Any of you guys ever hear this clacking/tapping noise? I did a valve adjustment but the noise didn't change one bit. All spark plugs and injectors look good/normal and are functioning correctly. It's constant, and does not stop regardless of how long the motor's been running or even what RPM the engine is at. Interesting thing to note are my compression #s: 220, 220, 210, 260. Yes, the cylinder that's making the tapping noise has unusually high compression.

No CEL. Any ideas? I'm thinking maybe a bent valve or something.

I took this video of it.
[media]http://www.youtube.com/watch?v=rWObWwby4M8 [/media]

 

Sounds like a Rod Bearing but it's always very difficult to diagnose via a video.

 

this happened to my buddy's turboed legacy the other day

his spark plug wire slipped off causing his cylinder to misfire like crazy making the same kind of noise..almost like a rod knock except it wasn't metal on metal..a lot like your noise here

since we have ignition coils it couldn't be a wire but perhaps something is making your 4th cylinder misfire because it sounds EXACTLY like my buddy's car

at first we all thought it was a rod knock and cried lol

hope this helps you find the problem

 

I was working on my dsm the other day and accidently crossed two wires in the ignition system and it was only running off 2 cylinders and sounded exactly like this... since you already know your getting compression one way to insure its not fuel/spark related is to pull the injector clip for # 4 while the engine is running.. if the car starts to sputter than it is NOT fuel or spark related.. but if the engine doesnt change tone at all your either not getting fuel or spark in that cylinder. Hope this helps

 

It's not fuel or spark related; we've pulled the spark plug and injector clip and it clearly runs different without the ignition in cylinder 4, but the tapping still remains.

I don't think it's a rod bearing since the noise definitely is coming from up top in the valve train. Thanks for the replies so far!

 

hmm i duno

 

Scored #4 cylinder.

The high compression in #4 is because of the excess oil getting past the rings, due to the wear.

Seen it before, a few times.

 

^ So what would be making the clacking sound? I pulled the pan and checked out the walls, they appeared to look fine.

 

cut the oil filter open, see if you see metal in the filter media.

if the tap/knock is still there even after you unplug the injector then its either the piston/cylinder wall or in the valve train.

check the valve adjustment on cylinder 4, abnormally high compression could mean a very loose valve adjustment.

 

^ I'll take a look at the filter tomorrow night. There weren't any shavings in the oil pan so hopefully the filter will be clean as well.

Already performed a valve adjustment, they're all set to spec now.

Thanks again