Lube Oil Analysis

BY DAVID CLINE

Lube Oil Analysis A Guide For Monitoring Lube Oil

Parker Racor 3400 Finch Rd Modesto, CA 95354 1-800-344-3286

Preface For many years lube oil testing has been an expensive and time consuming way to determine the condition of lube oil and the engine components based on the wear particle and chemical analysis.

As engines and lube oil’s become increasingly sophisticated it has become more important to be pro-active rather than reactive to problems which are the result of contaminated lube oil.

The following compilation of discussion topics are comprised from research of facts and documentation from many sources including Filtration Technology, bulletin #0247-B1, provided by Motion Control Training Dept. Hydraulics group, Parker Hannifin Corp.

No attempt is made to show component selection criteria or detailed operating characteristics of a component system which may be out side of the scope of this informational booklet.

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CHAPTER 1

Effects and Causes of Wear Oil analysis involves sampling and analyzing oil for various properties and materials that indicate wear and contamination in an engine, transmission or hydraulic system. Sampling and analyzing on a regular basis establishes a baseline of normal wear and can indicate when abnormal wear or contamination occurs.

Inadequate oil analysis can be worse than no analysis at all. The confidence is misplaced when the analysis does not adequately address wear, contamination and chemistry. Visual inspection of components is a necessary part of complete condition monitoring and equipment evaluation.

Oil analysis tells you a lot about how the equipment was used and what condition it's in. Oil that has been inside any moving mechanical apparatus for some time reflects the condition of that assembly. As moving parts make contact, wear occurs and introduces minute metal particles to the oil. These particles are so small that they remain in suspension. Many products of the combustion process also become trapped in the circulating oil. In addition, the oil may be exposed to external contamination. Identifying and measuring these impurities indicates the rate of wear and level of contamination. Thus, the oil becomes a working history of the machine. Oil analysis also suggests methods to reduce accelerated wear and contamination.

A typical oil analysis can indicate the presence of contaminants and tell you if you've been using the appropriate lubricants. Oil analysis detects: •Fuel dilution of the oil •Dirt contamination in the oil •Antifreeze in the oil •Excessive bearing wear

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Root causes of failure

Some wear is normal. However, abnormal or pre-mature or rapid increase in levels of a particular material can give an early warning of impending problems. The oil analysis report could prevent a breakdown and allow time for corrective action such as repairing an airintake leak before major damage occurs. One major advantage of an oil-analysis program is being able to anticipate problems and schedule repair work to avoid downtime during a critical time of use.

Contamination and chemistry are both proactive while wear is predictive. An effective oil analysis program should address the mechanisms as to why the engine failed or is about to fail.

Particle Interactions With The Surface In Parker’s book on Filtration Technology, Situations leading to wear mechanisms are categorized as two- body or three body interactions.

Early detection can: • Reduce repair bills

Internal generation of particulates is a source of contaminants.

• Prevent catastrophic failures • Increase machinery life • Reduce non-scheduled downtime EVALUATING USED EQUIPMENT A complete record of oil analyses you've performed can prove to be a great tool when selling a piece of used equipment. It shows the potential buyers how you have maintained the equipment as well as any adjustments you made to it during its life. The history also is a good indicator of potential future repairs and overhaul requirements. When buying a piece of used equipment yourself, you also can take advantage of the benefits an oil analysis can offer.

However, without knowing the amount of operation of the oil being analyzed, you should consider the test conclusive only if it indicates a problem. A good report could result from either no problems or a short length of service of the oil.

Before contaminant is present there is another area of concern.

It is friction-wear caused by lube oil that may be too thin.

This may be due to the incorrect oil being used or thinning by fuel dilution or other chemical reactions.

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Surface fatigue can start with particles.

In the absence of contaminants, two body interaction occurs when the lubricating film is too thin to prevent contact between two moving surfaces. Two body contact also can occur between a hard contaminant particle and a stationary surface. As the fluid flows around a stationary object, any particle carried by the fluid can impact on the objects surface. This can lead to one or more of the wear mechanisms discussed here.

There are many particle wear related issues that can occur, all of which are not discussed in this book, but the three usually associated with particulate contaminants are abrasion, surface fatigue, and adhesion.

Adhesion can occur when microscopic ridges of moving surfaces contact each other.

Two-body wear Abrasive wear occurs when a hard particle penetrates a softer surface, cutting away material on a single pass. The wear rate is proportional to the number of particles in the fluid, and their hardness compared to the wear surface. This is a type of two -body wear.

Surface fatigue is another source of two body wear. It is caused by particles denting a surface without actually removing any material.

The dents show up as surface roughness, and lead to stress cracks, a form of material fatigue. In time mechanical forces will cause material to break away from the fatigued area.

Hard particles can create three-body wear, and continue to generate more particles.

Adhesion wear is an effect of particles interacting with a surface.

