Dodge ram truck 3500 1996 Service Manual page 1036

I - 46 3.91 ENGINE —
DISASSEMBLY
AMD
ASSEMBLY
(Continued)
CHECK VALVE PLUNGER
SPRING CAP J9109-220
Fig. 50 Hydraulic Tappet Assembly
VALVES, GUIDES AND SPRINGS
WALWE
CLEANING
Clean valves thoroughly. Discard burned, warped,
or cracked valves.
Remove carbon and varnish deposits from inside of
valve guides with a reliable guide cleaner.
WALWE GUIDES
Measure valve stems for wear. I f wear exceeds
0.051 mm (0.002 in.), replace the valve.
Measure valve stem guide clearance as follows:
• (1) Install Valve Guide Sleeve Tool C-3973 over
valve stem and install valve (Fig. 51). The special
sleeve places the valve at the correct height for
checking with a dial indicator.
Fig. 51 Positioning Valve with Tool C-3973
(2) Attach dial indicator Tool C-3339 to cylinder
head and set i t at right angles to valve stem being
measured (Fig. 52).
(3) Move valve to and from the indicator. The total
dial indicator reading should not exceed 0.432 mm
(0.017 in.). Ream the guides for valves with oversize
stems i f dial indicator reading is excessive or i f the
stems are scuffed or scored.
WALWE GUIDES
Service valves with oversize stems are available
(Fig.
53).
(1) Slowly turn reamer by hand and clean guide thor­
oughly before installing new valve. Ream the valve
guides from standard to 0.381 mm (0.015 in.). Use
a two step procedure so the valve guides are
reamed true in relation to the valve seat:
B R
Fig. 52 Measuring Valve Guide Wear
Reamer O/S
Valve Guide Size
0.076 mm
8.026
- 8.052
mm
(0.003 in.)
( 0 . 3 1 6 - 0 . 3 1 7 in.)
0.381 mm
8.331 - 8 . 3 5 7 mm
(0.015 in.)
(0.328 - 0.329 in.)
J9309-30
Fig. 53 Reamer Sizes
• Step 1—Ream to 0.0763 mm (0.003 inch).
• ' Step 2—Ream to 0.381 mm (0.015 inch).
mEFACIMG WALWES AND WALWE SEATS
The intake and exhaust valves have a 43-1/4° to 43-3/4°
face angle and a 44-1/4° to 44-3/4° seat angle (Fig. 54).
WALWES
Inspect the remaining margin after the valves are
refaced (Fig. 55). Valves with less than 1.190 mm
(0.047 in.) margin should be discarded.
WALWE SEATS
CAUTION: DO NOT un-shroud valves during valve
seat refacing (Fig. 56).
(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
obtained.
(2) Measure the concentricity of valve seat using a
dial indicator. Total runout should not exceed 0.051
mm (0.002 in.) 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