Yeah, soooo . . . Pretty sure I broke it. 2000 XJ - 0331 head replacement fallout

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Ummm, hi. (Again.)

So, like the title says, I'm pretty sure I screwed something up. Possibly something important.

I have a 2000 XJ Limited, that had the infamous 0331 head. As you might guess, the head cracked. Been paranoid about that happening since I bought the thing (didn't know about the issue until after purchase), so I've been a little hyper-vigilant about it. For all I know, I may have just blown a head gasket.

Either way, a guy in my local jeep club just happened to have an almost brand new (and incredibly clean) head just sitting in his garage. The head is marked "DD" where the 0331 was on the old head. As far as I can tell, this means that it's a re-man sold by Advanced Auto Parts. So, not a TUPY or a Clearwater, or an Alabama, but still better than a 0331, right?

Anyway, swapped out the head, put in new lifters, new thermostat and a new flowcooler water pump while I had it all apart. Put it all back together like a boss and everything was perfect. All was right with the world. Birds were singing, the sun was shining. My wife and my children looked upon me with adoring eyes and they were humbled to be in the presence of such a manly freaking man.

And that lasted for about 150 miles or so.

Once I got everything back together, it started right up and it drove just like it did before. No loss of power, idle was steady, oil pressure was good, temp never quite hit 210, but it was only a little low. No leaks . . . everything was looking good.

Then, I started to notice a slight knock, only after the engine had warmed up, and only on in the 2-3,000 rpm range. The knock was faint, and the thing still ran fine, so I tried not to worry too much about it and just hoped it would work itself out.

It didn't. Instead, the knock started to get a little louder, and my idle would fluctuate up and down at stoplights. Giving it a little gas would take care of that though.

So, things progress. Knock gets a little louder, and now I'm starting to sputter a little. Will almost die if I let off the gas too quickly. Again, gas will make everything right with the world, but I'm starting to think that I'm losing a bit of power on accelerating.

But, since gas makes everything better, I decide to give 'er a little bit of hell to see if this is something I can just "clear out."

That was a mistake. Knock is now a full-fledged knock. No denying it anymore. Sputtering like crazy and eventually the check engine light comes on. Check my OBM reader on my phone and I've got a P0305 - misfire cylinder #5. Boy, I'll say.

Simplest fix first, I change my spark plugs. Twice. First to fancy platinums, then, because the internet told me to, to el cheapo brass. I will say that when it's NOT sputtering, the brass ones do actually seem to make it run a little more smoothly. For whatever that's worth.

BUT, ultimately spark plugs do not make a difference and knock and sputtering come back, bigger and badder. Obviously, whatever is going on, it's getting progressively worse.

Figure I have to see what I can see with regard to cylinder #5, so I remove the valve cover and check out the rockers and rods for #5. There is very clearly wear on the rockers and bridges, right where the convex part of the bottom of the bridges fit into the rockers. There has been some bad rubbing going on here. As far as I know, they were torqued down properly and lubed with engine grease. And, if that's true, I'm not sure how the wear would have occurred there. Maybe bad valve springs?
Springs not compressing right and causing rods to press rockers up in to bridges extra hard?

Well, no one in town had any rockers in stock, so I have to wait a couple days to get new ones to see if that helps at all. In the meantime I put it all back together and took a little video to see if I could get the opinions of this august forum. Unfortunately, the jeep was in my garage when I took the video, so the accoustics leave quite a bit to be desired. Hopefully you'll be able to hear the knock though. Video is here:http://youtu.be/DnAkJUgMWUg

I'm really hoping this isn't something hugely major. Valves or valve springs I can handle. I'd be fine if I just needed to upgrade my fuel injectors. But with that knocking sound, I'm thinking there's something very expensive lurking under my hood. I'm just hoping to not waste too much time tracking it down.

With that in mind, ANY advice you fine folks can offer will be GREATLY appreciated.

Thank you.

could be a rod knock.. mine started very faint and got louder over time, mine is a 2000 classic

Check valve installed height to determine if possibly it is a valve problem. The misfire would definitely lead me to believe that is the issue. However, with prolonged running you could have burned a valve too...making the misfire worse. Did you check seats and where they were contacting before you installed the head?

