3.4 engine swap for a 2.5?

[dunl]

How come nobody seems to do these in 2.5l vehicles?  They're really popular for Comanches, but yet when it comes to 2 doors, everyone seems to just sell their 2.5 instead of swapping in something else, like a 3.4 that will bolt up to the same bellhousing.

[barmanjay]

How come nobody seems to do these in 2.5l vehicles?  They're really popular for Comanches, but yet when it comes to 2 doors, everyone seems to just sell their 2.5 instead of swapping in something else, like a 3.4 that will bolt up to the same bellhousing.

I was planning and researching to do it (spent months researching),.. till the wife and I found out we are having another child,.. I have since abandoned the project.

I even kept my spare ax5 (needs syncros) for this project

you can use the 3400 from a 1998-2000 chevy/pontiac mini-van, 2000-2003 grand am, malibu

the better motor would be if you can find a gm factory 3400 replacement for the s10 and related rwd vehicles - the starter is in the correct spot otherwise you will need to cut out the starter spot on the bellhousing. I also believe you can use the 350 swap motor mounts on this version of the 3400. The other one will need custom motor mounts.

May need the flywheel from the cavalier aswell if the 2.5 one doesn't fit, but I believe it will.

will need:

wiring harness, ecu and body harness and all related engine sensors from: 2nd generation, phase 1 cavalier with the 2.8/3.1 (88-90) - Can use the 91-94 harness, but be prepared to splice for ign and turn signals and etc.

because the older YJ's share a similar steering column as many gm's and the cj's were basically gm parts,.. the likelyhood of a plug and play wiring swap is very high.

Will also need a chip to run the multec 2 injectors on the 3400 - research this site for the guy that makes them, I believe it's scott0999 or something like that - www.v6z24.com
will need the newer injector harness from the 3400 to splice into the older wiring harness.

 or you get the injectors, fuel rail and fpr from a 96-97 gm 3.1 (3100)

The only real issue I think with the ax5 is the weak 5th gear, as it was an add-on. I believe there are some stronger toyota gearboxes (4sp) that will bolt onto the bell housing.

I'm surprised no one else has done this swap either.

the 3400 is a much more fuel efficient motor with a very good power/torque ratio. With the chip you are looking at about 195-200hp and maybe 250+ ft/lbs trq.
$35 = 325kms (+/- 25)

This is basically all the info you will need,.. the rest will be trial and error.

[The Machinist]

Just don't let it get hot, I resurface more 3.1/3.4 litre heads than any other head.  Intake manifold gaskets are also prone to breaking apart by the water jacket.

[dunl]

I think you need to remove the flywheel and have it neutrally balanced too.

Looks like a lot of work to do, but I think that's only because you ran through everything....pretty much any motor SWAP as opposed to replacement would be the same I think.

But yeah, the ax5....that'd be an issue.  But the AW4 came behind those motors too.

[barmanjay]

good call on the aw4, I never really thought about that. Just so used to driving stick

[dunl]

good call on the aw4, I never really thought about that. Just so used to driving stick

So am I, but we bought two automatics last year (KJ and Dodge 3500). 

However, if I ever get (translation: sometime in the future WHEN I buy) an auto jeep, I'm going put in a lock-up:

http://www.lunghd.com/Tech_Articles/Transmission_and_Transfer_Case/TransmissionController.htm

Not the best article, I have one bookmarked somewhere  on another computer that looks pretty simple.

[dunl]

Here it is:

http://www.cherokeeforum.com/showthread.php?t=11804

[cLAY]

I did that on my old '89 XJ and on my Dad's '91 XJ. Well worth the time to be able to lock it in 1st gear or 2nd gear but I didn't find the TC lock up usefull at all. I thought it would add more engine braking but I didn't notice a difference.

Makes REALLY bad nosies when you try to stop with it engaged as well.