Chrysler RAM TRUCK 2500 1994 Service Manual page 799

¥AL¥ES
Inspect the remaining margin after the valves are
refaced (Fig. 10). Valves with less than 1.190 mm
(0.047 inch) margin should be discarded.
i
INTAKE
VALVE
T
\ MARGIN / >
\ F A C E '
* STEM*
VALVE SPRING
RETAINER LOCK
GROOVE
-
EXHAUST
VALVE
J 9 2 0 9 - 1 2 7
Fig. 10 Intake and Exhaust Valves
VALVE SEATS
CAUTION: DO NOT un-shroud valves during valve
seat refacing (Fig. 11).
REFACING STONE
MUST NOT CUT
VALVE SHROUD
Fig. 11 Refacing Valve Seats
(1) When refacing valve seats, i t is important that
the correct size valve guide pilot be used for reseat­
ing stones. A true and complete surface must be ob­
tained.
(2) Measure the concentricity of valve seat using a
dial indicator. Total runout should not exceed 0.051
mm (0.002 inch) total indicator reading.
(3) Inspect the valve seat with Prussian blue to de­
termine where the valve contacts the seat. To do this,
coat valve seat LIGHTLY with Prussian blue then set
valve i n place. Rotate the valve with light pressure.
I f the blue is transferred to the center of valve face,
contact is satisfactory. I f the blue is transferred to
the top edge of valve face, lower valve seat with a 15°
stone. I f 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
intake seats should be 1.016-1.524 mm (0.040-0.060
inch). The width of the exhaust seats should be
1.524-2.032 mm (0.060-0.080 inch).
WALVE SPUING 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
Valve Spring Tester Tool C-647 until surface is i n line
with the 1-5/16 inch mark on the threaded stud. Be
sure the zero mark is to the front (Fig. 12). Place
spring over stud on the table and lift compressing le­
ver 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. Re­
fer to specifications to obtain specified height and al­
lowable tensions. Discard the springs that do not
meet specifications.
SPECIAL
TOOL C-647
9209-37
Fig. 12 Testing Valve Spring for Compressed
Length with Tool C-647
INSTALLATION
(1) Coat valve stems with lubrication oil and insert
them i n cylinder head.
(2) I f valves or seats are reground, check valve
stem height. I f valve is too long, replace cylinder
head.
(3) Install new seals on all valve guides. Install
valve springs and valve retainers.
(4) Compress valve springs with Valve Spring
Compressor Tool MD-998772A, install locks and re­
lease tool. I f valves and/or seats are ground, measure
the installed height of springs. Make sure the mea­
surement is taken from bottom of spring seat i n cyl-