Chrysler neon 1997 Service Manual page 1253

VALVE GUIDE 13.25 — 13.75 mm (.521 — .541 in.)
9 - 82 2.0L DOHC ENGINE
DISASSEMBLY AND ASSEMBLY (Continued)
CHECK VALVE GUIDE HEIGTH
Valve Guide Heigth
TESTING VALVE SPRINGS
(1) Whenever valves have been removed for inspec-
tion, reconditioning or replacement, valve springs
should be tested Special Tool C-647. As an example,
the compression length of the spring to be tested is
33.34 mm (1-5/16 inches). Turn tool table until sur-
face is in line with the 33.34 mm (1-5/16 inch) mark
on the threaded stud and the zero mark on the front.
Place spring over stud on the table and lift compress-
ing lever to set tone device (Fig. 89). Pull on torque
wrench until ping is heard. Take reading on torque
wrench at this instant. Multiply this reading by two.
This will give the spring load at test length. Frac-
tional measurements are indicated on the table for
finer adjustments. Discard the springs that do not
meet specifications. The Following specifications
apply to both intake and exhaust valve springs;
• Valve Closed Nominal Tension— 58 ft. lbs. @
38.0 mm (1.50 in.)
• Valve Open Nominal Tension— 130 ft. lbs. @
29.25 mm (1.17 in.)
(2) Verify springs are not distorted with a steel
square and surface plate, check springs from both
ends. If the spring is more than 1.5 mm (1/16 inch)
out of square, install a new spring.
REFACING VALVES AND VALVE SEATS
(1) The intake and exhaust valve seats and valve
face have a 45 and a 45 1/2 degree angles.
(2) Inspect the remaining margin after the valves
are refaced (Fig. 91). Intake valves with less than 1.2
mm (3/64 inch.) margin and Exhaust valves with less
than 0.9 mm (1/32 inch.) margin should be discarded.
(3) When refacing valve seats, it is important that
the correct size valve guide pilot be used for the
reseating stones. A true and complete surface must
be obtained.
SPRING SEAT VALVE TESTER SPRING TORQUE WRENCH
Fig. 89 Testing Valve Spring
(4) Measure the concentricity of valve seat and
valve guide using a valve seat runout dial indicator.
Total runout should not exceed. 0.051 mm (0.002
inch.) (total indicator reading).
(5) 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 top edge of the valve face, lower valve seat
with a 15 degrees stone. If the blue is transferred to
the bottom edge of valve face raise valve seat with a
65 degrees stone.
• Intake valve seat diameter is 34.37 - 34.63 mm
(1.353 - 1.363 inch.)
• Exhaust valve seat diameter is 29.37 29.63 mm
(1.156 1.166 inch.)
(6) Valve seats which are worn or burned can be
reworked, provided that correct angle and seat width
are maintained. The intake valve seat must be ser-
viced when the valve seat width is 2.0 mm (0.079 in.)
or greater. The exhaust valve seat must be serviced
when the valve seat width is 2.5 mm (0.098 in.) or
greater. Otherwise the cylinder head must be
replaced. Refer to (Fig. 90) for valve specifications.
(7) When seat is properly positioned the width of
intake and exhaust seats should be 0.90 to 1.30 mm
(0.035 to 0.051 inch.) (Fig. 92).
(8) Check valve tip height dimensions A after
grinding the valve seats or faces (Fig. 93). Grind
valve tip to 47.99 mm (1.889 in.) for exhaust valve
and 48.04 mm (1.891 in.) for intake valve when
installed in the head (Fig. 93). The valve tip chamfer
may need to be reground to prevent seal damage
when the valve is installed.
PL