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| Illustration 1 | g00368854 |
Typical example | |
Note: Refer to Guideline for Reusable Parts for information on the pistons, the piston pins, and the retaining rings.
Top Piston Ring
The 1U-6431 Piston Ring Groove Gauge is used for measuring the ring grooves in keystone style pistons. Refer to the Special Instruction that is supplied with the Piston Ring Groove Gauge .
(1) Top piston ring
Install the piston ring with "UP-1" mark toward the top of the piston.
There is a clearance between the ends of the piston ring. When the piston ring is installed in a cylinder liner with a bore of 137.16 mm (5.400 inch), the clearance is the following value. ... 0.724 ± 0.190 mm (.0285 ± .0075 inch)
There is an increase in the clearance between the ends of the piston rings for each 0.03 mm (.0012 inch) increase in the cylinder liner bore. Increase ... 0.08 mm (.003 inch)
Intermediate Piston Ring
The 1U-6431 Piston Ring Groove Gauge is used for measuring the ring grooves in keystone style pistons. Refer to the Special Instruction that is supplied with the Piston Ring Groove Gauge .
(1) Intermediate piston ring
Install the piston ring with "UP-1" mark toward the top of the piston.
There is a clearance between the ends of the piston ring. When the piston ring is installed in a cylinder liner with a bore of 137.16 mm (5.400 inch), the clearance is the following value. ... 1.080 ± 0.190 mm (.0425 ± .0075 inch)
There is an increase in the clearance between the ends of the piston rings for each 0.03 mm (.0012 inch) increase in the cylinder liner bore. Increase ... 0.08 mm (.003 inch)
Oil Control Ring
Note: The engine has various horsepower ratings and ratios. The specifications for the oil control ring will vary because of the various horsepower ratings and ratios.
(3) The spring ends of the oil control ring should be assembled 180 degrees from the ring end gap.
The 5P-3519 Piston Ring Groove Gauge is available for checking the ring grooves with straight sides. Refer to the Guideline for Reusable Parts for instructions on using the Piston Ring Groove Gauge .
Width of groove in new piston for oil control ring
- 174-6102 Piston Body with 14.1 compression ratio ... 3.210 ± 0.010 mm (.1264 ± .0004 inch)
- 174-6103 Piston Body with 14.7 compression ratio ... 3.210 ± 0.010 mm (.1264 ± .0004 inch)
- 9Y-7212 Piston Body Assembly with 15.6 compression ratio ... 3.188 ± 0.013 mm (.1255 ± .0005 inch)
- 123-4612 Piston Crown Assembly ... 3.210 ± 0.010 mm (.1264 ± .0004 inch)
- 174-6103 Piston Body with 14.7 compression ratio ... 3.210 ± 0.010 mm (.1264 ± .0004 inch)
Thickness of new piston ring ... 3.137 ± 0.013 mm (.1235 ± .0005 inch)
Clearance between groove and new piston ring
- 174-6102 Piston Body ... 0.073 ± 0.025 mm (.0029 ± .0010 inch)
- 174-6103 Piston Body ... 0.073 ± 0.025 mm (.0029 ± .0010 inch)
- 9Y-7212 Piston Body Assembly ... 0.051 ± 0.025 mm (.0020 ± .0010 inch)
- 123-4612 Piston Crown Assembly ... 0.073 ± 0.025 mm (.0029 ± .0010 inch)
- 174-6103 Piston Body ... 0.073 ± 0.025 mm (.0029 ± .0010 inch)
Maximum permissible clearance of worn ring ... 0.15 mm (.006 inch)
There is a clearance between the ends of the piston ring. When the piston ring is installed in a cylinder liner with a bore of 137.16 mm (5.400 inch), the clearance is the following value. ... 0.572 ± 0.191 mm (.0225 ± .0075 inch)
There is an increase in the clearance between the ends of the piston rings for each 0.03 mm (.0012 inch) increase in the cylinder liner bore. Increase ... 0.08 mm (.003 inch)
Piston Pin Bore
(4) The piston pin has an elliptical pin bore. Measure the piston pin bore in a vertical direction only.
- 174-6102 Piston Body ... 50.895 ± 0.075 mm (2.0037 ± 0.0030 inch)
- 174-6103 Piston Body ... 50.895 ± 0.075 mm (2.0037 ± 0.0030 inch)
- 9Y-7212 Piston Body Assembly ... 50.815 ± 0.008 mm (2.0006 ± 0.0003 inch)
- 123-4612 Piston Crown Assembly ... 50.848 ± 0.008 mm (2.0019 ± .0003 inch)
- 174-6103 Piston Body ... 50.895 ± 0.075 mm (2.0037 ± 0.0030 inch)
Piston pin diameter ... 50.795 ± 0.005 mm (1.9998 ± .0002 inch)