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Discussion Starter #1
Hello everyone,

I am in a little bit of a pickle here with my 01 Z. I replaced the springs in my car with compcams dual valvesprings and also lapped the valves myself. I did this because I heard a valve tapping sound coming from my engine. Thought I may have spun a lifter but it turns out that the sound is still there after all the work I did done. After cleaning/lapping the valves and installing the new components, I end up with the same sound (click video below). Is this sound normal wear for the valvetrain break-in? It doesn't seem so to me. Please help!! I am afraid to keep running the engine with this sound. It seems to be coming from the middle/passenger side of the engine.

https://www.youtube.com/watch?v=LVsnY5caeV4
 

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Slide down to the bottom of the page and research the 'Similar Threads' section. Several comments in there about valve train noise.

Even though the Z has always had a louder than normal valve train noise, your video does seem to sound excessive to me.

Mike
 

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Discussion Starter #4
I don't know what is going on there but it doesn't good. Maybe one of your lifters is collapsing.
I actually just replaced the lifters as well. The sound was there before I replaced them and I thought that it would be gone by this point :/
 

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Just curious, what kind of oil pressure are you reading at idle?

What did the old lifters looks like....a lot of wear or uneven wear (especially the ones from the middle of the engine where the sounds seem to be coming from)?
 

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Yikes! No that doesn't sound good. It's intermittent nature makes me think it is a foreign object in a cylinder or a very sticky valve in its guide.
Use a stethoscope to try and locate an individual cylinder.
At worst it's a piston skirt or a wrist pin, but it's not constant enough for that.
Find the cylinder and yank that head off again.
 

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Discussion Starter #7
Just curious, what kind of oil pressure are you reading at idle?

What did the old lifters looks like....a lot of wear or uneven wear (especially the ones from the middle of the engine wear the sounds seem to be coming from)?
Oil pressure read as low as 9 psi at first, then let it ran for 5 min and went up to 20 psi at idle. The old lifters looked like they were alright from what I could tell. Pushrods seemed to be straight and in pretty good shape as well. My idle however is about 600-700rpm and was at around 900-1000 rpm prior to the work I did on it. Is it possible one of the lobes on the cam is grinded up?
 

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Discussion Starter #8
Yikes! No that doesn't sound good. It's intermittent nature makes me think it is a foreign object in a cylinder or a very sticky valve in its guide.
Use a stethoscope to try and locate an individual cylinder.
At worst it's a piston skirt or a wrist pin, but it's not constant enough for that.
Find the cylinder and yank that head off again.
Thanks I will take the heads off again and try to locate the prob. I didn't notice anything out of the ordinary when the heads were off before. I did clean the valves up pretty well and lapped them after I cleaned the heads. Not sure what my other alternative options really are....
 

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I'm just wondering about whether the noise is a roller lifter which is not aligned. I don't recall how the rollers are aligned with the cam but if one is able to turn so the roller is somewhat sideways to the lobe…..
Perhaps someone else will comment that this is even possible.
 

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Is it possible one of the lobes on the cam is grinded up?
Have you drained the oil and checked for filings in the oil... a magnetic drain plug would be nice to have. That would be a good indication of something amiss. Cut the oil filter open and check that the next time you change oil.

If that is a concern, you could always remove the valve cover and use a dial indicator to measure travel of each valve to see if all intakes and exhausts are similar in travel +- within reason (engine off, spark plugs out to rotate it easier). Just a thought.
 

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Discussion Starter #11
Have you drained the oil and checked for filings in the oil... a magnetic drain plug would be nice to have. That would be a good indication of something amiss. Cut the oil filter open and check that the next time you change oil.

If that is a concern, you could always remove the valve cover and use a dial indicator to measure travel of each valve to see if all intakes and exhausts are similar in travel +- within reason (engine off, spark plugs out to rotate it easier). Just a thought.
Thanks for the insight, I will try that tonight. I also did notice today that the passenger side head is smoking when this knocking/tapping noise is going on. The noise does not go away at higher engine temperatures either :/ Is this indicative of piston slap or does anyone think this is more of a cam lobe issue???
 

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Since that hard metal to metal noise was before and after your work it is hard to tell but it does not sound like it matches the engine RPM thus it could be a #4 rod issue, maybe the crank bearing for that piston and reason the oiling issue.

Best is pull the sparkplugs and see if anything shows on them and while plug are out do a compression and leak down on all 8 cylinders to see if a ringland has broken or bearing failure.

If possible use a thermal tool and with engine warmed up is see what each cylinders exhaust primary of manifold is and if one is reporting different temp then the others

Course problem could be the top of CAM lobe for #4 got wacked by a lifter issue.
 

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could be a damaged cam
 

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Discussion Starter #14 (Edited)
https://www.youtube.com/watch?v=dY_y84GBZpk

Now I hear this... Is it cheaper to just go now shortblock or should I rip her apart and have a machine shop fix up the crank/pistons and chambers???? A lot of people in person says this is a thrown piston rod or bearing. Any suggestions or is my former statement my only option. I am kinda on a budget too Btw the tapping was the original sound and this is the sound after the head work. Thought it was low on oil and then added a quart. Sound did go away. however the tapping/knocking is still there. ANyone have similar problems???? Helpful posts please
 

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Sounds like it's ready for the back straight of Sebring.
 
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