Jeep cherokee 1989, Owner'S Manual

Page: 108 / 336

2D-2
Chapter 2 Part D General engine overhaul procedures
six-cylinder engine
General
Cylinder compression pressure
Maximum variation between cylinders
Oil pressure
A t idle ( 6 0 0 rpm)
Above
Cylinder head and valves
l i m i t .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Minimum valve margin
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Valve stem diameter.
Valve stem-to-guide clearance
Valve spring pressure
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Valveopen
Valve closed
Valve lifter
Diameter.
. . . . . . . . . . . . . . . . . . . . . . . . . . .
Lifter-to-bore clearance
Crankshaft and connecting rods
Connecting rod journal
Diameter.
Bearing oil clearance
Desired
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Allowable
Connecting rod side clearance (end p l a y ) .
Main bearing
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Journal diameter
Bearing oil clearance
Desired
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Allowable
Crankshaft end play (at thrust bearing)
. . . . . . . . . . . .
Maximum taper and out-of-round (all journals)
Pistons and rings
Piston-to-bore clearance
Desired
Allowable
Piston ring end gap
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Compression rings.
Oil control ring (steel rails).
Piston ring side clearance
Compression rings
Desired
. . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . .
Allowable
Oil control ring
Desired
Allowable
Engine block
Maximum
Cylinder bore diameter (standard)
Maximum taper and out-of-round
Torque specifications
*
Main bearing cap bolts
. . . . . . . . . . . . . . . . . . . . . . . . . . .
Connecting rod cap n u t s .
Note: Refer to Part for additional torque specifications.
General information
Included in this portion of Chapter 2 are the general overhaul pro-
cedures for the cylinder and internal engine components.
The information ranges from advice concerning preparation for an
overhaul and the purchase of replacement parts t o detailed, step-by-
step procedures covering removal and installation of internal engine
components and the inspection of parts.
The following Sections have been written based o n t h e assumption
that the engine has been removed from the vehicle. For information
concerning in-vehicle engine repair, as well as removal and installation
of the external components necessary for the overhaul, see Part A,
or C of this Chapter and Section 7 of this Part.
The Specifications included in this Part are only those necessary for
1 2 0 t o psi
3 0 psi
1 3 psi
3 7 t o 7 5 psi
0 . 0 0 2 in per 6 in
1 / 3 2 in
0.312 i n
0 . 0 0 1 t o 0 . 0 0 3 in
2 0 5 t o 2 2 0 Ibs at 1.2 in
6 4 t o 7 4 Ibs at 1 . 6 2 5 in
0 . 0 0 2 in per 6 in ( 0 . 0 0 8 in overall)
3 . 8 7 5 1 t o 3 . 8 7 7 5 in
0 . 0 0 1 in
8 0
3 3
the inspection and overhaul procedures which follow. Refer t o Parts
A,
and C for additional Specifications.
- -
2 Engine overhaul
-
general information
Refer to illustrations and
It's n o t always easy t o determine when, or if, an engine should be
completely overhauled, as a number o f factors must be considered.
High mileage is n o t necessarily an indication that an overhaul is
needed, while l o w mileage doesn't preclude the need for an overhaul.
Frequency of servicing is probably the most important consideration.
A n engine that's had reguiar and frequent oil and filter changes, as
well as other required maintenance, will most likely give many thou-
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