YANGDONG SERIES Y85 Operation & Maintenance Manual page 31

Fig.S Measurement of side surface
gap of piston ring
Fig.7 Measurement of piston ring end gap
I.Thickness feeler(gauge) 2.Piston
ring 3.Cylinder liner
gauge.!n normal case,the measur -ing
value should be 0.2 -OAmm (Fig.7).!n
case the gap value is less, enlarge it by
a file.1f it is excess,replace it with
another one.!n addition,measurement
should be made with a feeler(gauge)to
check the side clearance between the
piston ring and ring groove.The side
clearance for the first ring should be
0.07 -0.102mm and 0.05 -0.082mm for
Check the ring end gap before
assembling the piston ring.The method
measuring this gap is recommended as
follows:Press down the piston ring
evenly into the cylinder liner by 15-
20mm from the top surface of liner.
Measure the clearance with a feeler
the second ring as shown in Fig.8.
When dismantling and assembling
the piston ring,a special tool may be
used.The ring end gap of piston rings
should be set off with each other by
120
0
,
to prevent being in line with the piston pin seat hole.
If the piston ring is seized and could not move when checking,soak it in diesel fuel(kerosine
or gasoline)for 24h or more.Then knock the piston ring slightly to make it become flexible of
itself.On getting out the piston ring,clean it in diesel fuel or carbon tetrachloride.
Check the piston to see whether there is any cracks or scars.Change the defective piston and
renew its rings.
The cross section of the cOllilecting-rod is I-shaped,with the splitting surface of large end
being perpendicular to the center line of connecting -rod.Boring the connecting -rod hole and
connecting-rod
c~p
must be mated.Therefore when as-sembling,pay close attention to the mating
marks on both the connecting-rod and connecting-rod cap in order to avoid making mistakes.
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