The scraping of the adhesion wear will cause the surrounding material to expand or form a ridge which will eventually impact the opposing surface. The impact or contact can be enough to cause a welding effect between the two heated surfaces causing a weld 4

junction. The adhesion of the Junction between two moving parts will immediately create a seizure or tearing effect with sever wear and equipment failure.

Third bodies or particles get between gaps or clearances of components that should be separated by a film of lubrication.

Three Body Wear When contamination or hard particles are allowed to enter the lube stream they will get in between moving parts where the lubrication should be. This can happen when the particle is approximately the same size as the clearance between the the surfaces. The presents of the hard particle occupying the space and making contact will cause grooves in the softer of the two materials and become imbedded. The continual movement and interaction will create increased wear and possible component seizure.

Unfiltered particles continue to work on the moving parts generating more and more wear particles until failure occurs.

Secondary Effects of Wear Moving parts are separated by a thin film of oil to prevent making contact with each other causing friction and wear. If you were to think of this oil film as tiny ball bearings that keep the moving components separated so they can not rub on each other you would see how important the oil film is.

The secondary effects of wear come in play when the fluid is allowed to contain particles that are small enough to flow in the lubricating fluid and over time wear away the surface of the components causing reduced performance first and eventually a complete failure.

Once the initial wear begins, the particle count in the fluid increases and so does the rate of wear. The cycle compounds until failure. Thus the need for a level of filtration that removes particulate down to an acceptable level which is explained later.

Clearly, the particle size and quantity of particulate has a large impact on the wear and the interference of the moving parts.

Lube oil analysis is used to determine the lube oil quality and to give a snap shot of the over all condition of the engine. Much like a blood test for our bodies.

This section has dealt with particulate which requires a test that actually counts the particles and categorizes them based on size distribution, The test is ISO 4406 cleanliness codes which is a standard to quantify particulate contamination.

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Journal Bearing Wear

cerned with on and engine or hydraulic system. The following is an example of a bearing with dirt in the lube oil supply.

Every moving part in an engine will eventually wear out. Each part has a life span which is dependent on many things. If all parts lived out their full expected life then a maintenance mechanic’s job would be fairly simple. The simple fact is that we can not expect all parts to fail just because the life span has been reached. I mentioned earlier that oil analysis is like a blood test for our bodies, and in the same way a Mechanic must be like a Doctor and be capable of diagnosing his patient whether it is an engine, gear train or hydraulic system. The information below is from Clevite 77® Engine Bearing Failure and Analysis Guide.

• • • • • • • •

Major Causes of Premature Bearing Failure Dirt..............................................45% Misassemble................................13% Misalignment...............................13% Insufficient Lubrication..............11% Overloading.................................8% Corrosion......................................4% Improper Journal Finish..............3% Other...............................................3%

Below are actual bearings from an engine failure caused by dirt.

The bearings seized, spun and cut off oil supply to the rod journals.

By studying the information above you can see that if a mechanic simply replaces the worn part whether it is a bearing or other component with out finding the root cause of failure, the new component will be subjected to the original cause of failure.

A point to be made here is the highest cause of bearing failure is dirt, thus good filtration is the most important thing to be con-

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CHAPTER 2

Physical and Metal Tests

By taking a small, 2-4 ounce sample of oil from the engine or equipment, many things can be determined by analyzing over 22 base metals and the chemical make-up of the lubricating oil. There are many laboratories across the country that offer analytical services or offer on-site oil analysis equipment that can be purchased for large fleets with on going oil analysis and condition based maintenance programs.

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PHYSICAL & METAL TESTS

Viscosity

During a complete oil analysis, you should test the sample for both physical properties and metals. Some of the physical properties tested for and usually included in an oil analysis:

Viscosity is a measure of oil’s resistance to shear. Oil may thin due to the incorrect viscosity oil or by dilution with fuel. Oil may thicken from oxidation if it is run too long or too hot. Oil also may thicken from contamination by antifreeze, moisture causing sludge and other materials.

Antifreeze This forms a gummy substance that may reduce oil flow. It leads to high oxidation, oil thickening, high acidity and engine failure if not corrected.

The following are some of the metals for which oil is tested and some of their potential sources: Aluminum

Fuel dilution

Thrust washers, bearings and pistons are made of this metal. High readings can be from piston-skirt scuffing, excessive ring-groove wear and broken thrust washers, among other problems.

This condition will thin the oil, lowering lubricating ability and potentially causing a drop in oil pressure. This usually causes higher wear.

Boron, magnesium, calcium, barium, phosphorous and zinc

Oxidation

These metals normally are from the lubricating oil additive package. They include detergents, dispersants and extreme-pressure additives.

Checking for oxidation is a measure of gums, varnishes and oxidation products. High oxidation from oil that became too hot or was used too long can leave sludge and varnish deposits and thicken the oil. Oxidation is reported as absorbance units, with 25 being the high limit.

