Piston Pins and Connecting Rods Inspection

Piston Pins and Connecting Rods Inspection
Reference: Piston, Piston Ring and Connecting Rod Disassembly and Reassembly

Piston Pin
Visual inspection
Check piston pin, connecting rod small-end bore and piston pin hole in piston for wear or damage, paying particular attention to condition of small-end bore bushing.
Replace piston pin, connecting rod and/or piston if piston pin, connecting rod small-end bore or piston pin hole in piston is badly worn or damaged.

Piston pin clearance
Check piston pin clearance in connecting rod small-end and piston. Replace connecting rod and/or piston if its small-end is badly worn or damaged or if measured clearance exceeds limit.

Piston pin clearance in connecting rod small-end
Standard: 0.003 - 0.017 mm (0.0002 - 0.0006 in.)
Limit: 0.040 mm (0.0015 in.)

Piston pin clearance in piston
Standard: 0.010 - 0.016 mm (0.00039 - 0.00062 in.)
Limit: 0.05 mm (0.0019 in.)

Small-end bore
21.003 - 21.011 mm (0.82689 - 0.83720 in.)

Piston pin outside diameter
20.994 - 21.000 mm (0.82654 - 0.82677 in.)

Diameter of piston pin hole in piston
21.007 - 21.013 mm (0.82705 - 0.82728 in.)





Connecting Rod
Big-end side clearance
Check big-end side clearance of connecting rod, with rod fitted and connected to its crankshaft pin in the normal manner.
Replace connecting rod if measured clearance exceeds standard value.

Big-end side clearance
Standard: 0.25 - 0.40 mm (0.0098 - 0.0157 in.)





Connecting rod alignment
Mount connecting rod on aligner to check for bow and twist.
Replace it if measured value exceeds the limit.

Connecting rod alignment
Limit on bow: 0.05 mm (0.0019 in.)
Limit on twist: 0.10 mm (0.0039 in.)





Connecting rod bolt deformation
Use micrometer (3) to measure each thread, diameter of connecting rod bolt (1) "A" at "a" and "B" at "b".
Calculate difference in diameters ("A" - "B").
Replace connected rod bolt if it exceeds limit.

Connecting rod bolt measurement points
"a": 28.5 mm (1.12 in.)
"b": 42.0 mm (1.65 in.)

Connecting rod bolt diameter difference
Limit ("A" - "B"): 0.05 mm (0.0019 in.)