Hi had well kinda got a similar problem when i changed my head and headgasket due to some bent valves but noticed that i had a slight crack in the block. I decided to put the new head back on anyway dont ask why and once it was all up and running there was no chatter noise again and didnt feel like the turbo was kicking in. Checked all the hoses and the charge carrier to intel manifold one was a bit lose tightend that up but there wasnt much difference.

Am changing my bottom end anyway so i wasnt really botherd but intrested in what could be wrong????