either a crank posistion sensor relocator with that trans not sure but you can use any 4.0 really if you get one out of a cherokee youll need a water pump out of a 4.0 yj but that and the other stuff should be it and its mostly bolt in

87YJWrangler 01-17-2009 11:46 AM

JPDocDave is the master when it comes to jeep issues

payj90 01-17-2009 06:55 PM

the 350 was just a for instance, maybe he should go with a 304.

jpdocdave 01-18-2009 09:10 AM

Quote:

Originally Posted by 87YJWrangler (Post 309589)
JPDocDave is the master when it comes to jeep issues

i see my brain washing is working:D

350 is a good swap, the 304 in the old jeeps made less horse power than the 4.0 304 was like 155 hp.

78cj7 01-18-2009 11:08 AM

Swapping to a v8 is alot more entailed than just dropping in a motor, and usually presents other issues. The engine is alot heavier and will wear on suspension and steering parts that already have been worn a bit. Also you will have to mate up the transmission to whatever you use and that can be a challenge as well.

i did a 4. swap on one of my jeeps to keep the weight factor down as the 4.2 was toast. i enjoyed that motor in the jeep due to its weight to torque ratio. A jeep isn't made to run 1/4 mile engines in its stock form, most of the time you are just using the torque and that needs to be considered against the weight you are adding. The 4.2 and the 4.2 are great torque engines and the rpms don't have to be as high to use it unlike many v8's.

87YJWrangler 01-18-2009 04:08 PM

Quote:

Originally Posted by 78cj7 (Post 309907)
Swapping to a v8 is alot more entailed than just dropping in a motor, and usually presents other issues. The engine is alot heavier and will wear on suspension and steering parts that already have been worn a bit. Also you will have to mate up the transmission to whatever you use and that can be a challenge as well.

i did a 4. swap on one of my jeeps to keep the weight factor down as the 4.2 was toast. i enjoyed that motor in the jeep due to its weight to torque ratio. A jeep isn't made to run 1/4 mile engines in its stock form, most of the time you are just using the torque and that needs to be considered against the weight you are adding. The 4.2 and the 4.2 are great torque engines and the rpms don't have to be as high to use it unlike many v8's.

You could always find a 440 with a 6pack and try to squeeze it in that would be one hell of a ride :punk:


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