172 weird engine noise

[markus1]

Hello
After a track day my engine gets loud and strange metallic noise, that seems to get from the belts area.
It comes and goes for couple of seconds to half a minute. I've checked compression and it's OK.
The noise gets stronger when rpm gets up.
Tried to disconnect one cylinder at a time, and the noise still noticeable. I worry that my one of the rods is not OK.
Any thoughts what it might be?

 

[markus1]

(You can hear at the end of the video that the noise stops)

 

[markus1]

Compression test

 

[bloke]

second video, 4 seconds, sounds like a bottom end knock. but first video sounds possibly like waterpump.