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Technical Discussions
Running-in of diesel engine cylider liner and piston rings MarineTalk Discussion Forums
All dates are given in mm/dd/yyyy format. Technical Discussions
  Running-in of diesel engine cylider liner and piston rings
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  Member: Ritinkar Sen Post Date: 8/9/2000  
Both Sulzer and MAN + B&W recommend longer running-in hours and using a low or 'zero' TBN cylinder oil, when running-in a new liner or piston rings if a low sulphur fuel oil is used. Why?
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Ritinkar Sen

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  Member: Chchch Post Date: 8/15/2000  
Ritinker,
What caused you to ask this question? What problems are you facing? Scuffing?
Which engine you having problem with?
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  Member: Ritinkar Sen Post Date: 8/15/2000  
It is not a problem, but a practice recommended by both MAN + B&W and Sulzer
Regards
------------------
Ritinkar Sen

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  Member: Jeom Paik Post Date: 8/17/2000  
Here is an answer from Mr. Robert Conachey and Mr. Takeshi Matsumoto who are experts in vessel engine related matters in American Bureau of Shipping:
High sulphur content fuels require cylinder oils with a high TBN (Total Base Number). High sulphur fuels generate sulphur oxides during the combustion process which when combined with water, also formed during combustion, can cause corrosive sulphuric acid. The alkaline additives in high TBN cylinder oils neutralize the corrosive acids generated during the combustion process. Accordingly, low sulphur fuels would need a cylinder with a lower TBN.

Typically your low sulphur fuel oils are gas oils or diesel oils which are "lighter" oils with lower viscosities and consequently lower lubricating qualities when compared to heavy fuel oil (HFO). All slow and most medium speed disel engines are designed to operate on HFO. If running-in an engine on a lighter fuel, more time would be required to wear in the cylinder liner and piston rings.

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  Member: Ritinkar Sen Post Date: 8/20/2000  
Thank you, Jeom Paik, Robert Conachey, Takeshi Matsumoto.
My question has not been fully answered. Perhaps, I did not make myself very clear.

I was not talking of diesel or distillate fuels. I was talking of residual fuel oil, which is normally used in service as well as during the initial running-in period of large slow speed crosshead type marine diesel engines. When running-in an engine with a low sulphur fuel oil (I repeat, residual fuel and not distillate), engine builders recommend using a low or ‘zero’ TBN cylinder oil.

Of course, lower the sulphur, the lower will be the amount of sulphuric acid formation and the lower the amount of alkali in oil needed to neutralize. So, why spend more money with a higher TBN oil? This is a simple answer, but I think there is more to it. It would appear that use of normal 70 TBN cylinder oil when running-in and engine with low sulphur residual fuel oil is actually harmful and can cause damage to the engine.

The following excerpts are from a Shell publication:

“Engines are usually run-in in factory before being installed in a ship, but sometimes a new engine has to be run-in in the ship. Similarly, when a new liner is fitted in service, it has to be run-in at sea. When this is necessary, the engine manufacturers generally prefer a low-alkalinity cylinder oil to be used for the first few hours of operation, and then replace with the normal high alkaline grade. The manufacturers themselves often use an oil of low TBN when running-in an engine on the test bed”


“ Some distillate fuels and certain residual fuels, specially those from Eastern Europe and the Far East, have very low sulphur content – 0.5 per cent or less. Their use in conjunction with highly alkaline cylinder oils has sometimes caused high wear and/or scuffing of cylinders and pistons”


“Certain low sulphur fuels undoubtedly present a problem, but the instances are rare and not solely dependent on fuel and lubricating oil. It seem that above a certain level, high piston and cylinder temperatures can cause ring-grove deposits, ring sticking and subsequent gas blow-by with destruction of oil the film on the cylinder walls”

Under running-in instructions, MAN + B&W advises “Some high alkaline cylinder oils are not compatible with certain low sulphur oils (having poor combustion properties) or with some diesel oils”

I wish to know in more detail what exactly happens when a high alkalinity cylinder oil is used in conjunction with low sulphur residual fuel during running-in. What are the chemical reactions and chemical / physical properties of the products that may cause damage?


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Ritinkar Sen

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  Member: Ritinkar Sen Post Date: 8/22/2000  
Just one more point to add in connection with the reply from Robert Conachey and Takeshi Matsumoto…
I agree that gas oil or diesel oil being lighter, have lower lubricating qualities. Would such consideration not result in faster liner wear and hence require a shorter running-in period?

