Chrysler DODGE D150 1993 Service Manual page 642

(5) Be sure the connecting rod and connecting rod
cap are identified with the cylinder number. Remove
connecting rod cap. Install connecting rod bolt guide
set on connecting rod bolts.
(6) Pistons and connecting rods must be removed
from top of cylinder block. When removing piston
and connecting rod assemblies from the engine, ro­
tate crankshaft so t h a t the connecting rod is centered
in cylinder bore and at BDC. B e careful not to nick
crankshaft journals.
(7) After removal, install bearing cap on the mat­
ing rod.
INSPECTION
Check the crankshaft connecting rod journal for ex­
cessive wear, taper and scoring.
Check the cylinder block bore for out-of-round,
taper, scoring and scuffing.
Check the pistons for taper and elliptical shape be­
fore they are fitted into the cylinder bore (Fig. 12).
DIAMETER (D)
SHOULD BE
0.0000-0.0152 mm
(0.0000-0.0006 in.)
LARGER THAN (C).
98.704-98.831 mm
-(3.886-3.891 in.)-
98.577-98.704 mm-
(3.881-3.886 in.)
(a) Measure piston ring gap 2 inches from bot­
tom of cylinder bore. An inverted piston can be
used to push the rings down to ensure positioning
rings squarely in the cylinder bore before measur­
ing.
(b) Insert feeler gauge in the gap. The top com­
pression ring gap should be between 0.254-0.508
mm (0.010-0.020 inch). The second compression
ring gap should be between 0.508-0.762 m m (0.020-
0.030 inch). The oil ring gap should be 0.254-1.270
mm (0.010-0.050 inch).
(c) Rings with insufficient end gap may be prop­
erly filled to the correct dimension. Rings with ex­
cess gaps should not be used.
(2) Install rings and confirm ring side clearance:
(a) Install oil rings being careful not to nick or
scratch the piston.
(b) Install the compression rings using Installa­
tion Tool C-4184. The top compression may be in­
stalled with either side up. The second compression
ring must be installed with the identification mark
face up (toward top of piston) and the chamfer
should face down. An identification m a r k on the
ring is a drill point, a stamped letter "O", an oval
depression or the word TOP.
(c) Measure side clearance between piston ring
and ring land (Fig. 13). Clearance should be 0.038-
0.076 mm (0.0015-0.0030 inch) for the compression
rings. The steel rail oil ring should be free in
groove, but should not exceed 0.203 m m (0.0080
inch) side clearance.
FEELER GAUGE
ELLIPTICAL SHAPE OF THE PISTON
SKIRT SHOULD BE 0.254-0.304 mm
(0.010-0.012 in.) LESS AT DIAMETER
(A) THAN ACROSS THE THRUST
FACES AT DIAMETER (B).
J9309-9
Fig. 12 Piston Measurements
FITTING PISTONS
Piston and cylinder wall must be clean and dry.
Specified clearance between the piston and the cylin­
der wall is 0.013-0.038 mm (0.0005-0.0015 inch).
Piston diameter should be measured at the top of
skirt, 90° to piston pin axis. Cylinder bores should be
measured halfway down the cylinder bore and trans­
verse to the engine crankshaft center line.
Pistons and cylinder bores should be measured at
normal room temperature, 21°C (70°F).
FITTING RINGS
(1) Measurement of end gaps:
J 9 2 0 9 - 1 3 6
Fig. 13 Measuring Piston Ring Side Clearance
(d) Pistons with insufficient or excessive side
clearance should be replaced.
(3) Orient the rings:
(a) Arrange top compression ring 90° counter­
clockwise from the oil ring rail gap (Fig. 14).
(b) Arrange second compression ring 90° clock­
wise from the oil ring rail gap (Fig. 14).