from the housing to push a pivoting tensioner arm 12 against the chain to take up slack and keep the chain at some minimum tension value for good chain control referring now to fig3 the tensioner housing 20 includes a relief valve 80 mounted on the external surface in this preferred embodiment the relief valve 80 includes a reed valve member 82 and a flat spring member 84 the reed valve free end 90 covers the exhaust port 32 or conduit that is in communication with the piston bore 22 as shown more clearly in fig2 and 4 however as fig3 clearly shows the flat spring member 84 overlays the reed valve 82 the fixed end 88 of the spring member and the fixed end 92 of the reed valve are fastened together to the housing by a machine screw 94 or other suitable fastener the free end 86 of the spring 84 includes a deformed tip 94 that protrudes to press against the free end 90 of the reed valve 82 preferably the tip 94 is a hemispherical protuberance that contacts the free end 90 of the reed valve centered over the exhaust port 32 the reed valve 82 seals against the.