Optimise your ZA40S engine to operate on LFO

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Wärtsilä ZA40S LFO Conversion Package

IMO 2020 rules have established a sulphur cap – but for vessels where installing large, heavy scrubbers doesn’t make sense operating on low-sulphur fuels is a viable alternative. 

The Wärtsilä ZA40S LFO Conversion Package increases the reliability of the engine’s injection system and cylinder cover, reduces specific fuel oil consumption (SFOC) and extends the time between overhauls by modifying the engine to permanently operate on LFO.

For more information about the upgrade, fill in the contact form and our sales will get in touch with you.

Key benefits

  • Reduce SFOC
  • Reduce OPEX
  • Increase reliability

    Technical info

    The upgrade package includes modification of the cylinder cover valve configuration, installation of a new injection plunger and barrel, and the addition of a fuel cooling system.

    The new valves, materials and rotating mechanism have been designed based on years of data gathered from the field, and the injection pump has been thoroughly tested in Wärtsilä’s Validation Centre.


    Reduce SFOC

    After the upgrade the minimum expected SFOC reduction is 1.6 g/kWh in the 85% load range. Expected savings for different load ranges can be checked from the table below.

    Engine Power (%)





    Minimum fuel saving measured on test engine (g/kWh)






    Reduce OPEX

    The upgrade allows the time between overhauls to be extended from 12,000 to 18,000 running hours, reducing operating costs over the lifetime of the equipment and increasing engine availability.

    Increase reliability

    The fuel cooling system included in the conversion package increases reliability by reducing the risk of injection pump seizure with a new and thoroughly tested design.




    To secure the best possible return on investment, the upgrade should be performed when the vessel’s engine is next scheduled for maintenance, but it can also be performed separately. It is suitable for engines running on low-sulphur fuels within the viscosity range 2-10 cSt.

    Please contact your Wärtsilä representative for more details about fuel compatibility.

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