Wednesday, December 30, 2009

What is Brake Cylinder Overstroke

»»  read more

Thursday, December 3, 2009

How to maintenance Air Dryer

AIR DRYER FOR VEHICLE AIR SYSTEMS

Maintenance

NOTE: The check for water may be made at 250 service hours but it is not expected that maintenance of the desiccant will be required for at least 1000 service hours.

Put a new or rebuilt desiccant cartridge in the air dryer when the desiccant in the cartridge does not have enough water absorption ability. First, make the checks that follow.

1. Check for water in the air tanks. Open the drains on the tanks. In areas where there is more than 30° F (17° C) change in ambient temperature, there can be water in the air tanks because of condensation. A small amount of water from condensation is normal and is not an indication that the air dryer is not in operation. Steps A, B and C are probable causes of too much water in the air tanks.

A. Air from another machine without an air dryer was put in the air reservoirs and did not go through an air dryer.
B. Too much air has been used for a long time and the air compressor has not been let to load and unload in a normal way (abnormal usage of air compressor).
C. The air dryer has been installed on a machine that did not have one before. This type of system will be saturated with moisture and several weeks of operation may be needed to dry it out.

2. Check all bolts that hold the air dryer to see that they are tight. Check all air and electrical connections.

3. Check the operation of the check valve in the discharge opening of the air dryer. Install an air pressure gauge in the line between the air dryer discharge and the air tanks. With the system air pressure at governor cut-out pressure and the engine not running, check the air pressure gauge. If there is a fast drop in air pressure, it could be an indication of a check valve with a defect. This can be checked by an inspection of the purge valve exhaust. The purge valve will be open when the air pressure has gone up to governor cut-out pressure. Let two minutes go by for a complete purge cycle. If there is a constant flow of air from the purge valve exhaust with the engine shut off and if the air pressure on the test gauge went down, it is an indication there is an air leak in the check valve.

4. With the compressor loaded (compressing air), put a mixture of liquid soap and water on the exhaust of the purge valve to see if there is an air leak in the valve.

5. Pull on the stem of the relief valve while the air compressor is loaded (compressing air). There must be an exhaust of air from the valve and it must stop when the stem of the valve is released.

6. Check all lines and fittings that go to and from the air dryer for leakage.

7. Check the operation of the heater and the thermostat during cold weather operation.
»»  read more

Saturday, November 21, 2009

How to Jumper Battery

Engine Starting with Jump Start Cables


------ WARNING! ------

Batteries give off flammable fumes that can explode resulting in personal injury.

Prevent sparks near the batteries. They could cause vapors to explode. Do not allow the jump start cable ends to contact each other or the machine.

Do not smoke when checking battery electrolyte levels.

Electrolyte is an acid and can cause personal injury if it contacts skin or eyes.

Always wear eye protection when starting a machine with jump start cables.

Improper jump start procedures can cause an explosion resulting in personal injury.

Always connect the battery positive (+) to battery positive (+) and the battery negative (−) to battery negative (−).

Jump start only with an energy source with the same voltage as the stalled machine.

Turn off all lights and accessories on the stalled machine. Otherwise, they will operate when the energy source is connected.


NOTICE

When starting from another machine, make sure that the machines do not touch. This could prevent damage to engine bearings and electrical circuits.

Turn on (close) the battery disconnect switch prior to the boost connection to prevent damage to electrical components on the stalled machine.

Severely discharged maintenance free batteries do not fully recharge from the alternator after jump starting. The batteries must be charged to proper voltage with a battery charger. Many batteries thought to be unusable are still rechargeable.

Use only equal voltage for starting. Check the battery and starter voltage rating of your machine. Use only the same voltage for jump starting. Use of a welder or higher voltage damages the electrical system.

Refer to Special Instruction, Battery Test Procedure, SEHS7633, available from your Caterpillar dealer, for complete testing and charging information.

Severely discharged maintenance free batteries will not fully recharge from the alternator alone after you jump start the machine. The batteries must be charged to the proper voltage with a battery charger. Many batteries that are considered to be unusable can still be recharged by this method.

Refer to Special Instruction, SEHS7633, "Battery Test Procedure" for complete information about testing and about charging. This document is available from your Caterpillar dealer.

When auxiliary starting receptacles are not available, use the following procedure.

1. Determine the reason that the engine will not crank. See Special Instruction, SEHS7768 for instructions about the use of a 6V-2150 Starting/Charging Analyzer. This is still a valid procedure if the machine does not have a diagnostic connector.

2. Engage the parking brake on the stalled machine. Place the transmission into neutral. Lower the equipment to the ground. Move all controls to the HOLD position.

3. Turn the start switch on the stalled machine to the OFF position. Turn off all accessories.

4. Turn the battery disconnect switch on the stalled machine to the ON position.

5. Move the machine that is being used as an electrical source near the stalled machine so that the jump start cables reach the stalled machine. Do not allow the machines to contact each other.

6. Stop the engine of the machine that is being used as an electrical source. If you are using an auxiliary power source, turn off the charging system.

7. Ensure that battery caps on both machines are tight and correctly placed. Ensure that batteries in the stalled machine are not frozen. Make sure that the batteries have enough electrolyte.

8. The positive ends of the jump start cable are red. Connect one positive end of the jump start cable to the positive cable terminal of the discharged battery. Some machines have battery sets.

Note: Batteries that are in series may be in separate compartments. Use the terminal that is connected to the starter solenoid. This battery or battery set is normally on the same side of the machine as the starter. The positive ends of the jump start cable are red. Connect one positive end of the jump start cable to the positive cable terminal of the discharged battery. Do not allow the positive cable clamps to contact any metal except for the battery terminals.

9. Connect the other positive end of the jump start cable to the positive cable terminal of the electrical source.

10. Connect one negative end of the jump start cable to the negative cable terminal of the electrical source.

Note: In 24 volt battery systems, the negative cable terminal of the electrical source is connected to the battery disconnect switch in the same battery set that is used in Step 9.

11. Finally, connect the other negative end of the jump start cable to the frame of the stalled machine. Do not connect the jump start cable to the battery post. Do not allow the jump start cables to contact the battery cables, the fuel lines, the hydraulic lines, or any moving parts.

12. Start the engine of the machine that is being used as an electrical source or energize the charging system on the auxiliary power source.

13. Wait at least two minutes before you attempt to start the stalled machine. This will allow the batteries in the stalled machine to partially charge.

14. Attempt to start the stalled engine. See your machine's Operation and Maintenance Manual, "Starting Above 0°C (+32°F)" for the correct starting procedure.

15. Immediately after you start the stalled engine, disconnect the jump start cables in reverse order.

16. Conclude the failure analysis on the starting system of the stalled machine and/or on the charging system of the stalled machine.

»»  read more

Tuesday, November 10, 2009

How if the Exhaust Temperature is to High

Exhaust Temperature Is Too High

Probable Causes

* Diagnostic codes

* Air inlet and exhaust system

* Air leak

Recommended Actions

Diagnostic Codes

Connect Caterpillar Electronic Technician (ET) in order to determine if any diagnostic codes for the injector solenoids are present. Check that the injector trim codes have been entered. Perform the "Injector Solenoid Test". Observe that the injector solenoids are being energized on Cat ET. Perform the "Cylinder Cutout Test". Locate the misfiring cylinder. Refer to the diagnostic functional test Troubleshooting, "Injector Solenoids".

Air Inlet and Exhaust System

1. Check the air inlet manifold pressure. Check for air inlet restrictions and/or leaks. Refer to the Systems Operation/Testing and Adjusting manual for more information.

2. Check for leaks between the exhaust manifold and the turbocharger. Check for exhaust restrictions. Refer to the Systems Operation/Testing and Adjusting manual for more information.
»»  read more

Thursday, October 29, 2009

Troubleshooting Boost Pressure Below Normal

Boost Pressure Below Normal

The probable root causes are listed below:

  • Air inlet restrictions
  • Fuel supply
  • Injector solenoid
  • Wastegate
  • Engine speed/timing signal
  • Low fueling rate
  • Active engine derate
  • Intermittent sensor problem

Perform the following checks:

