Page 74: of Maritime Reporter Magazine (November 2005)

• Valves (measure guides; process seatings; grind, inspect and lap spindles) Injection nozzles (exchange nozzle elements and seals) Pistons (remove, dismantle, clean; inspect crown and skirt; measure rings and grooves) Cylinder liners (inspection and fit replacement calibration ring) Connecting rod bearings (inspec- tion with routine replacement) Main bearings (inspection with rou- tine replacement) Camshaft (inspection of bearings and cam follower) Turbocharger (inspection of com- ponents and bearings)

According to the engine manufacturer, the good condition of the M43 was evi- dent during the dismantling of the cylin- der heads. All the seals were satisfacto- ry, the bottom surface of the cylinder head was only slightly dirty, and the whole of the upper valve drive and the valve guides were within the permissi- ble tolerances. The slightly dirty inlet valve spindles or slightly to moderately dirty exhaust valve spindles exhibited a satisfactory condition after cleaning, and the seating surfaces themselves were completely intact. There was minimum high temperature corrosion on the lower surface of the exhaust valve, and the expected valve life of 30,000 hours was, in consequence, reliably achieved. "In view of the exclusive operation on heavy oil (IFO 180) of the Anke Ehler, the small amount of valve pollution was impressive confirmation of the ability of the M 43 to burn even poor fuel satis- factorily," said Sikorski. "In the combus- tion bowl of the piston crowns, there was a marked and clearly limited injec- tion pattern.

Piston rings and piston skirt were clean and without irregularities. There was no wear of any type on the chromi- um layer of the piston rings and the wear of the ring grooves was less than 0.01 millimeters per 1,000 operating hours."

As a check, MaK Deutschland also removed and assessed one of the cylin- der liners. No traces of rust or relative motions between the support surface and the engine block could be recog- nized.

The calibration ring prevented the feared coke rubbing; it was replaced in accordance with the maintenance plan.

The original honing structure were still present over the whole of the liner region and, in the upper region, the wear rate was again less than 0.01 mm per 1,000 operating hours.

The inspection results for the connect- ing rod bearings and main bearings can be briefly summarized - very good con- dition of the running surfaces, uniform running pattern, no cavitation phenome- na, no findings with respect to the con- tact patterns on the back of the bearings.

Nevertheless, replacements were, of course, fitted for all the bearings, in accordance with the maintenance speci- fication, after 30,000 operating hours.

The camshaft also exhibited markedly stable running patterns - which were not apparent to the touch - on the rollers and cams. The rollers, bushes and pins of a cam follower drive, dismantled as a sample, exhibited no irregularities. "In the case of heavy oil operation, combustion residues must be regularly cleaned from the turbocharger; the cleaning method used for this purpose substantially determines its life,"

Sikorski emphasizes. "From a total of 28,470 engine hours of the Anke Ehler, cleaning by thermal shock is recorded for 11,500 operating hours and by low- load washing for 16,970 operating hours. Under these circumstances, the incipient cracks on the trailing edges of the nozzle vanes and the slight erosion traces on the nozzle ring and the turbine diffuser were within the tolerance limits.

Whereas the thrust bearing on the tur- bocharger could be reused because of its satisfactory condition, we have, as a pre- caution, fitted replacements for the jour- nal bearings because of slight wear traces and slight grooves."

For Sikorski, the results of the 30,000 operating hour overhaul on the Anke 74 Maritime Reporter & Engineering News

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Propulsion Update

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