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Main & Generator Engine Parts

Even the defective of one small machinery part possibly causes a problem and affects navigation.
Therefore, it is essential to select high quality parts even though they rather cost.
We offer following parts which have longer operating life and high quality.

Piston Ring

Piston Ring

Piston & Cylinder Liner

Piston & Cylinder Liner
Cylinder liner
For cylinder liner, pressure die casting or centrifugal casting is desirable way to increase density and avoid getting porosity.
Recently, special alloy material is required for low quality fuel.
Piston crown
Piston crowns are made of forged steel, cast steel or cast iron depending on their size and cooling system. For smaller engines, there are piston crowns that are chromed on top ring groove due to usage of low-grade fuel oil.
Please refer to the following concerning the repair of ring groove.
  1. Ring groove is often worn out undulately. Therefore, it machined to be even.(A)
  2. Usually, edges get worn out more, which also needs to be rebuilt & machined.(B)
  3. After these two processes mentioned above, there are two methods to repair, either replacing piston rings to oversized ones, or restoring ring groove to original size by chrome plating or welding for re-building.

    In general, when attrition is small, it is better chroming method than applying heat.
piston crown image

Valves & Seats

Valves & Seats

Heat-resisting steel "Grade-3 (austenitic)" and Heat-resisting steel "Grade-4 (ferritic) " are the standard material for exhaust valve stem.
In general, Grade-3 is used for 4-stroke smaller engine and Grade-4 is used for 2-stroke bigger engine.
Grade-4 is particularly outstanding in its hardness and tension.
However, knowledge and skill are required while repairing because it can get crack more easily and has less flexible workability.
Exhaust valve stem is basically made of a combination of

SUH3 + STELLITE (NO.6) & (NO.12), and also chromed on stem part because of corrosion countermeasure against low-grade fuel oil.

Recently, it is getting more popular for a better material of countermeasure against low-grade fuel oil to use "Nimonic" partially or thoroughly.

Crank pin bolt

Crank pin bolt

Crank pin bolt is one of the parts, which is required strength and tenacity, thus, forged part should be used for the material.
The most important thing is that it must not be stretched while being used even though it has to have tenacity.
In addition, the thread part is better made by component rolling than lathe machining for safety reason.


Bearing metal
The major way in metals is three-layer metal, which is given as follows.
  1. S10C (base material) + LBC + WJ + Overlay
  2. S10C (base material) + LBC + KJ + Overlay
  3. S10C (base material) + AL + Overlay
2) and 3) are used for high load of high-power engines. (HIGH-P-MAX)

Turbo Charger

Turbo Charger
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