  1. Check for restrictions in the air inlet system. Refer to Systems Operation, "Restriction of Air Inlet and Exhaust".
  1. Check fuel lines for the following problems: restrictions, collapse and pinched line. Repair the lines and/or replace the lines. Refer to Testing and Adjusting, "Fuel System Inspection".
    1. Check the fuel tank for foreign objects which may block the fuel supply. Check for air in the low pressure fuel supply system after you have performed the following procedures:
      • Replace the filters.
      • Work on the low pressure fuel supply circuit
      • Replace the fuel injectors.
    1. Purge air from the low pressure fuel supply circuit with the hand priming pump and by cranking the engine in 30 second cycles. After you crank the engine, stop for two minutes. This will allow the starting motor to cool. Loosen the vent plug at the fuel return. The plug is located on the rear upper left side of the engine block. Hand prime the engine again if air in fuel continues. A sight glass in the low pressure supply line is helpful in diagnosing air in the fuel.
    1. Check fuel quality. In temperatures below 0 °C (32 °F), check for solidified fuel (wax). Refer to Special Publication, SEBD0717, "Diesel Fuels And Your Engine". Check the fuel pressure while the engine is cranking. Check the fuel pressure at the filter. Refer to the Specifications manual for correct pressure values. If the pressure is low, check for plugged fuel filters. If the fuel pressure is still low, check the following items: fuel transfer pump, fuel transfer pump coupling and fuel pressure regulating valve. Check for a problem with the combustion system.
  1. Check for active diagnostic codes for the injector solenoids. Check for logged diagnostic codes for the injector solenoids. Perform the Injector Solenoid Test. Observe that the injector solenoids are being energized on the Caterpillar Electronic Technician (ET). Perform the Cylinder Cutout Test. Locate the misfiring cylinder. Refer to the diagnostic functional test Troubleshooting, "Injector Solenoids".
  1. Verify that the exhaust bypass valve for the wastegate can close. Use Cat ET to override the wastegate to 0 percent. Perform a torque converter stall test. After 15 seconds, a High Boost Pressure Event should result. If a High Boost Pressure Event occurs, the wastegate is closing properly.
  1. Check Cat ET for the following logged Diagnostic Codes 190-02 and 190-08. Refer to the diagnostic functional test Troubleshooting, "Engine Speed/Timing Sensor".
  1. Check the fueling rate. Refer to Specifications Manual. If the fuel rate is low, complete the cylinder cutout test.
  1. Connect Cat ET and check for "ACTIVE" engine derates. If the active engine derate is due to "Axle Protection", refer to the Service Manual for the transmission or implement control. Perform the torque converter stall test. Compare the achieved stall speed to specifications. If the output meets specifications, continue with diagnostic checks.
  1. Check for any recently logged diagnostic codes. Check the connectors and wiring for any signs of damage. Refer to the diagnostic functional test Troubleshooting, "Inspecting Electrical Connectors".
»»  read more

Sunday, October 25, 2009

Air Inlet and Exhaust System Operation

Air Inlet and Exhaust System Operation

The components of the air inlet and exhaust system control the quality and the amount of air that is available for combustion. There are separate turbochargers and exhaust manifolds on each side of the engine. An aftercooler is located between the cylinder heads in the center of the engine. The inlet manifold is a series of elbows that connect the aftercooler chamber to the inlet ports (passages) of the cylinder heads. There is one camshaft in each side of the block. The two camshafts control the movement of the valve system components.

Illustration 1

Air inlet and exhaust system

(1) Exhaust manifold

(2) Aftercooler

(3) Engine cylinder

(4) Air inlet

(5) Turbocharger compressor wheel

(6) Turbocharger turbine wheel

(7) Exhaust outlet

Clean inlet air from the air cleaners is pulled through air inlet (4) into the turbocharger compressor by turbocharger compressor wheel (5). The rotation of the turbocharger compressor wheel causes the air to compress. The air is forced through a tube to aftercooler (2). The aftercooler lowers the temperature of the compressed air before the air goes into the inlet chambers in each cylinder head. This cooled and compressed air fills the inlet chambers in the cylinder heads. Air flow from the inlet chamber into the cylinder is controlled by the inlet valves.

There are two inlet valves and two exhaust valves for each cylinder. Refer to Systems Operation, "Valve Mechanism". The inlet valves open when the piston moves down on the inlet stroke. The cooled, compressed air is pulled into the cylinder from the inlet chamber.

The inlet valves close and the piston starts to move up on the compression stroke. When the piston is near the top of the compression stroke, fuel is injected into the cylinder. The fuel mixes with the air and combustion starts. The force of the combustion pushes the piston downward on the power stroke. When the piston moves upward the piston is on the exhaust stroke. The exhaust valves open and the exhaust gases are pushed through the exhaust port into exhaust manifold (1). After the piston makes the exhaust stroke, the exhaust valves close and the cycle starts again.

Exhaust gases from the exhaust manifold go into the turbine side of the turbocharger. The exhaust gases cause turbocharger turbine wheel (6) to turn. The turbine wheel is connected to the shaft that drives turbocharger compressor wheel (5). The exhaust gases exit through exhaust outlet (7).
»»  read more

Sunday, September 27, 2009

CAT-Applied Failure Analysis OIL and your engine part 2

Diesel Engine Oil Recommendations

Caterpillar Diesel Engine Oil

Caterpillar Oils have been developed and tested to provide the full performance and service life that has been designed and built into Caterpillar Engines. Caterpillar Oils are currently used to fill diesel engines at the factory. These oils are offered by Caterpillar dealers for continued use when the engine oil is changed. Consult your Caterpillar dealer for more information on oils.

Due to significant variations in the quality and performance of commercially available oils, Caterpillar recommends:

* Caterpillar Diesel Engine Oil (10W30)
* Caterpillar Diesel Engine Oil (15W40)

Caterpillar multigrade Diesel Engine Oil is formulated with the correct amounts of detergents, dispersants, and alkalinity to provide superior performance in Caterpillar Diesel Engines.

Caterpillar multigrade Diesel Engine Oil is available in 2 viscosity grades: 10W30 and 15W40. For direct injection engines, see Table 1 to choose the correct viscosity grade for the ambient temperature. Multigrade oils provide the correct viscosity for abroad range of operating temperatures.

Multigrade oils are effective in maintaining low oil consumption and low levels of piston deposits.

Caterpillar multigrade Diesel Engine Oil can be used in other diesel engines and in gasoline engines. See the engine manufacturer's guide for the recommended specifications. Compare the specifications to those of Caterpillar multigrade Diesel Engine Oil. The current industry standards for Caterpillar Diesel Engine Oil are listed on the product label and the data sheets for the product.

Consult your Caterpillar dealer for part numbers and available sizes of containers.

NOTE: In addition to passing the API CH-4, CG-4, CF-4, CF oil classification tests, Caterpillar 15W-40 multigrade DEO (CH-4) also passes additional proprietary tests that include piston ring sticking, oil control, wear and soot tests. Proprietary tests help ensure that Caterpillar multigrade provides superior performance in Caterpillar Diesel Engines. In addition, Caterpillar multigrade surpasses many of the performance requirements of other diesel engine manufacturers so it is an excellent choice for many mixed fleets. True high performance oil is produced using a combination of industry tests, proprietary tests, field tests, and prior experience with similar formulations. All these factors are used to design and develop the high performance and high quality lubricants sold by Caterpillar.



Commercial Oils

The performance of commercial diesel engine oils is based on American Petroleum Institute (API) classifications, which are developed to provide commercial lubricants for abroad range of diesel engines that operate at various conditions.

If Caterpillar multigrade Diesel Engine Oil is not used, only use commercial oils that meet the following classifications:

* API CH-4 multigrade oil (preferred oil)
* API CG-4 multigrade oil (preferred oil)
* API CF-4 multigrade oil (acceptable oil)

NOTICE: In selecting an oil for any engine application, both the oil viscosity and oil performance category as specified by the engine manufacturer must be defined and satisfied. Using only one of these parameters will not sufficiently define an oil for an engine application.
Select an oil with a suitable viscosity and a proper performance classification.

Lubricant Viscosity Recommendations for Direct Injection (Dl) Diesel Engines

The proper SAE viscosity grade of oil is determined by the minimum ambient temperature during cold engine startup and the maximum ambient temperature during engine operation.

Refer to Table 1 (minimum temperature) in order to determine the required oil viscosity for starting a cold engine.

Refer to Table 1 (maximum temperature) in order to select the oil viscosity for engine operation at the highest ambient temperature that is anticipated.

Generally, use the highest oil viscosity that is available to meet the requirement for the temperature at start-up.

The API Donut
To aid customers in selecting the appropriate oil, the American Petroleum Institute has developed the API "donut" symbol. The symbol (see drawing below) indicates the API service classification (upper half of the circle), SAE viscosity grade (center of the symbol) and, if applicable, energy conserving feature of an oil (bottom half of the circle). Energy conservation is not applicable to heavy-duty diesel engine oils.

While any oil supplier may use the API service classifications to indicate the performance level of anyone of their commercial oils, only licensed companies may use the API donut symbol on their labels. Licensees who use this donut have certified that each licensed oil meets all prescribed technical performance standards. Some monitoring is done through the SAE Oil Labeling Assessment Program (OLAP), co- sponsored by API and the U.S. Army, which analyzes a representative sample of oils in the marketplace. Therefore, for best assurance that an oil does meet the advertised performance classification, select an oil that has the API donut display.


Cleanliness
Normal engine operation generates a variety of contaminants- ranging from microscopic metal particles to corrosive chemicals. If the engine oil is not kept clean through filtration, this contamination would be carried through the engine via the oil.

Oil filters are designed to remove these harmful debris particles from the lubrication system. Use of a filter beyond its intended life can result in a plugged filter. A plugged filter will cause the bypass valve to open, releasing unfiltered oil. Any debris particles in the oil will flow directly to the engine. When a bypass valve remains open, the particles that were previously trapped by the filter may also be flushed from it and then through the open bypass valve.

