Thanks à lot for your helps guys
@Porboynz : that was exactly what I had in mind. I will put some aluminium sheat all over the place to protect everything.
@T77911S : you are absolutly rigth as you can see on the picture below...
Maybe a solution to stop the leak is to tear down the engine and use some threebond around the oring.
I think I did lots of mistake when I rebuilt this engine. I put some helicoil with 993 head stud... I also have a seepage on a case through bolt... and some around rockers arms...
Unfortunatly, every time you speak about tearing down a 911 engine, it costs at least few hundred $ and possible mistake that can definitly break your engine for good!