For running-in new engine, Sulzer recommends starting on Heavy Fuel Oil (HFO). When engine must be started on diesel oil, then Sulzer advises switch over to HFO before 60% load is reached. As for running-in hours, following recommendations are taken from a Sulzer bulletin for their RTA engines:

When sulphur content is 1 per cent or more

MCR rpm per cent No. of hours

80 1.5
86.5 1.5
93.5 2.5
96.5 1.5

Total 7

Cylinder Oil Specification: SAE 50 TBN 10 to 20 for first 10 hours, thereafter normal TBN

When sulphur content is below 1 per cent

MCR rpm per cent No. of hours

75 2
80 1.5
85 1.5
90 1.5
95 2.5

Total 9

Cylinder Oil Specification (when fuel contains 0.25% or less sulphur) : SAE 50 TBN 0 for first 6 hours, thereafter, TBN 10 to 20; change over to normal cylinder oil to be determined after piston ring and cylinder liner inspections or by liner wall temperature monitoring.


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Ritinkar Sen

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  Member: Chchch Post Date: 8/23/2000  
RS you are doin' fine...
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  Member: Jeom Paik Post Date: 9/12/2000  
Here is an additional comment of Mr. Bob Conachey.
To answer Mr. Sen's last question concerning the effects of using a high alkalinity lubricating oil with a low sulfur residual fuel oil during running in, I think that he is going to have to consult with the engine companies directly. I found an article from the Motor Ship, May 2000 entitled "Pivotal Debate" that alludes to this issue. On page 33 in the first column, one of the Propulsion Conference attendees inquired about potential cylinder lubrication problems when using low sulfur fuel. Apparently, MAN B&W is currently examining extended running on 1.5% sulfur fuel and one of the findings is excess alkalinity can cause build-up on the piston crown.

In Pounder's Marine Diesel Engines, 7th edition, there is a good synopsis on the topic of lubricating oils starting on page 78. Formulating lubricating oils is a quite a challenge and an art to the manufactures of this product.

-The end-

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  Member: HAN021 Post Date: 10/29/2001  
Longer running in may be necessary, but at what cylinder oil consumption level?

We suggest that you check the possibilities in
SIP lubrication at www.hjlubri.dk. A way of reducing the overall cylinder oil consumption and maintaining good conditions.

Thomas Jensen

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  Member: Pacific Petroleum Ltd Post Date: 6/15/2002  
Wear in a cylinder liner is mainly due to friction, abrasion and corrosion, although under severe conditions adhesion may also occur. Each of them may have a number of causes.
Frictional wear takes place between the sliding surfaces of cylinder liner and piston rings. It will depend upon the materials involved, surface conditions, efficiency of cylinder lubrication, piston speed, engine load with corresponding pressure and temperatures, maintenance of piston rings, combustion efficiency and contamination of air or fuel.

Corrosion occurs mainly in engines burning heavy fuels, particularly with high sulfur content. Acids formed during combustion cause it and these must be neutralized by the use of alkaline cylinder oil. Sulfuric acid corrosion may be caused in the lower part of the liner if the jacket cooling water temperature is to low. This may allow vapor present after combustion to condense. The moisture formed will absorb any sulfur present to form sulfuric acid. Maintaining jacket temperature above the corresponding dewpoint can prevent this.

Water vapor will be present from the combustion of hydrogen together with any water present in the fuel. It may be increased if water passes from the charger air cooler.

Abrasion may take place from the products of mechanical wear, corrosion and combustion - all of which form hard particles. Ash may be present in some heavy fuels, as well as fines (aluminum compounds added as a catalyst during the refining process and not removed from the residual fuel) which may act as abrasives.

Adhesion or scuffing is a form of local welding between particles from the piston ring and the liner-rubbing surface, resulting in very rapid wear. It may occur it the lubricating oil film between ring and the liner is removed due to excessive temperature, insufficient supply or incorrect distribution of oil, piston blowpast, etc. Engines operating on some low sulfur grade of fuel may be prone to scuffing damage.

The rate of wear varies over the life of the liner. It is high during the initial running-in period after which it should reduce to an almost constant rate for most of the useful life of the liner. Finally the rate will progressively increase as wear become excessive.

Normal wear rate differs but an approximate figure of 0,1 mm per 1000 hours is accepted. For large engines wear is increased if the engine is overloaded. Maximum wear before renewal is usually limited to 0,6 - 0,8% of original bore diameter or less when manufacturer advice.

How to prevent metal-wear of liner?

By using Pacific Petroleum PP-C Cylinder oil additive blended into the cylinder lube oil with a dose around 3% by volume the cylinder oil wear protection characteristics will be improved. The additive has also a strong neutralization effect of sulfuric acid and will contribute to prolong the life of the liner and piston ring.

How much longer will the liners last when using PP-C Cylinder oil additive?

In an ASTM D2509, D2782 Timken Extreme Pressure tests the result of the additive show clearly, and how it increases the protection rate of normal cylinder lube oil.

Plain cylinder oils without additive have the wear protection factor 5.

The same cylinder oil with the dose 3% has the wear protection factor 250. Which means that the same oil with additive will reduce the normal metal-wear rate with (250: 5) 50 times above normal.

Detergent and clean piston ring seats.

The additive contain a detergent that will keep the piston ring seats clean and prevent blocking, and prevent build-ups of carbon.

