Service manual

ENGINE INSPECTION
2. Dimension L. Check the protruding length of the valve
stem,
if it exceeds the specification, correct it as follows:
Dimension L Standard
71 Bn1 C 48.0 mm (1.890 in)
/
a. When dimension L becomes large 0 - 0.5 mm (0-
0.0202 in) from the standard, it is possible to use both
the valve and the cylinder head.
I
I
DIMENSION L
b. When dimension L becomes to large 0.5 - 1.5 mm
(0.20 - 0.059 in) from the standard, adjust the
dimension L to the standard by adding some washers
(inner diameter 12.8
mm (0.504 in ), outer diameter 39
mm (1.535 in) between the lower spring seat and the
cylinder head.
c.
When dimension L becomes to large ( more than 1.5
mm,
0.059 in) from the standards, install the valve with
a
new one, and recheck dimension L.
d. When dimension L becomes 1Q large 0 - 0.5 mm
(0 - 0.0202 from the standard, replace the valve.
e. When dimension L becomes to large
0.5 - 1.5 111m
(0.020 - 0.059 in) from the standard, replace the valve
and adjust the dimension L
to the- standard by adding
some washers between the lower spring seat and the
cylinder head.
f. When dimension L becomes to large (more than 1.5
mm (0.059 in) from the standard, replace both the
valve
and the cylinder head.
,
l ..
\. \
I
,
'LOWER
SPRING
SEAT
! WASHER
g. Check for contact between the valve and valve seat by
applying a
thin coat of Prussion Blue (or Redlead) on
the valve seat contact face, then insert the valve into
the valve guide
and press fit the valve on the valve
seat.
NOTE: Do not rotate the valve!
CONTACT FACE
h. Check if the valve seat contact face contacts the
center position
of the valve contact face. If the contact
position is not
centered, repair the valve and the
valve seat.
..
2. Stem Wear Inspection. If the valve stem is bent or its
diameter is less than
the limit, replace the valve.
Stem diameter limit
71B Intake
Exhaust
71C Intake
Exhaust
8.884 mm (0.350 in)
8.864
mm (0.349 in)
7.880 mm (0.3102 in)
7.867
mm (0.3097 in)
i CHECKiNG VALVE STEM WEAR ....
Engines & Generators
14