CMS carries out first ever major overhaul of twin WingGD X-DF engines

Maintenance of twin X-DF engines was carried out by team from CMS Korea

In an operation involving an LNG tanker anchored in the Sabine Pass, Texas, CSSC Marine Service Co (CMS) has completed the first ever major overhaul on two Winterthur Gas & Diesel (WinGD) X-DF engines in only nine days.

CSSC Marine Service Co (CMS) is the equipment service subsidiary of China State Shipbuilding Corp (CSSC), which owns WinGD.

The twin 6X62DF engines overhauled by CMS are those in the first X-DF powered vessel to enter operation, the 2017-built 180,000-cu.m, Panama-flagged LNG tanker, SK Audace, which is owned and operated by South Korea’s SK Shipping.

In the three years since vessel delivery, the X-DF engines installed in SK Audace had reached 18,000 operating hours, more than 99% of which were in gas operation and less than 1% in diesel operation, required for maneuvering. Therefore, scheduled maintenance was required to ensure continuous uninterrupted operation.

A team from CMS Korea completed the full maintenance of the two engines within nine days, and the ship returned to commercial service after a successful sea trial run. This was accomplished despite the limitations on travel, logistics, health, and safety working plans caused by COVID-19 restrictions.

Although work scopes were varied, CMS and WinGD collaborated to execute the job according to the standard manual for the engine type. Original spare parts such as piston rings and gas components were delivered to the vessel’s location by CMS.

During the overhauls, no abnormalities were found. Although the CMS Korea team was the first ever to perform maintenance on X-DF technology, it prepared work guidelines well which included the reservation of correct materials and real-time support from the WinGD design team.

The CMS Korea team reported that the 6X62DF engine parts were in incredibly good condition compared to engines historically overhauled by CMS that operate on heavy fuel oil (HFO).

Following the overhaul, the trial run of the engines was performed and optimized engine performance was calibrated. To ensure optimal engine operating standards through to the next periodic maintenance, the CMS Korea team conducted maintenance on common components such as pistons, exhaust valves, flow limiting valve were overhauled and fuel pump component replacements were made where necessary. Additionally, the overhaul included more complex gas components such as gas admission valves (GAV), pre-chamber replacements and gas valve units (GVU).

In total, ten X-DF engines in five vessels will be overhauled by CSSC Marine Service in the coming months. Results of the ongoing condition-based investigation on all five vessels will enable increased TBO (time between overhaul) or CBM (Condition based Maintenance) decisions, to be agreed between the shipowner and classification society.

“For customers who operate X-DF engines and have concerns about service accessibility, CMS is able to provide qualified service through our growing network,” says Andrew Stump, President CMS. “This is the first X-DF major engine overhaul completed and our team provided such a short turnaround time for a twin-engine installation. that truly proves what is possible. As the demand for our services grows, CMS will continue its expansion into more locations worldwide.

“The results recorded in the service reports have been investigated together with WinGD Product Managers in the Swiss headquarters, and we are all extremely happy with the condition and cleanliness of engine components, in particular compared to an engine of the same running hours operating on HFO. The results of investigation by WinGD will enable any design optimization necessary and extension of the time between overhauls where appropriate. Once we have comparative results from the sister vessels we will be able to confirm the success of the X-DF product as the most reliable and sustainable LNG main engine solution”

To-date, CMS has established three service hubs located in South Korea, Singapore and Hamburg. In addition to the service hubs and operates five service stations located in China (Qingdao, Gaungzhou, Chengxi and Shanghai), South Korea, Singapore, Hamburg and Switzerland. Partner service stations are also located in countries including Brazil, Turkey, Poland, South Africa, Oman, Qatar, Dubai, U.S., New Zealand and Greece.