TM 9-2815-225-34&P 3-35.  CYLINDER HEAD AND VALVE REPAIR (Contd) LOCATION/ITEM ACTION REMARKS c.  Inspection and Repair (Contd) 15. Four intake valve inserts (5) Stake (peen) cylinder head (9). Use valve seat insert staking tool (12) and four exhaust valve (ST-1124) (36) and driver (37) inserts (15) (Contd) If valve seat insert staking tool (36) and driver (37) are not available, a punch with round end can be used to stake cylinder head (9). e.  Machine valve insert counterbore for installing oversize inserts (12) or (15) as follows: (1)  Clamp base of insert tool (40) Use valve seat insert tool (ST-257) to cylinder head (9). (40). (2)  Install cutter (39). Use valve seat insert cutter (ST-662) (39).  Ensure valve seat insert tool (40) is securely clamped before starting electric drill. (3)  Using arbor (38), center cutter Use valve guide arbor (ST-663) (39) on valve seat insert (12) or (38). (15). (4)  Cut counterbore 0.006-0.010 in. This allows room for peening (0.152-0.254 mm) deeper than of cylinder head (9) to secure valve insert thickness. valve insert (12) or (15).  Allow cut- ter to turn several revolutions to make sure counterbore surface is even.  Remove valve seat insert tool (40), valve seat insert cutter (39), and valve guide arbor (38). (5) Clean out all chips and debris from valve insert counterbore. 3-122