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VALVE SEATS Check valve seats for any evidence of pitting at valve contact sur- I Before repairing valve seats, check valve and valve guide I Use both hands to cut uniformly. REPLACING VALVE SEAT FOR SERVICE PARTS 1. Bore out old seat until it collapses. Boring should not continue 2. Ream cylinder head recess. Reaming bore for service valve seat Intake 35.500 - 35.516 mm (1.3976 - 1.3983 in) Exhaust 31.500 - 31.516 mm (1.2402 - 1.2408 in) Be sure to ream in circles concentric to the valve guide cen- Heat cylinder head to 110 to 130°C (230 to 266°F). 4. Press fit valve seat until it seats on the bottom. 5. Cut or grind valve seat using a suitable tool at the specified 6. After cutting, lap valve seat with abrasive compound. 7. Check valve seating condition. Seat face angle “ α ”: 44°53 ′ - 45°07 ′ Contacting width “W”: Intake 1.385 - 1.401 mm (0.0545 - 0.0552 in) Exhaust 1.385 - 1.401 mm (0.0545 - 0.0552 in) VALVE DIMENSIONS Check dimensions in each valve. For dimensions, refer to SDS Grinding allowance for valve stem tip is 0.2 mm (0.008 in) or SEM934C SEM795A . Recess diameter SEM008A Oil SEM892B . SEM188A T (Margin thickness) CYLINDER HEAD SR20DE Inspection (Cont’d) EM-95 |