Engine condition monitoring by Scheduled Oil sampling

All equipment operators should be familiar with sounds under the hood and smoke signals from the exhaust stack.

 1. More than 90 percent of all mechanical problems can be avoided with proper preventative maintenance.

2. Oil is the engine's lifeblood. It reduces frictions, aids in cooling, cleans vital parts, seals compression and will increase the efficiency of modern machinery. Key Points: a. Use the manufacturer's recommendations in determining classification, viscosity, grade, type and fluidity of oil.

b. Taking a chance on cheap bargain brand oil and economy brand filters is false efficiency.

3. Many agricultural manufacturers recommend the newer multi-grade (15W 40CD) oil over the single SAE 30 grade.

 4. Oil must be drained periodically to remove contamination such as water, sulfur, carbon and foreign matter.

5. Using the wrong type or classification of oil is the fastest way to void the dealer's warranty.

6. Sulfuric acid contamination is caused from excessive amounts of sulfur in diesel fuel in combination with water from condensation.

 7. A chemical analysis is the only way to really tell what is going on inside an engine.

8. Oil should be tested at regular intervals.

 9. Oil analysis can reveal where the wear is located by the type of metal accumulation in the oil.

S.O.S. program is aimed at lowering your operating costs. How does S.O.S. work? Each moving part of your engine has a normal wear rate. As these parts wear, very small metal particles float around in the oil. The number of these microscopic particles tells us the condition of your engine.

 S.O.S. analyzes these particles. S.O.S analysis results over past several years of study gets  interpretations and provides what is wearing and wrong. These wear rates were developed over years of extensive research including actual field tests covering millions of operating hours under all possible conditions. The effects of repair, load factor and working conditions were evaluated. Maintenance practices were taken into account. Many engines were disassembled to verify the data. Based on oil samples from your engine, these wear rates are then adapted to fit your particular operation. This information, is very valuable like a medical report for human beings.

S?O?S Oil Analysis

Using Scheduled Oil Sampling (S?O?S) analysis at regularly scheduled intervals to compliment a good preventive maintenance program.

Following is a brief description of the standard oil analysis tests offered in the S?O?S program.

Wear Analysis is performed with spectrophotometer instruments. Essentially, the test monitors a given component's wear rate by identifying and measuring concentrations of wear elements in oil. Based on known normal concentration data, maximum limits of wear elements are established. After three oil samples are taken, trend lines for the various wear elements can be established for the particular engine. Impending failures can be identified when trend lines deviate from the established norm. (a base sample of new oil) Wear analysis is limited to detecting components wear and gradual dirt contamination. Failures due to component fatigue, sudden loss of lubricant or sudden ingestion of dirt occur too rapidly to be predicted by this type of test.

Chemical and Physical Test detect water, fuel and anti-freeze in the oil and determine whether or not their concentrations exceed established maximum limits.

The presence and approximate amount of water is detected by a "sputter test." A drop of oil is placed on a hot plate controlled between 230 degrees and 250 degrees F. The appearance of bubbles is a positive indication (.1% to .5% is the acceptable range) with 0.5% as the maximum limit.

The presence of fuel is determined with a Setaflash Tester. The tester is calibrated to quantify the percentage of fuel dilution (4% maximum allowable fuel concentration).

The presence of antifreeze can also be determined by a chemical test. (Any indication that is positive is unacceptable.) Some new oils give a positive glycol reading. If glycol is detected, also look for an increase in sodium in the oil. Sodium compounds are used in the supplemental coolant additives. The new oil should be tested for glycol as well.

Oil Condition Analysis determines loss of the oil’s lubricating properties. An infrared analysis instrument is used to compare the properties of new oil to the properties of your used oil sample. This test allows technicians to determine the extent to which the oil has deteriorated during use and to verify that the oil is performing up to specification during the entire oil change period. Oil samples for these tests are generally taken by the customer. However, your dealer can do it for you as part of a customer support agreement designed to meet your needs.

The S?O?S analysis program must include infrared analysis to determine oil change intervals. Your dealer is the best qualified source to interpret data for the regulation of your oil change interval.

Recognizing the Causes & Effects of Contamination & Degradation.

Contamination--S?O?S identifies and measures various contaminants in the oil which cause engine failure. For example, high concentration of lead and aluminum indicates crankshaft or con-rod bearing wear. A high concentration of chromium indicates piston ring damage (with the exception of plasma coated rings.) S?O?S gives an opportunity to inspect the condition of these parts and, if necessary take action to prevent further damage. Her are some examples of typical contaminants and what effect they have on the condition of your engine.

Cause: Silicon

Effect: Above normal readings of silicon can indicate a major problem. Oil loaded with silicon becomes, in effect a grinding compound which can remove metal from any number of parts during operation. Some silicon will usually be in a new oil sample as a part of the anti-foam additive.

Cause: Sodium

Effect: A sudden increase in sodium readings indicates coolant is leaking from the cooling system into the oil. The sodium is from the coolant inhibitor. The coolant with its glycol can cause oil to thicken and become sludgy, leading to piston ring sticking and filter plugging.

Cause: Silicon, Chromium, Iron

Effect: A combination such as this signals dirt entry through the induction system, possibly causing ring and liner wear.

Cause: Silicon, Iron, Lead, Aluminum

Effect: This combination indicates dirt in the lower portion of the engine, possibly leading to crankshaft and bearing wear.

