Connecting Rod: Testing and Inspection

Connecting Rod Bend And Torsion:

BEND AND TORSION
Bend:
Limit 0.15 mm (0.0059 in)
per 100 mm (3.94 in) length

Torsion:
Limit 0.30 mm (0.0118 in)
per 100 mm (3.94 in) length

If it exceeds the limit, replace connecting rod assembly.

CONNECTING ROD BEARING (Big end)

Method A (Using micrometer)

1. Install connecting rod bearing to connecting rod and cap.

2. Install connecting rod cap to connecting rod.
Tighten bolts to: 14 to 16 N-m (10 to 12 ft.lb.)

Then tighten bolts 60 to 65 degrees clockwise with an angle wrench, or if an angle wrench is not available, tighten them to: 38 to 44 N-m (28 to 33 ft.lb.)

Inner Diameter - Connecting Rod:

3. Measure inner diameter "C" of each bearing.

Measuring Connecting Rod Journal:

4. Measure outer diameter "Dp" of each crankshaft pin journal.
5. Calculate connecting rod bearing clearance.
Connecting rod bearing clearance = C - Dp
Standard: 0.010 - 0.035 mm (0.0004 - 0.0014 in)
Limit: 0.09 mm (0.0035 in)

6. If it exceeds the limit, replace bearing.
7. If clearance cannot be adjusted within the standard of any bearing, grind crankshaft journal and use undersized bearing.

Connecting Rod Bearing Grade Numbers:

8. If crankshaft is replaced with a new one, select connecting rod bearing according to the Specifications for Connecting Rod.

Method B (Using plastigage)

Using Plastiguage For Rod Clearance:

CAUTION: Do not turn crankshaft or connecting rod while plastigage is being inserted.

1. Use plastigage according to directions on package.
2. When bearing clearance exceeds the specified limit, ensure that the proper bearing has been installed. Then, if excessive bearing clearance exists, use a thicker main bearing or undersized bearing so that the specified bearing clearance is obtained.

CONNECTING ROD BUSHING CLEARANCE (Small end)

Connecting Rod Bushing Clearance:

1. Measure inner diameter "C" of bushing.

Connecting Rod Bushing Diameter:

2. Measure outer diameter "Dp" of piston pin.
3. Calculate connecting rod bearing clearance (C - Dp).
Standard: 0.005 - 0.017 mm (0.0002 - 0.0007 in)
Limit: 0.023 mm (0.0009 In)

4. If it exceeds the limit, replace connecting rod assembly and/or piston pin.

CONNECTING ROD SIDE CLEARANCE

Connecting Rod Side Clearance:

1. Measure connecting rod side clearance with connecting rods installed on crankshaft, as shown.
Connecting rod side clearance:
Standard: 0.2 - 0.4 mm (0.008 - 0.016 in)
Limit: 0.6 mm (0.024 in)