EM-70
< SERVICE INFORMATION >
CYLINDER HEAD
• Check if the contact area band is continuous all around the circum-
ference.
• If not, grind to adjust valve fitting and check again. If the contacting
surface still has NG conditions even after the re-check, replace
valve seat.
VALVE SEAT REPLACEMENT
When valve seat is removed, replace with oversized [0.5 mm (0.020 in)] valve seat.
1. Bore out old seat until it collapses. Boring should not continue beyond the bottom face of the seat recess
in cylinder head. Set the machine depth stop to ensure this. Refer to EM-104, "
Standard and Limit".
2. Ream cylinder head (1) recess diameter for service valve seat.
• Be sure to ream in circles concentric to the valve guide center.
This will enable valve seat to fit correctly.
3. Heat cylinder head to 110° to 130°C (230° to 266°F) by soaking
in heated oil (A).
4. Provide valve seats cooled well with dry ice. Press-fit valve seat into cylinder head.
CAUTION:
• Never touch cold valve seats directly.
• Cylinder head contains heat, when working, wear protective equipment to avoid getting burned.
5. Using valve seat cutter set or valve seat grinder, finish valve
seat to the specified dimensions. For dimensions, refer to EM-
104, "Standard and Limit".
CAUTION:
When using valve seat cutter, firmly grip the cutter handle
with both hands. Then, press on the contacting surface all
around the circumference to cut in a single drive. Improper
pressure on with the cutter or cutting many different times
may result in stage valve seat.
6. Using compound, grind to adjust valve fitting.
7. Check again for normal contact. Follow the "VALVE SEAT CONTACT" procedure.
SBIA0322E
2: Valve seat
Oversize [0.5 mm (0.020 in)]
Intake : 35.200 - 35.227 mm (1.3858 - 1.3869 in)
Exhaust : 29.200 - 29.227 mm (1.1496 - 1.1507 in)
PBIC3218J
PBIC3214J
SEM934C
