• Bearings


Simplex-Turbulo is one of the largest stockists of 4 stroke engine bearings including undersized bearings. The bearings are manufactured by leading suppliers to the engine builders. Further information regarding our component manufacturers can be provided on request.

The types of bearings in stock are:

Large end/big end/conrod bearings • main bearings • thrust bearings • thrust washers • thrust segments • camshaft bearings • camshaft bushes • camshaft thrust washers • end shield bearings • piston pin/gudgeon pin bushes • spherical bearing • bearing bushes.

We hold stock of bearings (including undersizes) which are suitable for the following engine types:

Allen • Bergen • Daihatsu PS26 • Dorman • MaK 453, 551/552 • Mirrlees E Series • Mirrlees K Series • Nohab Polar • Perkins 4000 • Pielstick • Ruston • Stork TM410 • Sulzer Z • Wärtsilä 20, 32, 46 • Yanmar.

Parts suitable for other engine types are available on longer lead times.

Bearings are one of the most critical components in the engine and their quality is paramount. Simplex recommends that only bearings from the leading bearing manufacturers are fitted and that all bearings are stamped with the original bearing manufacturer’s logo.

Problems with high load capacity bearings and difficulties with bearing corrosion resistance

Bearing materials inevitably involve a compromise between different characteristics.  Bearings with high load capacity frequently have low corrosion resistance.  Likewise high load capacity can lead to poor adaptability.  Whereas high corrosion resistance and high adaptability can lead to poor load capacity.  The main problem recently for bearing manufacturers has been to find a material which can match the load requirements of the new generation of diesel engines whilst at the same time providing sufficient corrosion resistance for Heavy Fuel and Gas applications.  The standard SnSb7 overlay which has very high corrosion resistance and which has been used successfully for many years for these applications has now reached the limits of its fatigue strength.  The Rillenlager, which are made with the same overlay material, have lower corrosion resistance and poor adaptability. They are also more expensive to manufacture. Consequently all three leading manufacturers have been developing new materials to meet the higher performance being demanded by the new generation of engines.

Bearing failure

Bearing failure is a sensitive area as it nearly always involves major damage and the evidence which would establish the cause of the damage may well have been destroyed due to the severity of the damage. When this is combined with the temptation for the crew / operators to try to cover up any error which they may have committed, it is clear why there is often so much uncertainty regarding causality. Nevertheless, provided the bearings are sourced from one of the leading bearing manufacturers, whilst manufacturing errors can never be ruled out, the probability is that the cause of the failure lies elsewhere. In our experience the most common causes of failure relate to:

  • a lack of cleanliness when rebuilding the engine allowing foreign matter to enter the lube oil system,
  • failure to maintain the filtration system properly,
  • incorrect lube oil temperatures as the oil enters the separator,
  • operating the engine / lube oil outside the recommended maintenance periods,
  • overloading the engine, crankpin pin ovality etc.

In the event of bearing failure Simplex can help to identify the cause and at the same time can supply the necessary undersized bearings.  Simplex also works closely with companies which specialise in grinding the pins to the next undersize.

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