How did you go about breaking in your new set of lifters?

Rod Knock - I'm gonna see what I can see running it with the valve cover off when I get home. Hopefully if I've got a rod bouncing around in there I'll be able to see it.

Valve installed height - Might not be in my wheelhouse, though I do have a propensity to take ill-advized risks. Got any tips on how a guy would measure that? Did not check seats before installation. After talking to the Jeep club guy who sold/gave it to me, I was under the impression that it was in perfect working order.

Breaking in Lifters - Fluctuating my RPMs between 2-3k for about a half an hour or so. Maybe a little more. Though, like I said, my temp stays below 210 now, so maybe it never got hot enough to do a good job of breaking them in?

Brain fart. Rod knock . . . piston rod knock. This would be a bad, bad thing. I suppose I have a tiny little super powerful magnet I could put on the end of my oil pan drain plug and see if it collects any shrapnel. . . .

Was this a pre-assembled head, or did you have to remove valves/springs/etc. from your original head?

Based on what you're saying about wear on the pushrods/bridges/rockers, I'd guess you've found your problem. Either something went wrong in assembly or they aren't getting proper lubrication.

machinisttx said:

Was this a pre-assembled head, or did you have to remove valves/springs/etc. from your original head?

Based on what you're saying about wear on the pushrods/bridges/rockers, I'd guess you've found your problem. Either something went wrong in assembly or they aren't getting proper lubrication.

Click to expand...

Head was pre-assembled, and (thankfully) I'm pretty sure I've narrowed the problem down too.

Checked it out without the valvue cover on last night and, while there IS oil flowing through both pushrods in #5, there is less coming through the one toward the cab (intake?). The valve springs seem to be squishing nicely, just like all the non-problem-child ones.

When the thing got warmed up and the knocking started . . . it's hard to identify exactly what's happening, but the sound is definitely coming from right there. Top of the engine and not the bottom, thank God.

The knocking starts and the pushrod in question starts going kind of crazy - still technically in place, but where it had been rotating all nicely and consistently before, it starts changing direction, and just generally being much more erratic. Coincidentally, it does this in time with the knocking sound. There's something up with the timing there too, but it's really all happening too fast to tell what exactly. But, I think it's safe to say, this is where things get a little . . . off, and hence, the sputtering.

So, now I can see at least part of what's physically happening, but I don't think I'm seeing enough to tell me what the actual cause is. Right now, my theory is that there's something up with the lifter. I'm guessing this because the problem doesn't kick in until the block warms up, which I would think, causes a little expansion of the block(?), this, I think, would either constrict the lifter inside its hole or make the hole bigger letting the lifter loose inside its hole. In one case its movement is slowed down, in the other, it's knocking around loose (losing pressure and direction). If I'm right HOPEFULLY, it's something a new lifter (and pushrods and rockers/bridges) can fix and not a problem with the block itself.

Does it sound like I'm on the right track there? I'm just kind of making this sh!t up as I go based on internet folklore and just enough actual knowledge to get myself into messes like this, so really, any input is good input.

Thanks!

bad lifter not holding it's prime.

From the video it sounds like a valve or lifter problem. Take valve cover off and run the engine to see if you can narrow the sound down to a particular valve.

Yeah. It's the intake valve on the #5 cylinder. Took the valve cover off and that lifter/pushrod just isn't pumping anywhere near the amount of oil that the rest of them are. Fine-tuned the torque on the rocker bolts and that may have helped it a little (or placebo effect). Took longer to get the knock to show up tonight than it did last night and it idled way smoother. Was hoping it magically fixed itself, or was simply an overtightening thing.

New lifters, pushrods, and rockers will be here tomorrow.

I'm thrilled about having to treat the whole thing apart again and pop for new head and manifold gaskets just to put in ONE new lifter, but so it goes . . .

At least she's still pretty.

What lifters did you use?

Just plain ol' "sealed power" or whatever from O'Reilly's and Auto Zone. The other 11 seem to be doing just fine so far.

So I take it by no more posting that you got the issues sorted out?