The FSM calls it a tensioner.... and there are two styles.... the really skinny one does come off before taking the head off... there is a ' special' tool to grab it with and pull it out after taking out the holding pins.... the more robust one which looks cast with ribbing does not have to be removed to take off the head... so that is what we told the guy about given his description...
Interesting also is that he says he is from New Orleans.... there is a person by his name who is a musician from there...