- The scavenge space inspection provides careful information about the condition of cylinders, pistons and rings at low expense.
- The inspection consists of visually examining the piston, the rings and the lower part of the cylinder liner, directly through the scavenge air ports.
- To reduce the risk of scavenge box fire, remove any oil sludge and carbon deposits in scavenge air box and receiver in connection with the inspection.
- The port inspection should be carried out at the first stop after a long voyage, e.g. by anchoring if possible, to obtain the most reliable result with regard to the effectiveness and sufficiency of the cylinder lubrication and the combustion cycle.
- A misleading result may be obtained if the inspection is carried out after arrival at harbour, since during manoeuvring cylinders are excessively lubricated.
- Further during low load, combustion cycle might not be as effective due to the actual fuel oil qualities and running condition of the fuel injection equipment.
- Scavenge port inspections are best carried out by two men, the most experienced of whom inspects the surfaces, and states his observations to an assistant, who records them. The assistant also operates the turning gear.
- Keep the cooling water and cooling oil circulating, so that possible leakages can be detected.
- Block the starting air supply to the main starting valve and starting air distributor.
- Open the indicator valves. Engage the turning gear.
- Remove the inspection covers on the camshaft side of the cylinder frame, and clean the openings. Remove the cover(s) on the scavenge air receiver.
Note: Do not enter the scavenge air receiver before it has been thoroughly ventilated.
Begin the inspection at the cylinder whose piston is nearest BDC.
- Inspect the piston, rings, and cylinder Wall.
- Wipe the running surfaces clean with a rag to ensure correct assessment of the piston ring condition.
- Use a powerful lamp to obtain a true impression of the details.
- Keep the records to form a “log book’ of the cylinder condition.
- Measure the total clearance between the piston rings and the ring grooves,
- Continue the inspection at the next cylinder whose piston is nearest BDC, and so on according to the firing order. Note down the order of inspection for use at later inspections.
- Check the non-return valves (flap valves/ butterfly valves) in the auxiliary blower system for easy movement and possible damage.
- Remove any oil sludge and carbon deposits in the scavenge air boxes and receiver. Record the observations.