Straight 5 Engine Swap?

So after all my work converting an '88 2.5 to MPI, electric fan, etc. to give it more power, it just isn't enough after my ax-15 install, 4x4 conversion, 8.8 rear, etc. I've been thinking about different engine swaps that would make it nicer to drive. I've ruled out the 4.0 simply because IMO there are much better engines available now (better power & mileage). Here are the two that I'm currently thinking about:

The 5.3 chevy would be nice and is one candidate, but it seems like you'd have to get one from a camaro or a car to avoid hood mods or the engine hanging down lower. I believe the intake manifold, oil pans, etc. can vary a lot on these. The advantages to this one are that novak offers most of the parts if you don't want to fabricate them yourself. The downside is cost (if you buy the parts) or time, research, & difficulty if you do it all on your own (not much room in the MJ engine bay).

The other candidate that I've been thinking about is the LLR Vortec 3700 GM straight 5 engine that is in 2007 and later Colorados and Canyons (http://en.wikipedia.org/wiki/GM_Atlas_engine). It seems to me that a straight 5 would fit nicely between the narrow frame rails and generally be easy to swap in. Granted I would be custom fabricating everything. They are rated at 242hp/242 torque though and are supposed to get pretty good mileage. If it uses the 60 degree chevy pattern I might even be able to use my AX-15/231 behind it, but I could also use the tranny it comes with if necessary. I'm broke and it will be a year or two until this engine swap happens, so this is just future planning at the moment, but if anyone else thinks it might be interesting or has more info on this engine or has done this, please chime in on how feasible it would be.

Other thoughts:
Because the engine is narrower than a V engine I could possibly use the stock exhaust manifold and just have an exhaust system made from the down pipe back. Or if that doesn't work I'd have to just use the stock flange and create my own (I'd rather not).
For dashes and wiring, I'd probably just use a stock wiring harness for the engine, then either make the stock colorado gauges work or get aftermarket ones rather than try to mate them up to the mj gauges. I may end up building a custom dash at some point anyways because I'm tired of plastic that cracks and rattles on the stock dash.

I've wondered about that too. It seems like a really good engine.

I think you will find that the oil pan will give you some problems.on a colarodo 4x4 i think the axle goes throuh the oil pan.from bottom of the oil pan to the top of valve cover it is a pretty tall engine

sound good from the info you gave. looking forward to seeing something happen with this.

How about the GM 4.2 liter straight six that was in the Trailblazers and it's cousins. It's all aluminum so it's much lighter, and it's rated at 291 hp and 277 torque.

Physically fitting the engine in the bay is the easy part.

The huge issue you're missing here on all the late mod. motors. They're all OBD-III. To get them to run right with a stock computer, you have to have ALL of the sensors and systems hooked up and operating properly. That includes the evap. sys, sensors, all emissions, probably the full dash, air bags, ABS, and even the radio in some cases. You're basically fooling the computer into thinking it's still in the original chassis.




Not trying to shoot you down, but you'll have to do a lot of research on the computer side to make it work right. Get to know the expert trouble-shooter at the local GM dealership.(The guy who has to take on all the problems that nobody else can solve)

or you can mega squirt it.

BenDiesel said:

or you can mega squirt it.

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and control the variable valve timing how?

didnt know it was a vvt engine. you could set up a trigger from megasquirt to kick it on at specific times i think


you could always use a mercades diesel out of a 300dl

I think the latest and greatest was a 4.0 straight 6 from GM, but one of the appealing things about the 5 to me was that it wouldn't be as deep as a 6. I've owned a straight 6 in an xj and now a 4 in a mj, and it sure is easier to get to the transmission bolts, the last spark plug, and many things on the front of the vehicle with the smaller engine.

I'm not familiar with the oil pan or how tall the engine is at this point, but that's a valid point if it is really tall.

Seems to me that any late model engine is going to have the computer and all the sensors, and that's part of the reason they can pull so much power out and still get decent gas mileage. I don't mind working with the wiring and sensors, although I'm sure there will be much to learn with it. I'm leaning toward taking the easiest route to get a better engine in there. If the wiring becomes overwhelming I'll save up the money and just buy a harness that is ready to plug in (painless wiring?).

On the 5.3 side of things, it seems like the major challenge for a lot of the swaps is simply how narrow the frame rails are where the headers drop down, which could be solved either by cutting and rerouting the frame rails or simply paying the big bucks for the novak headers. There are other threads already discussing that swap though.

xj92 said:

....leaning toward taking the easiest route to get a better engine in there.

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As you sit in front of your computer in your bath robe and slippers, eating a bowl of cold cereal for your Supper, wishing you had a different engine in your XJ, you haven't set out a budget or considered any of the practical obstacles to your daydream.

Specifically, what makes the Jeep 4.0L so inferior to a Chevy engine when used in an XJ ?

Preliminary budget
Vortec 3700 Engine $1500
matching transmission $900
transfer case and adapters $500-800
Painless wire harness $800-1000 (if they even make one for this application)
misc parts $500

For that kind of money, you could buy and simple bolt in a 4.6L Jeep stoker motor. If you built the stroker yourself the cost would be 1/3 of a Chevy swap and the money you save would buy plenty of gas.

why not a chevy v6?

Thank you. MODS, please sticky this answer and post it for the daily "what if" engine swap questions.

Tim_MN said:

As you sit in front of your computer in your bath robe and slippers, eating a bowl of cold cereal for your Supper, wishing you had a different engine in your XJ, you haven't set out a budget or considered any of the practical obstacles to your daydream.

Specifically, what makes the Jeep 4.0L so inferior to a Chevy engine when used in an XJ ?

Preliminary budget
Vortec 3700 Engine $1500
matching transmission $900
transfer case and adapters $500-800
Painless wire harness $800-1000 (if they even make one for this application)
misc parts $500

For that kind of money, you could buy and simple bolt in a 4.6L Jeep stoker motor. If you built the stroker yourself the cost would be 1/3 of a Chevy swap and the money you save would buy plenty of gas.

Click to expand...

I think the real moral to this thread is don't waste time building a 2.5 jeep anything.

True, don't waste time building a 2.5. Good luck finding an MJ with all the options you want though. It's not like an XJ where it's easier to find twenty more in decent shape with the engine and tranny you want, etc. And I just enjoy building and tinkering. I can get engines at the local pick n pull for around $150 on half-off days, and trannys for around $100. Wiring harness for $30, etc. etc. Fuel mileage and power are what make chevy engines superior to the 4.0 in my opinion. From everything I've read, swapping in a 4.0 isn't easy either because you need firewall mods to make room for the long block. I have considered practical concerns like cost, but I'm fully aware from past experience on other projects that any budget would get blown out of the water anyways. Projects like this always nickel and dime you. I will do an engine swap someday, and this is simply part of the research for me. The end goal for me is to have a fun around town truck that handles nicely, accelerates quickly enough to put a smile on my face, stops on a dime, and that I can use to camp or hunt, not rock crawl. I'm planning to build a buggy for that at some point..... Am I the only one that studies, learns, daydreams, plans, etc. etc., even for months or a year in preparation of a project? Just cause the money's not there at the moment doesn't mean the plans stop.

5.3 never came in a Camaro.

I think you need to do quite a bit more research before diving into this.