Filter plugging can also cause distortion of the element. This happens when there is an increase in the pressure difference between the outside and inside of the filter element. Distortion can progress to cracks or tears in the paper. This again allows debris to flow into the engine where it can damage components.

1.New filter element(s) should be installed any time the engine sump oil is drained and the engine sump is filled with new oil.

2.Spiral Roving and Acrylic Beads maintain pleat
stability and spacing, prevent bunching, and maximize
efficiency and capacity.

3.Proprietary Media designed to maximize engine life.

4.Non-Metallic Center Tube prevents metal contamination
and is stronger than metal to prevent collapsing.

5.One-Piece Uretane End Caps bond tightly with filter
media for greater strength.



Contamination & Degradation

1. Taking an oil sample
2. Analyzing an oil sample using an inductively coupled plasma spectrophotometer.
3. The presence of water in the oil is verified and measured by the sputter test.
4. The presence of fuel in the oil is verified and measured with a Setaflash Tester.



Proper oil maintenance is imperative to keep diesel engines operating at peak performance. Oil maintenance includes scheduled oil changes and oil analysis. Oil analysis is important because the performance of engine oil slowly degrades with time. This degradation takes place as the amounts of wear metals and contaminants increase. Under severe operating conditions, the degradation process can be accelerated. For diesel engines, severe conditions are defined as one or more of the following: high load factor, excessive cycling, extended oil drains, high altitude, dusty air, prolonged idle, high sulfur fuel, and low jacket water temperatures. In either normal or severe conditions, crankcase oils eventually lose the ability to adequately lubricate and protect engine parts from accelerated wear and damage.

It is therefore important to analyze the oil at regular intervals. Caterpillar has developed a maintenance management tool that evaluates oil degradation and detects the early signs of internal component wear. The Caterpillar tool for oil analysis is called S·O·S SM Oil Analysis and it is part of the S·O·S SM Services program. S·O·S SM Oil Analysis divides engine oil analysis into three basic categories: wear rate, oil condition, and additional tests. Together, these 3 types of analysis are used to evaluate oil degradation and detect potential engine problems. A properly administered S·O·S SM Oil Analysis program will reduce repair costs and lessen the impact of downtime.

S·O·S SM Wear Rate Analysis
Prevent problems and reduce costs by knowing wear rates
Wear Rate Analysis is an integral part of our S·O·S SM Services program that helps you maintain engine performance and maximize availability. Through regularly scheduled testing of oil samples from your engine, Wear Rate Analysis detects tiny metal particles caused by component wear. By monitoring trends in the type and quantity of particles, you can get early warning of problems before major damage occurs.


Understanding wear metals
Every engine produces wear metals in everyday operation. If wear accelerates, the concentration of wear metal particles increases, signaling a problem. Wear Rate Analysis allows you to find problems before they result in major repairs or engine failure.

Wear Rate Analysis can detect particles that range up to about 10 microns in size. Wear metal concentrations are expressed in parts-per-million (ppm). The S·O·S SM Services program tests for at least 9 different substances: copper, iron, chromium, lead, tin, aluminum, molybdenum, silicon and sodium. All are wear metals found in Caterpillar engines except silicon (which generally indicates dirt) and sodium (which indicates water or coolant). Certain elements in a sample may be from the oil additive package rather than from wear within the system. Skilled dealer interpreters can tell the difference between normal elements and those that indicate abnormal wear.


Trending wear metals in your engine
Two identical engines under identical conditions may generate wear particles at different rates. Our S·O·S SM interpreters have access to a large database of samples for comparison with samples from your engine. However, your own engines may provide the best guidelines for appropriate levels of wear metals in each compartment. That's why trending is an essential part of Wear Rate Analysis. After three samples have been taken from a particular compartment, a trend for each wear metal is established. Our interpreters then compare subsequent samples to this trend line to quickly spot deviations as well as monitor gradual changes in concentration levels. This attention to trends also assists with life cycle analysis, helping you optimize productivity.



The Technology Behind Wear Rate Analysis
We use an emission spectrometer to perform Wear Rate Analysis. The spectrometer determines wear elements and silicon in a sample by subjecting the oil to very high temperatures. At these temperatures, the elements in the sample are "atomized," with each emitting a different wavelength of light energy. An optical system measures and records the light energy and calculates the results in parts-per-million for each element.


Pinpointing the Causes and Effects of Component Wear
By comparing infrared (Oil Condition) test results with wear metal buildup, we can pinpoint probable causes of elevated wear metals. The chart above illustrates some of the most common wear metals, their source(s), and the potential problems they indicate.

Spectrometry detects dirt contamination as well as wear metals. Silicon is the most common element indicating dirt entry, although some clay soils also produce increased aluminum readings.


Monitoring Your Components
When S.O.SSM analysis identifies an increase in the concentration of one or more metals, it can point to the wearing component most likely causing the increase and, often, the probable cause. For example, a sudden increase in silicon and iron in an oil sample would probably indicate a problem caused by either air system leaks or crankcase seal leaks (see chart above).


Silicon/Aluminum Ratio in Dirt Varies by Location
The primary constituents of dirt are minerals containing silicon and aluminum. The ratio of these 2 elements varies widely from place to place. Clay soils contain nearly as much aluminum as silicon. This is one reason why local interpretation of your sample results is important. We are familiar with the soils in your area, giving us the best understanding of the combinations of elements in your samples.



S·O·S SM Oil Condition Analysis

Maximize Performance by Knowing Your Oil Condition

Oxygen exposure, heat and contaminants cause all oils to degrade. Engine oil is particularly susceptible to degradation by sulfur, nitration, by- products of combustion, high temperatures, and water from the combustion process or condensation. Oil Condition Analysis, part of the comprehensive S·O·S SM Services program, helps prevent component damage by monitoring your oil and keeping track of its degradation. Oil Condition Analysis also allows you to correct problems that affect oil performance. The bottom. line benefit: maximum oil performance, optimum oil change intervals and reduced repair costs.


Understanding Oil Condition Analysis
Oil Condition Analysis is similar to Wear Rate Analysis with one important exception: it evaluates chemical compounds in the oil rather than wear element particles.

It works like this:

1. You submit a sample of new oil, called "reference oil," when you enroll in the S·O·S SM Services program and when you get new shipments of bulk oil. Reference oil samples are processed at no cost to you. If you are using Cat oil, new oil samples may not be necessary. Advise your S·O·S SM analyst of the viscosity of the Cat oil you use in each system; it has its own Cat oil reference samples.
2. The new oil is scanned by a special instrument using infrared light. Information is stored in the instrument's memory.
3. At each scheduled interval, you submit a sample of used oil.
4. The Oil Condition Analysis instrument focuses a beam of light through a film of used oil and records the data.
5. The instrument uses a mathematical formula to compare the used and new oils and quantify any differences.


Fourier Transform Infrared Analysis
S·O·S SM Oil Condition Analysis includes an infrared instrument that uses a mathematical method to convert raw instrument data into meaningful terms. This test, often called FT -IR (Fourier Transform Infrared Analysis), identifies and quantifies organic compound groups by measuring their infrared absorption at the specific wavelength of each group. Besides identifying oxidation, soot, sulfur products and nitration, the test is also used to scan for oil contamination by fuel, water or glycol (engine coolant).


Identifying Oil Condition Before It Causes Problems
Oil Condition Analysis detects soot, oxidation and nitration products and sulfur products/acids. This test can also detect contamination by water, fuel and glycol from coolant. If detected, specific contaminant tests are used to confirm findings. Oil Condition Analysis focuses on:

Soot
Soot is the insoluble residue of partially burned fuel. It is held in suspension by the oil additive package and causes engine oil to turn black. When soot drops out of suspension in the oil, it contributes to additive depletion and eventually increases oil viscosity. Heavy concentrations of soot can cause bearing damage by starving contact surfaces of lubrication.

Oxidation
Oxidation occurs when oxygen molecules chemically join with oil molecules. This chemical reaction is accelerated by high oil temperatures, glycol contamination from engine coolant, the presence of copper and from extended oil change intervals. Oxidation causes the oil to thicken, form acids, and lose lubrication qualities, which threatens the life of your components. Oxidized oil will cause deposits on engine pistons and valves, stuck rings, and bore polishing.

Nitration Products
Nitration occurs in all engine oils but is generally only a problem in natural gas engines. Nitrogen compounds from the combustion process thicken the oil and reduce its lubricating ability. If nitration continues unchecked, it can result in filter plugging, heavy piston deposits, lacquering of valves and pistons, and eventual failure.

Sulfur Products/Acids
Sulfur is present in all fuels and affects all engines. During combustion, fuel sulfur oxidizes then combines with water to form acid. Acid corrodes all engine parts but is most dangerous to valves and valve guides piston rings and liners.


Optimizing Your Equipment with the S·O·S SM Services Program
Oil degradation may be the result of a number of factors and conditions, including extended oil change intervals, abnormal temperatures, or contamination by fuel, water or coolant. Lower quality oils will degrade more rapidly than a premium quality lubricant.

With Oil Condition Analysis, you can determine the extent to which oil has deteriorated during use and verify whether it is performing up to specification during the entire oil change period.

