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MECHANIC DIESEL - CITS



           EXERCISE 2.12: Checking valve seat and valve guide



            Objectives

           At the end of this exercise you shall be able to
           •  check valve seat inserts
           •  check valve guide.

           Requirements


           Tools/Instruments                                   Materials/Components
           •  Trainee’s tool kit            - 1 No.            •  Emery paper                   - as reqd.
           •  Depth gauge                   - 1 No.            •  Kerosene                      - as reqd.
            Procedure


           Check valve seat inserts and valve guides
           •   Take out the valve seat insert, using the special tool.
           •   Drive the new valve seat insert carefully to its position, using a special punch.
           •   Assemble the valve to the valve seat and check its height with reference to the cylinder head surface.
           •   De-glaze the seat with an emery paper.
           •   Apply lapping compound on the valve face seat.
           •   Gently turn the valve on the seat with the help of the special tool using light force.
           •   Repeat this until a clear seating of the valve and valve seat is obtained.
           •   Remove the lapping compound using kerosene and visually. Check the surface of valve seat of valve face.
           •   If found any damages in valve seat and valve guide, replace it.
           •   Measure the valve stem diameter.
           •   Measure the internal diameter of the valve guide.
           •   If the clearance between the valve guide and valve stem is found more than the manufacturer’s specified limit,
              change the valve guide as per the following procedure.
           •   Drive out the old valve guide from the cylinder head using a suitable drift.
           •   Place the new valve guide (1) on the cylinder head. (Fig 1)
           •   Place the drift (3) on the valve guide and press the valve guide.
           •   Measure the height (2) of the valve guide from the spring seating surface (use depth gauge).

              Fig 1






















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