CYLINDER HEAD AND VALVE TRAIN 133
CAUTION: To prevent engine damage, maintain the
minimum valve face margin across the entire valve
face. An insufficient valve face margin will not provide
proper heat dissipation, ultimately causing the valve
to warp or break.
NOTE: Make sure that there is sufficient coolant in the
valve grinding machine reservoir. Turn coolant pump
on before grinding.
1. Use the dressing stud attachment on the grinder
to dress the cutting stone.
Figure 168 Grinding valve fac
e
Figure169 Valvefaceangles
1. Intake margin
2. Intake valve angle
3. Exhaust margin
4. Exhaust valve angle
NOTE: Intake valves and exhaust valves have
different valve face margins.
2. Install valve in the grinder and set the grinder to
the specified angle.
3. Turn on coolant and grinder.
NOTE: Removal of too much material may reduce the
margin below minimum specifications.
4. Grind the valve face. Only remove the minimum
amount of material necessary.
Figure 170 Measuring valve face margin
5. Use a caliper to measure the valve face margin
at four locations. If any of the measurements are
less than the minimum specification (Table 13),
replace valve.
Valve Stem Tip
CAUTION: To prevent engine damage, leave a
sufficient amount of material so that the valve bridge
does not contact the valve retainer keys or valve
rotator during operation. Refacing the tip of the valve
stem provides a new wear surface for the valve
bridge.
1. Use the dressing stud attachment on the grinder
to dress the cutting stone.
EGES-265-2
Read all safety instructions in the "Safety Information" section of this manual before doing any procedures.
Follow all warnings, cautions, and notes.
© 2009 Navistar, Inc.
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