Doctors have perfected the art of conducting physical exams. They know what questions to ask and how to examine the body for clues that signify health, injury or disease. Maintenance staff, lubrication technicians and even equipment operators should be competent to perform ‘physicals’ as well. Like the doctor, they need to be aware of subtle changes or symptoms that might be an early sign of machine malfunction or accelerated wear.

One of the obvious problems with conducting such inspections is that for most machines, the critical operating components, including the lubricant itself,  are shielded from view by panels, casings, guards and housings. It is like asking your doctor to give you a physical while wearing body armour. Nevertheless, the machine and the lubricant can telegraph hints and signals in various ways and the selection of machine inspections should be tailored to the machine design and operating environment. This is done by selecting which inspections are needed and how frequently they should be carried out.

Following is a list of problem-revealing tests and inspections related to lubrication. They require limited technical proficiency and most of the tests involve no special tools or instruments.

Colour Change:

Monitor changes in lubricant colour with sight glasses and oil samples. Oils that have been subjected to high temperatures will exhibit marked changes (darkening) in colour and opacity. Many types of contaminants will alter colour as well. Additionally, a wrong lubricant can often be recognized by a change in darkness or colour.

Air Release Capability:

Most healthy lubricants will release entrained air readily. Distressed and contaminated lubricants may fail to release air from the oil and may also form sustained surface foam. Aeration and foaming (see OilChat 49) are not always oil related and may point to air entering the system or mechanical problems. Sight glasses and inspection hatches may provide the first sign of a problem.

Water Shedding Ability:

Water and oil usually do not mix. However, if they become conjoined in an emulsion, the problem is often associated with a change in the oil properties or contamination. Observing oil/water separation after violently mixing quantities of each in a sample bottle or laboratory glassware is an easy check for this property.

Blotter Spot Test:

This inspection involves placing a drop of oil on blotter paper and then observe how the oil spot ‘develops’. Healthy oil does not produce any structures and will spread out evenly on the paper, leaving a uniform gradient of oil colour behind. When the oil is badly contaminated, serrated patterns may form or the contaminants can clump together and do not migrate with the oil front. The Blotter Spot Test was discussed in detail in OilChat 72.

Sediment and Water:

It is often said that what is bad for the oil or material that has been removed from machine surfaces is also heavier than the oil. We know that substances heavier than the oil will settle out when mixed with the oil. That is why there is great wisdom in inspecting for water and sediment using drain port sampling.

Noise:

Few machines are quiet during operation. Even completely healthy machines have something to say. You may have heard the saying “a singing gear is a happy gear”. This is often true, but not always. Machine sounds change for specific reasons. Try to locate the point of generation. Some maintenance technicians play doctor by using crude stethoscopes in the form of a garden hose, a screwdriver or a steel rod held to their ear, with the other end touching potential noise-generating areas.

Temperature:

Doctors use thermometers but maintenance technicians employ a variety of tools including online temperature probes/thermocouples, thermal imaging cameras or handheld heat guns. A few common causes of temperature changes are wrong lubricants, degraded lubricants, contaminated lubricants, abnormal friction/wear – and the list goes on.

Pressure Change:

In the same way oil temperature can change in response to an assortment of problems, oil pressure can increase or decrease as well. Anything that can change viscosity or form surface deposits can change system pressure. For similar reasons it is no surprise that doctors pay special attention to blood pressure during an exam.

Filter Life:

There usually is a good reason when filters plug prematurely and it is worthy to investigate what is plugging the filter. Areas of particular concern are soft contaminants (sludge, organic material, dead additive residue, etc.), dust and wear debris. The filter is the final resting place for a variety of machine and lubricant operational waste products as discussed in OilChat 76.

You should have noted the many interesting human health analogies above, but this is just a start. There are far too many field tests and inspections to discuss in a publication like this. For those who make a living caring for the health of lubricants and machinery, the value of being capable to perform machine physicals is immense. Backed by laboratory oil analysis and other predictive maintenance technologies, the modern-day lubrication engineer and condition-monitoring professional is indeed fortunate to have such a ‘clear’ view of the internal state and operational health of his machinery. If you have any queries about Machine Health Checks, please email us at info@bcl.co.za. Our lubricant experts will be happy to answer any questions you may have.

