3) Install piston rings to piston:
• As indicated in figure, 1st and 2nd rings have "T"
mark (4) respectively. When installing these piston
rings to piston, direct marked side of each ring
toward top of piston.
• 1st ring (1) differs from 2nd ring (2) in thickness,
shape and color of surface contacting cylinder
Distinguish 1st ring from 2nd ring by referring to
• When installing oil ring (3), install spacer first and
then two rails.
4) After installing three rings (1st, 2nd and oil rings),
distribute their end gaps as shown in figure.
1. Front mark
2. 1st ring end gap
3. 2nd ring end gap and oil ring spacer gap
Cylinders, Pistons and Piston Rings Inspection
Inspect cylinder walls for scratches, roughness or ridges
which indicate excessive wear. If cylinder bore is very
rough or deeply scratched, or ridged, rebore cylinder and
use over size piston.
Cylinder bore diameter, taper and out-of-round
Using a cylinder gauge (1), measure cylinder bore in
thrust and axial directions at two positions ("a" and "b")
as shown in figure.
If any of the following conditions is noted, rebore
4. Oil ring upper rail gap
5. Oil ring lower rail gap
1) Cylinder bore dia. exceeds limit.
2) Difference of measurements at two positions
exceeds taper limit.
3) Difference between thrust and axial measurements
exceeds out-of-round limit.
Cylinder bore diameter
Standard: 78.000 – 78.014 mm (3.0709 – 3.0714
Limit: 78.050 mm (3.073 in.)
Cylinder taper and out-of-round
Limit: 0.10 mm (0.004 in.)
If any one of four cylinders has to be rebored,
rebore all four to the same next oversize.
This is necessary for the sake of uniformity
"a": 50 mm (1.96 in.)
"b": 100 mm (3.94 in.)