Piston, Pin, and Piston Rings
- NOTE:
- Replace pistons, pins, and connecting rods that are damaged or show signs of excessive wear.
- The piston and pin are to be serviced as an assembly.
- Do not wire brush any part of the piston.
- Measurement of the components should be taken with the components at normal room temperature.
Clean the varnish and carbon from the piston (107) using cleaning solvent.
- Dry the components with compressed air.
Clean the piston ring grooves with a suitable ring groove cleaning tool.
- Clean the oil lubrication holes and slots.
Inspect the piston for the following conditions:
- Cracks in the piston ring lands, the piston skirt, or pin bosses
- Piston ring grooves for nicks, burrs, or warpage which may cause the piston ring to bind
MINOR imperfections may be removed from the piston with a fine file.
- Eroded areas at the top of the piston (1)
- Scuffed or damaged skirts (2)
- Scoring to the piston pin bore (3) or piston pin
Insert the edge of the piston ring into the piston ring groove.
Roll the piston ring completely around the piston. If binding is caused by a distorted ring groove, MINOR imperfections may be removed with a fine file. If binding is caused by a distorted piston ring, replace the rings, as required.
Measure the piston ring side clearance with a feeler gauge. If side clearance is not within specifications, try another piston ring. If the proper ring-to-groove clearance cannot be obtained, replace the piston and pin as an assembly. Refer to Engine Mechanical Specifications (LV1) .
To determine piston pin-to-bore clearance, use a micrometer and measure the piston pin outside diameter (OD).
To determine the piston pin-to-bore clearance, use an inside micrometer and measure the piston pin bore inside diameter (ID).
- Subtract the piston pin OD measurement from the piston pin bore ID measurement to determine pin-to-bore clearance. Refer to Engine Mechanical Specifications (LV1) .
Refer to Safety Glasses Warning .