 

An inspection of an used oil filter can be quite helpful to determine the condition of the engine. By dissecting a filter, you can discover information about the quality of the filter itself by checking for collapsed media, bad seals or weak points that may have formed in the filter media during use. You may also learn a lot about the health of the engine by analysing the debris caught in the filter.

The purpose of the oil filter is to trap contaminants suspended in the engine oil as it flows through the filter. This is accomplished by the filter medium inside the filter body. The medium typically allows the passage of very small particles (less than 5 microns) but traps the larger ones (greater than 5 microns). These are the ones you will find inside a filter when it is dissected.

If the filter is of the canister type, a simple and inexpensive method is to cut the filter housing open to remove the media. There are special tools available to do so. A typical example is shown on the right. Do not use a hacksaw since the metal shavings could be mistaken for wear metals. Once open, slice the filter media away from the centre tube with a sharp knife or razor blade. Lay the media out onto a clean surface and spread the pleats apart to look for any contaminants.

Filters prevent large particles from damaging the engine, but they also mask significant component wear from regular oil analysis. Following is a discussion of what you must look for in the filter media:

Ferrous Metals

Iron and steel particles are easy to identify because they are magnetic. Simply run a magnet across the particles to verify if they are ferrous. Iron and steel debris can originate from cylinder walls, camshaft lobes or the crankshaft. Abnormal wear of these components may release pieces into the engine oil and subsequently into the oil filter. Depending on the size of the pieces and the condition of the engine, you may want to inspect the components mentioned above sooner than later.

Non-Ferrous Metals

Many modern engines use lightweight aluminium components and pinpointing the origin of shiny aluminium particles in the oil filter can be difficult. One area that experiences regular wear is the piston skirt. Abnormal wear of the piston skirts is often due to contamination that has entered the combustion chamber or the use of the wrong engine oil. Checking the air intake and filter system is a good idea if you believe contamination has entered the engine.

 

Other small, shiny particles that can be confused with aluminium are tin, lead and copper. These materials are often used in the Babbitt alloy layer of the main and piston rod small end bearings. Insufficient lubrication of these bearings can lead to premature wear of the Babbitt layer and eventually to the failure of the bearing. If remnants of tin, lead or copper are found, it would be wise to ensure that the engine is being properly lubricated with the correct oil.

Non-Metallic Materials

In many cases, you will find some amount of carbon, which is difficult to identify, but the use of a magnifying glass can help. When rubbing carbon between your fingertips it will feel slightly gritty but it will break apart easily. Carbon accumulation is typically a result of blow-by getting past the piston rings. If your engine suffers from excessive oil consumption and low cylinder compression readings, you most probably have worn or damaged piston rings.

 

 

In many instances elements found trapped in the oil filter can point you in the right direction when attempting to diagnose an issue with an engine. Sometimes more information may be required and the filter will have to be sent to a professional laboratory for analysis. Either way the debris needs to be identified to take the necessary action to prevent possible serious engine damage.

At Q8Oils we have the people, products and proficiency to assist you with all your lubrication requirements. For more information phone 011 462 1829, email us at info@bcl.co.za  or visit www.bcl.q8oils.co.za. Our lubricant experts will be happy to answer any questions you may have.

A simple visual inspection of gear wear patterns can aid in identifying latent problems and looming gear failures. Once the problem is identified, there are ways to avoid some of the common culprits, such as gearbox design and materials, operating conditions and loading, misalignment and insufficient lubrication. Any of these can have a major influence on performance and reliability but in this publication we will focus mainly on misalignment and lubrication related problems.

Misalignment of the gearbox shafts is a common reason for gearbox failures and is often the result of wrong installation and setup procedures. Even if the initial alignment is within acceptable tolerances, operating and environmental conditions can eventually cause the shafts to become misalignment, e.g. loads generated during operation and the transmission of power through the gearbox can result in shafts or other gearbox components deflecting. Temperature variations can also result in expansion or contraction of the shafts or gearbox components (especially the gearbox housing) which will consequently cause the shafts to become misaligned. It is therefore essential to start the inspection by checking the alignment of the shafts and gears inside the gearbox.

