SECO - Spare parts for MAN B&W, Himsen, MaK and Wärtsilä power plant and marine diesel engines
Experience report – Reduction of spare part costs through the use of our WearResist® piston crowns for MAN B&W marine diesel engines of the series MAN 27/38, MAN 32/40 and MAN 48/60
Today, in our globalized world of acquisition, obtaining spare parts for MAN B&W marine diesel engines or power plants, starting with the MAN 16/24 up to the MAN 48/60 is not a problem anymore. Just feeding the search engine with your actual requirements and in seconds an almost barely manageable range of different providers from around the world is obtained.
Starting with the engine manufacturers themselves, to the well-known and successfully established traders, the search engine also lists other supply sources as well in quick order. Scrap yards from India up to Asian online-traders are offering all of what is available. From an O-ring via the piston and up to the crankshaft everything that your heard desires is listed. Cheap and of course in the highest quality! ... That is, at least the assertion of these specialists. Conveniently, sometimes also pictures are provided together with the offered products. You all know these pictures: in a dark and untrustworthy looking warehouse there is a lost, half unpacked piston which is looking sadly to its observer. If you are lucky, and the resolution of the picture is high enough you can zoom into the piston pin bore... as it already looks strange without zoom.
Now the expert sees a piston pin bore in which the cutting tool apparently resigned during the finishing process. Massive and non overlookable chatter marks over the entire visible surface of the bore. By drifting the sarcasm a little further at this point, we could highlight one of the advantages of this high-quality “Alibaba-piston”: This piston does not need locking rings to keep the piston pin in position. Once lammed into the pin bore, the piston pin is fixed for eternity. In other words: unuseable trash.
Unfortunately, the Internet doesn’t make it always that simple for our customers to make their spare part purchase decisions. Foresight and patience are needed. Depending on the spare part it will take long until customers’ decisions can be proven as right or wrong....
But precisely this patience and foresight a customer should have when buying piston crowns. Only after a couple of years in engine operation our customers will get the conformation of what we have promised at the beginning:
A considerable reduction of spare parts costs by using our WearResist® piston crowns.
SECO has been producing and supplying piston crowns in WearResist® Quality, useable for operation in MAN B&W marine diesel engines,quality since 2009. Thus, long enough to prove that the lifetime of our piston crowns is much longer, compared with the piston crowns of our competitors.
A good example therefore are our WearResist® piston crowns for the MAN 27/38 engine. The wear limit for the 1st piston ring groove is specified by the engine manufacturer with 6,42 mm. Our former experience with this piston type shows that - depending on the plant conditions - the standard pistons that can be achieved on the market, usually reach this wear limit after 15.000h. Unsurprisingly cheap piston crowns - made in Asia - are exceeding the wear limit already at 10.000h.
Here an example of our daily business:
End of March 2016 one of our customers send us cylinder heads, cylinder liners, connecting rods and the pistons of a MAN 27/38 engine for reconditioning. This shipment consists of 3 WearResist® piston crowns from SECO and 5 piston crowns from foreign competitors. Running hours of the pistons: approx. 15.000h.
The decisive factor in the evaluation of a used piston head for the MAN 27/38 is almost exclusively the evaluation of wear of the 1.ringnut. If the wear dimension of 6,42 mm groove width which is predetermined by the engine manufacturer is reached, it doesn’t make any difference even though the grooves II, III and IV are clearly within the wear limit; which is usually the case. The following table summarizes briefly the criteria which are crucial for the further use of the crown of this piston type:
|Calculation base|| Groove with of
| %-usage of
| Wear after
15.000 running hours
|Piston crown 1 SECO WearResist®||6,27 - 6,28 mm||36 %||0,085 mm|
|Piston crown 2 SECO WearResist®||6,26 - 6,29 mm||38 %||0,090 mm|
|Piston crown 3 SECO WearResist®||6,26 - 6,28 mm||36 %||0,085 mm|
|Piston crown 4- 8, foreign competitor||6,60 - 6,80 mm||219 %||0,515 mm|
The above table shows very clearly the customers’ primary advantage by using our WearResist® piston crowns. Taking into account the secondary benefits, the following overall picture is shown:
Significant reduction of spare part costs on medium- and long term
Reduced probability of piston ring damages
Reduced lub oil consumption
Less wear on cylinder liners
In this case, the pistons that we received for reconditioning, could be returned again to our customer with our WearResist® piston crowns still assembled. Thus, no additional costs for our customer. However, the pistons with the asian crowns had to be disassembled, the crowns scrapped and replaced by new piston crowns from SECO. Certainly, we do not offer those advantages only to the owners of MAN B&W engines; we produce and supply our WearResist® piston crowns also to customers with Himsen H17/28, Himsen 21/32 and Himsen 25/33 engines. Together with our sister company Marine Motor Service GmbH, we also offer our WearResist® piston crowns for MaK and Wärtsilä engines.
Trust our expertise as a manufacturer of high-quality engine spare parts. Give us a change to convince you about the quality of our products and services. Please contact us. We shall be pleased to submit a suitable offer for the inspection and reconditioning of your pistons. Moreover, the reconditioning of cylinder heads, cylinder liners, connecting rods and injection pumps for MAN and Himsen, is part of our delivery and service programme.
We wish you a nice and successful day!
Uwe Pränger and Jan Michael Rentsch