ENGINE
Inspecting the Cylinder Block and Components
12/05
6LY3 Service Manual
5-29
© 2007 Yanmar Marine International
Correcting the Valve Seat Angles
Use a seat grinder
(Figure 5-18)
to correct
unevenness of the seat surface as follows:
Figure 5-18
Figure 5-18
1. Widen the valve seat width
(Figure 5-19, (1))
using a 70° grinding wheel.
2. Grind the seat to the standard dimension
(45°) using a grinding wheel with a 15°
chamber.
NOTICE: When seat adjustment is necessary,
check the valve and valve guide. If the clearance
exceeds the tolerance, replace the valve or the
valve guide and grind the seat.
Figure 5-19
Figure 5-19
1 – Valve Seat Width
2 – Valve Seat
3. Knead valve compound with oil and finish the
valve seat
(Figure 5-19, (2))
with a lapping tool.
NOTICE: Use a rubber cap type lapping tool for
valves without a lapping tool groove slit.
Figure 5-20
Figure 5-20
Seat Angle Ø
Intake Valve
45°
Exhaust Valve
45°
0005600
0005601
(2)
(1)
000571
8