Oil Condition Analysis is just one part of the S·O·S SM Services program that provides information to reduce downtime and save you money by preventing major engine problems.


Additional Tests: Glycol, Water, Fuel Detection, Viscosity, and TBN
Additional oil analysis tests may be required to better define the condition of used engine oil. If the FT -IR results show the presence of glycol, water, or diesel fuel, additional testing will be needed to measure the quantity of these contaminants in the oil. Also in some cases, severe conditions may warranty the need for additional oil tests. These additional tests enhance the information already gathered in the Wear Rate Analysis and Oil Condition Analysis.

Glycol (Coolant)
Glycol causes rapid oxidation of the oil and usually indicates a cooling system leak. Severely oxidized oil becomes sticky and forms sludge that plugs the filter. Any amount of glycol contamination in the oil is unacceptable. Engines using water-to-oil coolers may become contaminated with coolant if a leak develops in a cooler tube or seal.

Water
If infrared analysis indicates the presence of water, the approximate amount is determined by placing a drop of oil on a plate heated to between 2300-250° F. If water is present, the oil will bubble and sputter. By comparing the amount of bubbling to laboratory control samples, experienced laboratory technicians can determine the quantity of water in the sample. Any amount over 0.5% is considered excessive.

Water can contaminate a system by leaking in from the outside or condensing in the engine's crankcase or compartment. When water combines with oil, it reduces the oil's ability to lubricate and forms a sludge that plugs filters. Water passing between very close components can create "hot spots." If the water gets hot enough, it causes tiny steam explosions that can fracture metal.

Fuel
Fuel contamination is confirmed using a flash test in which the used oil is heated to a prescribed temperature in a closed cup, then subjected to a flame. Fuel vapors driven off by the heat will flash.

Fuel in the engine oil reduces its lubricating properties. Small amounts of fuel are common as a result of the combustion process. But if fuel levels exceed 4% we will suggest a check for defective fuel injection nozzles and other sources of leakage. Fuel dilution is generally the result of extended idling, incorrect timing, or a problem with the fuel injectors, pumps or lines.

TBN
All diesel fuels contain some sulfur. How much depends on the amount of sulfur in the crude oil and/or the refiner's ability or desire to remove it. One of the functions of lubricating oil is to neutralize sulfur by-products (sulfurous and sulfuric acids), as well as organic acids formed by oxidation. In this way, the oil helps prevent corrosive damage. Additives in the oil contain alkaline compounds formulated to neutralize these acids. The measure of reserve alkalinity in the oil is known as the Total Base Number (TBN). Generally, the higher the TBN value, the more reserve alkalinity capacity the oil contains.

Sulfuric and other acids signal danger to metal engine parts, causing corrosive wear to the surfaces of valve guides, piston rings and liners. The type of corrosive wear attributed to high sulfur content fuel can also accelerate oil consumption. Because the level of sulfur oxides in a used oil increases with a longer oil change interval, checking the TBN of oil is important. The TBN of the oil should be checked for each oil sample.

Engine jacket water outlet temperature influences the formation of corrosive acids. Even when using a fuel with less than 0.5% sulfur coolant temperatures below 82.2° C (180° F) can cause acid vapors to condense in the engine oil system and corrosive attack occurs. Low temperatures also increase the amount of water condensation which otherwise might have evaporated out of the oil at normal operating temperature. This residual water depletes certain oil additives and reduces the oil's ability to protect engine parts. This causes deposits, sludge formation, lacquering, varnish and carboning. In applications where humidity is high, acids are more likely to form because of the additional water in the air. So, both low coolant temperature and high humidity can result in increased corrosive attack.

Viscosity
Viscosity is defined as a measure of a fluid's resistance to flow. The standard measure of this property for crankcase oils is termed "kinematic viscosity." Kinematic viscosity is based on the ability of an oil to flow under the influence of gravity through a capillary tube. The test for kinematic viscosity is defined by ASTM 0445.

Crankcase oil may begin to lose its lubricating properties after experiencing a 3 cSt. Change. An oil which has experienced a viscosity change of this magnitude should not be continued in use because damage to the engine may occur.

There are 2 most frequent causes for an increase in crankcase oil viscosity. The first is an accumulation of combustion by-products (mainly soot) which can thicken the oil. The second is heat, which can cause oxidation. Also, oxidation, with resultant oil thickening, can occur if engine coolant (glycol) enters the crankcase. Water from condensation or contamination can also contribute to oxidation.

There are two primary reasons an oil might experience a decrease in viscosity. The first is fuel dilution, which is not a failure of the oil but a contamination problem that must be resolved promptly. Another possible reason for a viscosity decrease is shearing of the long-chain polymer molecules that comprise the viscosity improver additives. In such an instance, the oil can no longer maintain performance at higher temperatures and migrates toward the lower viscosity of the base stock mineral oil. In either case, fuel dilution or shearing, the oil can "thin down" to the point it can no longer maintain an adequate oil film at operating temperatures.

When investigating a change in oil viscosity be alert to the possibility that the wrong oil was used during an oil change or as make-up oil. Careful analysis of FT -IR test results can help determine this possibility.

An oil that has experienced a 3 centistoke change has been used beyond its useful life. An increase in wear metal debris will probably be detected in samples of oil which have experienced this amount of viscosity change.



Typical Examples of Oil Related Failures

The Lubrication System
A basic understanding of the engine lubrication system is not only helpful in understanding how oil contamination/degradation can damage engine components but also in understanding how alack of oil can have an equally debilitating effect.

Most oil-related failures are caused either by contaminated or degraded oil flowing through the engine or by oil failing to flow to a given component. Knowing how the lubrication system "feeds" the engine can simplify failure analysis. An example of this would be a bearing failure due to lack of lubrication. If the failure is discovered early, the bearings farthest from the oil supply may show the greatest damage.

The lubrication system for each engine may differ slightly; however, most principles are the same. The lubrication system for the 3408 Engine is similar to other engine lubrication systems. As shown in the schematic, the oil pump sends oil through the oil cooler and then through the oil filters. The bypass valves for the oil cooler or oil filters protect the system if there is a reduction in the oil flow. When the engine is started with cold oil, or if the cooler or filter becomes plugged, the bypass valves assure a constant flow of oil to the engine oil passage.

Oil from the filter flows into the block oil manifold. This oil then flows into the various block oil passages to lubricate and cool the various engine components; then it returns to the oil pan.

Bearings
Oil-related bearing failure is usually attributed to one of two sources: lack of lubrication or dirt in the oil.

Lack of lubrication or oil starvation refers to an insufficient oil film between the crankshaft journal and bearing. Prolonged operation of an engine with an insufficient oil film will cause damage to progress quickly to a smeared bearing, then to a scuffed bearing, and finally to a seized bearing. The first stage of this type of damage is smearing. This stage will show displacement of the lead-tin overlay, normally in the center of the bearing.

In the second stage of damage, scuffing, the aluminum in the center of the bearing is displaced. The final stages of failure result in total seizure.

In all three stages the rotating journal displaces some of the bearing material from the crown toward the mating face of each bearing half. The amount of displaced material will depend on how severe the lack of lubrication is.

Contamination in the oil causes abrasion and results in scratching the bearing surface by wiping aluminum, plastic wood, cloth, etc. can also attack the journal surface. As the bearing and journal surfaces wear, clearances increase and oil film thickness changes, resulting in uneven support of the surfaces.

A major source of debris-Iaden oil is a plugged filter. Plugged filters allow unfiltered oil containing wear particles, dirt and debris to flow to the bearings, scratching and damaging their surfaces.

Excessively dirty oil can cause damage even after changing oil. Some old abrasives may remain embedded in the bearings and cause the bearings to act like a grinder on the crankshaft. See the next section, "Minimizing the Occurrence of Oil-Related Engine Failure," for examples of crankshaft damage.
Bearing shows smearing, which is the initial stage of damage caused by lack of lubrication.
Scuffed rod bearing with more severe damage as a result of lack of lubrication.
Seized bearing, which is the final stage of lack of lubrication damage.
Very heavy scratches and wear caused by lack of oil. Some of the lead-tin overly has been lost.
Set of main bearings that were damaged by debris. The bearings have all stages of damage.
Scratched bearing surface. Notice embedded particles of debris.

Scratches and wear on journal surface.


Crankshafts
The oil that flows to the bearings forms an oil film between the crankshaft journal and bearing. Rotation of the crankshaft journal tends to force oil between the journal and the bearing and, during normal operation, prevents metal-to-metal contact as the pressurized oil develops.

Lack of lubrication, or oil "starvation," causes metal- to-metal contact, increased friction, and higher temperatures that lead to the bearing seizing to the shaft. In extreme cases the bearing surface will adhere so tightly that the crankshaft surface will be completely destroyed.

Contaminated oil also causes excessive wear of the crankshaft. This is almost always a result of abrasives/contamination embedded in the bearing.

Oil film between crankshaft journal and bearing.

Result of oil starvation.

Deep circumferential scratches shows effects of abrasives embedded in the bearing surface.



