Chrysler Town & Country/Voyager, Dodge Caravan, Plymouth Voyager. Manual — part 299
CYLINDER BLOCK, PISTON AND CONNECTING
ROD ASSEMBLY SERVICE
PISTON AND CONNECTING ROD—REMOVAL
(1) Remove top ridge of cylinder bores with a reliable
ridge reamer before removing pistons from cylinder
block.Be sure to keep tops of pistons covered
during this operation. Mark piston with matching
cylinder number (Fig. 2).
(2) Remove oil pan. Inspect connecting rods and
connecting rod caps for cylinder identification. Identify
them if necessary. (Fig. 3)
(3) Valve relief toward manifold side of engine.
(4) Squirt hole on connecting rod must face timing belt
end of engine.
(5) Pistons and connecting rods must be removed
from top of cylinder block. Rotate crankshaft so that
each connecting rod is centered in cylinder bore.
(6) Remove connecting rod cap. Install connecting
rod bolt protectors on connecting rod bolts (Fig. 4).
Push each piston and rod assembly out of cylinder bore.
Be careful not to nick crankshaft journals.
(7) After removal, install bearing cap on the mating
rod.
Fig. 1 Cylinder Block, Piston and Connecting Rod Assembly
Fig. 2 Piston Marking
Fig. 3 Identify Connecting Rod to Cylinder
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CYLINDER BLOCK CLEANING AND INSPEC-
TION
(1) Clean cylinder block thoroughly and check all
core hole plugs for evidence of leaking.
(2) If new core plugs are installed, Refer to Engine
Core Oil and Cam Plugs.
(3) Examine block and cylinder bores for cracks or
fractures.
CYLINDER BORE INSPECTION
The cylinder walls should be checked for out- of-
round and taper with Tool C-119 (Fig. 5). If the cylinder
walls are badly scuffed or scored, the cylinder block
should be rebored and honed, and new pistons and
rings fitted. Whatever type of boring equipment is
used, boring and honing operation should be closely
coordinated with the fitting of pistons and rings in
order that specified clearances may be maintained.
Refer to Honing Cylinder Bores outlined in the
Standard Service Procedures for specification
and procedures.
Measure the cylinder bore at three levels in direc-
tions A and B (Fig. 5). Top measurement should be
10mm ( 3/8 inch) down and bottom measurement
should be 10mm ( 3/8 inch.) up from bottom of bore.
Refer to (Fig. 6) for specifications.
SIZING PISTONS
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. 7). Cylinder
bores should be measured halfway down the cylinder
Fig. 4 Connecting Rod Protectors
Fig. 5 Checking Cylinder Bore Size
Fig. 6 Piston Size Location and Clearance Chart
Fig. 7 Piston Installation and Sizing Information
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bore and transverse to the engine crankshaft center
line shown in (Fig. 5). Refer to (Fig. 6) for specifica-
tions.
Pistons and cylinder bores should be measured
at normal room temperature, 70°F. (21°C).
PISTON RING—REMOVAL
(1) ID mark on face of upper and intermediate piston
rings must point toward piston crown.
(2) Using a suitable ring expander, remove upper
and intermediate piston rings (Fig. 8).
(3) Remove the upper oil ring side rail, lower oil ring
side rail and then oil ring expander from piston.
(4) Clean ring grooves of any carbon deposits.
FITTING RINGS
(1) Wipe cylinder bore clean. Insert ring and push
down with piston to ensure it is square in bore. The
ring gap measurement must be made with the ring
positioning at least 12mm (.50 inch) from bottom of
cylinder bore. Check gap with feeler gauge (Fig. 9).
Refer to specifications (Fig. 12).
(2) Check piston ring to groove clearance: (Fig. 10).
Refer to specification (Fig. 12).
PISTON RINGS—INSTALLATION
(1) The No. 1 and No. 2 piston rings have a different
cross section. Install rings with manufacturers I.D.
mark facing up, to the top of the piston (Fig. 11).
Fig. 8 Piston Rings—Removing and Installing
Fig. 9 Piston Ring Gap
Fig. 10 Measuring Piston Ring Groove Clearance
Fig. 11 Piston Ring End Gap Position
Fig. 12 Piston Ring Specifications
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CAUTION: Install piston rings in the following order:
(a) Oil ring expander.
(b) Upper oil ring side rail.
(c) Lower oil ring side rail.
(d) No. 2 Intermediate piston ring.
(e) No. 1 Upper piston ring.
(2) Install the side rail by placing one end between
the piston ring groove and the expander. Hold end
firmly and press down the portion to be installed until
side rail is in position. Do not use a piston ring
expander (Fig. 13).
(3) Install upper side rail first and then the lower
side rail.
(4) Install No. 2 piston ring and then No. 1 piston
ring (Fig. 8).
(5) Position piston ring end gaps as shown in (Fig.
14).
(6) Position oil ring expander gap at least 45° from
the side rail gaps but not on the piston pin center or on
the thrust direction. Staggering ring gap is important
for oil control.
PISTON AND CONNECTING ROD ASSEMBLY
INSTALLATION
(1) Before installing pistons, and connecting rod
assemblies into the bore, besure that compression ring
gaps are staggered so that neither is in line with oil
ring rail gap.
(2) Before installing the ring compressor, make sure
the oil ring expander ends are butted and the rail gaps
located as shown in (Fig. 14).
(3) Immerse the piston head and rings in clean
engine oil, slide the ring compressor, over the piston
and tighten with the special wrench. Be sure position
of rings does not change during this operation .
(4) The valve cut should be toward the manifold side
of the engine (Fig. 16).
(5) Install connecting rod bolt protectors on rod bolts
(Fig. 4).
Fig. 13 Installing Side Rail
Fig. 14 Piston Ring End Gap Position
Fig. 15 Installing Piston
Fig. 16 Piston Markings
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