An even wear pattern along the tooth surface as shown on the left, indicates that the gears are aligned correctly. Misalignment is exhibited as abnormal wear at one end of the tooth as depicted on the right.

 

Gear tooth surface wear can be described as the removal or displacement of material due to mechanical, chemical or electrical action. In this publication discussions will be limited to the following mechanical wear modes which are lubrication related:

ABRASION

Abrasion can range from mild to severe. Very mild abrasion may cause polishing of gear teeth. Moderate abrasion consists of fine scratches with little removal of material from the contact surfaces. Severe abrasion manifests itself as deep grooves on gear teeth as shown on the right. Abrasive wear is brought about by particle contamination of the oil or rough gear surfaces as discussed below:

 

Three-Body Abrasion occurs when hard contaminants (dirt or wear debris) in the oil are trapped between two meshing gear teeth. When the size of the particles is greater than the fluid film thickness of the oil, scratching, scraping or ploughing can occur. This creates parallel scrape marks in the direction of motion (from the base of the gear tooth to the tip), like rough sanding. Mild abrasion by fine particles can cause polishing with a satiny or matt appearance. Three-body abrasion may be prevented with improved oil filtration, flushing and sealing out foreign particles.

Two-Body Abrasion happens when metal asperities (surface roughness, peaks) on one gear tooth cut directly into a meshing tooth. Contaminant particles are not directly involved in this instance. The contact occurs in the boundary lubrication regime (see OilChat 22) due to inadequate lubrication or excessive surface roughness which could have been caused by some other form of wear. Higher oil viscosity may help to reduce two-body abrasion.

PITTING (ALSO KNOWN AS SPALLING)

The formation of pits or holes on gear teeth is called pitting and is caused by overload conditions on the gear tooth surface. Severe pitting is also referred to as spalling. A pit forms when small cracks (due to overloading) grow long enough to separate a piece of material at the surface. These irregularities cause additional friction and result in a lot of heat being generated, which in turn reduces the viscosity of the oil. A possible solution would be to use an EP oil with higher viscosity.

SCUFFING, SCORING OR GALLING

Scuffing or scoring can be described as grooves over a wide area of gear teeth. Scuffing leads to the much more serious wear mechanism referred to as galling as seen on the left. It occurs when a lack of lubrication causes metal-to-metal contact of gear teeth, resulting in elevated temperatures. This can result in localized welding in contact areas. Metal is then ripped from one surface and transferred to the other. This type of wear is also referred to as adhesive wear.

 

 

On driven gears metal ‘flows’ towards the middle of the gear teeth, along the length of gear teeth, as shown above and on the left gear tooth in the adjacent diagram. On driving gears metal propagates away from the centre line of the gear as depicted on the far right. Possible solutions would be to use an EP oil with a higher viscosity and reducing the temperature of the oil.

 

Gear wear pattern analysis can identify the root cause of many gear problems and with appropriate lubrication practises the wear modes discussed above may be avoided. Should you have any questions about gear lubrication or want to find out more about the extensive range of Q8Oils gear oils, please phone 011 462 1829, email us at info@bcl.co.za or visit www.bcl.q8oils.co.za

Cavitation is a phenomenon that occurs in various formats around us every day of our lives. In terms of fluid dynamics it can be described as the formation and collapse of cavities or bubbles in flowing liquids. Cavitation may well result in the pitting or erosion (wearing away) of solid surfaces, such as metal or concrete, that are in contact with the liquid.

 

Cavitation is often associated with components that rotate in a liquid, e.g. boat propellers, hydraulic oil pump elements and water pump impellers as shown on the right. Other common examples of cavitation are found in diesel engines with wet liners and where water is flowing over dam walls.

Surfaces in contact with a liquid undergo cavitation erosion or pitting due to pressure fluctuations in the surrounding liquid. In most instances the pressure fluctuations are generated by the movement of the surface itself. Following is a brief description of the cavitation process:

1. Bubbles in the liquid grow when pressure decreases.
2. Maximum bubble size at lowest pressure.
3. Reduction in bubble size when pressure increases.
4. Bubbles collapse (implode) when pressure is high enough.

