Oil and the Boxer - Revisited
Posted: Tue Sep 18, 2007 9:57 am
The intent of this post is to provide the BMW boxer owner with the information necessary to understand what is the fundamental relationship between oil and the Boxer engine design. Hopefully after perusing the document, the owner will be in possession of information that will assist with the proper lubrication selection at the minimal cost that will supply the engine longevity based on the owner’s ridding habits.
First let’s identify some terms:
Owner’s manual – This document provides “basic†recommendations to the new owner. I emphasize basic because one has to understand that these bikes are sold both in Alaska as well as Tierra del Fuego and the lubrication requirements are different in either of the locations. It is a guideline, period.
Air cooled engine – Older engine design that enjoys the benefits of simplicity and fewer parts. However it does give up some performance primarily because the range of operational temperatures is greater than that of a water cooled engine. Air cooled engines can never reach the “tight†clearances of water cooled ones, there for the efficiency will always suffer.
Nikasil – Electrodeposited nickel/silicon carbide matrix which when applied to aluminum cylinders has shown some excellent wear characteristics. Please note that this coating is very specific to the Boxer design. The logic being is that if one makes the cylinder hard to wear, the rings will be the sacrificial material; however it is much easier and less costly to change rings than cylinders. This is one of the reasons while the boxer engines can go 200,000 miles (with proper maintenance) on the original cylinders.
Break in – A phenomena usually associated with operation and temperature cycles within the engine, that allow the rings to conform to the cylinder in such a way that it minimizes “blowby†or passage of combustion gases into the oil as well as preventing the oil to gain passage to the combustion chamber. Boxers typically use a significant amount of oil during the break in period. Let it be known that the way the bike is ridden plays a tremendous effect on the duration of the “break in†period, read oil consumption. Some owners will complete the “break in†within the first 5000 miles (stopped oil consumption) others have run 20,000 to 30,000 miles and haven’t completed the “break inâ€Â. Let me suffice to say that there are various schools of thought on how to break in a boxer, but that is a topic for another post.
Oil – A liquid whose primary function is to lubricate and act as a heat transfer medium in internal combustion engines, amongst other uses.
Organic oil – Hydrocarbon derived (petroleum based). Two organizations, API (American Petroleum Institute) and SAE (Society of Automotive Engineers) regulate the grades and additive packages in the oil.
Organic oil, operational temperature – The rule of thumb is to keep engine oil temperature between 180 F to 220 F to attain maximum engine life. Yes, one can exceed 220 F with the understanding that the rotating parts will wear a bit more than normal. Once you exceed 260 F the oil viscosity begins to suffer and the engine life will be reduced significantly.
Synthetic oil – Artificially synthesized lubricants such as esters and polyalpha-olefins. These lubricants, because of their highly refined state, typically exhibit improved viscosity and a wider temperature range at temperature extremes than organic oils. In addition, these lubricants have improved efficiency over the organic variety; therefore they don’t degrade as quickly as the organic oils. It is very important to note that there is no difference in the retention of particulate matter, meaning that the filter will deteriorate (plug) at the same rate as that on the organic lubricant.
Synthetic oil, operational temperature – This oil has improved lubricity across its operational range. Typical range is defined between 170 F to 260 F. Once past 300 F, viscosity begins to suffer with end results similar to those of organic oil.
Grades – The grades have to do with oil viscosity. There are single grades like 30W and multigrade like 10W30. Basically the first one has one viscosity; the second one has a range of viscosities which change according to ambient temperature. It is very important to understand that multigrade oils, because they are a blend one can never reach the extremes. So in a 10W30 the oil will never be as viscous as a single 10W or as viscous as a 30 W.
Additives – Oils used on internal combustion engines use additive packages to minimize sludge, corrosion, mitigate metal to metal contact (zinc), along with friction reducers (moly) and extreme pressure compounds, amongst others. Some of the above are included with the oil to reduce the by-products of combustion.
OK so what now?