Pistons, Rings and Liners

Oil-related piston failure is most commonly caused by the abrasive action of contaminated oil which results in wear of the piston skirt. Indications include a very dull gray piston skirt, chrome facings worn off on all rings, oil ring rails worn away, badly worn grooves and some liner wear.

Piston scuffing, which appears in streaks on the skirt, particularly in the pin bore area, and little or no scuffing on the first land, may be caused by inadequate liner lubrication. Breakdown of oil film can produce seizure marks.

Piston rings can show wear in the spring groove. Some spring groove wear is normal, but neglected oil changes will cause severe ring "lock-up" that occurs when the spring catches in a worn groove and prevents full expansion.

Liner damage can be caused by lack of lubrication or by abrasives which can polish the bore (remove the crosshatch pattern) and leave a shiny surface.

Piston skirt damaged by abrasive wear.

Seizure marks from top to bottom can indicate a cooling or lubrication
system failure.

Wear caused by no lubrication for a short period of time.

The heavy first and second land deposits indicate the oil can no longer keep
the piston clean. The extreme degradation and deterioration of the oil maybe
due to extended oil change intervals or improper oil performance
classification selection.

Shiny areas on the inside liner surface caused by heavy deposits on the
piston lands.

Turbochargers

Oil-related turbocharger damage is caused by oil contamination or lack of oil that can be related to operating practices. The oil supplied to the turbocharger is required to provide bearing (both journal and thrust) lubrication and also for cooling the bearing, particularly on the turbine end.

In operating the engine, startup and shutdown practices can aggravate turbocharger bearing failures. When starting the engine, particularly at colder ambient temperatures when the oil is more viscous, allow a short idling time. This idle time will allow the oil to warm up for proper filtration and flow before high engine and turbocharger speeds are attained. On engine shutdown, a short time at idle speed will allow the flowing oil to cool the turbocharger bearing housing. Without the cooling period, the oil will oxidize or coke, creating deposits on bearing surfaces and in oil passages which can restrict oil flow on the next operating period.

Oil contamination can erode oil holes and can scratch and wear bearing surfaces as well as damage shaft and housing surfaces. The lack of oil for proper lubrication will cause bearing surface damage and also cause metal discoloration due to increased temperature.

Damage to the turbocharger bearings from contamination or lack of lubrication allows motion of the shaft that permits the compressor wheel to contact its housing. Typical contact damage caused by shaft motion will be indicated by face rubbing on a few blades near their inducer section. On the back of the wheel, 180° from where the face rubbing appears, there will be some evidence of contact with the center housing.

Deep scratches and damage to oil holes on bearings.

Damage from large abrasive particles in oil. Large, wide grooves around the
journal bearings indicate that big particles, such as steel chips, have gone
through the turbocharger lubrication oil.

Lack of lubricant caused this journal bearing to be deformed.

Oil holes damaged on the O.D. and reduced in size on the I.D. of journal
bearing due to lack of lubricant.

Rubbing on face and back of compressor wheel. This is caused by shaft
motion due to imbalance or shaft bent at assembly.


Lack of lubricant and contaminated oil both cause wear on thrust bearings, making it difficult to pinpoint the cause of failure. Checking journal bearing condition will help determine the exact cause of the failure. Heat discoloration of thrust rings also points to lack of lubrication. On AiResearch turbochargers, distortion is most commonly seen on the inboard side of the thrust rings. On the Schwitzer models, discoloration tends to be confined to one area of the ring face. Often, rubbing marks are present. Damage appears on both rings.
Heat discoloration on the shaft

Shaft broke when contact on turbine hub, due to thrust bearing failure, weakened.

Heat discoloration on inboard side of thrust ring (AiResearch).

Heat discoloration and rubbing marks confined to one area on face of both
rings (Schwitzer).

Scratches on both bearing journals...dirty oil.
Bearing damage and excessive shaft motion caused by lack of lubrication or abrasives in the oil may eventually cause the shaft to bend or break. Generally, parts worn by abrasives will look eroded As a rule, the bearing surfaces will not look smeared and parts will show no heat discoloration. Of the illustrations, the first typifies wear from foreign material in the lubricating oil; deep grooves are worn into the two steel thrust washers. The second shows abrasive wear on the AiResearch turbocharger; deep grooves are worn in the thrust washer. The damage in the third illustration is harder to identify. It is very fine abrasive wear, which makes the thrust bearing surface look polished, and there is no heat discoloration

Schwitzer. Wear grooves on mating surfaces of thrust washers. Center
washer is new thrust washer.

AiResearch. Wear grooves on surface of thrust washer

Schwitzer. Thrust bearing surface polished by fine abrasives in the oil.


Valves
Most oil-related valve failures result from deposit formation or oil starvation.

The usual cause of valve stem seizure is deposit collection between the valve stem and guide. Seizure is indirectly caused by the accumulation of deposits-contamination in the oil. More specifically, deposits accumulate from the decomposition of lubricating products into oxidized residue and the normal wastes generated from the combustion process. The progressive buildup of these deposits acts to accelerate bell mouthing of the guide.

Valve stem scuffing and/or seizure can also be caused by lack of lubrication to the valve and valve guide.

Valve seat carbon deposits can create problems if the deposits are excessive. Some lubrication is necessary to prevent extreme wear of the valve seat and the insert in the head. But excessive deposit formation can lead to thick carbon build-up on the valve seat that will then break up and flake out, allowing combustion gas leakage. This hot gas leakage (guttering) allows high temperature across the valve face with cracking and/or melting of the valve.

This type of valve failure can exist in liquid and gas fueled engines. The carbon formation tendency of the oil and the sulfated ash level of the oil affect the carbon formed on the valve seat.

Valve guttering effect caused by excessive deposit formation.
Valve stem scuffing or seizure.

Minimizing the Occurrence of Oil Related Engine Failure

Fuel Sulfur
Oil contamination can take a number of forms, but none is more rapid in its harmful effect than the sulfuric acid that can be produced by high sulfur fuels.

In October 1993, low sulfur fuel was mandated in the United States for on-highway vehicles. In the state of California "ALL" vehicles are required to use low sulfur fuel. Low sulfur fuel was introduced as a means to meet the engine manufacturers' (EMA's) need for emissions control in these applications. There are few or no negative effects of low sulfur fuels.

Coping with the effects of fuel sulfur is not a simple task. Even though the use of proper lubricants and correct intervals reduces the degree of corrosive damage, engine wear will increase significantly when fuels with high sulfur content are used. Not only do these fuels produce acids which chemically attack the engine, causing corrosive wear, but the oils used to negate the acid effects have a higher ash content which increases chances of deposit formation.

Know the fuel sulfur content by periodically asking your supplier or by having the fuel analyzed. Sulfur content can change with each bulk delivery.


Total Base Number (TBN) and Fuel Sulfur Levels for Direct Injection (Dl) Diesel Engines
The Total Base Number (TBN) for an oil depends on the fuel sulfur level. For direct injection engines that use distillate fuel, the minimum TBN of the new oil must be ten times the fuel sulfur level. "STM 02896" defines the TBN. The minimum TBN of the oil is five regardless of fuel sulfur level. Illustration 2 demonstrates the TBN.

1. TBN of new oil
2. Change the oil when the TBN deteriorates to 50 percent of the original TBN.

Use the following guidelines for fuel sulfur levels that exceed 1 .5 percent:

* Choose an oil with the highest TBN that meets one of these classifications: API CH-4, API CG- 4, and API CF-4.
* Reduce the oil change interval, basing the interval on the oil analysis. Ensure that the oil analysis includes the condition of the oil and a wear metal analysis.

Oil with a high TBN can produce excessive piston deposits. These deposits can lead to a loss of control of thJustify Fulle oil consumption and to the polishing of the cylinder bore.

NOTICE: Operating Direct Injected (Dl) diesel engines with fuel sulfur levels over 1.0 percent may require shortened oil change intervals in order to help maintain adequate wear protection.



Total Base Number (TBN) and Fuel Sulfur Levels for Precombustion Chamber (PC) Diesel Engines
The TBN for a new oil depends on the fuel sulfur level of the fuel used. The minimum TBN of the oil used in PC engines must be 20 times the fuel sulfur level. The TBN is defined in "ASTM 02896." Regardless of fuel sulfur level, the minimum TBN of new oil is 5. See Illustration 2, below.

1. TBN of new oil
2. Change the oil when the TBN deteriorates to 50 percent of the original TBN.



Whenever the fuel sulfur exceeds 1.5 percent, do the following tasks:

* Choose an oil with the highest TBN that meets one of these classifications: API CF, API CF-4 API CG-4, and API CH-4.
* Reduce the oil change interval, basing the interval on the oil analysis. Ensure that the oil analysis includes the condition of the oil and a wear metal analysis..

NOTICE: Operating PC engines at fuel sulfur levels over 1.0 percent may require shortened oil change intervals to maintain adequate wear protection.

