Dodge RAM TRUCK 1500 1995 Service Manual page 945

B R 5.9L ENGINE 9 -101
(2) Hold the oil pump base flush against mating
surface on No.5 main bearing cap. Finger tighten
pump attaching bolts. Tighten attaching bolts to 41
N-m (30 ft. lbs.) torque.
(3) Install the oil pan.
PISTON ANi CONNECTING ROi ASSEMBLY
The pistons are elliptically turned so that the di­
ameter at the pin boss is less than its diameter
across the thrust face. This allows for expansion un­
der normal operating conditions. Under operating
temperatures, expansion forces the pin bosses away
from each other, causing the piston to assume a more
nearly round shape.
All pistons are machined to the same weight, re­
gardless of size, to maintain piston balance.
The piston pin rotates in the piston only and is re­
tained by the press interference fit of the piston pin
in the connecting rod.
REMOVAL
(1) Remove the engine from the vehicle.
(2) Remove the cylinder head.
(3) Remove the oil pan.
(4) Remove top ridge of cylinder bores with are li­
able ridge reamer before removing pistons from cyl­
inder block. Be sure to keep tops of pistons covered
during this operation.
(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, rotate crankshaft center
the connecting rod in the cylinder bore and at BDC.
Be 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. 1).
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, 2PC (70°F).
PISTON PIN BORE DIAMETER
A
PISTON
SIZE
A DIA = PISTON DIAMETER BORE DIAMETER
PISTON
SIZE MIN. mm (IN.) M A I . ram (IN.) MIN. mm (IN.) MAX.
KM
(IN.)
A
B
101.580 (3.9992) 101.592(3.9997) 101.605(4.0002} 101.618(4.0007)
C
101.592 (3.9997) 101.605(4.0002) 101.618(4.0007} 101.630(4.0012)
D 101.605 (4.0002) 101.618(4.0007) 101.630 (4.0012) 101.643 (4.0017)
E
39509-79
Fig. 1 Piston Measurements
FITTING RINGS
(1) Measurement of end gaps:
(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 stock in the gap. The compres­
sion 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 mm (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. Install the oil control rings ac­
cording to instructions in the package. It is not nec­
essary to use a tool to install the upper and lower
rails. Insert oil rail spacer first, then side rails.
(b) Install the second compression rings using In­
stallation Tool C-4184. The compression rings must
be installed with the identification mark face up
(toward top of piston) and chamfer facing down. An
identification mark on the ring is a drill point, a
stamped letter O, an oval depression or the word
TOP (Figs. 2 and 4).