5
5-23
4st 2/2.5/3.5 2007
a
b
c
20) Inspection of Piston Ring Side
Clearance
1.
Measure piston ring side clearance. Replace piston and
piston rings as a set if the clearance is over specified value.
Piston Ring Side Clearance :
Top Ring
a
: 0.04 - 0.08mm (0.0016 - 0.0031 in)
Second Ring
b
: 0.03 - 0.07mm (0.0012 - 0.0028 in)
Oil Ring
c
: 0.05 - 0.15mm (0.0020 - 0.0059 in)
Functional Limit
Top Ring
a
: 0.10 mm (0.0039 in)
Second Ring
b
: 0.09 mm (0.0035 in)
Oil Ring
c
: 0.17 mm (0.0067 in)
Replace oil ring together with top ring or second
ring when the ring is replaced.
21) Inspection of Piston Rings
1.
Push piston ring
1
into ring gauge 55.000mm (2.16535in)
parallel to top edge. If the gauge is not available, measure
at the top or bottom of cylinder bore with no wear.
2.
When ring gauge is not available, use piston crown to
push piston ring
1
into to cylinder parallel to top edge.
3.
Measure piston ring closed gap
a
. Replace if it is over
specified value.
Piston Ring Closed Gap
a
:
Top Ring : 0.15 - 0.30 mm (0.0059 - 0.0118 in)
Second Ring : 0.30 - 0.45 mm (0.0118 - 0.0177 in)
Oil Ring : 0.20 - 0.70 mm (0.0079 - 0.0276 in)
Functional Limit :
Top Ring : 0.50 mm (0.0197 in)
Second Ring : 0.70 mm (0.0276 in)
a
1
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