Crivens
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I tried to add this to the "Never-Ending Pointless Recurring Threads" but I can't create a new topic there. Perhaps an admin would be kind enough to move it and delete this paragraph?
After reading some of the numerous “Engine Oil” threads I thought I would try to shed some light on a few of the misconceptions and misunderstandings about motor oil.
First the disclaimer: I am not a petroleum engineer or a chemist, however I have had cause and the inclination to study motor oils, their performance characteristics and related information, in depth.
If you ask anyone to tell you why an engine needs oil they will most likely know it is to provide lubrication for moving parts.
Seems pretty straight forward: We put oil in our engines because it is slippery and metal things moving next to other metal things need something slippery between them right? That is true as far as it goes. But if that where the only consideration we would be having long discussions center around the film strength of our preferred brand rather than debates over the best viscosity and the negative effects of friction modifiers.
While providing lubrication is motor oils primary job it is not its only job. Not by a long way.
In addition to lubricating moving parts it is also responsible for, among other things, holding contaminants such as silica (dirt), wear metals, and combustion byproducts in suspension so they end up in the filter rather than the bottom of you engine, providing rust and corrosion protection, neutralizing acids formed by the aforementioned combustion byproducts, cooling of critical components and cleaning up the buildup of tars, waxes and other “gunk” left behind from the last time you over-extended your drain interval (oil change).
It has to do all those things across a wide range of temperatures from sub-zero to 250° Fahrenheit, remaining thin enough to be pumpable at -10° and thick enough to lubricate at 210°.
To be able to do all those things modern motor oil is a hybrid concoction of various chemicals created by blending some kind of “base stock” and an additive "package". The base stock can be petroleum based, fully synthetic (that is synthesized by mixing various chemicals) or a combination of both, (typically referred to as semi-synthetic depending on the ratio of petroleum based and synthetic oils).
Much of the debate in the various oil discussions seems to be centered around viscosity, often called weight. Amusingly enough an oils weight is on rather loosely an indication of its actual viscosity.
Viscosity is officially defined as: “resistance of a liquid to shear forces (and hence to flow)” in more practical terms: its thickness. Viscosity is actually measured in centi-Stokes(cSt). Weight on the other hand is an arbitrary measurement created by the SAE (Society of Automotive Engineers) and covers a range of actual viscosities.
To establish a weight, the oil it is heated to 210°F (100° C) and the speed it flows through a viscometer is measured. For instance an SAE 40 has a cSt at 100°C of 12.5 to < 16.3. Under that system an oil with a viscosity of 16.29cSt would be an SAE 40, but one with a viscosity of 16.3cSt would be an SAE 50. Because of the way that the SAE classification system works it is entirely possible to have an SAE 40 and an SAE 50 that are virtually identical in actual viscosity!
This brings us to the much misunderstood and often debated “Multi-Weight” oils. First the biggest misconception: the W in 10W-40 does NOT stand for weight, it in fact stands for Winter. Winter ratings are created using a different method all together and are not directly comparable to the other half of the number.
For practical purposes however a 10W-40 will act like an SAE 10 weight oil would at 210° when it is "cold", and an SAE 40 weight oil when it is at 210°. This is desirable to reduce wear on start up, thinner oil flows more quickly to vital parts, or if it’s cold enough to even be able to start up at all. If the oil got thick enough your entire engine could become one giant viscous damper and be impossible to turn over at least quickly enough to start.
The way that this multiple personality is achieved is interesting and relevant in itself. Long-chain molecules called polymers are added to a thin base stock as part of the additive package. This part of the package is called a Viscosity Improver or VI. When they are cold these added polymers are coiled up. As the oil is heated these polymers “unwind” into long straight chains keeping the oil from thinning as much.
So far so good, VIs keep a thin oil that flows well at low temperatures from thinning as the temperature increases, but there is a problem. One that is particularly relevant to motorcycles: these additives degrade in high heat or in high shear force situations.
In most motorcycle applications the engine and transmission share a common oil sump. That is we expect the same oil that lubricates, cools and protects the engine to lubricate the clutch and transmission as well.
