I WOULD JUST REPAIR THE SIDE THAT THE CHAIN TENSIONER BROKE ON , THAT IS A PRETTY UNUSUALL FAILURE , THE VLVS SHOULD NOT HAVE HIT THE PISTONS ON THIS ENG IF THE TENSIONER JUST BROKE , VLV TIMING WOULD BE OFF BUT I DOUBT THE CHAIN COULD EVEN JUMP A TOOTH, THERE IS JUST NOT ENOUGH SLACK IN THAT CHAIN , BUT IT WOULD RATTLE LIKE CRAZY ,I HAVE SEEN THEM COMPLETELY COLLAPSED AND STILL RUN BUT RATTLE ,SOUNDS LIKE AN OLD GM DSL, JUST ABOUT AS LAZY ALLSO, PROB ABOUT 4 HRS LABOR PLUS THE PARTS FOR ONE SIDE , THE TENSIONER IS ABOUT 80-85 DOLLARS AND A VLV CVR GASKET 15.00,AND MAYBE A TIMING BELT WHILE THE FRT CVR IS OFF 55.00 AND A WATER PUMP AROUND 125.00 THE ACTUAL REPAIR IS A BOUT 15 MIN, BUT GETTING TO IT IS A GOOD DEAL LONGER, JERRY