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Home >> Honda >> 2021 >> Passport EX-L, FWD >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Mechanical / Engine Control System - Service, Testing And Troubleshooting >> Repair Regeneration >> Valve Seat Reconditioning >> Reconditioning
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Valve Seat Reconditioning: Reconditioning

  1. Valve Seat - Reconditioning
    GHH370134Courtesy of HONDA, U.S.A., INC.
    		 1. Inspect valve stem-to-guide clearance . If the valve guides are worn, replace them 

    before cutting the valve seats.

    2. Renew the valve seats in the cylinder head using a valve seat cutter.

    3. Carefully cut a 45 deg. seat, removing only enough material to ensure a smooth and concentric seat.
    GHH370135Courtesy of HONDA, U.S.A., INC.
    		 4. Bevel the upper and lower edges at the angles shown in the illustration. Check the width of the seat and adjust accordingly.

    5. Make one more very light passes with the 45 deg. cutter to remove any possible burrs caused by the other cutters.

    Valve Seat Width 
    Standard (New):  1.25-1.55 mm (0.0492-0.0610 in) 
    Service Limit:  1.55 mm (0.0610 in) 
    GHH370136Courtesy of HONDA, U.S.A., INC.
    		 6. After resurfacing the seat, inspect for even valve seating: Apply Prussian Blue compound (A) to the valve face. Insert the valve in its original location in the cylinder head, then lift it and snap it closed against the valve seat several times.

    7. The actual valve seating surface (B), as shown by the blue compound, should be centered on the valve seat:

    • If it is too high (closer to the valve stem), you must make a second cut with the 67.5 deg. cutter (intake seat) or 60 deg. cutter (exhaust seat) to move it down, then one more cut with the 45 deg. cutter to restore seat width.
    • If it is too low (close to the valve edge), you must make a second cut with the 30 deg. cutter to move it up, then make one more cut with the 45 deg. cutter to restore valve seat width.
    NOTE: The final cut should always be made with the 45 deg. cutter.
    GHH370137Courtesy of HONDA, U.S.A., INC.
    		 8. Insert the intake and exhaust valves in the cylinder head, and measure valve stem installed height (A).

    Valve Stem Installed Height 

    9. If valve stem installed height is over the service limit, replace the valve and recheck. If it is still over the service limit, replace the cylinder head; the valve seat in the cylinder head is too deep.
    Intake: 
    Standard (New):  47.1-47.9 mm (1.854-1.886 in) 
    Service Limit:  47.90 mm (1.8858 in) 
    Exhaust: 
    Standard (New):  46.93-47.73 mm (1.8476-1.8791 in) 
    Service Limit:  47.73 mm (1.8791 in) 
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