Chromium You typically associate chromium with piston rings. Dirt coming through the air intake system will cause a high rate of wear on piston liners, and cause broken rings. Ingested contamination through the intake will show up as high silicon in oil analysis.

TBN - Total base number This generally indicates the acid-neutralizing ability still in the lubricant.

Copper and tin

Total solids

These metals normally come from bearings or bushings and valve guides. Oil coolers also can contribute to copper readings along

These include ash, carbon, lead salts from gasoline engines and oil oxidation.

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with some oil additives. In a new engine, these results normally will be high during break-in but will decline in a few hundred hours.

Tests include: !

•!

24 Metals by ICP

!

•!

Viscosity @ 40° C 100° C

!

•!

Fuel Dilution %

!

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Soot %

Lead

!

•!

Water by Crackle %

Lead is associated with bearing wear, but fuel source (leaded gasoline) and sampling contamination (use of galvanized containers for sampling) are critical factors in interpreting this metal.

Advanced

Iron This can come from many places in the engine, such as liners, camshafts, crankshaft, valve train and timing gears.

To safely extend oil drain intervals, Total Base Number and Oxidation / Nitration will determine if the oil is suitable for continued use.

Silicon High readings generally indicate dirt or fine sand contamination from a leaking air intake system, which cause excessive wear from abrasion.

Tests include: !

•!

24 Metals by ICP

Sodium

!

•!

Viscosity @ 100°

You normally would associate high readings of this metal with a coolant leak. But they also can be from an oil additive package.

!

•!

Fuel Dilution %

!

•!

Soot %

Diesel Engine Test Packages

!

•!

Water by Crackle %

Following is a summary of some of the tests that are available through oil analysis labs.

!

•!

Total Base Number

!

•!

Oxidation / Nitration

Basic

Sample kits part number LFS RK760, are available from:

Basic testing monitors both the unit and the fluid for wear and contamination.

Parker Racor - www.parker.com/racor

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CHAPTER 3

Taking The Oil Sample Movie 3.1 Oil Sample Video

This short video will show how to properly take an oil sample. To view the video click on the arrow. To view in full screen, start the video then touch the two opposing arrows in lower right corner of the screen .

TAKING SAMPLES - GUIDELINES & BEST PRACTICES Oil analysis is only as good as the sample taken. The goal is to take samples that are truly representative of the oil in the engine. Remember the old saying: Garbage in, garbage out.

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When to sample?

Take samples during operation or within 30 minutes of shutdown.

Sample information is very important.

Discuss the reasons for oil analysis before beginning so the correct procedure and timing and proper reports are determined.

Fill out the sample information label accurately and completely.

Wrap it up. Wrap the sample information label around each sample container, and attach with a rubber band.

Where to sample?

The best and most consistent is a sample port on the engine main oil gallery or on the inlet side of the bypass filter. A sample may be taken from the oil galley, or engine crankcase via the dipstick tube.

Do not take samples from the oil filter or drain plug in the pan.

Draw from the middle of the reservoir to avoid any sludge at the bottom.

•!

Always take a base sample of the clean oil right from the source, such as the barrel or the bottle. This will give you a base line of the elements and additive. •!

Sampling to extend the oil drain interval or installation of aftermarket products should be done early enough to allow time to get the report back and review.

Be consistent. Take samples from same location every time. Consistency is key.

•!

Sampling to monitor the installation of a bypass oil filter should be done before the installation of the bypass and at frequent intervals to determine the oil degradation process. Particle counts are very important for bypass monitoring but because of the black oil it is very difficult to do without diluting the sample. A qualified lab should be able to do this if they have the particle counting equipment.

Do not overfill the sample container. We recommend threequarters full.

Cleanliness counts. Make sure that the sample container is a certified clean and dry bottle before use.

Do not re-use tubing, pumps, probes or dirty rags.

You obtain samples without draining oil by suctioning oil out through plastic tubing routed down the dipstick tube into the oil reservoir. In any case, it is important to have an appropriate container and follow sampling directions thoroughly. A lot of testing laboratories will provide you with a kit that includes a sample bottle, such as Racor LFS RK760. sterile or the test may pick up contaminants what previously in the container.

Test results are reported in parts-per-million, so the container must be from a source such as a laboratory supply or oil analysis lab to guaranty bottle cleanliness.

After sample is taken, close cap tightly. Seal the container securely to prevent any contamination or loss of oil during transit.

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RESULTS CHARACTERISTICS

The Lab typically provides the results of your laboratory analysis 24-48 hours after they receive your sample. They note when the analysis shows an abnormal condition and issue a caution or recommendation accordingly.

Fuel Dilu8on

Example 1: Critical fuel dilution. Change oil and filter.

Example 3: Possible wrong unit ID. Please resample to verify.

