Can I replace a 4 cylinder engine with a 6 cylinder

[stepheng67]

I am in the market for a jeep YJ or TJ years 1993-1999. I have found many with 4 cylinder high mileage engines. I am not opposed to finding a 6 cylinder, but I don't mind buying and changing the engine out if it is possible without much trouble? How much trouble is it to replace the 4 cylinder engine with the 4.0 6 cylinder? Are the engine mounts the same? Bell housing? Transmission? What other issues would I need to be aware of? I have not owned a jeep since the early 80s when I had an underpowered 4 cylinder CJ 5.

[Bounty__Hunter]

Nothing easy about it. Tranny won't work, motor mount perches need cut off and rebuilt, new wiring, etc. Since you're in the market, hold out for a 4.0L.

[stepheng67]

Thanks for the answer, that was kind of what I have been leaning towards. I just needed someone with more knowledge to keep me from making a bad decision. Do the fuel injected fours have enough power to run the YJ and TJ? I just remember my 4 cylinder CJ-5 barely getting the speed limit with a 20 mph tail wind.

[Bounty__Hunter]

The FI 2.5L has come a long way, '91+ has a lot more power, but it's personal preference on if it's enough power for you. I like mine, even after owning a v8 YJ. Most of the driveability is in the gearing, mine runs 5.38 axle gears to turn the 35" and 36" tires.

[volaredon]

better choice; put a 318 in it. or maybe a 3.9 out of a Dakota; they used the same AX 15 trannys (other than bellhousing) teh same 231 t case etc and being also a Mopar product a similar year swap oughtta be plug n play.

[Bounty__Hunter]

A v8 or v6 will not be plug and play. Still need to address cooling, motor mounts, and a custom wiring harness.

[jfrabat]

Well, if you are considering the engine swap, then I'd say a V6 or V8 is a better option than the I6 (it will make it more worth your time and effort, anyway). I do agree with Bounty, though, in that the 4 banger is not that bad. Mine runs on 31's and I run 4.88 gears, and I can hold steady at 75 mph even in headwinds (I can even accellarate in 5th at 60mph, or hold 65 mph going uphill - which in Miami means overpasses). but if what you really want is the I6, better to buy that directly.

[Carleysjeep]

I agree with Bounty Hunter, you are better off buying what you want in the first place than getting something else and trying to turn it into what you want. Buying a jeep with a 4.0 already in it will also be cheaper in the long run.

[marlor]

There are things you can do to an engine short of replacing it. Sometimes just regular maintenance is all you need. Have a compression test done on the cylinders. If bad rings are causing a compression loss, a ring job is alot less expensive than an engine swap, and give you the power you need.