 

 

The sudden volume contraction/collapse results in an energetic implosion accompanied by shock waves and high velocity microjets that impact and damage the solid surface.

Vapour cavities or air bubbles may be present in a liquid due to various reasons. In the following diagram a restriction in the suction (low pressure) line of a hydraulic system results in the formation of vapour bubbles in the oil. As the oil passes from the suction side of the pump to the delivery (high pressure) side, the bubbles implode.

The imploding bubbles create the shockwaves that erode the internal pump components. The shockwaves also cause pump vibration and noise. A high speed hydraulic pump that sounds as if it is full of rocks or gravel is a sign of cavitation, which can lead to complete pump failure if you do not track down the cause.

By preventing cavitation, you will increase the efficiency and lifespan of your hydraulic pumps significantly. Keep an eye on internal parts for signs of pitting and corrosion and listen to the pump to ensure you do not hear what sounds like marbles banging around. If you have any questions about cavitation email us at  info@bcl.co.za. Our lubricant experts will be happy to answer any questions you may have.

The crackle test was discussed briefly in OilChat #71 (Dipstick Oil Analysis). It is a quick and easy method to detect the presence of water in oil. To do a crackle test simply put a drop of oil on a hot surface with temperature just over 100⁰C. The oil will bubble, crackle or pop when moisture is present.

With practice, and together with keen eyes and ears, the crackle test can be a semi-quantitative estimate of the amount of moisture present in lubricating oil.  Water is one of the biggest enemies of lubricants and the warning limit for moisture in petrol and diesel engine oil is 0.2 % maximum. A moisture content as little to 0.05% can be detected with the test. Rather than just listening for the crackle, add a visual observation and rating of the number and size of the vapor bubbles produced. This will give an indication of the amount of moisture present in the oil. This method is referred to as the visual crackle test.

Success in using this procedure depends on practice and maintaining a constant hotplate temperature around 160°C. Place a homogenous drop of oil on the hot plate. To ensure a homogenous suspension of water in the oil, agitate the oil sample violently or take a dipstick sample when the engine is still hot. Observe and interpret the test result as follows:

Although the test is reliable in most instances, it does have some limitations:

• Hot plate temperatures above 160°C induce rapid evaporation that may be undetectable.
• The method does not measure the presence of chemically dissolved water.
• The presence of fuel and volatile solvents in the oil could be mistaken for water – indication of light hydrocarbons is a sizzling sound rather than a crackle.

There you have it – dipstick oil analysis in a few simple steps. Checking your engine oil level should never be the same again. Analysing the oil in your vehicle is like sending your blood to the lab for tests and engine oil analysis can provide clues about the health of your engine – without any invasive surgery. The real benefit of oil analysis is that it acts as an early warning system, alerting you of potential problems before they become an engine failure.

Once you have mastered the crackle test and the other oil tests discussed in OilChat #71 and #72 you should be competent to determine the condition of your oil as well as the health of your engine. If you have any questions about these tests email us at  info@bcl.co.za. Our lubricant experts will be happy to answer any questions you may have.

More than normal interest was generated by OilChat #71 (Dipstick Oil Analysis) – particularly the section about the blotter spot test – and it was suggested that we elaborate on the subject. The blotter spot engine oil test is cheap and easy and can tell you a great deal about the condition of the oil in your engine.

All you need for the blotter spot test is a piece of white blotting (chromatography) paper, obtainable from stationary suppliers. Whatman 3MM CHR paper with thickness 0.34mm is commonly used for the test.

To do the test, support the paper in a horizontal position so that the spot area is not in contact with any surface. The rim of a a cup or glass provides an ideal support. Take the dipstick from the engine while the oil is still hot and put a small drop of oil in the centre of the test paper. Allow the oil spot to dry. Drying may be accelerated by applying mild heat. An initial observation can be made when the oil spot is dry, but the best results are obtained after twenty-four hours.

The colour of the blotter spot will depend on the type of fuel being used. A petrol engine oil will have a brownish colour as shown on the right. Oil from a diesel engine will leave a grey to black spot (see far right).

 

The blotter spot has three zones. The significance of each zone is as follows:

Deposit Zone – indication of undispersed soot and dirt. Short service or low contamination/soot level will have a light discolouration or may not appear at all. Excessive service or high soot level will leave a dense, dark small spot.

