Page 49 - CTS - Mechanic Diesel - TP

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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