That sounds rough and no they arnt supose to sound like that. Mine sounded the same and I eventually found what the problem was. It was my cam chain, tensioner and ajuster. The ajuster aint cheap though 300 quid. All in all cost was just over 600 with new chain and tensioner. The mechanic told me that when the ajuster starts to fail it deprives the top of the engine of oil as it regulates some of the oil pressure. Was the best money I have spent on my car it has improved my mpg get around 40 on a long run on the motorway, more responsive and the best part it sounds like a kitten on tick over cold or hot.
