An MB mechanic I know in Corpus Christi told me that he has seem 4.5 lts. go as much as 400k miles w/o serious wear. We were talking about replacing the timing chain at 100k. He said that he had seen chains at 350k+ but that the slides should be replaced at 100k intervals. Any engine that can take that king of wear should not have a cam failure at 105k unless there has been lack of oil to the cam.