7mgte noise

[1SLOMK3]

So about a moth ago my car started making a knocking noise in the top end at 1500-2k rpm. It isnt present at idle and goes away after 2k. The motor has exactly 2,742 miles on a stock rebuild and is an auto trans. Heres a video of it in the garage. I was in drive...
http://www.youtube.com/watch?v=sPL8Uini394&context=C37d0a28ADOEgsToPDskKWGvnVMdDXFXw8l9Echfro

 

[radiod]

Just out of curiosity....have you checked to see how the tension is on the timing belt? I've seen the timing belt slapping the casing from being too loose at around those rpm's.

Checked everything over for loose nuts and bolts?

 

[hvyman]

Any exhaust leaks?

 

[supraguy@aol]

To me, that kinda sounds like the fan might be hitting the shoud, or a bad alternator bearing.
It's kind of hard to diagnose. I would think you could pinpoint it with a stethescope.

 

[Nick M]

I would think you could pinpoint it with a stethescope.

Also, the timing belt being strechted isn't likely because it would be noisy at idle when there is little tension on it. Possible, just not probable.

 

[1SLOMK3]

The tension on the belt seems fine, there is no timing cover on the car... There is an exhaust leak by the cat underneath the car, I dont think that has anything to do with it since I ran open dp for a while. It sounds like the noise is coming from closer to the front of the head by the cam gears. Im thinking it might be bad valve shims but im not sure. Im going to pop the valve covers and have a friend come take a look at it this weekend.

 

[Albert]

Valve clearance

 

[radiod]

Valve clearance

Yeah, always something to check if can't find anything obvious on the outside. Should be able to narrow down the area with a stethescope fairly easily so you know which shims to check right away (though if you have the covers off, may as well check them all).

 

[Albert]

Okay well I went over there to help and I checked his clearances. Other than maybe 2 or 3 shims that are out of print by .001, there is one shim that is either bad, or a keeper came off, because I couldn't even get the .0015 feeler gauge to pass through.

So the cam is constantly hitting the shim. But it runs perfect, no misfiring.

Gonna have to take off the cam to investigate.

Anyone think that could be the noise?

 

[Albert]

Anyone?

 

[Nick M]

Where is the noise with the stethescope? Noise travels in solids pretty well, so you you have to check several spots.

 

[tyang82]

Possibly

 

[Albert]

He never checked it with a stethoscope. He pulled off the valve covers, and I came over to check it

 

[CyFi6]

Something may have happened to the valve seat allowing the valve to move up into the head farther

 

[CyFi6]

Did he ever figure this out?

 

[tmsperformance]

Mine sounded just like that. It ended up being the downpipe was rattling of the subframe. Just something to check, but since it seems to be a stock rebuild I doubt thats your issue. Just some insight

 

[1SLOMK3]

Havent been able to get it back together to start and check it... Been pretty busy. I guess it could possibly be the dp, being that it started making that noise after I put a stock dp with cat on for emissions. But I doubt it

 

[1SLOMK3]

So after replacing the shim I finally got the car back together to start it. First start the cps was way off... fixed that. Tried again and car started right up, runs/drives perfect and doesnt make that noise anymore!!! Wohoo! :icon_bigg