thanks for quick reply guys
The oil im using is quite thin at 5w. (When i spoke to my mechanic on the phone he seemed to think it might be the oil as well) But im not sure about that
However the smog pump could be the answer also....to give you an idea of the sound it makes....,It has a rhythm to it like someone was tapping out a tune! it sounds a bit like what you would image a small spanner being tapped against metal would sound like.
Sorry, that the best explainataion i can give!