strange noises

This is going to be a very long thread sorry. Long story short looking for a ticking noise. 1990 XJ 4.0L AW4 makes really loud noise at start up. Also continues to tick for a little while after the engine is shut down. Clatter at higher rpms. Got sick of the noise and my leaky valve cover, so I decided to check some things out. Pulled the valve cover and while engine was ticking(shut off) felt rockers and could feel the tapping reverberating through the rockers and push rods, so I am immediately thinking lifters. Been using additives and different oil weights for a while now MMO Lucas nothing helps. I had to drop my oil pan to fix a few more leaks. So while I was in there I have been checking out the lower end. When I turned the engine over by hand to get a better look at a few of the piston rods and bearings. It starts that infernal ticking. So while its ticking I feel the lifters from the bottom side. I don't feel anything weird I thought it was lifters, and I thought I would feel the tap for sure. I keep feeling around while its ticking I can't find it. Sounds like the upper end. Could this be rocker arms, or push rods making this noise? Any other suggestions? I am so close to finding it. It's getting a rear main, oil pan gasket, high flow oil pump, and new bearings. Upon inspection bearings are toast. I have ruled it out as lower end it has to be upper. I inspected valve springs they looked and felt fine. Torque rocker bolts. The only other things I cam think of are push rods or rockers. possibly a valve, but I doubt it. has anyone ever had a noise like this. thanks.

The tapping does not always stay on the same cylinder either. It will tap on different cylinders every time ypu turn it over. And sometimes multiple different cylinders.

Post up a picture of the bearings. "toast" is a relative term. You may be too late in fixing this if crankshaft damage has been done.

Crank Journals have slight scoring, but they do not look too bad. Couldn't get very good pics of crank. Lots of copper showing on piston bearings. One of the the main bearings has a heavy score through it, but I did not see the same heavy score on the crank journal.

I know for sure the tapping has nothing to do with these bearings. I am going to take my chances with new bearings I have already decided that. Sorry about the poor pics if you want to give me you 2 cents about the crank and bearings I am ok with that. But its the upper end tap tic I want to take care of. But if I have to pull the head off anyway I might as well just yank the crank for re-grind and do the build. Why would I not feel lifter tap through the bottom end? I don't get it.

I am at the point of no return. Just wondering if the rockers or push rods(doubting push rods) could cause that tap. If its a valve, Valve Spring, or Lifters. I am going to have to yank the head anyway, so I might as well yank the crank. But Why would the tap switch cylinders? If it was lifters and I had it tapping while I was feeling them through the bottom end and felt nothing How could it possibly be lifters. I have pretty muck isolated it to the head. If I yank the head it is going to get Push Rods, Rockers, Lifters, and Valves anyway. I guess its time for a head re-build and a crankshaft grind. Hell I might as well throw pistons at it while I am in there. After I get the head off. Ridge reamer and they are pretty much out.

"Also continues to tick for a little while after the engine is shut down."

Ticking noises well after the engine is shut-down rules out the valves, bearings ...no?

Get a stethoscope (local drug store) and probe around the engine compartment.

Pulled valve cover back off. Turned engine manually to get ticking to duplicate. Inspected valve train again. Tapping reverbs through push rods and rockers. But its loudest at the valve springs. Springs are stretching and making a ticking noise. For sure. I have never seen anything like this. Pry on spring with screwdriver and noise quiets down. Wildest thing. Has anyone ever seen a valve or spring make a noise like this? Either way I have narrowed it down to a head job. Getting rockers, push rods, liters, valves, and springs. Taking my chances with new bearings. I really want to know if anyone has heard a noise like this. When I get the bearings back in I will make a video.

lots of carbon on springs. by the way. thanks for the tip on the scope, but I don't need it when I can feel the noise. unless the rods and rockers are not holding springs right enough. do these have spring seats? Maybe a broken seat. this tap is not your common 4.0L problem. already checked every other suspect. exhaust man, flex plate, lifters, pulleys, all the common stuff the list goes on. Definatly something in the upper valve train.

Unless changing valve springs is possible with head installed? But I am not so sire I want to to that anyway.

Springs are stretching? What do you mean?

I guess not stretching more like sagging. I think the springs are weak and not holding enough tension on the valves. They are weak and the noise is the springs stretching back out slowly. Does that make sense to anyone? I have never heard a weak valve spring before. Believe it or not I am like 99.9% sure that is what the noise is. It's like the springs stay compressed and it takes too long to stretch back out after they are compressed. They kind of I guess recoil too slowly.

Valve springs and valve seals can indeed be changed without removing the head. Use compressed air into the cylinders through the spark plug hole. There's a valve spring compressor tool that you can use to compress the spring, remove the collets, along with the retainer and spring.

We have an 89 with 219,000 miles that makes the same noises after the engine is shut down. I have a question about the engine while it is running. When the engine is started it runs normal with a little noise coming from the oil pan area. After a few minutes of running it starts making clicking or chattering noise at the valve cover area, and it seems to move (the noise is never in the same place under the valve cover). Should I be thinking about replacing the engine since the mileage is so high, or just try to correct the problem and hope for another 100,000 miles out of the thing? Any advice is greatly appreciated.

Well that kind of depends on what you plan on doing. I love my two door XJ and plan on keeping it for as long as possible. I am able to do almost all the work on it myself, so fixing it is always less then buying a new one. And it would just be another XJ anyway. But I have considered getting a later model without the Renix. I just can't bring myself to let it go. It also depends on how far you have to tear into the engine to find your noise (assuming its a engine noise.) That's what I am weighing right now. But considering I got a new TJ to toy with. I am probably going to go with the quick fix. Really depends on you no one can make that kind of decision for you with so many unknown factors. Including not knowing what the problem is and the budget your working. Problem with buying a "new" XJ is you have to start all over.

If you truley think the problem is from the valve springs then you can replace them with the head on. Its a pia though. If you don't have compressed air you can fill the cylinder with some clean rope and run the piston as far as it will go. You can replace the valve seals at the same time. You will want a compressor of one of these two styles:

http://www.amazon.com/Lisle-16750-Valve-Spring-Compressor/dp/B0009OR96K

http://www.sears.com/shc/s/p_10153_...21x00003a&ci_src=14110944&ci_sku=00994097000P

However, I don't think your problem lies in the valve springs. If you hear the noise at the valves than you could have worn valve guides.

Never considered a valve guide thanks for that info.

Ok, I pulled the valve cover and ran the engine. I noticed that only 4 of the rocker arms are getting oil from the push rods. That would lead me to think the lifters are not working properly. Am I on the right track? If i need to replace the lifters do I have to pull the head?

Yes you have to pull the head to replace lifters.

Check your oil pressure with a mechanical gauge. If the oil pressure is good your lifters could be stuck in some manner or the push rods could be clogged. Which rocker was getting oil?