Dispersion Zone – indicative of remaining dispersancy. Size of this zone is the important factor. The bigger it is, the more dispersancy remains.

Oil Zone – indication of oxidation. A progressive darkening from light straw to amber indicative   of increased oxidation.

 

Below are interpretations of seven typical engine oil spot tests:

Petrol engine oil with evenly dispersed, light coloured blotter spot – oil fit for further use.

 

Petrol engine oil with dense, dark blotter spot – oil heavily contaminated, drain oil as soon as possible.

 

Diesel engine oil with evenly dispersed, light coloured blotter spot – oil fit for further use.

 

Diesel engine oil with dense, dark deposit zone – oil heavily contaminated, dispersancy depleted, drain oil as soon as possible.

 

Petrol and diesel engine oil with dark center and distinct brownish coloured outer ring – oil severely oxidized, drain oil as soon as possible.

 

Soot ring around a yellow/brown centre – oil contaminated with antifreeze/glycol, drain oil as soon as  possible.

 

Dark center with surrounding rings – possible fuel dilution. Confirm with other tests discussed in OilChat 71 and drain oil if necessary.

 

Initially it may be difficult to interpret the blotter spot on the basis of a single test result, but as we all know practice makes perfect. Once you have mastered the art of the blotter spot, you will not be able to resist pulling the dipstick of your engine.

If you have any further questions regarding oil analyses phone 011 462 1829, email us at info@bcl.co.za or visit www.q8oils.co.za. Our lubricant experts are at your disposal and ready to provide you with advice and answer any questions you may have.

OilChat numbers 69 & 70 addressed the dangers of and possible reasons for engine oil level rising on the dipstick.  But your dipstick can tell you much more than the level of the oil in the engine.  Dipstick oil analysis may sound a bit farfetched, but in fact it can reveal a great deal about the condition of the oil, and even the engine itself.

During its working life inside the engine, motor oil gets contaminated with water, fuel, soot  and other contaminants. The oil is also subjected to chemical  changes,  such as additive depletion and oxidation. Dipstick engine oil analysis is quick, easy and cheap. Simply pull the dipstick out and check the oil as follows:

Water: Bubbles on the dipstick, a brownish residue just above the oil level or milky-brown oil with a thick consistency (high viscosity) are all indications of water in the oil. To confirm the presence of water do a crackle test by putting a drop of oil from the dipstick on a hot surface (temperature 100⁰C or more). The oil will bubble, crackle and pop when moisture is present. Check for white, sweet-smelling smoke coming from the tailpipe. This is a sign of coolant (water and glycol) in the oil.

Fuel: Oil on a dipstick that smells like petrol or diesel is the first sign of fuel dilution. Fuel dilution can reduce the viscosity of motor oil substantially. Another indication of fuel in the oil is when the oil bubbles and boils without a crackle when doing the crackle test.

Soot: Thick darkened oil on the dipstick as shown above, is a sure sign of excessive soot in the oil – diesel engine oil in particular. A carbonaceous odour is another indication of high soot levels in the oil.

Oxidation: When oil oxidises, its colour tends to darken. Badly oxidised oil usually has a  foul, pungent and burnt odour. Oxidised and contaminated oil will lose interfacial tension. A simple test for interfacial tension is to place a drop of oil from the dipstick on the surface of water. If the oil drop spreads out over the surface of the water (instead of clustering up like new oil) it may be time for an oil change.

Additive Depletion: If you are still not sure whether you should change the oil, you can do a blotter spot test to check the additive reserve/concentration of the oil. To do the blotter test,  place a small drop of oil on a piece of blotting (chromatography) paper. The paper should be elevated to avoid contact with the flat surface below. Allow at least one hour for the oil drop to spread out on the paper.

As the oil spreads out, it should carry with it the dark contaminants. Ideally the contaminant band should spread with the oil to leave a fairly even discoloration. When the oil is badly contaminated, the contaminants clump together and do not migrate with the oil front. This indicates that the dispersancy additive of the oil is depleted.

