I'm trying to help a friend who has a 2001 Ford Explorer Sport Trac with a 4.0 V-6 SOHC. He came in and said he's got a knock and very little oil pressure. The needle does come off the stand, but just barely. When he started it up a bad knock was coming from the top of the engine on the driver's side. Being a SOHC, does some part of the valvetrain control the oil pump or is it driven off of the timing chain? What component could break inside the valve cover that would cause a knock like that. He's an outside salesman and needs this truck for work. I'd like to get him up and running by Monday if possible, provided we have the parts we need.