Section 03
ENGINE
Subsection 09
(CYLINDER AND HEAD)
VMR2004_132_03_09A.FM
03-09-17
Replace valve guide out of cylinder head if valve
guide is out of specification or has other damages
such as wear or friction surface (see VALVE
GUIDE PROCEDURE
below).
Valve Face and Seat
1. Valve seat
2. Exhaust valve contaminated area
3. Valve face (contact surface to valve seat)
Check valve face and seat for burning or pittings
and replace valve or cylinder head if there are signs
of damage.
Ensure to seat valves properly. Apply some lapping
compound to valve face and work valve on its seat
with a lapping tool (see VALVE GUIDE PROCE-
DURE below).
Measure valve face contact width.
NOTE:
The location of contact area should be in
center of valve seat.
Measure valve seat width using a caliper.
If valve seat contact width is too wide or has dark
spots, replace the cylinder head.
A. Valve face contact width
B. Valve seat contact width
VALVE STEM DIAMETER
NEW MINIMUM
EXHAUST
4.956 mm (.1951 in)
INTAKE
4.966 mm (.1955 in)
NEW MAXIMUM
EXHAUST
4.970 mm (.1957 in)
INTAKE
4.980 mm (.1960 in)
SERVICE LIMIT
EXHAUST
4.930 mm (.1941 in)
INTAKE
VALVE GUIDE DIAMETER
SERVICE LIMIT
EXHAUST
5.050 mm (.1988 in)
INTAKE
1
R400motr84A
3
2
VALVE SEAT CONTACT WIDTH
NEW
EXHAUST
1.25 to 1.55 mm
(.049 to .061 in)
INTAKE
1.15 to 1.35 mm
(.045 to .053 in)
SERVICE LIMIT
EXHAUST
2 mm (.078 in)
INTAKE
1.8 mm (.07 in)
V01C1HA
B
A