Piston clearance:
Measure cylinder bore diameter and piston diameter to find their
difference which is piston clearance. Piston clearance should be
within specification as given below. If it is out of specification, re-
bore cylinder and use oversize piston.
Piston clearance : 0.025 – 0.045 mm (0.0009 – 0.0017 in.)
NOTE:
Cylinder bore diameters used here are measured in thrust
direction at two positions.
“a”: 20 mm (0.79 in.)
Ring groove clearance:
Before checking, piston grooves must be clean, dry and free of
carbon.
Fit new piston ring into piston groove, and measure clearance
between ring (1) and ring land by using thickness gauge (2).
If clearance is out of specification, replace piston.
Ring groove clearance:
Top:0.03 – 0.07 mm (0.0012 – 0.0027 in.)
2nd:0.02 – 0.06 mm (0.0008 – 0.0023 in.)
Piston Pin
Check piston pin, connecting rod small end bore and piston bore
for wear or damage, paying particular attention to condition of
small end bore bush. If pin, connecting rod small end bore or pis-
ton bore is badly worn or damaged, replace pin, connecting rod
or piston.
Piston pin clearance:
Check piston pin clearance in small end. Replace connecting
rod if its small end is badly worn or damaged or if measured
clearance exceeds limit.
Small-end bore:
16.003 – 16.011 mm (0.6300 – 0.6303 in.)
Piston pin dia.:
15.995 – 16.000 mm (0.6297 – 0.6299 in.)
ENGINE MECHANICAL (F8D ENGINE)
6A1-45
Item
Standard
Limit
Piston clearance
in small end
0.003 – 0.016 mm
(0.0001 – 0.0006 in.)
0.05 mm
(0.0020 in.)