The clutch and transmission introduce forces, primarily shear forces, that an automotive engine typically doesn’t subject its oil to. Those forces can break up these polymers, reducing their ability to thicken the oil at operating temperature and thus rendering that 10W-40 into a 10W-20 or even a 10W-10 in a fairly short time. Some studies indicate that breakdown in the VIs can happen in as little as 1500 miles.
As I implied above, most motorcycles, Japanese motorcycles anyway, have a “wet” clutch. This means that the clutch is bathed in engine oil along with the rest of the transmission.
While this offers several benefits over a dry clutch it presents additional problems when deciding on an oil to use. Modern automotive “Energy Saving” oils have an additional set of additives called friction modifiers that in effect make the oil slipperier. This reduced friction can dramatically affect a wet clutches ability to remain engaged under load and could result in slipping, accelerated wear and ultimately premature failure.
Motorcycle engines tend to be much more powerful for their size than a comparable automotive engine and commonly are both capable of, and operated at, much higher RPMs than a normal cage driver would along with being designed to be as light as practical. Because of all of that a motorcycle requires a different additive package than a normal automobile would.
In recognition of this and because automotive requirements are moving in a different direction powersports manufactures have created their own oil spec know as JASO. This spec addresses the specific and different needs of motorcycles and other powersports engines.
Many people in the various discussions report using diesel spec oils such as Rotella T, Delo, or Delvac these are probably better choices than automotive spec oils, but will be formulated for the specific requirements of a diesel engine, such as high solid suspension characteristics and detergents with no thought given to how those might affect things such as clutch materials.
Which oil to use in your motorcycle is your choice and will undoubtedly be influenced by things such as your financial situation, the drain intervals and personal preference.
Personally I will use an oil specifically designed for use in wet clutch motorcycle engines, produced by a reputable manufacture, that meets the appropriate JASO requirements and that I can get the best price on, but with little concern for the actual brand, specific viscosity, or base stock used to create it.
Oh and yes you can mix different brands, base stocks and even weights of oil if you want. You actually can create your own custom blends if you are of a mind to. Mixing 2Qts of 10W-40 with 2Qts of 20W-50 will net you something much like a 15W-45.
After reading some of the numerous “Engine Oil” threads I thought I would try to shed some light on a few of the misconceptions and misunderstandings about motor oil.
First the disclaimer: I am not a petroleum engineer or a chemist, however I have had cause and the inclination to study motor oils, their performance characteristics and related information, in depth.
If you ask anyone to tell you why an engine needs oil they will most likely know it is to provide lubrication for moving parts.
Seems pretty straight forward: We put oil in our engines because it is slippery and metal things moving next to other metal things need something slippery between them right? That is true as far as it goes. But if that where the only consideration we would be having long discussions center around the film strength of our preferred brand rather than debates over the best viscosity and the negative effects of friction modifiers.
While providing lubrication is motor oils primary job it is not its only job. Not by a long way.
In addition to lubricating moving parts it is also responsible for, among other things, holding contaminants such as silica (dirt), wear metals, and combustion byproducts in suspension so they end up in the filter rather than the bottom of you engine, providing rust and corrosion protection, neutralizing acids formed by the aforementioned combustion byproducts, cooling of critical components and cleaning up the buildup of tars, waxes and other “gunk” left behind from the last time you over-extended your drain interval (oil change).
It has to do all those things across a wide range of temperatures from sub-zero to 250° Fahrenheit, remaining thin enough to be pumpable at -10° and thick enough to lubricate at 210°.
To be able to do all those things modern motor oil is a hybrid concoction of various chemicals created by blending some kind of “base stock” and an additive "package". The base stock can be petroleum based, fully synthetic (that is synthesized by mixing various chemicals) or a combination of both, (typically referred to as semi-synthetic depending on the ratio of petroleum based and synthetic oils).
Much of the debate in the various oil discussions seems to be centered around viscosity, often called weight. Amusingly enough an oils weight is on rather loosely an indication of its actual viscosity.
