Dodge dakota 2002 Service Manual page 1625

9 - 376 ENGINE 8.0L
INTAKE/EXHAUST VALVES & SEATS (Continued)
REFACING VALVES AND VALVE SEATS
The intake and exhaust valves have a 45° face
angle and a 45° to 44 1/2° seat angle (Fig. 16).
Fig. 16 Valve Face and Seat Angles
1 - CONTACT POINT
VALVE FACE AND SEAT ANGLES CHART
ITEM DESCRIPTION
A SEAT WIDTH
SEAT WIDTH
B FACE ANGLE
(INT. and EXT.)
C SEAT ANGLE
(INT. and EXT.)
D CONTACT
SURFACE
VALVES
Inspect the remaining margin after the valves are
refaced (Fig. 17). Valves with less than 1.190 mm
(0.047 inch) margin should be discarded.
VALVE SEATS
(1) When refacing valve seats, it is important that
the correct size valve guide pilot be used for reseat-
ing stones. A true and complete surface must be
obtained.
SPECIFICATION
1.016 - 1.524
mm
INTAKE (0.040 - 0.060
in.)
1.016 - 1.524
mm
EXHAUST (0.040 - 0.060
in.)
45°
44 ⁄
1
2
—
Fig. 17 Intake and Exhaust Valves
1 - MARGIN
2 - VALVE SPRING RETAINER LOCK GROOVE
3 - STEM
4 - FACE
(2) Measure the concentricity of valve seat using a
dial indicator. Total runout should not exceed 0.038
mm (0.0015 inch) total indicator reading.
(3) Inspect the valve seat with Prussian blue to
determine where the valve contacts the seat. To do
this, coat valve seat LIGHTLY with Prussian blue
then set valve in place. Rotate the valve with light
pressure. If the blue is transferred to the center of
valve face, contact is satisfactory. If the blue is trans-
ferred to the top edge of valve face, lower valve seat
with a 15° stone. If the blue is transferred to bottom
edge of valve face raise valve seat with a 60° stone.
(4) When seat is properly positioned the width of
valve seats should be 1.016-1.524 mm (0.040-0.060
inch).
VALVE SPRING INSPECTION
Whenever valves have been removed for inspection,
reconditioning or replacement, valve springs should
be tested. As an example the compression length of
°
the spring to be tested is 1-5/16 inch. Turn table of
Universal Valve Spring Tester Tool until surface is in
line with the 1-5/16 inch mark on the threaded stud.
Be sure the zero mark is to the front (Fig. 18). Place
spring over stud on the table and lift compressing
lever to set tone device. Pull on torque wrench until
ping is heard. Take reading on torque wrench at this
instant. Multiply this reading by 2. This will give the
spring load at test length. Fractional measurements
are indicated on the table for finer adjustments.
Refer to specifications to obtain specified height and
allowable tensions. Discard the springs that do not
meet specifications.
DR