Viscosity – High

Viscosity – Low

Solids

EFFECT

Contamina(on (wrong fluid) Oxida(on

Reduced oil flow and oil filter by-­‐pass

High opera(ng temperature

Overhea(ng

Wrong fluid

Insufficient lubrica(on

Dilu(on

Metal to metal contact

Addi(ve shear

Over hea(ng

Water / Coolant contamina8on

Defec(ve seals Low opera(ng temperature Start-­‐up and go driving

Increased wear

Incomplete combus(on

Decreased oil pressure

Stop and go driving

Higher opera(ng costs

Reduced engine life

Wear debris

Poor lubrica(on

Oxida(on products

Increased wear

Fuel soot

Filter plugging

Extended oil drain

Reduced oil flow

Environmental debris

Deposits / lacquer

Overhea(ng Extended drain interval Total Base Number (TBN) -­‐ Low

Increased cost

Total Acid Number (TAN) -­‐ High

Coolant leak Poor storage prac(ces

Faulty injectors

Incorrect air fuel ra(o

Example 2: Abnormal copper. Abnormal silicon. Possible break-in.

CAUSES

EFFECT

Extended idling

Examples of recommendations might be:

CHARACTERISTICS

CAUSES

Increased wear Decreased oil pressure Reduced engine life

Par8cle Count

Higher opera(ng costs

Incorrect air-­‐fuel ra(o

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Improper lubricant

Oil degrada(on Addi(ve deple(on

High sulphur fuel (off-­‐ highway engines)

Increased viscosity

Overhea(ng

Oil degrada(on

Extended drain

Corrosion of metal

Improper lubricant

Acidic increase in oil

Water contamina(on

Increased wear

Oil oxida(on

System failure

Worn seals

Equipment failure

Ineffec(ve filtra(on

Plugging / leakage

CHAPTER 4

Oil Tests

The oil testing is accomplished by using some very sophisticated equipment in a controlled laboratory environment. The Lab Tech uses the sample taken from the equipment and passes it through several individual machines to separate and identify contaminants, metals and the chemical make-up of the oil.

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Oil Tests

Nitration

Additives & Contaminants

Nitration products are formed during the fuel combustion process in internal combustion engines. Most nitration products are formed when an excess of oxygen is present. These products are highly acidic, form deposits in combustion areas and rapidly accelerate oxidation. Nitration indicates excessive "blow-by" from cylinder walls and/or compression rings. It also indicates the presence of nitric acid, which speeds up oxidation. As oxidation/nitration increases, so will total acid number and viscosity, while total base number will begin to decrease.

An additive is a chemical substance added to a petroleum product to impart or improve certain properties. Common additives are: antifoam agent, anti-wear additive, corrosion inhibitor, de-mulsifier, detergent, dispersant, emulsifier, EP additive, oiliness agent, oxidation inhibitor, pour point depressant, rust inhibitor, tackiness agent, viscosity index improver. A contaminant is any foreign or unwanted substance that can have a negative effect on system operation, life or reliability.

Oxidation

Fuel Dilution

Oxidation will increase and cause the breakdown of a lubricant due to age and operating conditions. Oxidation occurs when oxygen attacks petroleum fluids. The process is accelerated by heat, light, metal catalysts and the presence of water, acids, or solid contaminants. It leads to increased viscosity and deposit formation. It prevents additives from performing properly and therefore allows acid content and viscosity to increase.

Measures the amount of fuel contamination in the oil, specifically the amount of raw, unburned fuel that ends up in the crankcase.

Dilution lowers an oil's viscosity -- creating friction-related wear almost immediately -- and decreases unit load capacity. Fuel dilution is reported as a percentage of volume.

Fuel Soot

Particle Count, ISO4406

Used to determine combustion efficiency. Soot can be caused by over-fueling, air restrictions, blow-by, excessive engine brake use and/or excessive exhaust back-pressure. Soot reported as a percentage of volume.

A measure of all particles that have accumulated within a system, including those metallic and non-metallic, fibers, dirt, water, bacteria and any other kind of debris. It is most useful in determining fluid and system cleanliness in filtered systems such as hydraulics, turbines, compressors, auto/power shift transmissions, recirculation systems and filtered gear systems.

Glycol Oil analysis will check oil for contamination from a glycol product such as antifreeze. Levels should range from 40% to 60% to ensure proper freeze point protection. A high percentage of glycol can cause additive drop out and shorten coolant life.

Particle counting is the industry accepted method for measuring dust contamination. The results of particle counting are given in 14

particle size and size distribution as well. Both are very important for monitoring the condition of the lube oil and determining level of filtration performance.

Viscosity Index represents oil’s change in viscosity with respect to changes in temperature. The viscosity index of oil is determined experimentally by testing its viscosity at 40 C. and 100 C.

pH

Factors Affecting Viscosity

pH is a measure of oil's alkalinity or acidity. It indicates the intensity of acid-forming or base-forming materials present.

