This informative piece by Mr Goran Jonsson may help shed some light on our engine wear problems. 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
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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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