O2 Liberty Limited / engine issue

Hello,
I'm new here, my neighbor sold his 02 Liberty, 2 wheel drive, auto, Limited model to me for 1,200 dollars.
The Jeep is like new, however has a major engine issue. I took a look at it and found # 2 cylinder had no compression, upon removing the valve cover I found the rocker off to the side and out of place. It looks like the intake valve is not returning to the up-right/closed position. I haven't moved lower in the engine as yet. The engine cranks and will run, HST its won't go over 20 mph.. Theres no odd noise or any kind of harsh metal to metal sounds etc.
I think the seat fell out and is jammed up against the #2 valve..

The car did get hot 3 months ago, the radiator and water pump were replaced, it ran perfect until it was restarted after a short stop for fast food.
Everything happened just like that...

What do you think ?

How many miles are on the engine?

Marlon_JB2 said:

How many miles are on the engine?

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The engine has 100k miles.

Do a search on this site for "Valve Springs".

Some of the '02s had issues with these. (Later years too, but not NEARLY as often)

Marlon_JB2 said:

Do a search on this site for "Valve Springs".

Some of the '02s had issues with these. (Later years too, but not NEARLY as often)

Click to expand...

Hey,
I did a search on this site and Google as well, didn't really come up with much. I did take the valve cover off and found the rocker have drooped out of place because the valve stem/spring Assembly didn't take up enough slack to hold it in place. The valve itself as a Assembly along with the spring was not rising up enough to hold in the rocker. It didn't look like the spring was damaged but that might be hard to see and be sure about it. .....

ShafferNY said:

http://www.jeepkj.com/forum/showthread.php?t=26447&highlight=rocker+fell

Click to expand...

I did see that one if it were just a spring that would be great! Replacing those is quite fast compared to removing the heads etc....


How often do these engines drop valve seats??

driveability said:

I did see that one if it were just a spring that would be great! Replacing those is quite fast compared to removing the heads etc....


How often do these engines drop valve seats??

Click to expand...

Not often,there have been a few,mostly the '02 engines,I've heard of about 5 cases,out of 10,000 or so memebers on variuos forums so that's not bad at all.There will be engine problems with any vehicle line,just look at GM,there most used engines,3.1L/3.4L/3.8L,have a major problem with all of them,there intake gaskets leak and the ones with the plastic intakes often end up with warped intakes.

Even if you need to get new heads,about $1500-$2000,you'd still be making out like a bandit for only paying $1500 for the KJ to start with.

Yea, sounds like its just a valve spring. Ive read about those breaking a couple times.

I haven't done much more but have inspected the valve springs and they look fine on the effected cylinder. Theres no compression and the valve isn't stuck as it responds if I tap on the top. The rocker however will no longer stay locked in as the valve overall height is too low.. I did get some oil spray out of the cylinder and thats not good news.
My thoughts are a big crack in the head and the valve seat has come out keeping the valve open. Sure there could be other things going on but the engine never made any noises, it just failed to run correctly once it was shut down and restarted 20 minutes later..
I'll pull the head soon, hopefully in the next two weeks. Should be interesting...

I have a bit more to add, I removed the intake manifold and could see down the intake port. I saw a intake valve and a valve seat stuck together. I didn't see much of the piston at this point, so I can't determine if its damaged.

Any one know what kind of compression/piston style, dome or flat, cutouts etc.?

http://dodgeram.org/tech/gas/Cammer/4_7_v8.html

Take a look at that page. It's for the 4.7L, but the 3.7L is pretty much the same engine, minus two cylinders.