CHECKS/ EXAMINATIONS WHEN A CROSSHEAD BEARING OF A LARGE SLOW-SPEED ENGINE IS OPENED UP FOR SURVEY

As second engineer, the following checks/ examinations are carried out:

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. 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.
11. On completion, confirm the clearance is to specification, torque the bolts, prime the oil supply, bar the engine, and run at low load checking temperature/ vibration.