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INSPECTION (1) Inspect for cracks in the combustion chambers and valve ports. (2) Inspect for cracks on the exhaust seat. coolant passage. (4) Inspect valves for burned, cracked or warped heads. (5) Inspect for scuffed or bent valve stems. VALVE REFACING (1) Use a valve refacing machine to reface the intake and exhaust valves to the specified angle. (2) After refacing, a margin of at least 4.52-4.49 mm (.178-.177 inch) must remain (Fig. 3). If the mar- VALVE SEAT REFACING (1) Install a pilot of the correct size in the valve guide bore. Reface the valve seat to the specified (2) Use tapered stones to obtain the specified seat width when required. VALVE STAND DOWN Valve stand down is to maintain the adequate com- pression ratio. (1) Invert cylinder head. (3) Using a straight edge and feeler gauge (Fig. 4), check valve head stand down: Inlet valve head stand (3) ins.). with above, discard original valves, check stand down Fig. 2 Valve Spring Chart LOAD Kg HEIGHT mm STATE P1 0.00 H1 44.65 FREE LENGTH P2 32-36 H2 38.60 VALVE CLOSED P3 89-96 H3 28.20 VALVE OPEN Fig. 3 Valve Specification MEASUREMENT INTAKE EXHAUST A 7.940-7.960 7.922-7.940 B 8.00-8.015 8.000-8.015 C 1.08-1.34 0.990-1.250 D 2.2 6 0.08 2.09-+0.07 −0.09 E 1.80-2.20 1.65-2.05 F 2.73-3.44 2.45-3.02 G 41.962-41.985 35.964-35.987 H 42.070-42.086 36.050-36.066 I 7.14-7.19 7.00-7.05 L 3.11-3.26 3.10-3.25 9 - 12 ENGINE XJ SERVICE PROCEDURES (Continued) 2000 JEEP CHEROKEE |