Engine Overhaul-Reassembly Sequence; Piston Rings-Installation - Jeep cherokee 1989 Owner's Manual

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20 Engine overhaul
reassembly sequence
Before beginning engine reassembly, make sure you have all the
necessary new parts, gaskets and seals as well as the following items
on hand:
Common hand tools
Piston ring installation tool
Piston ring compressor
Vibration damper installation tool
Short lengths of rubber or plastic hose
to fit over connecting rod bolts
Plastigage
Feeler gauges
A fine-tooth file
New engine oil
Engine assembly lube or moly-base grease
Gasket sealant
Thread locking compound
2 In order to save time and avoid problems, engine reassembly must
be done in the following general order:
New camshaft bearings (must be done by automotive machine shop)
Piston rings
Crankshaft and main bearings
Oil pump
Camshaft and lifters
Oil pan
Timing chain and sprockets
Cylinder headls), pushrods and rocker arms
Timing cover
Intake and exhaust manifolds
Rocker arm coverls)
Engine rear plate
Fly wheel/driveplate
21 Piston rings installation
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Refer to illustrations 2 1.3, 2 1.4, 2 1.5, 2 l.ga, 2 l.9b and 2 1. 12
1 Before installing the new piston rings, the ring end gaps must be
checked. It's assumed that the piston ring side clearance has been
checked and verified correct (Section 17).
2 Lay out the pistoniconnecting rod assemblies and the new ring
sets so the ring sets will be matched with the same piston and cylinder
21.4
With the ring square i n the cylinder, measure the
end gap with a feeler gauge
The Motor Manual Guy
Chapter 2 Part General engine overhaul procet?res
during the end gap measuremen,? and engine assembly.
3 Insert the top (number one) ring.into the first Winder and square
up with the cylinder walls by
it
(see illustration). The ring should be near
at the lower limit of ring travel.
To measure the end gap, slip feeler gauges b e t w e e r i t h ends of
4
the ring until a gauge equal to the gap width is found (see illustration).
The feeler gauge should slide between the ring ends with a slight
amount of drag. Compare the measurement t o the Specifications. If
the gap is larger or smaller than specified, double-check t o make sure
you have the correct rings before proceeding.
5 If the gap is too small, must be enlarged or the ring ends may
it
come in contact with each other during engine operation, which can
cause serious damage to the engine. The end gap can be increased
by filing the ring ends very carefully with a fine file. Mount the file in
a vise equipped with soft jaws, slip the ring over the file with the ends
contacting the file face and slowly move the ring t o remove material
from the ends. When performing this operation, file only from the out-
side in (see illustration).
6 Excess end gap isn't critical unless it's greater than 0.040-inch.
Again, double-check to make sure you have the correct rings for your
engine.
21.3 When checking piston ring end gap, the ring must
be square i n the cylinder bore (this is done by pushing the
ring down with a piston as shown)
21.5 I f the end gap is too small. clamp a file i n a vise and
file the ring ends (from the outside i n only) t o enlarge the
gap slightly