Basic Maintenance of the Lubrication System
Probably the most important step in preventing oil-related failure is to be on the alert as a matter of routine. Specifically, this means being sensitive to the early signs of trouble. One way to do this is with a very basic check for obvious warning signals. Such a check would best be made often and include these 3 key elements:

1. An external check of the engine for any obvious signs of leakage from any compartment.
2. A check of the oil pressure gauge. A change here could indicate anything from a defective oil pump to a stuck pressure relief valve.
3. A check of the oil level gauge. A low oil level could reveal excessive consumption, leakage, or failure of oil lines.

Another important rule of thumb is to adhere to recommended oil and filter change intervals. This is paramount in the fight against oil contamination / degradation, especially with regard to high sulfur fuels.

»»  read more

Wednesday, September 9, 2009

CAT-Applied Failure Analysis OIL and your engine

Applied Failure Analysis
OIL and your engine

Bearing failure, piston ring sticking, and excessive oil consumption are classic symptoms of oil-related engine failure. How do you avoid them? There are numerous ways, three of the most important being Scheduled Oil Sampling (S·O·S SM), regular maintenance of the lubrication system, and the use of correct lubricants. Following these recommendations can mean the difference between experiencing repeated oil related engine failure and benefiting from a productive and satisfactory engine life. This booklet attempts to tell the story of oil: what it is composed of and what its functions are, how to identify its contamination and degradation, typical consequences, and some preventive measures to help you protect your engine against the devastating effects of oil related engine failure.

Understanding Oil

Function
Engine oil performs several basic functions in order to provide adequate lubrication. It works to keep the engine clean and free from rust and corrosion. It acts as a coolant and sealant; and it provides an oil film cushion that keeps metal-to- metal contact to a minimum, thereby reducing friction and wear. But these are only the basic functions of oil. It is the particular demands of a given application and the special conditions under which an oil is used that largely determine the numerous additional functions oil must perform. These additional functions make choosing the correct oil for the job vital.

The selection of a suitable lubricating oil should be based on the engine performance requirements as specified by the manufacturer, as well as the application and the quality of the available fuel. Diesel engines, for instance, normally operate at lower speeds but higher temperatures than gasoline engines, making conditions exceptionally conducive to oil oxidation, deposit formation and corrosion of bearing metals. Under these conditions, the oil is expected to function in an expanded capacity. This is where additives are noticed. The final performance characteristics of the oil depend on the base oil and the additives used. The amount or types of additives used vary according to the properties of the base oil and the environment in which the oil will function.


Base Stocks
Lubricating oil begins with base oil or base stock. Base stocks are mineral (petroleum) or synthetic origin, although vegetable stocks may be used for specialized applications. The base stock provides the basic lubricating requirements of an engine. However, unless it is supported with additives, base oil will degrade and deteriorate very rapidly in some operating conditions. Depending on the type of base stock, petroleum, synthetic or others, different additive chemistries are used.

Mineral Oils

Mineral stocks are refined from petroleum crude oils. The crude oil source and the refining process will determine the base stock characteristics. The crude oils used for diesel engine lubricants are primarily made up of paraffin, napthene, and aromatic compounds. The crude oils with higher paraffin content are most frequently used in blended engine oils.

The refining process begins with vacuum distillation. Vacuum distillation separates the oil into products with a similar boiling range and similar viscosities. After vacuum distillation, the oils must be purified to remove or modify undesirable compounds. Base oil purification is usually done by solvent extraction and hydrofinishing or by hydrocracking and hydrofinishing. Both of these processes are used to limit or eliminate wax, sulfur, and aromatics. Variations in these refining process produce base oils with different characteristics.

Mineral base stocks are most prevalent for diesel engine oil formulation because they exhibit proven characteristics and are readily available at a reasonable cost.

Synthetic Oils
Synthetic base stocks are formed by processes that chemically react materials of a specific chemical composition to produce a compound with planned and predictable properties. These base stocks have viscosity indexes much higher than HVI mineral base stocks, while their pour points are considerably lower. These characteristics make them valuable blending components when compounding oils for extreme service at both high and low temperatures. The main disadvantage of synthetics is the significantly higher price and the somewhat limited supply. The group of synthetic oils known as esters causes greater seal swelling than mineral oils. The possible use of ester synthetic oils requires that component design be carefully considered for seal and ester oil compatibility. The use of synthetic base stocks lubricants in Caterpillar engines and machines is acceptable if the oil formulation meets the specified viscosity and Caterpillar performance requirements for the compartment in which it will be used. For very cold ambient conditions, the use of synthetic base stock oils is necessary.


Additives
Additives strengthen or modify certain characteristics of the base oil. Ultimately, they enable the oil to meet requirements beyond the abilities of the base oil.

The most common additives are detergents, oxidation inhibitors, dispersants, alkalinity agents, anti-wear agents, pour-point depressants and viscosity index improvers.

Here is a brief description of what each additive does and how.

Detergents help keep the engine clean by chemically reacting with oxidation products to stop the formation and deposit of insoluble compounds. The detergents in use today are metallic salts called: sulfonates, phenates, phosphonates or salicylates.

Alkalinity agents help neutralize acids. The detergents are also strong acid neutralizers, changing combustion and oxidation acids into harmless neutralized salts.

Oxidation inhibitors help prevent increases in viscosity, the development of organic acids and the formation of carbonaceous matter. These anti-oxidants are the following chemicals: zinc dithiophosphates, phenate sulfides, aromatic amines, sulfurized esters, and hindered phenols.

Depressants help prevent sludge formation by dispersing contaminants and keeping them in suspension. Common dispersant types include polyisobutenyl succinimides and polyisobutenyl succinic esters.

Anti-wear agents reduce friction by forming a film on metal surfaces and by protecting metal surfaces from corrosion. The principal types of agents are alkaline detergents, zinc dithiophosphates and dithiocarbamates.

Pour-point depressants keep the oil fluid at low temperatures by preventing the growth and agglomeration of wax crystals. Pour point depressant types are polymethacrylates; styrene- based polyesters, crosslinked alkyl phenols and alkyl naphthalenes.

Viscosity Index improvers help prevent the oil from becoming too thin at high temperatures. Viscosity index improvers (VI improver) are chemicals which "improve" (reduce) the rate of viscosity change with temperature change. Chemicals used as VI improvers are polyisobutenes, polymethacrylates, styrene-based polyesters, styrene-based copolymers and ethylene propylene copolymers.


Total Base Number (TBN)
Understanding TBN requires some knowledge of fuel sulfur content. Most diesel fuel contains some amount of sulfur. How much depends on the amount of sulfur in the crude oil from which it was produced and/or the refiner's ability to remove it. One of the functions of lubricating oil is to neutralize sulfur by-products, namely sulfurous and su.lfuric acids and thus retard corrosive damage to the engine. Additives (primarily detergents) in the oil contain alkaline compounds which are formulated to neutralize these acids. The measure of this reserve alkalinity in an oil is known as its TBN. Generally, the higher the TBN value, the more reserve alkalinity or acid- neutralizing capacity the oil contains.


Ash or Sulfated Ash
The ash content of an oil is the noncombustible residue of a lubricating oil. Lubricating oil detergent additives contain metallic derivatives, such as barium, calcium, and magnesium compounds that are common sources of ash. These metallo-organic compounds in the oils provide the TBN for oil alkalinity. Excessive ash content will cause ash deposits which can impair engine efficiency and power.


Viscosity
Viscosity is one of the more critical properties of oil. It refers to its resistance to flow. Viscosity is directly related to how well an oil will lubricate by forming a film to separate surfaces that would contact one another. Regardless of the ambient temperature or engine temperature, an oil must flow sufficiently to ensure an adequate supply to all moving parts.

The more viscous (thicker) an oil is, the thicker the oil film it will provide. The thicker the oil film, the more resistant it will be to being wiped or rubbed from lubricated surfaces. Conversely, oil that is too thick will have excessive resistance to flow at low temperatures and so may not flow quickly enough to those parts requiring lubrication. It is therefore vital that the oil has the correct viscosity at both the highest and the lowest temperatures at which the engine is expected to operate.

Oils change viscosity with temperature, becoming less viscous as their temperatures increase. Refining techniques and special additives increase the Viscosity Index (VI) of oil. The higher the VI number of the oil, the lower its tendency to change viscosity with temperature.

The Society of Automotive Engineers (SAE) standard oil classification system (SAE J300) categorizes oils according to their viscosity (via a number system such as SAE 10W, SAE 30, SAE 15W40, etc.).

Each of the viscosity grades or numbers has limits on the viscosity of the oil at given temperatures. For viscosity grades specified with a "W" the oil viscosity is defined by both viscosity at 100°C and at maximum low temperature for cranking and pumping. In other words, the oil's viscosity has been tested to verify the oil's flow under specified low temperatures. Therefore the "W" in an oil viscosity grade is commonly understood to mean that the oil is suitable for winter service. For grades without the W, the oil viscosity is defined at 100°C. only. The attached chart indicates the viscosities for the various oil viscosity grades.

View Image



API Engine Oil Classifications
The gasoline and diesel engine oil performance classifications are defined by the American Petroleum Institute (API) service classifications established jointly by API, SAE and ASTM (American Society of Testing Materials).

API gasoline engine oil classifications have two letter designations that start with the letter "S." The current active designations are API SJ, and API SL.

