Toyota Land Cruiser 1988 Repair Manual page 52

ENGINE MECHANICAL- Cylinder Head EM-21
u u u u u u
()
36a
EM1379
EM0183 EM0184
Intake
25.
;
~Width
Intake
Exhaust
EM0185
45°
EM0186
(e) Check the surface of the valve stem tip for wear.
If the valve stem tip is worn, resurface the tip with a
grinder or replace the valve.
CAUTION: Do not grind off more than the mini-
mum overall length.
12. INSPECT AND CLEAN VALVE SEATS
(a) Using a 45• carbide cutter, resurface the valve seats.
Remove only enough metal to clean the seats.
(b) Check the valve seating position.
Apply a thin coat of prussian blue (or white lead) to
the valve face. Install the valve. While applying light
pressure to the valve, rotate the valve against the
seat.
(c) Check the valve face and seat for the following:
• If blue appears 360° around the face, the valve is
concentric. If not, replace the valve.
• If blue appears 360° around the valve seat, the
guide and seat are concentric. If not, resurface the
seat.
• Check that the seat contact is on the middle of the
valve face with the following width:
Intake 1.1 -1.7 mm (0.043- 0.067 in.)
Exhaust 1.4-2.0 mm (0.055- 0.079 in.)
If not, correct the valve seat as follows:
(1) (Intake)
If the seating is too high on the valve face, use
25° (IN) and 45° cutters to correct the seat.
(2) If the seating is too low on the valve face, use
70• (IN) or 65. (EX) and 45• cutters to correct
the seat.