2.5 swap to 4.2 what is involed?

[deadred]

Acc Lamps

While working on my curent upgrade I had someone stop by asking me If I would be intrested in swaping out his 2.5 and drop-in a 4.2 anyone do this??
If so how bad is it? I would think that it can be done but am I geting in to too much? The main concurn that I can think of off the top of my head is the ECU, the motermounts and the cooling. just thought I would post it here for some feed back before I comment to anything. By the way it is a 95 YJ 2.5

 

[redrooster]

RE: Re: RE: Re: RE: Re: RE: Re: RE: HELP!!! Need opinions fr

If you have never done the swap then you should be hesitant to try it on someone else's Jeep. If there are problems it will come back to you for repairs.

 

[djak12]

I have done the 2.5 to the 4.0 in my 95 jeep. It took me one (1) weekend and a day to do the swap and if I new then what I new know we could have had it done in two days. All that you need are the right brackets and wiring harnesses and it's not that difficult.

 

[mud4feet]

I have done the 2.5 to the 4.0 in my 95 jeep. It took me one (1) weekend and a day to do the swap and if I new then what I new know we could have had it done in two days. All that you need are the right brackets and wiring harnesses and it's not that difficult.

Did you keep the same transmission? Just curious, I've heard the 4banger transmission won't hold up to the added HP/Torque of the 4.0

 

[djak12]

Re: How is that right?

The 2.5 has the ax-5 which is not suited for the 4.0 engine. I needed to install the ax-15 to work with this motor.

 

[Snitty]

RE: How

If you are converting from the 2.5, you are better off finding something more powerful than the 4.0. It requires a new drivetrain, relocated motor mounts, wiring and all sorts of things either way. If you are just looking to go 6 cyl, I say sell and buy rather than go through the trouble to build something that is availible already built

 

[Bounty__Hunter]

RE: Re: RE: Re: RE: Idoling too low

All that you need are the right brackets and wiring harnesses and it's not that difficult.

What about something to cut the motor mount perches off the frame and weld on new ones?

The 4.2L is generally a computer controlled carbed engine, so there are a ton of better options out there. I wouldn't do this swap even if I had a 4.2L lying around.

Did you mention to the guy the MPFI 2.5L has a higher horsepower rating than the 4.2L engine?

 

[deadred]

Thanks for all the replies Idont think I will be doind this upgrade I dont neeed the headach

 

[Snitty]

RE: Re: RE: Question?

good choice

there are many options for helping the 2.5 with power.

I heard somewhere that there's some restrictor in the intake that you can remove to make it run like a 4.0.... and you can take the muffler off to make it sound like a small block V8
(please do not believe that)

Bounty is the man to talk to on 2.5 performance