My timing chain is new, The cam is synchronized whith the Cranck at TDC, 0° stretch.
I've changed the valve seats, and read an article that says that for bad valve seat we can have the phenomenon described in the attached picture. (sounds like the valves R hiting the pistons' heads
I hope i am wrong )
My vaccum pump's string seems to be OK,I don't know how to check its diaphragm !!! (but no noise when cold : so i don't think that is the cause)