a tensioner for a closed loop power transmission system for an internal combustion engine having a drive shaft terminating in a sprocket and at least one camshaft , each terminating in a sprocket , with a single continuous chain wrapping around all of the sprockets . the tensioner contains a pair of elongated tensioning arms , each one in slidable contact with one of the two strands of chain that traverses between the driving sprocket and the driven sprocket . each tensioning arm contains a wear face that remains in constant slidable contact with the strand of chain to which it is adjacent . an adjusting arm connects one of the ends of the tensioning arms . the adjusting arm has a ratchet means that adjusts for the backlash in the system and takes up any slack in the chain .