Doosan DX60R Shop Manual page 322

Inspection of Cylinder Block
1. Ensure that oil passages are clear and unobstructed.
2. Check for discoloration or evidence of cracks. If a fracture
is suspected, use the color check method or the
Magnaflux method to determine if the cylinder block is
fractured.
3. Inspect cylinders for roundness, taper, or evidence of
scoring. Collect and record the measurements. Consider
honing, reboring or replacing the cylinder block if the
measurements are not within specification.
• Take measurements at three places (Figure 193) (a,
b, c), and in two directions (d and e) in each
cylinder.
Inspection of Pistons, Piston Rings and Wrist Pin
NOTE: On an engine with low hours, the pistons, piston rings
may be reused if they are found to be within
specifications. The pistons and piston rings must be
reinstalled in the same cylinders from which they
were originally removed.
On an engine with high hours, the pistons rings
should be replaced and the cylinder honed (See
"Honing and Boring" on page -147) or replaced. The
piston should be replaced as necessary.
1. Clean piston ring grooves using a piston ring groove
cleaning tool. Follow manufacturer's instructions for
correct operation.
2. Wash the pistons in an appropriate solvent using a soft
brush.
3. Visually inspect each piston for cracks. Pay particular
attention to the ring lands between the piston ring
grooves.
4. Measure the diameter of the piston skirt at 90° to the wrist
pin bore as shown (Figure 194). Measurements must be
taken at a specified distance (1, Figure 194) from the
bottom of the piston, based on engine model. Record the
measurements.
specifications.
5. Subtract the piston measurement from the greatest
measurement acquired during cylinder inspection (See
"Inspection of Cylinder Block" on page -142) to obtain
piston-to-cylinder clearance. Record the measurements.
See "Piston" on page -98 for specifications.
Engine
Page 142
See "Piston" on
Figure 193
page -98 for
Figure 194
SP001693