Piston, Engine
PISTON TO PISTON PIN OIL CLEARANCEPiston Pin Hole Diameter
Measure the inner diameter of piston pin hole with an inside micrometer.
Standard: 19.993 - 20.005 mm (0.7871 - 0.7876 inch)
Piston Pin Outer Diameter
Measure the outer diameter of piston pin with a micrometer.
Standard: 19.989 - 20.001 mm (0.7870 - 0.7874 inch)
Piston to Piston Pin Oil Clearance
(Piston to piston pin oil clearance) = (Piston pin hole diameter) - (Piston pin outer diameter)
Standard: 0.002 - 0.006 mm (0.0001 - 0.0002 inch)
^ If oil clearance is out of the standard, replace piston and piston pin assembly.
^ When replacing piston and piston pin assembly, refer to EM-97, "Piston to Cylinder Bore Clearance".
NOTE:
^ Piston is available together with piston pin as assembly.
^ Piston pin (piston pin hole) grade is provided only for the parts installed at the plant. For service parts, no grades can be selected. (Only grade "0" is available.)
PISTON TO CYLINDER BORE CLEARANCE
Cylinder Bore Inner Diameter
^ Using a bore gauge, measure the cylinder bore for wear, out-of-round and taper at six different points on each cylinder. ("X" and "Y" directions at "A", "B" and "C") ("Y" is in longitudinal direction of the engine)
NOTE: When determining cylinder bore grade, measure cylinder bore at "B" position.
Standard inner diameter: 89.010 - 89.030 mm (3.5043 - 3.5051 inch)
Wear limit: 0.2 mm (0.008 inch)
Out-of-round (Difference between "X" and "Y"): 0.015 mm (0.0006 inch)
Taper limit (Difference between "A" and "C"): 0.01 mm (0.0004 inch)
^ If the measured value exceeds the limit, or if there are scratches and/or seizure on the cylinder inner wall, hone or re-bore the cylinder inner wall.
^ Oversize piston is provided. When using oversize piston, re-bore the cylinder so that the clearance of the piston to cylinder bore satisfies the standard.
CAUTION: When using an oversize piston, use oversize pistons for all cylinders with oversize piston rings.
Oversize (OS): 0.2 mm (0.008 inch)
Piston Skirt Diameter
Measure the outer diameter of piston skirt with a micrometer.
Measure point: Distance from the top 42.98 mm (1.692 inch)
Standard: 88.990 - 89.010 mm (3.5035 - 3.5043 inch)
Piston to Cylinder Bore Clearance
Calculate by piston skirt diameter and cylinder bore inner diameter (direction "X", position "B").
(Clearance) = (Cylinder bore inner diameter) - (Piston skirt diameter)
Standard: 0.010 - 0.030 mm (0.0004 - 0.0012 inch)
Limit: 0.08 mm (0.0031 inch)
^ If it exceeds the limit, replace piston and piston pin assembly.
Re-boring Cylinder Bore
1. Cylinder bore size is determined by adding piston to cylinder bore clearance to piston skirt diameter.
Re-bored size calculation: D = A + B - C where,
D: Bored diameter
A: Piston diameter as measured
B: Piston - to - cylinder bore clearance (standard value)
C: Honing allowance 0.02 mm (0.0008 inch)
2. Install lower cylinder block, and tighten bolts to the specified torque. Otherwise, cylinder bores may be distorted in final assembly.
3. Cut cylinder bores.
NOTE:
^ When any cylinder needs boring, all other cylinders must also be bored.
^ Do not cut too much out of cylinder bore at a time. Cut only 0.05 mm (0.0020 inch) or so in diameter at a time.
4. Hone cylinders to obtain the specified piston to cylinder bore clearance.
5. Measure the finished cylinder bore for out-of-round and taper.
NOTE: Measurement should be done after cylinder bore cools down.
PISTON, PISTON RING AND PISTON PIN
Available Piston:
Available Piston
Piston Ring:
Piston Ring
Piston Pin:
Piston Pin