Chrysler Pacifica. Manual — part 701
(5) Using a feeler gauge, check connecting rod side
clearance (Fig. 73). Refer to Engine Specifications
(Refer to 9 - ENGINE - SPECIFICATIONS).
STANDARD PROCEDURE - FITTING PISTONS
NOTE: Pistons and connecting rods are machined
to tight weight tolerances and need not be sorted in
any way.
The piston and cylinder wall must be clean and
dry. Piston diameter should be measured 90 degrees
to piston pin at size location shown in (Fig. 74).
Cylinder bores should be measured halfway down
the cylinder bore and transverse to the engine crank-
shaft center line shown in (Fig. 75). Refer to Engine
Specifications (Refer to 9 - ENGINE - SPECIFICA-
TIONS). Pistons and cylinder bores should be
measured at normal room temperature, 21°C
(70°F).
REMOVAL
NOTE: Refer to the connecting rod Description
before beginning repair. (Refer to 9 - ENGINE/EN-
GINE
BLOCK/PISTON
&
CONNECTING
ROD
-
DESCRIPTION).
(1) Disconnect negative cable from battery.
(2) Remove the cylinder heads. (Refer to 9 -
ENGINE/CYLINDER HEAD - REMOVAL)
(3) Remove the oil pan. (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - REMOVAL)
(4) Remove the top ridge of cylinder bores with a
reliable ridge reamer, if necessary, before removing
Fig. 73 Checking
Fig. 74 PISTON MEASUREMENTS
1 - 33.0 mm (1.29 in.) 3.8L ENGINE
Fig. 75 Cylinder Bore Size Checking
Fig. 76 CONNECTING ROD TO CYLINDER
IDENTIFICATION
1 - PAINT MARK OR SCRIBE
CS
ENGINE 3.8L
9 - 159
PISTON & CONNECTING ROD (Continued)
pistons from cylinder block. Be sure to keep tops
of pistons covered during this operation. Pis-
tons and connecting rods must be removed
from top of cylinder block. When removing pis-
ton and connecting rod assemblies from the
engine, rotate crankshaft so that each connect-
ing rod is centered in cylinder bore.
(5) Inspect connecting rods and connecting rod
caps for cylinder identification. Identify them with a
paint mark or scribe, if necessary (Fig. 76).
(6) Remove connecting rod cap. Install connecting
rod bolt protectors (Fig. 77). on connecting rod bolts
or use special tool #8189 to guide cracked connecting
rod.
(7) Remove each piston and connecting rod assem-
bly out of the cylinder bore.
NOTE: Be careful not to nick crankshaft journals.
(8) After removal, install bearing cap on the mat-
ing rod.
INSTALLATION
NOTE: Refer to the connecting rod Description
before beginning repair. (Refer to 9 - ENGINE/EN-
GINE
BLOCK/PISTON
&
CONNECTING
ROD
-
DESCRIPTION).
(1) Before installing pistons and connecting rod
assemblies into the bore, ensure that compression
ring gaps are staggered so that neither is in line with
oil ring rail gap (Fig. 78)and that the arrow on top of
the piston is facing the front of the engine, if
equipped (Fig. 79).
(2) Before installing the ring compressor, ensure
the oil ring expander ends are butted and the rail
gaps located as shown in (Fig. 78).
Fig. 77 Connecting Rod Protectors
1 - COVER ROD BOLTS WITH A SUITABLE COVERING WHEN
REMOVING OR INSTALLING PISTON ASSEMBLY
Fig. 78 PISTON RING END GAP POSITION
1 - SIDE RAIL UPPER
2 - NO. 1 RING GAP
3 - PISTON PIN
4 - SIDE RAIL LOWER
5 - NO. 2 RING GAP AND SPACER EXPANDER GAP
Fig. 79 PISTON ORIENTATION TYPICAL
1 - ARROW FACES FRONT OF ENGINE
9 - 160
ENGINE 3.8L
CS
PISTON & CONNECTING ROD (Continued)
(3) Lubricate the piston and rings with clean
engine oil. Position a ring compressor over the piston
and rings, and tighten the compressor (Fig. 80). Be
sure position of rings does not change during
this operation.
(4) Position upper bearing onto connecting rod.
Lubricate bearing with oil.
(5) Install connecting rod bolt protectors (rubber
hose or equivalent) (Fig. 80). on the connecting rod
bolts, or use special tool (Fig. 81) #8189 for cracked
cap design
(6) The pistons are marked with a “F” located near
the piston pin, or an arrow on top of the piston.
