Mitsubishi Grandis. Manual - part 662
CYLINDER HEAD AND VALVES
ENGINE OVERHAUL
11B-43
VALVE SEAT
Assemble the valve, then measure the valve stem
projection between the end of the valve stem and the
spring seating surface. If the measurement exceeds
the specified limit, replace the valve seat.
Standard value:
<Intake> 48.33 mm
<Exhaust> 48.34 mm
Limit:
<Intake> 48.83 mm
<Exhaust> 48.84 mm
VALVE SEAT RECONDITIONING
PROCEDURE
1. Before correcting the valve seat, check for
clearance between the valve guide and valve and,
if necessary, replace the valve guide.
2. Using the seat grinder, correct to obtain the
specified seat width and angle.
3. After correcting the valve seat, lap the valve and
valve seat using lapping compound. Then, check
the valve stem projection.
VALVE SEAT REPLACEMENT
PROCEDURE
1. Cut the valve seat from the inside to thin the wall
thickness. Then, remove the valve seat.
2. Rebore the valve seat hole in the cylinder head to
a selected oversize valve seat diameter.
Intake seat ring hole diameters
0.3 oversize: 35.30
− 35.33 mm
0.6 oversize: 35.60
− 35.63 mm
Exhaust seat ring hole diameters
0.3 oversize: 33.30
− 33.33 mm
0.6 oversize: 33.60
− 33.63 mm
3. Before fitting the valve seat, either heat the
cylinder head up to approximately 250
°C or cool
the valve seat in liquid nitrogen, to prevent the
cylinder head bore from galling.
4. Using a valve seat cutter, correct the valve seat to
the specified width and angle.
See "VALVE SEAT RECONDITIONING
PROCEDURE" on the previous page.
VALVE GUIDE REPLACEMENT
PROCEDURE
1. Using a press, remove the valve guide toward the
cylinder block.
AK300596
Valve stem
projection
Spring
seating
surface
AB
Valve stem
end
AK300385AB
Intake side
Exhaust side
43.5˚ – 44˚
20˚
10˚
65˚
65˚
0.9 – 1.3 mm
0.9 – 1.3 mm
AK300719AB
0.5 - 1 mm
0.5 - 1 mm
Cut
AK300720AB
Oversize hole diameter
Valve seat
height