4cyl to 6cyl swap

[purpleyjgirl]

ok, got my new tj and it's a 4cyl. my husband asked me to post about swapping in a 4.0 we have a low millage late model 4.0 that he's going to stroke and do some port polish/gasket match the head ect. we had a yj previously that had a 4cyl but was mated to a ax5 and we would have to swap out it and the xfer (splines different?) anyway this has the auto (999), would it bolt to the 4.0? so we figured we'd post asking for some input/oppinions. so far we have a list of the following to change; custom intake because the 4cyl is on the opposide side, exhaust, injection harness and computer. anyone think of anything we're missing??

 

[jps4jeep]

RE: RC Car

Assuming that the input spline count is the same for the two Motors, the transmission should be fine, the power out put from the 4 to 6 cyl is not that different, and a port and polish job will give some good feedback to the motor, but not enought ot crush it! Gearing should be fine..

You will need to address the following
Motor mounts will need to be cut off and re-welded
Transmission mount will have to be custom fabbed
New Front and rear drive shafts (front longer, rear shorter)
Computer, take it all out, PCM and all!
Exhaust will have to be re-routed and up-graded.
Cooling system change (Bigger radiator)
Stall converter, torque converter
and all the little things...

Assuming that it is gonna be un-lifted
axles would be fine
again transmission should be OK
T-case should be OK

It would be easier to source a totalled jeep that has a 6cyl, and is the same year or newer, and swap it all over, will save money in the long run!

 

[Junkpile]

The bellhousing bolt pattern is different. You'll need a new transmission. You are right about the 2.5l and the 4.0l YJs having different Tcase splines, but I don't know if it's the same in the TJ, so I don't know if you could reuse your Tcase or not.

 

[purpleyjgirl]

RE: fuel filter?

thanks jps4jeep & Junkpile. not sure about the xfer case. my husband hasn't even looked at the trans. he knows the motor is a gm motor. perhaps they used an adapter to mate it to the (a999) assuming it is such. the rest is straight forward, figured on the harnesess ect. thanks again.

 

[Junkpile]

he knows the motor is a gm motor.

Nah, it's a Chrysler engine. The CJs used a GM 4 cylinder and the XJs used a GM V6 in the early eighties, and there were a couple of other GM engines used before that, but your TJ engine is a Chrysler.

 

[djak12]

Re: RE: Re: RE: Ginger or Mary Ann?

What year TJ do you have? I did the 4 to 6 swap in my 95 yj and it was easy. I was going to put a 2001 motor in for the swap the the senors and wiring would have been a real pain to swap so I put a 94 motor in. I have a 2001 6 with everything that I am looking to get rid of. It only has 9000 miles on it if you are interested. I was real glad that I did the swap. I have everything that you need. except the transmission. You might have to get a different one. I did for my year.

 

[Bounty__Hunter]

I wouldn't recommend it, you'll have another run of the mill 4.0L jeep (along with thousands out there) with an install worse than factory. It's cheaper and easier to get a 4.0L jeep or to swap an engine in that will make it more worth while.

Just make sure you research it a lot before you decide on doing this.