INSPECTION OF A CROSSHEAD BEARING (CSM SURVEY)

1. Preparation and safety: Stop the engine, secure the turning gear, drain the lubricating oil, isolate pressurised sources, and obtain the maker's manual. Prepare a work/risk assessment and tooling, and lift the unit to give access to the crosshead pin.
2. Lift the piston and crosshead: Remove the cylinder cover and lift the piston (with rod) clear to expose the crosshead bearing (inside the crosshead, under the piston rod clamp). Support the piston.
3. Clean the bearing: Drain the oil; clean the bearing cap, shells and the crosshead pin with a clean cloth/ solvent and inspect.
4. Visual inspection: Examine the white-metal surfaces for cracks, pitting, wiping, scuffing, scoring, overheating (discoloration) and looseness of the white metal from the shell (detect by tapping). Check the shell seating, dowels/ locating lugs and the bolt/ stud condition.
5. Measurement of clearances: Measure the bearing clearance (diametral) using a feeler gauge at the parting faces, or the maker's clearance gauge/ plastigage/ lead-wire method, and record against the specified limits.
6. Check bolt torque and stretch: Confirm the bearing bolts are at the maker's torque and measure bolt stretch/ elongation as applicable.
7. Inspect the crosshead pin and its fillets: Check for scoring, pitting and cracks (dye-penetrant or magnetic particle check on the fillet radius); measure the journal diameter for wear/ out-of-round.
8. Inspect the oil ways and feed holes: Ensure the crosshead pin oil holes and the bearing supply drillings are clear and clean.
9. Check the bearing shells alignment to the pin by bluing/ contact marking.
10. Record all readings and findings on the survey/overhaul sheet for trend comparison.

• Isolate and secure the barring gear; tag the engine not-to-run.
• Use correct lifting gear and properly sling the piston/crosshead; secure against swinging.
• Keep the working area clean, dry and well lit; observe oil/ chemical hygiene.
• Protect precision surfaces (pin, shell, filter faces) from damage and contamination.
• Handle the white-metal shells carefully - they are soft and easily damaged.
• Never re-use damaged or distorted bolts; use genuine spares and correct tooling.
• Use the correct torque wrench setting and sequence; check bolt stretch.
• Keep fuel/ oil away from heat or ignition sources, and use the correct PPE.

• Overheating/ wiping of white metal: from oil starvation, excessive clearance, overloading, or misalignment. Rectify: renew the shell, correct clearance/supply.
• Cracking/ sinking of white metal: fatigue from cyclic loading and/or poor shell seating. Rectify: renew shell, check seating.
• Scoring/galling: from contamination (dirt, abrasive), oil starvation, or misalignment. Rectify: clean system, renew shell, check oil filter and clearance.
• Pitting: from water/ acid in the oil or cavitation. Rectify: address oil condition, renew shell.
• Loose shells (shell not seating/ hammering): from incorrect clearances, fretting of the shell back or damaged locating lugs. Rectify: renew shell, repair lugs.
• Excessive clearance: from normal wear. Rectify: renew/stim shims to restore the clearance range.
• Seizure of bearing: from severe oil failure; engine may have suffered consequential damage - renew bearing and fully investigate.

• Confirm the bearing clearance is to specification (feeler/plastigage) and record.
• Torque the bolts to specification and check bolt stretch.
• Carry out an oil-flow/ priming check: turn on the lubricating oil, allowing oil to reach the crosshead bearing and confirm oil is discharged from the feeds.
• Bar the engine several revolutions by turning gear to confirm free rotation and no tight spots or binding.
• Re-run the engine at low rpm initially and check for abnormal noise, temperature rise of the bearing, and oil pressure/temperature.
• Perform a full power run and monitor bearing temperature and vibration; confirm no excessive heating.
• Verify the securing/locking of all bolts and oil connections.