Break in - Suggest that one completes the break in with organic oil before going to synthetic. Synthetic oil has more lubricity than organic oil and therefore will hamper the break in period. You want the rings to reach maximum sealing against the cylinder wall as quickly as possible; this in turn will reduce the amount of oil consumption significantly. The break in is accomplished faster if the owner revs through the gears and stays away fro steady state operation.
Organic or synthetic – That will depend on the ridding style and the frequency of use. For instance; if one uses the bike every day, runs through the gears and will run 30 minutes or more, organic will be my choice and there will not be any abnormal wear issues. On the other hand if the bike is used occasionally, not started daily and the runs are short…..not enough run time to warm the oil, there are benefits to using synthetic because of the superior lubricity.
Cost – In reality, there is not much of a cost difference. Let’s assume that the synthetic is 2x the cost of organic and assume that the organic oil is changed every 3,000 miles. So in the case of the synthetic you can probably run 6,000 miles before changes, although, because of the particle retention the filter will have to be changed at 3,000 mile intervals. So in the long run the cost is a washout.
Extreme conditions – If the ambient temperature is consistently above 90 F, I would suggest synthetic oil as the lubricant, since it enjoys a wider temperature range than the organic oil.
And last but not least
What should be my oil level – Middle of the window (sight glass) after a minimum of a 20 minute run, 3 to 5 minutes on the side stand and then onto the center stand. Come back when the bike is cold and check the level. Never run the bike below the lower circle as it will bring unpleasant and costly results, nor higher than the middle of the glass, as you will be burning the oil of at the combustion chamber increasing the potential of carbon deposits.
In some remote instances one might run for 20 minutes or more, however the ambient temperature might be low enough that it will not allow the engine to open the thermo valve to the oil coolers, therefore trapping some oil there from the previous ride.
To your surprise you will find that upon checking, the oil level it is fairly low and in turn you will add oil until the middle of the window is reached. After the following ride you then find out the oil level is now at the top of the window…Arrgghhh…..the oil coolers path opened up and the entrapped oil went back into the system………I rest my case.
If this article in anyway helps you out, brings a smile to your face or makes you cry please consider making a small donation to the boxermania retirement fund, your kindness will be greatly appreciated.
First let’s identify some terms:
Owner’s manual – This document provides “basic†recommendations to the new owner. I emphasize basic because one has to understand that these bikes are sold both in Alaska as well as Tierra del Fuego and the lubrication requirements are different in either of the locations. It is a guideline, period.
Air cooled engine – Older engine design that enjoys the benefits of simplicity and fewer parts. However it does give up some performance primarily because the range of operational temperatures is greater than that of a water cooled engine. Air cooled engines can never reach the “tight†clearances of water cooled ones, there for the efficiency will always suffer.
Nikasil – Electrodeposited nickel/silicon carbide matrix which when applied to aluminum cylinders has shown some excellent wear characteristics. Please note that this coating is very specific to the Boxer design. The logic being is that if one makes the cylinder hard to wear, the rings will be the sacrificial material; however it is much easier and less costly to change rings than cylinders. This is one of the reasons while the boxer engines can go 200,000 miles (with proper maintenance) on the original cylinders.
Break in – A phenomena usually associated with operation and temperature cycles within the engine, that allow the rings to conform to the cylinder in such a way that it minimizes “blowby†or passage of combustion gases into the oil as well as preventing the oil to gain passage to the combustion chamber. Boxers typically use a significant amount of oil during the break in period. Let it be known that the way the bike is ridden plays a tremendous effect on the duration of the “break in†period, read oil consumption. Some owners will complete the “break in†within the first 5000 miles (stopped oil consumption) others have run 20,000 to 30,000 miles and haven’t completed the “break inâ€Â. Let me suffice to say that there are various schools of thought on how to break in a boxer, but that is a topic for another post.
Oil – A liquid whose primary function is to lubricate and act as a heat transfer medium in internal combustion engines, amongst other uses.
