DeereHunter

I just recently bought a 2001 Grand Cherokee WJ, Laredo, 4x4, all power, 242 I6 motor, but I picked it up really cheap, looking to lift it, put some bigger tires under it, and OH YEAH! Get it running! Haha. I bought it cheap because the motor is locked!
What years/ models can I pull the 242 I6 from, and plug and play? I'm looking for a quick swap, I dont want to rewire, or change the wiring harness, what year models are interchangeable?

I'll have more questions down the line, I'm a Wrangler guy, I love Jeeps, and I'm a pretty good mechanic, I can do most jobs myself, just looking for a little help from someone who may be a long time Cherokee person!

aleet25

As far as I know and from what I've read, an engine from a 01-04 will be and exact "plug in play" fit. Any 242 from a wrangler, cherokee, or grand cherokee will fit as long as its distributorless. The only thing you might run into is your accessories might not bolt up to the engine in the exact location they would if you got one from a 01-04 WJ. Good luck.

DeereHunter

Thanks! That's a huge help, I know that through model years they like to swap engines, like the JK did I'm 2012 moving from the 3.8 to the 3.6 pentastar.
But finding information for WJ's is very difficult, doesn't seem as many people are twisting wrenches on these like they do wranglers!

I also haven't ruled out rebuilding the 4.0 that I currently have. Anyone rebuild one, it stroked one?

aleet25

Wjjeeps.com is a good website for all things WJ

DeereHunter

This is what I found when I pulled my spark plugs out.
I heard you could put transmission fluid in the top on the cylinder (through the spark plug holes) or wd-40 and on a lucky shot get it to free the engine. I figured it was worth a shot because I had an extra bottle of transmission fluid sitting around.
However cylinder #1 spark plug is smashed, and when I poured the fluid in, I could hear it immediately dripping down into the engine oil.

Still considering rebuilding/ pulling from the junk yard.

dave1123

I saw the same thing on a 57 Ford motor. An exhaust valve head melted off busting the piston, pounding the head, spark plug, and two rods on the way to the bottom. However, my dad drove it over 100 miles like that, just adding oil and never shutting it off. From the looks of the plug, something similiar has happened to your motor.

He was going 70 mph with 4.11 gears running about 4000 rpm for 2 hours before this happened.

DeereHunter

The p/o said the motor was knocking for 2 years before it locked up.
She had just replaced the radiator, and said it only ran a couple days after.
Also, the engine oil is really watery, and loaded with coolant.

dave1123

I probably had a bad rod bearing or a cracked piston which finally destroyed itself. You can pull the head, but don't hope for much. The front side of #1 cylinder barrel is not supported very well and I'll bet it's cracked.

DeereHunter

Do you think it damaged the head/ block? Anything machining can fix? Or would you think I need a new motor?

dave1123

If the cylinder barrel is cracked, the block is toast. The head chamber may be damaged but maybe not badly. The only way to check it out is to pull the head, then decide.

DeereHunter

This will be my first time swapping a car engine. I've done 4 wheelers dirt bikes etc. But never a car so I'm proceeding slowly and thoroughly.

DeereHunter

Will i be better off pulling the head off, and inspecting it, before deciding what to do? Or will my best bet be to go ahead and remove the engine?
Seems like I will have to pull the engine no matter what.

Also, what's going to be easier for me? Removing the engine and transmission together, or pulling just the motor? Seems like its going to be a big pain in the behind to reconnect them if I pull just the motor.

dave1123

Don't forget you've got a transfer case on the back as well! I myself would split the motor and trans. It's pretty easy to get it back together again. Just be careful of the transmission input shaft. Leave the torque convertor installed. Make sure the convertor spins freely before you draw up the bell housing bolts. It must be engaged with the pump or you can damage the pump. There are two slots on the convertor shaft that drive the pump.

I would install a new Crank Position Sensor when putting it back together. It's good insurance.

I would suspect there is considerable damage to the engine, but again, you'll have to pull the head to see it. If the piston is pounded, don't forget the rod bearing is probably destroyed as well. Years ago, a cylinder could be rebored and the crank turned with the engine still in the vehicle, but it's a lost art today.

Just think how much fun and experience you'll get by doing it yourself. You'll be a veteran in no time!

DeereHunter

What issues will I run into swapping an XJ 2001, into my '01 WJ? Both 242 inline 6 motors.

dave1123

First of all, the "242" refers to the transfer case, not the engine. The I6 is 4.0 liter. As far as I know, the only other engine used in the WJ was the 4.7 V8.

The NP/NV 242 transfer case is the one that has the 2WD option. If you have the 4.0, I believe you have the 42re transmission. This gives you 3 forward gears with O/D and lock-up converter.

As I said, split the engine at the bell housing, remove the three converter drive bolts, and leave the converter on the transmission. At some point around the turn of the century, Jeep changed the engine block and motor mounts. You'll have to do the research to find out just when this happened. If you wind up with an earlier engine, use the intake manifold from your original engine because it flows better. The engine to transmission connection is just 2 dowel pins and a few bolts. The tricky part is making sure the torque converter is installed properly and not binding before you tighten up the bolts. After you've done one, it's simple.