Important: The powdered metal connecting rod and cap are machined for the proper clearance.
The connecting rod and cap must be used as an assembly with no repair or modifications
to either mating surface.
- Do not attempt to repair the connecting rod or the cap mating surfaces. If service
is required, the connecting rod and cap must be replaced as an assembly.
Notice: Do not damage the piston's aluminum surfaces during cleaning.
- Clean the piston:
| 2.1. | Using a gasket scraper, remove the carbon from the piston top. |
| 2.2. | Using a soft brush and solvent, thoroughly clean the piston. |
| 2.3. | Using a groove cleaning tool or broken ring, clean the ring grooves. |
- Inspect piston diameter and oil clearance:
- Using a micrometer, measure the piston diameter at a right angle to the
piston pin hole center line, 7 mm (0.27 in) from the bottom of the
piston.
Standard Piston Diameter
Standard: 81.966-81.992 mm (3.227-3.228 in)
- Measure the cylinder bore diameter using a SA9178NE-A
or equivalent at 2 axis, transverse and longitudinal, 63.5 mm (2 1/2 in)
from top of block. Average the 2 measurements together for determining correct cylinder
bore size and piston fit. Subtract the piston diameter measurement, measured at 5 mm
(0.2 in) from the bottom of the piston, from the cylinder bore diameter measurement.
Cylinder No. 2 and 3
| • | Standard: 0-0.044 mm (0-0.0017 in) |
| • | Service Limit: 0.07 mm (0.0028 in) max. |
Cylinder No. 1 and 4
| • | Standard: 0.008-0.054 mm (0.0003-0.0021 in) |
| • | Service Limit: 0.07 mm (0.0028 in) max. |
| • | If the clearance is greater than maximum, replace the piston. If necessary,
hone or bore each cylinder required and replace the piston. If necessary, replace
the cylinder block. |
- Inspect clearance between flank of piston ring groove and new piston ring.
Using a SA91101NE
or equivalent,
measure side clearance between new piston ring and the flank of the piston ring groove.
Ring Groove Clearance
| • | Standard: 0.04-0.07 mm (0.0016-0.0028 in) |
| • | Service Limit: 0.09 mm (0.0035 in) max. |
No. 2 Ring
| • | Standard: 0.03-0.08 mm (0.0012-0.0031 in) |
| • | Service Limit: 0.08 mm (0.0031 in) max. |
| • | If the clearance is not within specification, replace the piston and rings. |
- Inspect piston ring end gap:
| 7.1. | Insert the piston ring into the cylinder bore. |
| 7.2. | Using a piston, push the piston ring a little beyond the bottom of the
ring travel (100 mm (3.94 in)) from the top surface of the cylinder
sleeve or block. |
| 7.3. | Using a SA91101NE
or equivalent,
measure the end gap. |
Standard End Gap -- No. 1 Ring
| • | Standard: 0.18-0.33 mm (0.0071-0.013 in) |
| • | Service Limit: 0.45 mm (0.0177 in) max. |
No. 2 Ring
| • | Standard: 0.35-0.55 mm (0.0138-0.0216 in) |
| • | Service Limit: 0.65 mm (0.0256 in) max. |
Oil Ring (Side Rail)
| • | Standard: 0.1-0.5 mm (0.0039-0.0197 in) |
| • | Service Limit: 0.65 mm (0.0256 in) max. |
| • | If the gap is greater than maximum, replace the piston ring. |
- Check piston pin bore diameter and pin diameter.
Pin Diameter
| • | Standard: 19.496-19.5 mm (0.7676-0.7677 in) |
| • | Service Limit: 19.488 mm (0.7678 in) min. |
Piston Pin Bore Diameter
| • | Standard: 19.502-19.507 mm (0.7678-0.768 in) |
| • | Service Limit: 19.51 mm (0.7686 in) max. |
Oil Clearance
| • | Standard: 0.002-0.011 mm (0.0001-0.0004 in) |
| • | Service Limit: 0.015 mm (0.0005 in) max. |
| • | Oil the pin and push it into the piston with your thumb. The pin must rotate
freely when centered in the piston pin bore. |
- Check connecting rod bushing and large end diameters:
Rod Bushing Diameter
| • | Standard: 19.42-19.506 mm (0.7670-0.7685 in) |
| • | Service Limit: 19.526 mm (0.769 in) max. |
Large End Bore Diameter
| • | Standard: 50.193-50.207 mm (1.9761-1.9767 in) |
| • | Service Limit: 50.207 mm (1.9767 in) max. |
- Inspect connecting rods:
| 10.1. | Using a rod aligner, check the connecting rod alignment. Check for bend. |
Maximum bend per 100 mm (3.94 in)
0.28 mm (0.011 in) max
| | Important: When replacing the connecting rod, always replace the bearings.
|
| 10.1. | If bend is greater than maximum, replace the connecting rod assembly. |
Maximum twist per 100 mm (3.94 in)
0.32 mm (0.0126 in) max
If twist is greater than maximum, replace the connecting rod assembly.