 

It is as simple as that. We trust you will now be competent to do your own dipstick oil analysis and that checking oil levels will never be the same again. If you have any further questions regarding oil analyses phone 011 462 1829, email us at info@bcl.co.za or visit www.q8oils.co.za. Our lubricant experts are at your disposal and ready to provide you with advice and answer any questions you may have.

In response to OilChat #69 (Overfilling Engine Oil) the question was asked if it is possible for the oil level to rise on the dipstick between services even if no oil was added to the engine. The answer is YES and the reason is that the oil may get contaminated with water, fuel or engine coolant.

Water:  As engines heat up and cool down condensation is formed. Some of the condensed water ends up in the engine oil, but normally condensation is not too much of an issue. Of more concern is the water formed during the combustion process in petrol and diesel engines.

For every litre of fuel burned in an engine, approximately one litre of water is formed in the combustion chamber. At operating temperature this is not a problem since the water goes out through the exhaust in vapour form (steam). When the engine is cold, however, some of the water gets past the piston rings into the oil sump. Water is one of the most destructive contaminants in lubricants. It attacks oil additives, causes rust and corrosion, induces base oil oxidation and reduces oil film strength.

Fuel:  Fuel dilution of the engine oil can occur due to several reasons, including internal leakage of the fuel injection system, dirty or faulty fuel injectors, extended periods of idling and frequent cold starts.

Internal leakage can be related to injector sealing ring failure and loose components. A dirty or faulty fuel injector will cause ‘dribbling’ of liquid fuel into the combustion chamber and it may end up in the crankcase where it dilutes the oil. An idling engine is not operating at optimum performance and leads to incomplete fuel combustion. Extended periods of idling result in unburned fuel getting past the rings and running down into the crankcase oil. Furthermore, during cold starts some of the atomised fuel comes into contact with the cold cylinder walls, condenses and ends up in the crankcase where it dilutes the oil. On the way down the fuel also washes the oil on the cylinder walls away, resulting in accelerated ring, piston and cylinder wear.

In addition fuel dilution of the oil in the crankcase results in premature depletion of the alkalinity of the oil (base number or TBN) that leads to loss of corrosion protection, deposit formation and degradation of the oil.

Engine Coolant: Glycol and water in the engine cooling system may enter an engine as a result of defective seals, blown head gaskets, cracked cylinder heads and corrosion damage. Glycol reacts with oil additives and reduces the  ability of the oil to protect engine components. Furthermore, less than 1% glycol contamination is enough to drop out soot dispersed in the oil, leading to sludge formation, restricted oil flow and blocked filters.

In OilChat 69 we discussed the dangers of too much oil in the crankcase and how it can ruin an engine. Not only will these contaminants raise the level of the oil in the crankcase, it may also damage the engine as discussed above. It is therefore in your own interest to check your engine oil level regularly and to ensure that it stays between the upper and lower limits on the dipstick.

If the oil level changes drastically in a relative short period of time you may have a serious problem. Do not start the engine and investigate as soon as possible. If you are not confident doing this yourself, you will need to get your vehicle towed to a mechanic or service centre – driving it could damage the engine, requiring expensive repairs. Whatever the cause of the high oil level, the condition needs to be corrected without delay.

Oil is the lifeblood of the engine in your vehicle. It lubricates the engine and protects against the two biggest enemies of any motor – friction and heat. The dipstick indicates the oil level in your engine, whether it be with two pinholes, the letters L and H (low and high), the words MIN/ADD and MAX/FULL, or simply an area of crosshatching. If the top of the oil streak is between the two marks or within the crosshatched area, the level is fine.

It is a well known fact that too little oil in the crankcase can lead to oil starvation and result in engine damage and possibly complete engine failure. Is more oil therefore always better? Correct? Wrong! If you drive your vehicle with the engine overfilled with oil, it is asking for trouble. Here is why:

Aerated Oil: When there is too much oil in the engine, the rotating crankshaft whips the oil up and mixes air into it. This causes the oil to be bubbly or frothy and the oil pump pickup-tube draws up aerated oil. Think of it as your engine turning cream into whipped cream. No one wants whipped oil lubricating their engine. The result is normally low oil pressure – ironic, isn’t  it?

