Cylinder Bore Measurement; Cylinder Bore Resurfacing - Jeep 1987 Wrangler Workshop Manual

CYLINDER BLOCK
DISASSEMBLY
CYLINDER BORE MEASUREMENT
U s e a bore gauge (A) to m e a s u r e e a c h cylinder
bore diameter. If a bore g a u g e is not available,
u s e an inside micrometer.
A
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Measure the cylinder bore diameter c r o s s w i s e
to the cylinder block n e a r the top of the bore.
Repeat the measurement at the bottom of the
bore.
Determine the taper by subtracting the smaller
diameter from the larger diameter.
Rotate the measuring d e v i c e 120 d e g r e e s a n d
repeat the previous steps.
Lastly, rotate the device another 120 d e g r e e s
a n d repeat the m e a s u r e m e n t s .
Determine out-of-roundness by comparing the
d i f f e r e n c e b e t w e e n e a c h 120 d e g r e e
measurement.
If the cylinder bore taper d o e s not e x c e e d 0.025
mm (0.001 in.) a n d the out-of-roundness d o e s
not exceed 0.025 m m (0.001 in.) the cylinder bore
c a n be trued by honing.
If the cylinder bore taper or out-of-round condi-
tion exceeds these maximum limits, the cylinder
must be bored a n d then honed to accept an
oversize piston.
N O T E : A slight amount of taper always exists
in the cylinder bore after the e n g i n e h a s been
in u s e for a period of time.
CYLINDER BORE RESURFACING
C A U T I O N : Do not u s e rigid type h o n e s to
remove cylinder wall glaze.
U s e an expanding type hone to true the cylinder
bore and to remove the glaze for faster piston
ring seating.
Move the hone down and up (stroke) at sufficient
s p e e d to produce a uniform 60 degree angle
Crosshatch pattern on the cylinder walls. Do not
u s e more than ten strokes per cylinder (one
stroke is one down-and-up movement).
C l e a n the cylinder bores by scrubbing clean with
a solution of hot water and detergent.
Immediately apply light engine oil to the cylinder
walls. Wipe with a c l e a n , lint-free cloth.
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