Jeep Wrangler 1997 Manual page 711

TJ
CLEANING AND INSPECTION (Continued)
OIL FILTER
ADAPTOR HOLE
REAR OIL
GALLEY
HOLE
FILTER BYPASS
HOLE
Fig. 63 Oil Filter Adaptor Hole
Fig. 64 Front Oil Galley Hole
Fig. 65 Rear Oil Galley Hole
J9009-50
FRONT OIL
GALLEY HOLE
J9009-51
J9009-52
INSPECTION-CYLINDER BORE
(1) It is mandatory to use a dial bore gauge to
measure each cylinder bore diameter (Fig . 66) . To
correctly select the proper size piston, a cylinder bore
gauge, capable of reading in 0 .003 mm ( .0001in .)
INCREMENTS is required. If a bore gauge is not
available, do not use an inside micrometer.
10 mm -
(3/8 IN .)
USE FOR
SIZING
PISTON
2.51 . ENGINE 9- 49
Fig . 66 Cylinder Bore Measurement
(2) Measure the inside diameter of the cylinder
bore at three levels below top of bore . Start perpen-
dicular (across or at 90 degrees) to the axis of the
crankshaft and then take two additional reading.
(3) Measure the cylinder bore diameter crosswise
to the cylinder block near the top of the bore . Repeat
the measurement near the middle of the bore, then
repeat the measurement near the bottom of the bore .
(4) Determine taper by subtracting the smaller
diameter from the larger diameter.
(5) Rotate measuring device 90° and repeat steps
above .
(6) Determine out-of-roundness by comparing the
difference between each measurement .
(7) If cylinder bore taper does not exceed 0 .025
mm (0 .001 inch) and out-of-roundness does not
exceed 0 .025 mm (0 .001 inch), the cylinder bore can
be honed. If the cylinder bore taper or out- of-round
condition exceeds these maximum limits, the cylinder
must be bored and then honed to accept an oversize
piston . A slight amount of taper always exists in the
cylinder bore after the engine has been in use for a
period of time .
HONING-CYLINDER BORE
The honing operation should be closely coordinated
with the fitting of pistons and rings. This will ensure
specified clearances are maintained.