Install piston with this mark positioned to front of
engine on both cylinder banks. The connecting rod oil
squirt hole faces the major thrust (right) side of the
engine block (Fig. 82).
(7) Rotate crankshaft until the connecting rod
journal is located in the center of the cylinder bore.
Insert connecting rod and piston into cylinder bore by
tapping down on the piston using a hammer handle.
At the same time, guide connecting rod into position
on connecting rod journal. (Fig. 80).
(8) Install lower bearing shell and the appropriate
connecting rod cap (Fig. 80).
(9) Install connecting rod cap retaining nuts on
cleaned and oiled rod bolts and tighten to 54 N·m (40
ft. lbs.) PLUS
1
⁄
4
turn. Install connecting rod bolts
and tighten to 7 N·m (5 ft. lbs) initially. Tighten the
Fig. 80 PISTON AND ROD INSTALL - TYPICAL
1 - RING - OIL CONTROL
7 - CAP - CONNECTING ROD
2 - RING - NO. 2 COMPRESSION
8 - BEARING - CONNECTING ROD LOWER
3 - RING - NO. 1 COMPRESSION
9 - CRANKSHAFT JOURNAL PROTECTOR (RUBBER HOSE)
4 - RING - SIDE RAIL UPPER & LOWER
10 - BEARING - CONNECTING ROD UPPER
5 - PISTON RING COMPRESSOR
11 - PISTON AND CONNECTING ROD ASSEMBLY
6 - NUT - CONNECTING ROD
12 - PISTON LOCATION MARK (F = FRONT)
CS
ENGINE 3.8L
9 - 161
PISTON & CONNECTING ROD (Continued)
bolts an additional 21 N·m (15 ft. lbs.) and then turn
each bolt 90° to final clamping load.
(10) Repeat procedure for each piston and connect-
ing rod installation.
(11) Install the cylinder heads. (Refer to 9 -
ENGINE/CYLINDER HEAD - INSTALLATION)
(12) Install the oil pan. (Refer to 9 - ENGINE/LU-
BRICATION/OIL PAN - INSTALLATION)
(13) Fill engine crankcase with proper oil to cor-
rect level.
(14) Connect negative cable to battery.
CONNECTING ROD BEARINGS
STANDARD PROCEDURE - MEASURING
CONNECTING ROD BEARING CLEARANCE
CAUTION: Two styles of connecting rod with bear-
ing caps are available (standard forged and forged
cracked cap). Either may be used as a replacement
part, as both rods interchange. The difference is the
tightening specification between designs.
Either style of bearing cap is not interchangeable
and should be marked at removal to ensure correct
assembly. The bearing shells must be installed with
the tangs inserted into the machined grooves in the
rods and caps. Install cap with the tangs on the same
side as the rod. Fit all rods on one bank until com-
plete. Connecting rod bearings are available in the
standard size and the following undersizes: 0.025
mm (0.001 in.) and 0.250 mm (0.010 in.).
CAUTION: Install the bearings in pairs. Do not use a
new bearing half with an old bearing half. Do not
file the rods or bearing caps.
Measure connecting rod journal for taper and out-
of-round. (Refer to 9 - ENGINE/ENGINE BLOCK/
CRANKSHAFT - INSPECTION)
The connecting rod bearing clearances can be
determined by use of Plastigage or the equivalent.
The following is the recommended procedure for the
use of Plastigage:
(1) Rotate the crankshaft until the connecting rod
to be checked is at the bottom of its stroke.
(2) Remove oil film from surface to be checked.
Plastigage is soluble in oil.
(3) Place a piece of Plastigage across the entire
width of the bearing shell in the bearing cap approx-
imately 6.35 mm (1/4 in.) off center and away from
the oil hole. In addition, suspect areas can be
checked by placing Plastigage in that area.
(4) Assemble the rod cap with Plastigage in place.
Tighten the rod cap to the specified torque. Do not
rotate the crankshaft while assembling the cap
or the Plastigage may be smeared, giving inac-
curate results.
Fig. 81 Piston and Connecting Rod
1 - “F” TOWARD FRONT OF ENGINE
2 - RING COMPRESSOR
3 - SPECIAL TOOL 8189
4 - OIL SQUIRT HOLE
9 - 162
ENGINE 3.8L
CS
PISTON & CONNECTING ROD (Continued)
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