Cause: Aluminum

Effect: This can be critical. Concentrations of aluminum suggest bearing wear. Relatively small increases in the levels of this element should receive immediate attention because once rapid wear begins the crankshaft may produce large metal particles. (Aluminum can also be coming from piston skirt scuffing.)

Cause: Iron

Effect: Iron can come from any number of sources. It can also appear as rust, after engine storage. Frequently, when accompanied by a loss of oil control, increases in iron contamination indicate severe liner wear.

Cause: Soot

Effect: A high Soot content is not usually the direct cause of failure. But as an insoluble particulate, it can plug oil filters and deplete dispersant additives. Soot indicates a dirty air cleaner, engine lug, excessive fuel delivery, or repeated acceleration in the improperly set rack limiter (smoke limiter). It can also indicate a poor quality fuel.

Cause: Oxidation Products

Effect: Oxidation is a chemical reaction between oil and oxygen, just as rust is a chemical reaction between iron and oxygen. Oil oxidation rate is controlled by oxidation inhibitor additives; whenever oil is in contact with air, oxidation occurs. Oxidation agents in combustion gases of diesel engines, temperature, and certain contaminants (such as copper and glycol), accelerate oxidation. As oil oxidation increases, lubricating properties in the oil decrease, resulting in thickening of the oil, formation of organic acids, plugged filters and ultimately, ring sticking, piston deposits and lacquering.

Cause: Nitration Products

Effect: Nitration occurs in all engines but only reaches problem levels in natural gas engines. Nitrogen compounds, resulting from the combustion process, cause the oil to thicken, lose its lubricating abilities and leads to filter plugging, heavy deposits and lacquering.

Cause: Water

Effect: Water combined with oil will create an emulsion which will plug the filter. Water and oil can also form a dangerous metal corroding acid. Most instances of water contamination are the result of condensation within the crankcase. More serious contamination occurs when a leak in the cooling system allows water to enter from outside the engine oil system.

Cause: Fuel

Effect: Fuel contamination decreases the oil's lubricating properties. The oil no longer has the necessary film strength to prevent metal -to-metal contact. This can lead to bearing failure and piston seizure.

Cause: Sulfur

Effect: The presence of sulfur signals danger to all engine parts. The type of corrosive wear attributed to high sulfur content can also cause accelerated oil consumption. Also, the more fuel consumed during an oil change interval the more sulfur oxides are available to form acids. Therefore, the TBN in engines working under heavy loads should be checked more often. Fuel sulfur damage can cause piston ring sticking, and corrosive wear of the metal surfaces of valve guides, piston rings and liners.

Degradation--Causes of impending failure can take forms other than contamination. These causes are potential sources of oil degradation. Let's examine each and its effect on your engine.

Cause: Low Jacket Water Temperature

Effect: Engine jacket water outlet temperature influences the formation of corrosive acids in the engine. First, even with less than 0.5% sulfur fuel, when the temperature is below 79 degree C (175 degree F), acid vapor forms easily and corrosive attack occurs. Secondly low temperature increases the water content of the oil which can react with certain additives, deplete them and reduce the oil's protection. This can cause deposits, sludge formation, lacquering, varnish and carbon build-up, which, in turn lead to increased blowby, liner bore polishing and ring sticking.

Cause: High Humidity

Effect: In applications where humidity of 85% or over is part of the operating conditions gaseous acids are most likely to form because of the additional water content in the air. This can result in more corrosive attacks.

Cause: Oil Consumption

Effect: Oil consumption rate can provide valuable information concerning the engine. Changes in consumption, whether they are gradual or sudden are signals of ring and liner wear or ring sticking. It is critical that sufficient amounts of oil (with an adequate TBN level or alkalinity reserve) are pumped up to the ring belt area in order to neutralize acid.

Cause: Incorrect Load/Speed Ratio

Effect: Engine load plays a critical role in oil degradation. Engines running at rated speed and high load will be operating at maximum efficiency for both lubrication and cooling system. If, however, the load is reduced with the engine still running at rated speed, the lubrication and cooling systems will continue to operate efficiently, but the engine can become overcooled resulting in condensation. This can effect liners, rings and cause increased blow-by.

Wear Element Sources

Oil samples from engines show abnormal readings for the basic wear elements can indicate component problems.

Copper (CU)           Indicates

Oil Additives

Oil Cooler Leaching (no failure)

Turbochargers

Oil Pump

Wrist Pin

Rocker Arm

Cam Roller Shaft

Idler/Timing Gears

Water Pump

Oil Pump Drive

Thrust Bearing

Iron (Fe)

Cylinder Liner

Gear

Crankshaft

Camshaft

Wrist Pins

Oil Pump

Valve Train

Cam followers

Chrome

Roller Ball Bearings

Piston Rings

Exhaust Valves

Aluminium (AL)

Main Bearing

Rod Bearing

Camshaft Bearing

Crankshaft thrust Bearing

Oil Pump Bearing

Timing Gear Bearing

Piston

Dirt Entry

Lead (Pb)

Main and Rod Bearing Overlay

Camshaft Bearing Overlay

Molybdenum (Mo)

Moly Grease

Silicon (Si)

Dirt Entry

Silicon Grease

Anti foam oil additive

Sodium

Cooler Leak

Water or condensation entry

Oil Additive