5-26 ENGINE TOP END
Valve/Valve Guide Clearance Measurement
If a small bore gauge is not available, inspect the valve
guide wear by measuring the valve/valve guide clearance
with the wobble method as indicated below.
Insert a new valve [A] into the guide [B] and set a dial
gauge against the stem perpendicular to it as close as
possible to the cylinder head mating surface.
Move the stem back and forth [C] to measure the valve
Repeat the measurement in a direction at a 90° angle to
the first measurement.
If the reading exceeds the service limit, replace the guide.
The reading is greater than the actual valve/valve guide
clearance because the measurement is taken outside
of the guide.
Valve/Valve Guide Clearance Measurement (Wobble
0.14 ∼ 0.26 mm (0.0055 ∼ 0.0102 in.)
0.09 ∼ 0.22 mm (0.0035 ∼ 0.0087 in.)
0.57 mm (0.022 in.)
0.53 mm (0.021 in.)
Valve Seat Inspection
Remove the valve (see Valve Removal).
Check the valve seating surface [A] between the valve [B]
and valve seat [C].
Measure the outside diameter [D] of the seating pattern
on the valve seat.
If the outside diameter is too large or too small, repair the
seat. (see Seat Repair)
Valve Seating Surface Outside Diameter
30.4 ∼ 30.6 mm (1.197 ∼ 1.205 in.)
35.4 ∼ 35.6 mm (1.39 ∼ 1.40 in.)
Check the seating surface width of the valve seat.
Measure the seat width [E] of the portion where there is
no build-up carbon (white portion) of the valve seat with a
Valve Seating Surface Width Standard
0.8 ∼ 1.2 mm (0.032 ∼ 0.047 in.)
0.5 ∼ 1.0 mm (0.020 ∼ 0.039 in.)
If the width is too wide [G] , too narrow [H] or uneven [J],
repair the seat (see Valve Seat Repair).