Makers Service Letters

The paper describes the MAN HyProp ECO concept and application examples with various operating modes. For vessels with flexible operation profiles and running hours with both high and low power demands, advantages are fuel savings and emission reductions due to reduced propeller and engine speeds.

The MAN B&W LGIM engine is the methanol-burn-ing version of our dual-fuel solution for liquid injection of fuels, the ME-LGI engine. This paper describes the service experience from the two generations of ME-LGIM engines, which have accumulated almost 90,000 running hours in total. In the further development of the LGIM engine, a methanol-and-water blending concept has been introduced to the LGIM-W engine, which has passed Tier III compliance tests.

One of the future fuel candidates receiving a growing global interest and likely to play a significant role in the decarbonisation is ammonia (NH3). Our aim with this paper is to share our current knowledge about ammonia as a potential long-term fuel for two-stroke marine engines and to give a new update on the development of an ammonia-based propulsion

Issue 009 2021-03. (This document must be read and used in conjunction with the WinGD document “Lubricants” Link)

This Service Letter lists major international cylinder and system oil brands available in the market. For guidelines on how to use the cylinder and system oils, please refer to the most recent lubrication guideline available for your specific engine type, e.g. Service Letters and Circular Letters.

Service Letters are available on: www.marine.man-es.com/two-stroke/service-lettersFor questions and inquiries regarding the content in this letter, contact our Operation department at: This email address is being protected from spambots. You need JavaScript enabled to view it.

This Service Letter defines the overhaul criteria for cermet-coated piston rings, and it provides guidance on how to estimate the remaining lifetime of a cermet-coated piston ring based on the remaining coating thickness. Cermet-coated piston rings were introduced as a scuffing preventive countermeasure.

Update of the instruction for piston clean-ing ring Replacement of SL2016-620/AAB

It has come to our attention that misunderstandings have occured re-garding piston cleaning ring (PC ring) replacement when a liner is worn.

The “wide seat” bore-cooled bottom piece design was introduced in response to the steadily raised temperature level of combustion chamber components aiming at energy efficiency and compliance with emission regulations.

Based on the latest service experience and engine development we are pleased to issue a revised version of the guiding overhaul inter-vals tables. The guiding overhaul intervals apply to electronically con-trolled ME and dual fuel type engines.

Adjusting the ACC factor in service.
For engines where the feed rate ACC factor has already been established and confirmed, new cylinder oils with a different BN level can be used to change the feed rate ACC factor by multiplying the present feed rate ACC factor by the fraction of the BN in the present and the new cylinder oil. Afterwards, the new setting has to be confirmed, either by a feed rate sweep and/or a conventional drip oil analysis.

Important routines that should be observed when overhauling a unit equipped with a PC ring are highlighted in the following.
A) In principle the PC ring remains (unchanged) together with the liner for the entire lifetime until replacement of the liner or PC ring due to wear of one of these above the standard wear acceptance criteria.

The owners of engines operated on VLSFO and ULSFO may face certain challenges with scuffing between the cylinder liner and piston rings. Operation on gas or other low-flashpoint fuels containing no sulphur gives challenges similar to those faced when operating on ULSFO in a SECA or on 0.5% S fuel. Prolonged operation on these fuels may lead to bore polished liner surfaces with a subsequent risk of liner scuffing as the consequence.

This letter was written to inform our customers of operation guidance for HiMSEN Engine to comply with IMO MARPOL ANNEX Ⅵ Reg.14.8 which is to come into force as of 1 January,2020 and the regulation of the SECAs.

All following service letters provides operational guidelines when operating on max 0.50% sulphur fuel.

In Service Letter SL2019-671 it is stated for the JBB and the load dependent cylinder liner (LDCL) cooling water system that closing down the LDCL system and deactivating any JBB system is recommended when using up to 0.50% S VLSFO.

Our guidelines on cylinder lubrication of MAN B&W low speed engines have called for an update in response to the below development:
recent changes in operational patterns towards lower-load operation development of new cylinder oils aiming at being better able to cater for a larger variation of fuel oil sulphur contents the general development of engines towards larger stroke-to-bore ratios and changed process parameters triggered by environmental compliance rules.

This paper provides information and guidance on 0.50% S fuel operation and how to prepare for the change from operation on high-sulphur fuel to 0.50% S fuel. Attention is drawn to specific fuel properties that should be in focus and how 0.50% S fuels affect the equipment on board. Expectations for the new types of fuels are given, and information on biofuels, fuel testing, and fuels that are not fit for purpose is also included.

This Service Letter was written to inform our customers of exhaust gas back pressure for HiMSEN engines with regard to SOx Scrubber installation in order to comply with IMO MARPOL ANNEX VI Reg.14.8 which is to come into force as of 1st January 2020.
Basically, there is no influence when the back pressure is below than 300mmWC for all HiMSEN engine as the engine has been originally designed for maximum allowable back pressure of 300mmWC. In case that the back pressure is increased over the allowable limit due to installation of scrubber, generally increased back pressure causes the deterioration of engine performance.

Updated instruction for indicator valves. By following precautionary measures and actions as recommended by MAN Diesel & Turbo increased safety and reliability
can be achieved.