In use, an oil's viscosity will increase or decrease from new oil viscosity. Increases in viscosity are due to high temperature oxidation, soot accumulation, water or coolant contamination. A decrease in viscosity usually signals fuel dilution; however, in multigrade oils, it may be due to a shearing of the viscosity index improver additive used in these types of oils.

Total Acid Number Acid Number is the amount of acid present. Values higher than that of the new lubricant is an indication of oxidation or contamination.

Engine conditions that change the oil's SAE viscosity grade can be detrimental to engine life. Indications of this type require immediate oil and filter change. In multi-grade oils, a loss in viscosity due to shearing of the, VI improver additive, is a characteristic of the brand of oil used and can only be corrected by changing oil brands. Viscosity changes caused by engine contamination must be investigated and corrected.

Viscosity A measure of a lubricant's resistance to flow (fluid thickness) at temperature. Viscosity is considered the most important physical property of oil. Depending on lube grade, viscosity is tested at 40 C. and/or 100 C. Reported in Centistokes.

It is critical for the oil to be in the right range for proper engine lubrication. If the viscosity is too low, the oil will cause excessive engine wear. If it is too high, the oil may not provide sufficient flow to critical engine components.

Water Measure the amount of water in the oil. Water can be measured by the crackle method (using a hot plate) or by the Karl Fisher method (titration). Water in oil decreases lubricity, prevents additives from performing properly and furthers oxidation.

Viscosity is dependent on temperature. Generally, viscosity will decrease as temperature increases. The change in viscosity with temperature is referred to as the "viscosity index" (VI).

Measurement of Viscosity The most common technique for measuring viscosity is kinematic viscosity, as defined by ASTM D445. This test method measures the time it takes for a known volume of oil at a specific temperature to

Viscosity Index

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flow under gravity through a specially designed precision glass tube. Different types of tubes are used depending on whether the oil is new or used. Kinematic viscosity is measured at two temperatures -- 40°C. (Approximately 100°F.) and 100°C. (Approximately 210°F.) -- to simulate ambient temperatures and high engine coolant temperatures.

Fuel Dilution Contamination and dilution of engine oil by fuel may occur from incomplete combustion due to extended periods of idling and/or the use of a heavy fuel. Fuel dilution may also be caused by over fueling from a malfunctioning or improperly sized fuel injector.

Poor fuel atomization and leaking are two likely injector malfunctions.

Both measurements may be used in new oils to calculate viscosity index. VI values greater than 100 indicate a multi-grade oil, and values less than or equal to 100 are mono-grade oils.

While the viscosity measured at 100° C. is used to determine the oil grade, the viscosity at 40° C. provides a better indication of fuel dilution or water contamination. These contaminants generally boil off at higher temperatures, and they are often not detected by changes in viscosity. An increase of 40% or a decrease of 15% from new oil viscosity at 40° C. indicates that there may be a problem with the oil. In this case, we would recommend a confirming test for fuel dilution.

A small amount of engine oil fuel dilution occurs in normal engine operation. It becomes a potential problem when it causes a significant lowering of oil viscosity. As a general rule, you can generally tolerate up to 5% by volume, but you should investigate any reading over 2.5%, regardless of oil hours or miles. The engine and oil are less tolerant of some fuels than others. Some fuels (such as high-sulfur fuel, methanol, ethanol and biodiesel) may cause harm below 2.5% by volume. Total base number (TBN), wear metals and viscosity may provide additional information for a particular engine or application.

Typical Viscosity Values

Measurement of Fuel Dilution

Viscosity Grade 15W-40 30 40 50 Viscosity, Kinematic, cST

The two test methods for fuel dilution are flash point reduction (ASTM D92) and gas chromatography (ASTM D3524). Gas chromatography is considered to be more sensitive and precise. Gas chromatography is a technique in which the fuel is separated from the oil by passing the heated mixture through a special column which permits faster passage of the more volatile fuel components. The relative quantities of fuel and oil are determined by a flame ionization detector that differentiates these components.

@ 40° C. 95 – 115 / 100 - 120 / 130 - 150 / 200 - 230 @ 100° C. 12.5 - 16.3 / 9.3 - 12.5 / 12.5 - 16.3 / 16.3 - 21.9 15/40w

30w

40w

50w

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Water Content

corrode bearings and form a tar-like substance which can block oil galleries. Quantities above 1,000 PPM require corrective action and an immediate oil change, regardless of oil service hours or mileage.

When large concentration of engine coolant are detected, the engine should be flushed out using an accepted procedure.

Water contamination of engine oils in concentrations as little as 500 ppm can seriously affect the oil's ability to be filtered and the function of the oil's additive package. The detection of water in concentrations above 0.3% by volume (about 3,000 ppm warrants immediate corrective action and an oil change.

