Checking/repairing the valve seat of the timing mechanism (Mazda CX-5KE)

1. Measure the contact surface width of the valve and valve seat using valve lapping compound. If the measured value is not within the standard (1.37-1.84 mm), bore the valve seat using a reamer with a chamfer angle of 45°.



2. Ensure that the valve seating area is centered on the valve surface.

• If the seating position is too high, adjust the seating position using a reamer with a chamfer angle of 70° (inlet valve/outlet valve) and reamers with a chamfer angle of 45°.
• If the seating position is too low, adjust the seating using reamers with chamfer angles of 20° and 45° (inlet valve) or one 45° sweep (exhaust valve).

3. Check the valve seat for settlement. To do this, measure the protrusion height (length L) of the valve stem using a standard length valve. If the measured value is not within the norm, replace the cylinder head with a new one.

Note:

Valve stem protrusion height (L dimension):

• intake: 48.93-50.17 mm
• release: 48.87-50.11 mm