108 ENGINE 273 MPFI VALVE Valve Dimensions: NO VALVE DIMENSIONS INLET EXHAUST 1. Valve head dia ‘A’ mm ø32.5 ± 0.2 ø29.5 ± 0.2 2. Valve seat angle 45° +15’ 45° +15’ 3. Valve stem dia ‘B’ mm ø5.968 ø5.936 ± 0.007 ± 0.007 4. Valve seat dia ‘C’ mm ø30.11 ø26.0 5. Valve seat end 1.2 1.25 distance from valve face ‘D’ mm 6. Maximum run out of 0.03 0.03 valve seat with respect to valve stem in mm Valve Repair : • Check valve leakages by pouring gasoline on valve head. Gasoline must not seep past valve seat. • Valves with burnt heads, excessive scoring and wear on stem should be replaced. • Check valve seat run out with respect to valve stem. If it exceeds specified limit (0.03 mm) replace valve. No attempt should be made to straighten bent valves. If valve is free from any other defects except worn out seat, then only it can be rematched on valve grinding machine as follows : i. Clamp valve on grindingmachine jaws as close as possible to valve head. ii. Adjust grinding angle on graduated scale to achieve correct valve seat angle. iii. Feed valve slowly towards grinding wheel until wheel just touches valve head. iv. Grind at low feed until valve seat is just clean all around. Valve Lapping: Lap the valve on the seat in two steps, first with a coarse size lapping compound applied to the face and the second with a fine-size compound, each time using a valve lapper according to the usual lapping method.
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