Repair Manual

CRANKSHAFT AND CYLINDER BLOCK
ENGINE OVERHAUL <4A9>
11B-51
BORING CYLINDERS
AK401446
AB
A
1. Oversize pistons should be based on the largest
bore cylinder.
Size Size mark
0.25 mm oversize 25
NOTE: The size mark is stamped on the piston
top.
2. In case of 0.25 mm oversized piston, a hole shall
be bored through the cylinder block so that the
clearance can have the standard value. The
standard measuring point for the outside piston
diameter is at "A" shown in the illustration.
Standard measuring point A: 12.0 mm
3. Based on the measured piston outside diameter
(O.D.), calculate the boring finish dimension.
Boring finish dimension = Piston O.D. +
0.015
− 0.035 mm (Clearance between piston
O.D. and cylinder) - 0.02 mm (honing margin)
4. Bore each cylinders to the calculated boring finish
dimension.
CAUTION
To prevent distortion caused by heat increased
during boring, bore the cylinders in the following
order: No.2, No.4, No.1, No.3.
5. Hone the cylinders to the final finish dimension
(piston O.D. + piston-to-cylinder clearance).
6. Check the clearance between the pistons and
cylinders.
Standard value: 0.015 − 0.035 mm
NOTE: When boring cylinders, finish all of four
cylinders to the same oversize. Do not bore only
one cylinder to an oversize.
Main
Index
Group
TOC