Connecting Rod

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Replace the connecting rod, if the large or small end thrust surface is damaged.
Check for bend or twist using a connecting rod aligner. Replace the connecting rod if it has the bend or twist.

Fig 1: Checking Connecting Rod Bend
Courtesy of SUBARU OF AMERICA, INC.
Install the connecting rod fitted with bearing to crankshaft and measure the side clearance (thrust clearance). If side clearance exceeds the limit or offset wearing is emitted, replace the connecting rod.
Connecting rod side clearance:

Standard

0.070 - 0.330 mm (0.0028 - 0.0130 in)

Fig 2: Measuring Connecting Rod Side Clearance
Courtesy of SUBARU OF AMERICA, INC.
Inspect the connecting rod bearing for scar, peeling, seizure, melting, wear, etc.

Measure the oil clearance on individual connecting rod bearings by means of plastigauge. If any oil clearance is not within the specification, replace the defective bearing with a new one of standard size or undersize as necessary. (See CONNECTING ROD BEARING SPECIFICATIONS .)

Connecting rod oil clearance:

Standard

0.016 - 0.043 mm (0.0006 - 0.0017 in)

CONNECTING ROD BEARING SPECIFICATIONS

Unit: mm (in)
Bearings	Bearing size (Thickness at center)	Outer diameter of crank pin
Standard	1.490 - 1.506 (0.0587 - 0.0593)	51.984 - 52.000 (2.0466 - 2.0472)
0.03 (0.0012) undersize	1.509 - 1.513 (0.0594 - 0.0596)	51.954 - 51.970 (2.0454 - 2.0461)
0.05 (0.0020) undersize	1.519 - 1.523 (0.0598 - 0.0600)	51.934 - 51.950 (2.0446 - 2.0453)
0.25 (0.0098) undersize	1.619 - 1.623 (0.0637 - 0.0639)	51.734 - 51.750 (2.0368 - 2.0374)

Inspect the bushing at connecting rod small end, and replace if worn or damaged. Also measure the piston pin clearance at the connecting rod small end.
Clearance between piston pin and bushing:

Standard

0 - 0.022 mm (0 - 0.0009 in)

Fig 3: Measuring Piston Pin Clearance At Connecting Rod Small End
Courtesy of SUBARU OF AMERICA, INC.

Fig 4: Measuring Bushing Diameter
Courtesy of SUBARU OF AMERICA, INC.
Replacement procedure is as follows.
1. Remove the bushing from connecting rod with ST and press.
2. Press the bushing with ST after applying oil on the periphery of bushing.
  ST 18350AA000 CONNECTING ROD BUSHING REMOVER AND INSTALLER
  
  Fig 5: Pressing Bushing Using Connecting Rod Bushing Remover And Installer ST 18350AA000
  Courtesy of SUBARU OF AMERICA, INC.
3. Make two 3 mm (0.12 in) holes in bushing. Ream the inside of bushing.
4. After completion of reaming, clean the bushing to remove chips.