Glycol contamination is determined by spectrochemical analysis for sodium and boron, by gas chromatography (ASTM D 4291), or by a chemical test described in ASTM D 2982. This chemical test involves mixing a sample of the engine oil with several chemical reagents. The presence of glycol is confirmed with the presence of a purple color. The intensity of the color is directly related to the concentration of glycol present.

For screening purposes, water contamination may be detected effectively with a crackle test. This (low tech, but effective), test is conducted either by dropping a small quantity of oil in a heated aluminum pan, or by immersing a hot electric soldering iron in a sample of the oil. A crackling noise indicates the presence of water.

An exact quantity of water may be determined by distillation (ASTM D 95) or by Karl Fischer titration (ASTM D 1744). The distillation test method measures total water only, while the titration method determines combined and free water. While the titration method can measure smaller quantities of water, it requires a new sample and may not give accurate results if the oil is badly contaminated by other materials.

Soot Content A characteristic of diesel fueled engines is that they produce soot from combustion. The soot makes its way into the engine oil via the piston rings due to, worn cylinders, engine timing, heavy load conditions. The quantity of soot in the engine oil is related to the engine operation, not the oil. However, the ability of the oil to function and protect the engine when soot is present is related to the oil's performance. High concentration of soot can reduce wear protection and increase viscosity. The ability to handle some level of soot contamination is built into the oil formulation. The determination of soot concentration by itself is only of benefit in judging the operation of the engine.

In the distillation method, a measured quantity of the oil is dissolved in xylene and heated in a distillation flask. The water codistills with the xylene and is collected in a graduated trap where the water settles to the bottom and the volume present is measured.

Glycol Content

Restricted air intake, excessive idling, lugging, and worn cylinders and piston rings are conditions which are generally related to high soot concentrations.

Engine antifreeze is also a serious contaminant. As with water, small concentration of glycol can reduce filtration ability and functionality of the oil. In addition, large quantities of antifreeze can 17

Total Base Number

for used oil analysis, either may be used. Be sure to compare TBN numbers from the same method when determining oil condition.

Since most contaminants and engine combustion by-products are acidic, engine oil formulations are designed to neutralize these acids and, therefore, tend to be alkaline. As an oil ages with use, the alkalinity decreases, signaling a need to change the oil. Total Base Number (TBN) can only be replenished by an oil change. Operating with an oil with too low a TBN can cause increased wear and deposit formation.

Spectrometric Analysis Metals content in lubricating oil is determined by subjecting the oil sample to an excitation which creates spectral lines of the oil metals where their identity and concentration may be measured. Spectroscopic methods include atomic emission, inductively coupled plasma, atomic absorption, and X-ray fluorescence. All of these methods are capable of determining additive and wear metals.

An oil should be changed when the TBN drops to 1/3 of its new oil value. If high sulfur fuel (greater than 0.5% sulfur) is used, the oil should be changed at 1/2 of new oil TBN. TBN should never be below 2.0. TBN and viscosity are the most important parameters used to establish the condition of the oil. These must be monitored for optimizing oil drain intervals.

Spectrometric analysis can be used to determine changes in oil formulation, relative engine component wear, and contamination. A common problem made in the interpretation of used oil analysis, particularly with spectrometric analysis, is whether one or more of the metals is above a limit. As discussed below, a trending approach is a better way to interpret results from a spectrometric analysis. Systematic errors from sampling and the analysis itself make the declaration of whether a single sample result is abnormal or critical somewhat suspect.

TBN Test Methods TBN is the amount of acid in milligrams required to acidify 10 milligrams of oil. It is a chemical test determined by titrating a known quantity of oil to a pH of 4.5, representing the most severe condition an oil would see in use. There are two TBN test methods:

It must be recognized that only metals which have chemically reacted with the oil and particles below one micron in size are analyzed by this technique. Gross wear debris will not be detected.

Generally, chemically generated wear debris tracks with particulate wear.

ASTM D 2896 is intended to be used for new oils and measures weak and strong alkaline components.

ASTM D 4739 recommended for used oil analysis measures only the strong alkaline components.

Infrared Spectroscopy

ASTM D 2896 will give one to two TBN numbers higher than ASTM 4739 on the same oil. Although ASTM D 4739 is preferred

Infrared Spectroscopy (IR) is one of the most versatile test techniques available for both new and used oil analysis.

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For new oils, IR can identify formulation changes, even when the metals' fingerprints do not change.

For used oils, it can identify contamination from soot and water, depletion of antioxidant additives, and degradation from oxidation and nitration.

When used with other analysis techniques the IR becomes a very powerful analytical tool.

Fourier Transform Infrared (FTIR) is a relatively new variation to IR made possible by the availability of on-board instrument computers. FTIR has the advantage of speed, short analytical cycle time, small sample size requirements, and can adapt well to automation. The disadvantage of using IR more widely in used oil analysis is that a new oil sample is required and that interpretation of the data could be rather complex. The computerized instruments with their resident libraries of compounds are helping to minimize these concerns.

