2008 Denali XL engine noise

[KraigThomas]

2008 Yukon Denali XL L92 engine has a noise. 130000 miles. Does not have AFM. Noise is the same with belts temporarily removed. Inspected behind the timing cover and saw nothing unusual. Listen to the noise here:

, any suggestions.

 

[KraigThomas]

Measuring the sound frequency I get approximately 300 chirps/minute.

 

[dubyagee01]

Rocker arm fulcrum about to ghost?