Viscosity is officially defined as: “resistance of a liquid to shear forces (and hence to flow)” in more practical terms: its thickness. Viscosity is actually measured in centi-Stokes(cSt). Weight on the other hand is an arbitrary measurement created by the SAE (Society of Automotive Engineers) and covers a range of actual viscosities.
To establish a weight, the oil it is heated to 210°F (100° C) and the speed it flows through a viscometer is measured. For instance an SAE 40 has a cSt at 100°C of 12.5 to < 16.3. Under that system an oil with a viscosity of 16.29cSt would be an SAE 40, but one with a viscosity of 16.3cSt would be an SAE 50. Because of the way that the SAE classification system works it is entirely possible to have an SAE 40 and an SAE 50 that are virtually identical in actual viscosity!
This brings us to the much misunderstood and often debated “Multi-Weight” oils. First the biggest misconception: the W in 10W-40 does NOT stand for weight, it in fact stands for Winter. Winter ratings are created using a different method all together and are not directly comparable to the other half of the number.
For practical purposes however a 10W-40 will act like an SAE 10 weight oil would at 210° when it is "cold", and an SAE 40 weight oil when it is at 210°. This is desirable to reduce wear on start up, thinner oil flows more quickly to vital parts, or if it’s cold enough to even be able to start up at all. If the oil got thick enough your entire engine could become one giant viscous damper and be impossible to turn over at least quickly enough to start.
The way that this multiple personality is achieved is interesting and relevant in itself. Long-chain molecules called polymers are added to a thin base stock as part of the additive package. This part of the package is called a Viscosity Improver or VI. When they are cold these added polymers are coiled up. As the oil is heated these polymers “unwind” into long straight chains keeping the oil from thinning as much.
So far so good, VIs keep a thin oil that flows well at low temperatures from thinning as the temperature increases, but there is a problem. One that is particularly relevant to motorcycles: these additives degrade in high heat or in high shear force situations.
In most motorcycle applications the engine and transmission share a common oil sump. That is we expect the same oil that lubricates, cools and protects the engine to lubricate the clutch and transmission as well.
The clutch and transmission introduce forces, primarily shear forces, that an automotive engine typically doesn’t subject its oil to. Those forces can break up these polymers, reducing their ability to thicken the oil at operating temperature and thus rendering that 10W-40 into a 10W-20 or even a 10W-10 in a fairly short time. Some studies indicate that breakdown in the VIs can happen in as little as 1500 miles.
As I implied above, most motorcycles, Japanese motorcycles anyway, have a “wet” clutch. This means that the clutch is bathed in engine oil along with the rest of the transmission.
While this offers several benefits over a dry clutch it presents additional problems when deciding on an oil to use. Modern automotive “Energy Saving” oils have an additional set of additives called friction modifiers that in effect make the oil slipperier. This reduced friction can dramatically affect a wet clutches ability to remain engaged under load and could result in slipping, accelerated wear and ultimately premature failure.
Motorcycle engines tend to be much more powerful for their size than a comparable automotive engine and commonly are both capable of, and operated at, much higher RPMs than a normal cage driver would along with being designed to be as light as practical. Because of all of that a motorcycle requires a different additive package than a normal automobile would.
In recognition of this and because automotive requirements are moving in a different direction powersports manufactures have created their own oil spec know as JASO. This spec addresses the specific and different needs of motorcycles and other powersports engines.
Many people in the various discussions report using diesel spec oils such as Rotella T, Delo, or Delvac these are probably better choices than automotive spec oils, but will be formulated for the specific requirements of a diesel engine, such as high solid suspension characteristics and detergents with no thought given to how those might affect things such as clutch materials.
Which oil to use in your motorcycle is your choice and will undoubtedly be influenced by things such as your financial situation, the drain intervals and personal preference.
Personally I will use an oil specifically designed for use in wet clutch motorcycle engines, produced by a reputable manufacture, that meets the appropriate JASO requirements and that I can get the best price on, but with little concern for the actual brand, specific viscosity, or base stock used to create it.
Oh and yes you can mix different brands, base stocks and even weights of oil if you want. You actually can create your own custom blends if you are of a mind to. Mixing 2Qts of 10W-40 with 2Qts of 20W-50 will net you something much like a 15W-45.
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