API diesel engine oil classifications have two letter designations that start with the letter "C." The current active four-stroke cycle diesel engine oil classification designations are API CF, API CF-4, API CG-4, and API CH-4.

API CH-4 oils were developed in order to meet the requirements of the new high performance diesel engines. Also, the oil was designed to meet the requirements of the low emissions diesel engines. API CH-4 oils are also acceptable for use in older diesel engines and in diesel engines that use high sulfur diesel fuel. API CH-4 oils may be used in Caterpillar engines that use API CG-4 and API CF-4 oils. API CH-4 oils will generally exceed the performance of API CG-4 oils in the following criteria: deposits on pistons, control of oil consumption, wear of piston rings, valve train wear, viscosity control, and corrosion.

Three new engine tests were developed for the API CH-4 oil. The first test specifically evaluates deposits on pistons for engines with the two-piece steel piston. This test (piston deposit) also measures the control of oil consumption. A second test is conducted with moderate oil soot. The second test measures the following criteria: wear of piston rings, wear of cylinder liners, and resistance to corrosion. A third new test measures the following characteristics with high levels of soot in the oil: wear of the valve train, resistance of the oil in plugging the oil filter, and control of sludge.

In addition to the new tests, API CH-4 oils have tougher limits for viscosity control in applications that generate high soot. The oils also have improved oxidation resistance. API CH-4 oils must pass an additional test (piston deposit) for engines that use aluminum pistons (single piece). Oil performance is also established for engines that operate in areas with high sulfur diesel fuel.

All of these improvements allow the API CH-4 oil to achieve optimal oil change intervals. API CH-4 oils are recommended for use in extended oil change intervals. API CH-4 oils are recommended for conditions that demand a premium oil. Your Caterpillar dealer has specific guidelines for optimizing oil change intervals.

API CG-4 oils were developed primarily for diesel engines that use a 0.05 percent level of fuel sulfur. However, API CG-4 oils can be used with higher sulfur fuels. The TBN of the new oil determines the maximum fuel sulfur level. See Illustrations 1 and 2 on pages 31 and 32.

API CG-4 oils are the first oils that are required to pass industry standard tests for foam control and viscosity shear loss. API CG-4 oils must also pass tests that were developed for corrosion, wear and oxidation.

API CF-4 oils service a wide variety of modern diesel engines. API CF-4 oils provide more stable oil control and reduced piston deposits in comparison to API CF and the obsolete CE and CD classifications of oil. API CF-4 oils provide improved soot dispersancy in comparison to API CF and obsolete CD oils. The API CF-4 classification was developed with a 0.40 percent sulfur diesel fuel. This represents the type of diesel fuels that are commonly available worldwide.

NOTE: Do not use single grade API CF oils or multigrade API CF oils in Caterpillar Direct Injection (Dl) Diesel Engines (except Caterpillar 3600 Series Diesel engines).

NOTICE: API CF is not the same classification as API CF-4. API CF oils are only recommended for Caterpillar 3600 Series Diesel Engines and Caterpillar engines with precombustion chamber (PC) fuel systems.

Some commercial oils that meet the API classifications may require reduced oil change intervals. To determine the oil change interval, closely monitor the condition of the oil and perform a wear metal analysis. Caterpillar's S·O·S Oil Analysis Program is the preferred method.

NOTICE: Failure to follow these oil recommendations can cause shortened engine service life due to deposits and/or excessive wear.
»»  read more

Saturday, September 5, 2009

How to the Contamination Control at CAT machine

Caterpillar Machine Fluids Recommendations

Contamination Control

Defining Contamination
Contaminants are any substance in the system that is not intended to be in the system. Contamination is the wear particles, water, fibers, dirt, dust, or products of combustion that are suspended in the oil or the fuel. The size of these particles is much smaller than the size of a human hair. A human hair is 80 microns in diameter. The newer machine systems operate at higher pressure. The newer machine systems are designed with closer tolerances. This emphasizes the importance of filter maintenance, as well as clean fuels and clean lubricants.

Measuring Cleanliness

The fluid cleanliness can be measured by taking fluid samples from the machine hydraulic compartments and from drive train compartments and having them analyzed by your Caterpillar dealer. The analysis is similar to monitoring the engine oil with S·O·S Services Oil Analysis. The amount of particulate matter is expressed in ISO (International Organization for Standardization) units. This standard of cleanliness is expressed as two numbers. An example of a standard for cleanliness is ISO16/13. The first number (16) relates to the number of particles that are larger than 6 microns in size. The second number (13) relates to the number of particles that are larger than 14 microns in size. There are 28 code numbers on the ISO Code scale. Each code has a given range of particles per milliliter. The smaller code number designates fewer particles.

Note: Currently, sample pretreatment is the recommended way to accurately complete the particle count measurement process. Contact your local Caterpillar dealer S·O·S Services Lab for guidance.

Standards for Machine Systems

Maintain the machine systems as close as possible to the standards for the new machines.

Recommended Maximum Contamination Levels - Through fluid system testing and accepted industry wide contamination targets, a maximum contamination level has been established for various machine systems (see table 1 below). If a system is maintained at or below this target, the system should not see any harmful effects from contamination throughout its engineered life.

Table 1 Caterpillar Recommended Cleanliness Targets
Hydraulic Systems (Implement & Steering) ISO 18/15
Vehicles With Electronic Controled Transmissions ISO 18/15
Vehicles With Mechanical Transmissions ISO 21/17
Fill oils ISO 16/13
Non-Pressurized, Non-Filtered Compartments. Target To Be Established

Although older technology machines may not be able to consistently maintain the recommended cleanliness targets of today's advanced models, the same contamination control intervention measures and subsequent service procedures should be used on all Caterpillar products.

Note: Do not use the particle count for the evaluation of the engine's oil. Large amounts of soot are produced within an engine. Evaluate the engine's oil by using S·O·S Services Oil Analysis.

Recommendations or Practices

Some guidelines to use for controlling contaminants are listed in this Special Publication. By maintaining a low contaminant level, a machine's maintenance cost can be controlled. The machine's productive life may also be increased.

Follow the general guidelines for controlling contaminants.

1. Use fuels that meet Caterpillar diesel fuel specifications. Filter all diesel fuel through a 4 or less micron(c) absolute filter when you refuel the machine. Make sure that you use Caterpillar Advanced Efficiency Fuel Filters for all engines that have a high pressure fuel injection system.

NOTICE

In order to meet expected fuel system component life, 4 micron(c) absolute or less secondary fuel filtration is required for all Caterpillar diesel engines that are equipped with common-rail fuel systems, and for all Caterpillar diesel engines that are equipped with unit injected fuel systems. For all other Caterpillar diesel engines (mostly older engines with pump, line and nozzle type fuel systems), the use of 4 micron(c) absolute or less secondary fuel filtration is strongly recommended. Note that all current Caterpillar diesel engines are factory equipped with Caterpillar Advanced Efficiency 4 micron(c) absolute fuel filters.

In order to obtain additional information on Caterpillar designed and produced filtration products, refer to the "Reference Material" article, "Filters" and "Miscellaneous" topics in this Special Publication, and then contact your Caterpillar dealer for assistance with filtration recommendations for your Caterpillar machine.

2. Use only coolants that are recommended by Caterpillar for your machine. Follow the recommended maintenance procedure for the cooling system in the Operation and Maintenance Manual for your machine.

3. When you add oil to a machine, filter the oil through a 5 or less micron(c) absolute filter to ensure that it is clean.

4. Refer to the machine's Operation and Maintenance Manual for the required maintenance for all machine compartments.

5. Perform scheduled S·O·S Services Oil Analysis for contamination in order to maintain the recommended ISO cleanliness level. Refer to the S·O·S Oil Analysis section in this Special Publication. The particle count analysis can be performed by your Caterpillar dealer. Particle count can be conducted during the scheduled S·O·S Services Oil Analysis for the compartment. Extra oil samples are not required for the particle count sampling.

6. Maintain the engine's intake air filters. This will minimize contamination at the engine's air intake system.
»»  read more

Friday, August 21, 2009

What the action if the panel shown Intermittent Engine Shutdown

Intermittent Engine Shutdown


Note: Use this procedure only if the engine shuts down completely during operation.

Probable Causes

* Diagnostic codes

* Event codes

* Electrical connectors

* Air inlet and exhaust restrictions

* Circuit breakers

* Fuel supply

Recommended Actions

Diagnostic Codes and/or Event Codes

Certain diagnostic codes and/or event codes may cause an engine shutdown. Connect the Caterpillar Electronic Technician (ET) and check for active codes and for logged codes. Troubleshoot any codes that are present prior to continuing with this procedure.

Electrical Connectors

1. Check for correct installation of the J1/P1 and J2/P2 connectors for the Electronic Control Module (ECM). Also, thoroughly inspect the connectors for the engine speed/timing sensors. Refer to the diagnostic functional test Troubleshooting, "Electrical Connectors - Inspect".