Flash Point Flash point is normally determined for material safety and handling precaution requirements.

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CHAPTER 5

Maintenance Intervals

Determining the optimum service interval takes many things into consideration. The same pieces of equipment in two different applications could require two different service intervals. Operating conditions, service loads, driving habits and location, are some of the conditions that could determine service intervals.

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OPTIMUM MAINTENANCE INTERVAL

Most lube manufactures have some sort of contaminant control in place and we all may assume that the oil we purchase is clean. Testing of several different oil products found on the shelf proves that there is a lack of control some where in the process from blending to packaging.

Most maintenance experts realize that the "average need" usually determines the oil-change intervals for both engines and transmissions. No two pieces of equipment have the same preventive maintenance needs. Each machine has different imperfections and operates under different conditions. Operators performing smaller or lighter jobs can cause different conditions on engine and transmission wear than those that occur during more extended use. When using oil analysis to determine maintenance intervals, little guesswork exists. Records show that some equipment can run safely two or three times longer than recommended intervals. The oil analysis may show that you are changing the oil more often than necessaryor not often enough. By eliminating too-frequent oil changes, you reduce the cost for oil and servicing, and also reduce the amount of used oil. Doing this can reduce waste oil dumping charges or the need for expensive oil and oil filter recyclers.

Examples of the elements and the possible source

Common Sources of Contaminants( Elements) Knowing where contaminants originate provide clues to how they might be prevented or removed.

• Fluid manufacture process, containment and transport are origins of contamination that begins right from the start and continues on even through packaging including bulk or barrel storage.

• Actual system production of the contaminants such as soot, fuel dilution.

• Contaminants that enter during service or maintenance.

• Poor or defective air filtration or crank or tank vent systems.

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(1) setting a quantifiable target or standard relating to a root cause of concern (e.g., a target fluid cleanliness level for a lubricant), ! •!

(2) implementing a maintenance program to control the root cause property to within the target level (e.g., routine exclusion or removal of contaminants), ! •!

(3) routine monitoring of the root cause property using a measurement technique (e.g., particle counting) to verify the current level is within the target.

Condition Based Maintenance is closely related to proactive or predictive maintenance where thresh holds are set and the equipment and lube oils tested and monitored to predict impending failure of a component.

Over the last 20+ years, a great deal of research has been devoted to fluid analysis to determine the effects of contamination from organic and inorganic contaminants on lubricating fluids.

There are three main approaches maintenance.

The result is a much better understanding of the chemical and mechanical effects of these contaminants.

Reactive Maintenance performed only after the engine or equipment has failed. This is a very costly way of operating. The catastrophic failure due to poor or lack of lubrication is typically major requiring rebuild or replacement and a substantial loss of valuable equipment run time.

The laboratory testing, analysis and reporting of the base metals and chemical make up of the fluids used in a piece of equipment has also improved to a point of being able to have the ability to do on site oil testing.

Proactive maintenance is a maintenance strategy for stabilizing the reliability of machines or equipment. Its central theme involves directing corrective actions aimed at failure root causes, not active failure symptoms, faults, or machine wear conditions.

The availability of lab equipment, ,though still expensive, has changed many fleets from reactive to proactive and condition based maintenance.

A typical proactive maintenance regimen involves three steps:

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CHAPTER 6

Racor Lube Oil Products For almost 40 years, the Parker Racor Division has bean the most trusted name in filtration for

Interactive 6.1 Beneficial Effects of Bypass Filtration – Using oil analysis to monitor the oil condition.

the engines in fuel, oil, air and water separation industries for mobile, marine and stationary applications.

Parker Racor 3400 Finch Rd. Modesto. CA 95357 1-800-344-3286 www.parker.com/racor

The powerpoint attached discusses the beneficial effects of bypass oil filtration. Lube oil analysis was used to monitor the oil condition through out the testing. To view the document, touch the arrow. Continue touching the presentation to view each individual page.To view the complete article use the following link.http://www.parker.com/literature/Racor/7774_Rev_A_Beneficial_Ef fects_of_Bypass_Filtration.pdf 23

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Parker Racor 2400 Finch Rd. Modesto, CA 95357 1-800-344-3286 www.parker.com/racor

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Absolute Rating Absolute rating means that 100% of the particles larger than the filter rating (micron) will be removed or entrapped in the filter medium.

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Absorption Absorption Is A Condition In Which Something Takes In Another Substance.This Is A Different Process From Adsorption, Since Molecules Undergoing Absorption Are Taken Up By The Volume, Not By The Surface (as In The Case For Adsorption).

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Adhesion Adhesion is the tendency of dissimilar particles and/or surfaces to cling to one another.

Lube oil provides a barrier between two moving parts to prevent the damage cused by adhesion.

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Analysis a·nal·y·sis/"ˈnal"sis/

Noun: !

1.! Detailed examination of the elements or structure of something, typically as a basis for discussion or interpretation. !

