Orlando

Piston, Connecting Rod, and Bearing Cleaning and Inspection

Connecting Rod

Warning: Refer to Safety Glasses and Compressed Air Warning in the Preface section.




1. Clean the connecting rods (1) in solvent and dry with compressed air.
2. Inspect the connecting rods for the following:

•	Signs of being twisted, bent, nicked, or cracked

•	Scratches or abrasion on the rod bearing seating surface

3. If the beam of the rod is scratched or has other damage replace the connecting rod.
4. If there is still excessive clearance, replace the connecting rod.

Piston

1. Clean the piston skirts and the pins with a cleaning solvent. DO NOT wire brush any part of the piston.
2. Clean the piston ring grooves with a groove cleaner. Ensure that the oil ring holes and slots are clean.
3. Inspect the pistons for the following conditions:

•	Cracked ring lands, skirts, or pin bosses.

•	Ring grooves for nicks, burrs that may cause binding.

•	Eroded areas at the top of the piston (1).

•	Scuffed or damaged skirts (2).

•	Worn piston pin bores (3).

4. If there is any excessive wear, replace the piston.

Piston Pin to Connecting Rod Bore and Piston Bore Clearance

1. Measure clearance between piston pin and connecting rod bore. Use the following procedure:
2. Measure the piston pin outside diameter.
3. Measure the connecting rod bore diameter.
4. Subtract the piston ring diameter from the connecting rod diameter.

Refer to Engine Mechanical Specifications .

Piston Ring Clearance

1. Install the piston rings to the cylinder as shown (1) and measure the piston ring end gap. Compare the measurements with the Engine Mechanical Specifications .
2. If the clearance is greater than the provided specifications, the piston rings must be replaced.



3. Measure the piston ring side clearance as shown (1). Compare the measurements with the Engine Mechanical Specifications .
4. If the clearance is greater than the provided specifications, replace the piston rings.
5. If the clearance is still to great, replace the pistons.

Connecting Rod Bearing Clearance

1. Inspect the connecting rod end play and refer to Engine Mechanical Specifications .
2. Measure the piston pin to connecting rod bore using the following procedure:

2.1.	Using an outside micrometer, take 2 measurements of the piston pin in the area of the connecting rod contact.

2.2.	Using an inside micrometer, measure the connecting rod piston pin bore (2).

2.3.	Subtract the piston pin diameter from the piston pin bore diameter.

3. Compare the measurements with the Engine Mechanical Specifications .
4. If there is excessive clearance, replace the gudgeon pin.



5. Inspect the connecting rod end play (1).
6. Compare the measurements with the Engine Mechanical Specifications .