By consuming 10 liters PP-C Cylinder oil additive per day in a full size vessel you avoid most of the cleanliness, corrosion and metal-wear problem in the liner and piston ring seats.

PACIFIC PETROLEUM LTD.
Goran Jonsson.
additive@panafonet.gr

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  Member: Pacific Petroleum Ltd Post Date: 6/15/2002  
Just for your information!


It was found in a research program performed by the National Technical University of Athens Greece, an increase of the mechanical efficiency in Marine diesel engines up to 4,2% when PP 2000 Engine protector was in use. The improvements was soley due to less internal friction in the engine. At the bottom line the same level of improvements will result in a net fuel saving in the same order. The cost from using PP2000 Engine Protector represent about 1% of the fuel saving. Clear net profit about 3%!!!! The main profit will however come from reduced wear and tear of liners, piston rings bearings etc.

For more information, contact:


Pacific Petroleum LTD.
Mesogeion Ave. 433
Agia Paraskevi Attica Gr 15343
Greece
Phone: -30 106009241
Fax: -30 106396545
email additive@panafonet.gr


------------------
Goran Jonsson

[This message has been edited by Pacific Petroleum Ltd (edited 6/15/2002).]
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  Member: meh_force12 Post Date: 3/20/2004  

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  Member: Johannes Post Date: 3/20/2004  
Well, Goran Jonsson of Pacific Petroleum Ltd., nobody is wanting to know about your companies product. Please answer the query to the point.
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  Member: additive Post Date: 3/21/2004  
Well Johannes it is up to you to learn or not about new problem solving products or not. The result from the users of the additives speak for it self.

It is normally called preventive maintenance!


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  Member: mossman1551 Post Date: 9/24/2005  
gday mate I'm after information concerning the running and maintaining of marine slow speed diesel engines with regards to low sulpher residue oil. I'm currently completing my chiefs engineers certificate and require detailed information on this topic. I would be much appreciated if pacific petroleum could help me out thanks.
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  Member: RolloTomkins Post Date: 10/19/2005  
At one time Sulzer recommended using a straight SAE 50 oil as a cylinder oil for the first 24 hours of running in. I believe they have now discontinued the practise (refering to their more recent engine manuals). As far as I am aware MAN B&W have never used that practise.
The only reason I can think of is that the initial use of oil with a low alkalinity reserve was to encourage a small amount of corrosion to take place in the 24 hours. This would help ensure an oil retentative surface. Some years ago I tried to find someone in Sulzer to corroborate this theory with no success.
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  Member: bukawchief Post Date: 6/7/2007  
dear ritinkar sen
im your avid fan i was impressed by your technical contribution on this forum. im a student and eager to know how the computation process of engine power.
thanks.
brgds.

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  Member: tattaseshur Post Date: 6/29/2007  
Dear All Marine engineers- This is one subject in discussion for hfo/70tbn case do/50tbn case and so on. Running -in as per makers manuals and recommendations are not practically possible at various port conditions.after overhauls the running in process was done as a formality.

1.After every overhaul at ports departure manoeuvering with various movements from ds ahd - full ahd and start stop astern and so on. later the coastal water restrictions and local conditions may not provide support to running in process correctly.
2. Now-a days most of these engines are running with HFO and 70 TBN cyl oil a straight running in is continued with several variations.

3. Commercial pressures/ schedule maintaining etc., are another factor for many vessels left with limited running in.

4. Present day 12 units engines, 1 unit o'hauled running for quite long time is difficult to adhere and engineers are forced to run the short interval running ins.

5. Low sulfur with High TBN has it's own difficulties and not recommended due to various failures occurred.

today in market the cyl lub techniquies have been increased due to focussing economy and savings. However, with increase in pmax levels the stresses between rings and liners also increased exponentially and causing failures.

Even after all the above facts Marine engines are still performing in the Industry even the fuel quality is deteriorating significantly.

all above are experienced in my sailing period and as superintendent in a major company operating 85 vessels of different types.

your feed back and comments are highly appreciated.
Best regards
TSR chari

With all these above restrictions the running is still effective and engines are continued running in Maritime Industry.


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  Member: additive Post Date: 7/2/2007  
Gentlemen.
I can’t understand why you don’t like to try some new technology regarding the cylinder lubrication and add PPC Cylinder liner oil additive. It will protect from all type of scuffing, maintain clean ring seats and very clean scavenge ports and vet liner surface. The only thing you can lose from too good lubrication is problems. It will cost you just a few dollars per day for a medium size vessel

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  Member: Docdsl Post Date: 7/9/2007  
Right Answer - low or non alkaline cylinder oil will allow for the corrosive etching of the cylinder liner which is required to maintain a suitable oil film during regular operation. This is also one of the problems when encountering today's low sulphur fuels. Use of high TBN oils with low sulphur fuels results in substantially increased deposits to piston crowns and ring pack areas as the addtives are not completely consumed when using low sulphur fuels.
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