2.!

The process of separating something into its constituent elements.

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Antifreeze Antifreeze is a freeze preventive used in internal combustion engines and other heat transfer applications, The purpose of antifreeze is to prevent a rigid enclosure from undergoing catastrophic deformation due to expansion when water turns to ice. Antifreezes are chemical compounds added to water to reduce the freezing point of the mixture below the lowest temperature that the system is likely to encounter. Either the additive or the mixture may be referred to as antifreeze.

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Base Metals In chemistry, the term base metal is used informally to refer to a metal that oxidizes or corrodes relatively easily, and reacts variably with diluted hydrochloric acid (HCl) to form hydrogen. Examples include iron, nickel, lead and zinc. Copper is considered a base metal as it oxidizes relatively easily, although it does not react with HCl.

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Centistokes A unit of kinematic viscosity, one hundreth of a stokes. Symbol, cSt. In practice, measurements are usually stated in centistokes, not stokes.

The kinematic viscosity of water is about 1.0038 centistokes.

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Debris Scattered remains of something destroyed, fragments left by friction or contact causing wear.

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Dielectric A dielectric is an electrical insulator that can be polarized by an applied electric field.

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Fatigue Fatigue is the progressive and localized structural damage that occurs when a material is subjected to cyclic loading

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Flash Point The flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air.

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Glycol Antifreeze percentage (Ethylene or Propylene Glycol) levels should range between 50% and 60% to ensure proper freeze protection and boil point control. High glycol concentration can result in loss of heat transfer. Low concentrations can result in internal boiling which can cause severe metal corrosion and degradation acid formation. Freezing can result in a cracked block.

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ICP Elemental Analysis by ICP (inductively-coupled plasma) detects up to 24 metals, measuring less than 5# in size, that can be present in used oil due to wear, contamination or additives.

Wear Metals include iron, chromium, nickel, aluminum, copper, lead, tin, cadmium, silver, titanium and vanadium. Contaminant Metals include silicon, sodium, and potassium. MultiSource Metals include molybdenum, antimony, manganese, and lithium. Additive Metals include boron magnesium, calcium, barium, phosphorous and zinc. Elemental Analysis is instrumental in determining the type and severity of wear occurring within a unit.

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IR - Infrared Spectroscopy Infrared spectroscopy (IR spectroscopy) is the spectroscopy that deals with the infrared region of the electromagnetic spectrum, that is light with a longer wavelength and lower frequency than visible light. It covers a range of techniques, mostly based on absorption spectroscopy. As with all spectroscopic techniques, it can be used to identify and study chemicals. A common laboratory instrument that uses this technique is a Fourier transform infrared (FTIR) spectrometer.

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Nitration Nitration indicates excessive "blow-by" from cylinder walls and/or compression rings. It also indicates the presence of nitric acid, which speeds up oxidation. Too much disparity between oxidation and nitration can point to air to fuel ratio problems. As oxidation / nitration increases, so will total acid number and viscosity, while total base number will begin to decrease. Nitration is primarily a problem in natural gas engines.

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Oxidation A reaction that refers to all chemical reactions in which atoms have their oxidation state changed. Oxidation measures the breakdown of a lubricant due to age and operating conditions. It prevents additives from performing properly, promotes the formation of acids and increases viscosity.

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Spectrometer A spectrometer (spectrophotometer, spectrograph or spectroscope) is an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials.

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TBN - Total Base Number Total base number (TBN) is a measure of a lubricant's reserve alkalinity. It is measured in milligrams of potassium hydroxide per gram (mg KOH/g).

TBN determines how effective the control of acids formed will be during the combustion process. The higher the TBN, the more effective it is in suspending wear-causing contaminants and reducing the corrosive effects of acids over an extended time. The associated measurement ASTM D2896 and ASTM D4739-06 generally range from 6-80mg KOH/g in modern lubricants, 7-10mg for general automotive use and 10-15 for Diesel operations.

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Viscosity Viscosity index (VI) is an arbitrary measure for the change of viscosity with temperature. It is used to characterize lubricating oil in the automotive industry.

The viscosity of liquids decreases as temperature increases. The viscosity of a lubricant is closely related to its ability to reduce friction. Generally, the least viscous lubricant which still forces the two moving surfaces apart is desired. If the lubricant is too viscous, it will require a large amount of energy to move (as in honey); if it is too thin, the surfaces will rub and friction will increase.

As stated above, the Viscosity Index highlights how a lubricant's viscosity changes with variations in temperature. Many lubricant applications require the lubricant to perform across a wide range of conditionsfor example, in an engine. Automotive lubricants must reduce friction between engine components when it is started from cold (relative to engine operating temperatures) as well as when it is running (up to 200 °C/392 °F). The best oils (with the highest VI) will not vary much in viscosity over such a temperature range and therefore will perform well throughout.

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