I remember seeing a post about valve adjustment talking also about a tin cover held by two screws and cautioning to make sure to tighten it up or else it will come lose. Now that I think about it I think it was an oil tube with two banjo bolts. Twice in the last month I have heard a rattle which seems to come from the lifters, but this may be just wishfull thinking. It happens on overrun and idle but seems to go when the power is on. By revving the engine it went away again today. On idle the noise was cyclic, coming and going over a 10 second period approx. Anyone else had this or know what it is? Thanks John T.