Ok so about a month ago I want to say, I was on my way to my girlfriends and I stopped at a local gas station to get gas. Just happens to be payday weekend for me as well so it was right after I had put a brand new set of tires on, finished my suspension upgrade and so on..

SOOOOO I shut my truck off, fill this hog with a full tank and then I go to crank her up and next thing you know, she sounds like she's missing a cylinder and starving..

I limped it over to a parking spot, check the oil and other fluids, everything was fine. I cranked up my Jeep again and listened to this noise again.. sounds like a massive air leak coming from the top.. hard to tell at night.

Fast FWD a few days and tearing half the motor down..

I ran a spark and compression test.. it gets spark in the cylinders, but no compression in the first cylinder on the passenger side. I pulled the plug and it's a little moist with fuel.

A little further into taking things apart, I pulled the pssnger valve cover off.. well right off the bat I noticed the 1st rocker arm is very, I mean VERY loose.. like I can pull this thing out with out compressing the valve spring or even rotating the crank to adjust the cam. So I pulled the rocker arm, checked the lifter.. looked at the valve spring, everything seems ok.

The master mech. I work with looked at the back side of the valve spring to see if it was broken.. absolutely nothing. So he tells to grab a deep well and 1/2 drive breaker..

So I'm rotating the crank, keeping an eye on the cam shaft, watching as all the lifters, valve springs and rockers compress, decompress and so on.. only problem is, the 1st rocker isn't doing any of that.

Well I'm told the problem is that the valve seats fell out.. 2 mechanics told me this.. 1 worked for the Chrysler Dodge dealer in town for a long while and the other has been with the company well over 10 years.

I even called a cylinder head repair shop and the guy on the phone told me the same thing, after I explained everything to him.

SOOO, where I am going with this.. I'm sure out of everyones collective experience on here dealing solely with Jeep.. can anyone tell me what it MIGHT be and if it's possibly an easier fix that replacing a head, gasket kit, chains and all that?

I hit a wall and no idea where to go next on this..

 

When you turn the engine over manually, that in turn spins the camshaft. The lobes on the camshaft lifts up the lifters which are attached to pushrods which in turn push on one side of the rocker arm which toggles on a pivot and the other arm pushes the valve open. The valve spring closes the valve only after the lifter has receded down the camshaft lobe.

If you're seeing that all the rocker arms are toggling except for one or two, this could indicate a failed lifter or pushrod. The Jeep uses hydraulic lifters which "pump up" with oil. It is quite common for lifters to "just fail". Debris makes its way to a lifter oil hole and clogs the lifter, preventing it from pumping up. You can usually see this by attempting to rotate your pushrods. Hint, pushrods should not be easy to rotate unless the engine has not been started in a very long while)

Here is a good video showing a bad lifter:

I would check this first...

 

I think he's saying the valve is stuck in the open, or down position. The 318 and 360 do have problems with the valves failing, but I haven't seen any with the seats that have fallen out. If it were mine I would pull the heads and take a closer look. The lower end should be ok.

 

Don't lose sight that we are talking about a 4.7 overhead cam engine. Those rockers work as third class levers with the valve at one end, the cam in the middle, and the hydraulic tensioner on the other. It seems to me if the seats dropped out of the head, they would be holding the valves open and the rockers would be loose. Just as he described. You're going to have to put the head.

 

Well with time I'll be tearing it down and doing a further inspection