911 Engine make whine noise

[martin2day]

Hello,

i have a 82 3,0SC US model an have some whine engine noise.
I have test some parts and did not find what it can be so I want to here your opinion what I have to look for.

Here is a video of the noise.
https://youtu.be/OyUSVNWD6iw
The noise is cold and warm. And it gets louder if the car have more rpm.
For me it sound like an air fan or a fault pulley ore servo pump... the last to things I did not have in the car. It is to discibe the sound better.

First I have remove the V-belt, the noise is still there, so it is not the alternator or the fan.
Than I have check the distributor, it rotate very free and have no play. It looks also very good.

Than I think about what can do such noise... the Oil Pump? I have now checked the oil pressure.... about 4bar at startup und 1,5bar at idle fit it is hot.
Max i See at about 3000rpm 5bar...
Than I have check the oil pressure valve under the car... it is okay.
I know there is a second valve , but therefor I have to remove the exhaust...

What do you think can make such a noise in the car?
Do you have any idea?

Thank you for helping
Have a nice day
Martin