upgrade 4cyl to 6cyl

:scottm: my 4 banger has 150k miles and thinking about an upgrade. what am i lookin at to swap in an 6 cyl? will it mount to my 5speed? could i run an carb and forget the comp. ? just curious.

Welcome to , and the 2.5-4.0 swap is pretty in depth, but doable. I dont think you can keep your carb. Besides the FI gets you better mpgs.

Sell yours and buy one with a 6 already in it. You'll be money ahead.

MUDDPUPPY78 said:

:scottm: my 4 banger has 150k miles and thinking about an upgrade. what am i lookin at to swap in an 6 cyl? will it mount to my 5speed? could i run an carb and forget the comp. ? just curious.

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If it's 1987-up, the engine bay should accommodate the long six.

If it's 1986 and earlier, you can do the AMC six - but it's a load more work. Easier to swap in a better version of the V6-60 AMC was using then - the RWD 3.1L/3.4L should drop right in. Grab the donor electronics while you're about it, and you'll get the FI - which is better than a carb anyhow (especially for efficiency and in off-camber terrain.)

Besides, your four-cylinder carb will be woefully undersized for pretty much any six-cylinder engine...

Possible donors for the V6 swap (for earlier rigs) will be the Camaro, Firebird, and S-10/S-15 series light trucks.

(The firewall and engine bay were reconfirgured for the 1987MY to accommodate the much longer inline six, thus the headache. The six swap into an early rig has been done before, but it's loads of work...)

thanx for the info. i cant sell it we bought it new in 98 its apart of the family ,just needs more ballz. Ill look into late model 6 with FI and see if itll mount trans (ax5???)

I am in the same boat too. My wimpy 2.5 really gets to me after driving my '99 with the 4.0. Unfortunately you WILL be money ahead in just purchasing a used XJ with a 4.0 from the factory. Once you figure in the downtime, labor, time of hunting parts, fabrication, electrical wiring and the time to tune you WILL be waaaay ahead of the game if you just get an XJ with a 4.0. If this is a project jeep and you really REALLY want to burn some $$, then possibly a GM 4.3 V6 swap. Plan on major fabrication work to the suspension and drivetrain, plus electrical. Probably not any more out of line than what you are already planning though.

MUDDPUPPY78 said:

thanx for the info. i cant sell it we bought it new in 98 its apart of the family ,just needs more ballz. Ill look into late model 6 with FI and see if itll mount trans (ax5???)

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Grab the AX-15 from the donor as well - the AX-5 isn't long for life behind the 242ci engine... Transfer cases, however, should be the same.

The AX5 won't bolt up anyway. I vote for selling it and buying a 4.0 Cherokee instead. Far less work, especially if you're not overly mechanically inclined.