2. Inspect the battery wires from the ECM to the battery compartment. Refer to the Schematic for specific wiring information. Check the unit injector connectors and associated wiring for damage, or for intermittent problems. Inspect the wires and connectors to all circuit protection for the engine. Check the power and ground connections to the ECM. Check any engine shutdown switches and associated wiring. Refer to the diagnostic functional test Troubleshooting, "Electrical Power Supply Circuit - Test".

Air Inlet and Exhaust Restrictions

Check the air inlet system for the following problems: restrictions, collapse and pinched line. Repair the lines and/or replace the lines.

Check for an air filter restriction. Replace plugged air filters and/or clean filters. Repair any leaks.

Circuit Breakers

Check the state of each of the circuit breakers. Reset the circuit breakers if the circuit breakers are tripped. Prior to returning the engine to service, determine the condition that caused the circuit breaker to trip. Make the necessary repairs.

Fuel Supply

1. Visually check the fuel level in the fuel tank. Do not rely on the fuel gauge only. If necessary, add fuel to the fuel tank. If the engine has been run out of fuel, it will be necessary to prime the fuel system. Refer to the Operation and Maintenance Manual.

2. Check the fuel lines for the following problems: restrictions, collapsed lines and pinched lines. If problems are found with the fuel lines, repair the lines and/or replace the lines.

3. Check the fuel tank for debris or foreign objects which may block the fuel supply.

NOTICE

Do not crank the engine continuously for more than 30 seconds. Allow the starting motor to cool for two minutes before cranking the engine again.

4. Prime the fuel system if any of the following procedures have been performed:

* Replacement of the fuel filters

* Service on the low pressure fuel supply circuit

* Replacement of unit injectors

Note: Check the fuel system for air. Refer to the Systems Operation/Testing and Adjusting manual.

5. Check fuel quality. Cold weather adversely affects the characteristics of the fuel. Refer to the Operation and Maintenance Manual.

6. Check the filtered fuel pressure while the engine is being cranked. Refer to Systems Operation/Testing and Adjusting.

If the fuel pressure is low, replace the fuel filters. Clean the primary filter/water separator of debris. Refer to the Operation and Maintenance Manual.

If the fuel pressure is still low, check the operation of the fuel pressure regulating valve. Also, check for the proper operation of the fuel transfer pump. Refer to Systems Operation/Testing and Adjusting.


»»  read more

Tuesday, August 4, 2009

Troubleshooting-Vital Information Management System (VIMS)

Troubleshooting
784C, 785B, 785C, 789B, 789C, 793B, 793C, 793D, 797 and 797B Off-Highway Truck/Tractors Vital Information Management System (VIMS)

General Information

Troubleshooting the Vital Information Management System requires additional information from the machine Service Manual, the Electrical System Schematic, and the Operation and Maintenance Manual.

As a guide, a "VIMS schematic" is provided in the Testing and Adjusting section of this manual. Refer to the Electrical System Schematic that is located in the machine Service Manual for a complete representation of the machine that is being diagnosed.

When the troubleshooting procedure instructs the service personnel to REPAIR THE HARNESS, always use the Electrical System Schematic that is located in the machine Service Manual to trace the circuit. Perform continuity checks at the connectors in order to locate the harness failures. At component connectors, always check the ground circuit. The power circuits of the control require less than 2 ohms of resistance between the ground contacts of the connector and frame ground. Signal circuits ("sensors, switches, solenoids etc.") require less than 5 ohms of resistance for normal operation. Resistance that is greater than 5 ohms can cause incorrect diagnosing of problems.

Repairs of the machine harness should be performed with wire of the same gauge. All joints should be soldered. All joints should be taped tightly. Use the 1P-0810 Vinyl Tape or shrink sleeving for all repairs to the harness. Repairs to the data link circuit in the harness must maintain the same "twist" ratio in the wiring that was provided in the original harness. The "two wires" of the Cat Data Link must maintain a twist rate of 2 ±1 turns per inch. Wiring of the display data link must maintain the twist rate of 2 ±1 turns per inch. The wires of the display data link are listed here: A251-BK (ground), C414-BU (Load), C413-YL (Data) and E708-PK (clock). Twisting is VERY IMPORTANT! Twisting will minimize the electrical interference to other circuits that is caused by the data link. Interference to the data link from other circuits will also be minimized.

During troubleshooting, inspect all component and harness connections before any component is replaced. Electrical problems can be caused if harness connections are not clean and tight. The electrical problem can be permanent or the electrical problem can be intermittent. Make sure that the connections are tight before other tests are made.

The failure of an electrical component can cause the failure of one or more related components. Always attempt to find the cause of the electrical system failure and then correct the cause of the electrical system failure before replacing a component.

Some machine functions that use solenoid valves require a suppressor diode across the valve coil. If the suppressor diode is faulty, electronic noise that is generated by the solenoids turning ON and OFF can cause erratic operation of the display components.

Data events and system events are defined by the machine's configuration software. Diagnostic functions for a given event are also defined in the configuration software. The VIMS 10.0X and later software use an improved "event definitions" in order to reduce the number of "nuisance events" for both machine and system conditions. An important change that was made to the software is the addition of a longer evaluation time. The longer evaluation time allows the VIMS to display an event only if an actual electrical failure exists. The VIMS may wait up to 8 SECONDS before displaying a system event on the message center or the VIMS may wait up to 8 SECONDS before storing a system event. During this time period, the gauges that are located on the "VIMS display components" may fall to the "red zone". The message area will show "ERR". During troubleshooting, allow an adequate amount of time for the VIMS to report that a new condition exists. For example, unplug a sensor from the machine harness. The VIMS may wait up to 8 seconds before reporting this condition as an "ERR". Some "system events" for filters may require SEVERAL MINUTES before the VIMS reports the condition. Likewise, when the condition is corrected, several minutes may be required before the event ceases to be reported. When the VIMS has received an event from an electronic control via the Cat Data Link, the VIMS adds zero time to these events. The VIMS displays the events immediately. The "event delay" is defined in the software of the control.

Repairs are considered complete when the system event is no longer present and the parameter appears to read the condition of the machine correctly.

Note: If an event is displayed for a bypass filters switch and the bypass switch has been replaced use the Electrical System Schematic as a troubleshooting aid. Check the components that are listed here: wire harness, the bypass switch and the ECM. Refer to the Testing and Adjusting, "Troubleshooting Switch Circuits" section.

Note: If consistent incorrect "fuel levels" are reported with no "reported faults", verify that the "program input" (contact 3) of the fuel level sensor is grounded "(the short tank configurations only)". If the contact is not grounded, repair the harness.

Quick Reference

* See the Troubleshooting, "Troubleshooting Diagnostic Codes Using Abbreviated Procedures" section for failures that have diagnostics (MID/CID/FMI).

* See the Troubleshooting, " Switch Circuits" section for failures in the operation of the alert indicator.

* For the "experienced service technician", see the Troubleshooting, "Troubleshooting Diagnostic Codes Using Abbreviated Procedures" section for troubleshooting failures that have diagnostics (MID/CID/FMI).

Note: Refer to the Special Instruction, REHS0126, "Diagnostic Code Information for Caterpillar Electronic Control" for information on diagnostic codes utilized by Caterpillar machines that are equipped with Caterpillar electronic controls.
»»  read more

Saturday, July 25, 2009

CAT-Belts - Inspect/Adjust/Replace



Belts - Inspect/Adjust/Replace

784C and 785C Off-Highway Truck/Tractor

Inspection

To maximize the engine performance, inspect the belt for wear and for cracking. Check the belt tension. Adjust the belt tension in order to minimize belt slippage. Belt slippage will decrease the life of the belt.

To check the belt tension, refer to the Engine Specifications, "Belt Tension Chart". A correctly adjusted belt will deflect 13 to 19 mm (0.50 to 0.75 inch).

Note: The belt tension for the engine fan is spring applied. The fan drive belt cannot be adjusted. If the fan drive belt is loose, see Engine Supplement, Disassembly and Assembly, "Belt Tightener - Remove and Install" for instructions on replacement of the spring. If the fan drive belt is cracked or worn, refer to Engine Supplement, Disassembly and Assembly, "Belt Tightener - Remove and Install" for replacement information.

Adjustment

Alternator


(1) Adjusting nuts

(2) Mounting bolt

1. If necessary, remove the belt guard.

2. Loosen mounting bolt (2) and adjusting nuts (1) .

3. Turn adjusting nuts (1) in order to increase or decrease the belt tension.

4. Tighten adjusting nuts (1). Tighten mounting bolt (2) .

5. If necessary, reinstall the belt guard.

If new belts are installed, check the belt adjustment again after 30 minutes of engine operation at the rated rpm.

Refrigerant Compressor


1. Loosen two bolts (3) .

2. Loosen nut (4) .

3. Use nuts (5) to adjust the belt tension.

4. Tighten nut (4) and nuts (5) .

5. Tighten bolts (3) .

Replacement

For applications that require multiple drive belts, replace the belts in matched sets. Replacing only one belt of a matched set will cause the new belt to carry more load because the older belts are stretched. The additional load on the new belt could cause the new belt to break.

Refer to Engine Supplement, Disassembly and Assembly, "Belt Tightener - Remove and Install" for more information on replacement of the belts.
»»  read more