Organic oil – Hydrocarbon derived (petroleum based). Two organizations, API (American Petroleum Institute) and SAE (Society of Automotive Engineers) regulate the grades and additive packages in the oil.
Organic oil, operational temperature – The rule of thumb is to keep engine oil temperature between 180 F to 220 F to attain maximum engine life. Yes, one can exceed 220 F with the understanding that the rotating parts will wear a bit more than normal. Once you exceed 260 F the oil viscosity begins to suffer and the engine life will be reduced significantly.
Synthetic oil – Artificially synthesized lubricants such as esters and polyalpha-olefins. These lubricants, because of their highly refined state, typically exhibit improved viscosity and a wider temperature range at temperature extremes than organic oils. In addition, these lubricants have improved efficiency over the organic variety; therefore they don’t degrade as quickly as the organic oils. It is very important to note that there is no difference in the retention of particulate matter, meaning that the filter will deteriorate (plug) at the same rate as that on the organic lubricant.
Synthetic oil, operational temperature – This oil has improved lubricity across its operational range. Typical range is defined between 170 F to 260 F. Once past 300 F, viscosity begins to suffer with end results similar to those of organic oil.
Grades – The grades have to do with oil viscosity. There are single grades like 30W and multigrade like 10W30. Basically the first one has one viscosity; the second one has a range of viscosities which change according to ambient temperature. It is very important to understand that multigrade oils, because they are a blend one can never reach the extremes. So in a 10W30 the oil will never be as viscous as a single 10W or as viscous as a 30 W.
Additives – Oils used on internal combustion engines use additive packages to minimize sludge, corrosion, mitigate metal to metal contact (zinc), along with friction reducers (moly) and extreme pressure compounds, amongst others. Some of the above are included with the oil to reduce the by-products of combustion.
OK so what now?
Break in - Suggest that one completes the break in with organic oil before going to synthetic. Synthetic oil has more lubricity than organic oil and therefore will hamper the break in period. You want the rings to reach maximum sealing against the cylinder wall as quickly as possible; this in turn will reduce the amount of oil consumption significantly. The break in is accomplished faster if the owner revs through the gears and stays away fro steady state operation.
Organic or synthetic – That will depend on the ridding style and the frequency of use. For instance; if one uses the bike every day, runs through the gears and will run 30 minutes or more, organic will be my choice and there will not be any abnormal wear issues. On the other hand if the bike is used occasionally, not started daily and the runs are short…..not enough run time to warm the oil, there are benefits to using synthetic because of the superior lubricity.
Cost – In reality, there is not much of a cost difference. Let’s assume that the synthetic is 2x the cost of organic and assume that the organic oil is changed every 3,000 miles. So in the case of the synthetic you can probably run 6,000 miles before changes, although, because of the particle retention the filter will have to be changed at 3,000 mile intervals. So in the long run the cost is a washout.
Extreme conditions – If the ambient temperature is consistently above 90 F, I would suggest synthetic oil as the lubricant, since it enjoys a wider temperature range than the organic oil.
And last but not least
What should be my oil level – Middle of the window (sight glass) after a minimum of a 20 minute run, 3 to 5 minutes on the side stand and then onto the center stand. Come back when the bike is cold and check the level. Never run the bike below the lower circle as it will bring unpleasant and costly results, nor higher than the middle of the glass, as you will be burning the oil of at the combustion chamber increasing the potential of carbon deposits.
In some remote instances one might run for 20 minutes or more, however the ambient temperature might be low enough that it will not allow the engine to open the thermo valve to the oil coolers, therefore trapping some oil there from the previous ride.
To your surprise you will find that upon checking, the oil level it is fairly low and in turn you will add oil until the middle of the window is reached. After the following ride you then find out the oil level is now at the top of the window…Arrgghhh…..the oil coolers path opened up and the entrapped oil went back into the system………I rest my case.
If this article in anyway helps you out, brings a smile to your face or makes you cry please consider making a small donation to the boxermania retirement fund, your kindness will be greatly appreciated.
