noise in engine?

Hi I have a 2004 volkswagon golf 1.6fsi. I have a noise in the engine when excellerating. The car is in the garage at the moment and they have told me that who ever previously owed the vehicle had rebuild the engine, and not to a good standard. I was told that It soulds like the tensioner which was replaced along with the timing chain. However when reving the engine the sound is still there, my mechanic thinks it could me a release valve which is not working as there could be too much oil going through the tensioner. Does anyone know where the valve would be located or if you think it could be another problem.