Engine Oil Leaks: Too much oil can create excessive pressures inside the engine that will look for an escape – usually through gaskets and seals.  Head gaskets, crankshaft oil seals and valve cover gaskets are normally the first to fail. This will lead to oil leaks and costly repairs. Furthermore, if the oil seal on the flywheel end of the crankshaft goes,  the oil can contaminate and damage the clutch.

Blue Exhaust Smoke: When the crankshaft rotates in the engine oil, it splashes more than normal oil up into the cylinders. Some of the excessive oil ends up in the combustion chambers where it mixes with the fuel. Since the oil is heavier than the atomised fuel it fails to burn completely and goes out the exhaust as foul-smelling blue smoke.

Damaged Catalytic Converter:  The oily exhaust gases also coat the inside of the catalytic converter. When this happens, it is only a matter of time before the oil clogs the converter completely, causing it to overheat and fail.

Spark plug fouling ­– Excess oil in the combustion chamber may well foul up spark plugs, which will then need to be replaced.

Serious Engine Damage: Too much oil can create resistance against moving parts, such as  pistons and connecting rods. Excessive resistance will result in catastrophic engine failure, often beyond repair, and the engine will need to be replaced.

The moral of the story is too much oil can damage your engine. If you notice the oil level is too high, have some of it removed straight away to prevent these serious problems from occurring.

To find out more about the complete Blue Chip  grease portfolio phone 011 462 1829, email us at info@bcl.co.za  or visit www.bcl.co.za

0ver-greasing or under-greasing:
which is the bigger problem when it comes to bearing lubrication?

To answer this question, it is important to understand that over-greasing and under-greasing can refer to two different things. It may mean that the volume pumped into a bearing during a greasing service can be too much or too little. It can also mean that regreasing services are occurring too often or too seldom. It can be difficult to determine which is the bigger problem, but the following discussion should help you decide what might cause the most damage in your specific application

Over-greasing by applying too much grease to a bearing may result in seal failure. If there is no relief port on the bearing housing, the excess grease will blow past the seals and damage them. This can present several problems since the grease that remains in the housing can leak out. It also provides a path for external contaminants to enter the housing.

In addition, a bearing housing overfilled with grease can generate heat. A big difference between grease and oil is that grease cannot transfer heat away from the load zone. Too much grease in a bearing can create heat from fluid friction. Because the heat has nowhere to go, it can degrade the grease by causing too much churning. If there are proper purge points to relieve excess grease, the only problem with greasing too often is that you will be purging good grease out of the bearing.

Under-greasing or not putting enough grease into a bearing housing can be just as detrimental, but it has the opposite effect than over-greasing. By not providing enough lubrication for the bearing, heat can be generated by the friction between the moving parts. Also, if there is a void inside the bearing housing, it can allow contamination to enter the load zones, resulting in damage to the moving elements.

Not greasing often enough would generally be considered a bigger problem. After an extended period of time, the grease may harden as a result of oxidation. This will cause excessive component wear due to lack of lubrication and the presence of possible contaminants. The best practice would be to avoid both these conditions.

It is therefore essential to acquaint yourself with the greasing procedures recommended by your equipment manufacturer. If such recommendations are not available, the following guidelines can be used to establish suitable greasing frequencies and amounts:

FREQUENCY: The chart below shows approximate relubrication intervals. Start at the bottom and select the bearing speed; go straight up until you meet the curve that matches your bearing I.D. (or d); then go straight left to see the relubrication interval (in hours) for your particular bearing type (a, b or c):

AMOUNT:  To calculate the amount in grams, multiply OD in mm x Width in mm x 0.005

EXAMPLE: Let us say you have a 6209 ball bearing, running at 1,800 RPM, 24 hours a day, 7 days a week.  A 6209 bearing has a shaft diameter (ID or d) of 45 mm, an OD of 85 mm, and a width of 19 mm.  Using the chart and the formula, the bearing needs 8 grams of grease every 10,000 hours.  If your grease gun delivers around 1.35 grams per stroke, the bearing needs 6 strokes every 13 months. You can also average it out to one stroke every 8 weeks.

To find out more about the complete Blue Chip  grease portfolio phone 011 462 1829, email us at info@bcl.co.za  or visit www.bcl.co.za