LO consumption high Wartsila 46 Engine

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mdjahirul
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LO consumption high Wartsila 46 Engine

Post by mdjahirul »

Hi,

I am Jahirul. In recent treads we found that LO consumption is high on Wartsila 46 engine compared to previous. Present consumption is 0.95 gm/kwh where as previous it was 0.65 gm/kwh. We checked the separator. Its okay. What checking should be done on engine side?
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pradeep6096
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Re: LO consumption high Wartsila 46 Engine

Post by pradeep6096 »

1)did u overhaul gene, if yes then maybe scrapper ring is inverted
2)one vessel turbochrger seals were kaput and were loosing lub oil there, how is the general condition of lube oil
3)check pcomp pressure after discoonecting the racks, if have different values then chances of loosing oil due to broken rings or ovality of liner
4)stem seals in cylinder head
5)ensure drain valves are properly shut
right now can think of these things, do check and update
Big Pete
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Re: LO consumption high Wartsila 46 Engine

Post by Big Pete »

Hi there,

Long ago everyone used to hone cylinder liners, when overhauling engines, then some Engine makers started to produce piston rings which they claimed did not require the liners to be honed.
In my experience, the cost of honing the liners is much more than covered by the saving in L.O. consumption.
Some years ago I sailed on a ship with twin 6 cylinder MAK engines, which were using the special piston rings and not honing the liners. Ove a period of years the L.O. consumption steadily increased until we started honing the liners again, then the Super produced a very pretty graph showing how our L.O. consumption dropped each time an individual liner was honed on overhaul and proved conclusively that paying for a shore side squad to hone the liners as they overhauled each unit, and demonstrated clearly that despite the special rings, honing more than paid for itself in reduced oil consumption.
It is always better to ask a stupid question than to do a stupid thing.
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Merlyn
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Re: LO consumption high Wartsila 46 Engine

Post by Merlyn »

Glaze Buster Boy.
Me too.
Many happy hours doing that, chasing that barrel effect.
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.
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Merlyn
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Re: LO consumption high Wartsila 46 Engine

Post by Merlyn »

Further to BP's comments re ring/liner contacts I well remember in the mid seventies the advent of chromed liners.
Chromard was the trade name.
The chromed liners being much harder than close grain cast iron liners rapidly accelerated ring wear.
Plus of course no graphite being present in chrome liners did not help the situation unlike the close grain cast iron liners who did of course have graphite present necessary to assist the lube. situation.
Then advancement announced chrome rings with cast iron liners.
Some variations had the top two or three compression rings chrome with the third ring being a cast iron oil control ring.
The lower ring down on the skirt was of course the scraper ring being made of cast iron.
However the chrome present in whatever format did not possess the graphite impregnation that cast iron possessed so after a few years of constantly changing liners and pistons it was back to close grain cast iron all round.
It was around this time that we decided the old strongback method of pulling liners was hard work so our first hydraulic kit was purchased so for me some good came out of the Mr Chromard era.
Then of course came the advent of synthetic oil which of course extended oil changes and piston/liner changes so you now do not have to take your fancy liner puller with its 101 mandrels every where you go ( both metric and imperial )
Again back in the old days mandrels were all imperial but nowadays its nearly all MM out there.
( Micky Mouse that is )
Remembering The Good Old days, when Chiefs stood watches and all Torque settings were F.T.
popeye62
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Re: LO consumption high Wartsila 46 Engine

Post by popeye62 »

Hello Jahirul, I have looked at the project guide for the 46 (the project guide is the 'brochure' to get you to buy one) and the SLOC is given as 0.5 g/kWh but this is at 100% load. I have looked in the manual for the SLOC but it is not given. I don't think you are ever running the engine at this load. How are the engines utilised, are they power generation or propulsion? Did the operation change at the same time as the increased consumption? How many hours on them? Check your paperwork onboard for the acceptance record of the engines and check the consumption stated. Having said that, if we are talking about a consumption of oil way beyond that stated then the first thing to determine is whether it is leaking or being burnt. Some numbers would help so if I assume the engine is a 12V46(?) developing 12,600 kW at 100% then the consumption is 0.65 x 12,600 x 24 = 197 kg/day approx. 232 litres. If the SLOC is 0.95 then it is 0.95 x 12,600 x 24 = 287 kg or 328 litres an increase of 92 litres/day (if the power output at 100% is half this example then so is the the consumption). It is not likely to be going overboard because the LO is LT cooled, yes? if it is sea water cooled then it is a possibility. Is the engine pit bilge filling with oil? I presume it is a dry sump so have a look in the void spaces around the LO tank for leaks and the sump drain lines. Any other leaks should be obvious, check the tank-tops for oil from the pipework. If the oil is passing through the unit then it is coming in with the air; T/C seals, through the valve guides or most likely up through the piston ring pack due to sticking/broken rings (carbon from low load running burning IFO380?), polished liner (the anti-polishing ring can only do so much) or worn liner. I don't think you would see it in the smoke. Use your PMI to take some readings and check them with the previous, is Pcomp down? You can always pressure test the units if the engine is off; valves closed, air line with press gauge on the indicator cock.
When were the units last overhauled? How did you determine the SLOC figures, from the top-ups and sump levels?
Keep the LO as clean as you can and don't miss a sampling/testing. I have know engineers who try to 'pass' a LO test; this is insane. The separators should be running on this engine 24 hours/day, 98 degrees and minimum throughput running or stopped and never run it more than 30 minutes without.
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