Jacobsen SXG323, Service Manual

Page: 54 / 230

CHAPTER 4. ENGINE
53
4
Fig. 4-63
- Measure cylinder bore diameter at a point of 12
to 14 mm (0.47 - 0.55 in.) below the cylinder
block top surface in two directions: one is in
alignment with the crankshaft axis and the other
is at right angles to the crankshaft axis.
- If wear is in excess of 0.2 mm (0.008 in.), cor-
rect by honing.
- Honing should be done to fit an oversize piston,
which should be done at a specialist's work-
shop.
- Honing accuracy should be to the extent that
bore diameters measured in two directions at A
and B and in three levels at a, b, and c differ less
than 0.02 mm (0.0008 in.) from each other.
Fig. 4-64
Fig. 4-65
(2) Inspection of the crankshaft
• Check the crankshaft journals for oil clearance.
a. Clean the journals and bearings.
b. Install the upper bearings and crankshaft on the
cylinder block.
c. Put plasti-gauge over the journal width.
Fig. 4-66
d. Install the bearings on respective bearing caps.
Install the assembled and tighten them to the
specified torque.
While tightening, the crankshaft should be held
securely so as not to turn.
e. Loosen the tightening bolts and remove the bear-
ing caps carefully. Then measure the most
stretched parts of the plasti-gauges.
Wear limit 0.2 mm
Oversize 0.5; 1.0 mm
Specified torque 4.5 kgf ･ m