Chrysler Town, Dodge Caravan. Manual — part 1091
VM.1067 HIGH PRESSURE PUMP REMOVER
VM.1068 90 DEGREES AFTER TDC ALIGNMENT PIN
VM.1069 CRANKSHAFT REM/INSTALL SLEEVE
VM.1070 FLYWHEEL LOCKING TOOL
VM.1072 COMPRESSION TESTER ADAPTER
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ENGINE
9 - 17
CYLINDER HEAD (Continued)
VM.1073 CRANKSHAFT FRONT BEARING
REMOVER/INSTALLER
VM.1074 TIMING BELT RETAINER
VM.1075 FLYWHEEL ALIGNMENT PINS
VM.1077 POWER STEERING BELT REMOVER
VM.1078 POWER STEERING BELT INSTALLER
9 - 18
ENGINE
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CYLINDER HEAD (Continued)
CYLINDER HEAD
STANDARD PROCEDURE
STANDARD PROCEDURE - VALVE SERVICE
This procedure is done with the engine cylinder
head removed from the block.
DISASSEMBLY
(1) Remove the engine cylinder head from the cyl-
inder block. Refer to cylinder head removal and
installation in this section.
(2) Use Valve Spring Compressor Tool and com-
press each valve spring.
(3) Remove the valve locks, retainers, and springs.
(4) Inspect and remove any burrs on the top of the
valve stem, especially around the groove for the
locks.
(5) Remove the valves, and place them in a rack in
the same order as removed.
VALVE CLEANING
(1) Clean all carbon deposits from the combustion
chambers, valve ports, valve stems, valve stem
guides and head.
(2) Clean all build-up and gasket material from
the engine cylinder head machined gasket surface.
INSPECTION
(1) Inspect for cracks in the combustion chambers
and valve ports.
(2) Inspect for cracks on the exhaust seat.
(3) Inspect for cracks in the gasket surface at each
coolant passage.
(4) Inspect valves for burned, cracked or warped
heads.
(5) Inspect for scuffed or bent valve stems.
(6) Replace valves displaying any damage.
(7) Check valve spring height (Fig. 11).
Fig. 11 VALVE SPRING CHART
LOAD Kg
HEIGHT mm
STATE
P1
0.00
H1
45.26
FREE LENGTH
P2
182-5 +10%
H2
38.00
VALVE CLOSED
P3
395±5%
H3
28.20
VALVE OPEN
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ENGINE
9 - 19
VALVE REFACING
(1) Use a valve refacing machine to reface the
intake and exhaust valves to the specified angle.
(2) After refacing, a margin of at least 4.52-4.49
mm (.178-.177 inch) must remain (Fig. 12). If the
margin is less than 4.49 mm (.177 inch), the valve
must be replaced.
VALVE SEAT REFACING
(1) Install a pilot of the correct size in the valve
guide bore. Reface the valve seat to the specified
angle with a good dressing stone. Remove only
enough metal to provide a smooth finish.
(2) Use tapered stones to obtain the specified seat
width when required.
VALVE STAND DOWN
Valve stand down is to maintain the adequate com-
pression ratio.
(1) Invert cylinder head.
(2) Fit each valve to its respective valve guide.
(3) Using a straight edge and feeler gauge, check
valve head stand down: Inlet valve head stand down
1.08 to 1.34 mm (.042 to .052 ins.) and exhaust valve
stand down .99 to 1.25 mm (.035 to .049 ins.).
(4) If valve head stand down is not in accordance
with above, discard original valves, check stand down
with new valves and recut valve seat inserts to
obtain correct stand down.
VALVE GUIDES
(1) Valve Guides height requirement.
(2) Measurement A (Fig. 13): 16.50 - 17.00 mm.
Measurment B : 14.50 - 15.00 mm.
VALVE STEM-TO-GUIDE CLEARANCE
MEASUREMENT
(1) Measure and record internal diameter of valve
guides. Valve guide internal diameter is 8.0 to 8.015
mm (.3149 to .3155 ins.).
(2) Measure valve stems and record diameters.
Intake valve stem diameter 7.94 to 7.96 mm (.3125 to
.3133 in). Exhaust valve stem diameter 7.92 to 7.94
mm (.3118 to .31215 in).
(3)
Subtract diameter of valve stem from internal
diameter of its respective valve guide to obtain valve
stem clearance in valve guide. Clearance of inlet
valve stem in valve guide is .040 to .075 mm (.0015
to .0029 in). Clearance of exhaust valve stem in valve
guide is .060 to .093 mm (.0023 to .0036 in).
(4) If valve stem clearance in valve guide exceeds
tolerances, new valve guides must be installed.
Fig. 12 VALVE SPECS.
MEASUREMENT
INTAKE
EXHAUST
A
7.940-7.960
7.922-7.940
B
8.00-8.015
8.000-8.015
C
1.08-1.34
0.990-1.250
+0.07
D
2.2 ± 0.08
2.09
2
0.09
E
1.80-2.20
1.65-2.05
F
2.73-3.44
2.45-3.02
G
41.962-41.985
35.964-35.987
H
42.070-42.086
36.050-36.066
I
7.14-7.19
7.00-7.05
L
3.11-3.26
3.10-3.25
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ENGINE
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CYLINDER HEAD (Continued)
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