JHZR2
Staff member
Hi,
In reading the MBZ diesel forum list, I found a few statements regarding oil choics for out indirect injection diesels that were quite informative. The first is very short, ad the second very long, but extremely well written. I just dont know enough to believe his comments on TBN, etc., and thus my reason why I am posting it here to see what everyone has to say. I would like to see what the experts here have to say about these posts (please note that these posts are written with regards to Indirect injection MB diesel engines, mopst from the late 70s to the early 90s):
I'd be MUCH more interested in seeing a B4-98/B4-02 spec than just a CF.
One of the major factors differentiating most CH-4 oils (somewhat similar to the MB 228.x rated oils) from CF rated oils (I haven't digested the final CI-4 standard yet - but the API CF rating is similar to the MB 229.x rating) is the increased TBN (that rates the oil's capacity to neutralize acidic combustion by-products). A high number(usually 11-12) dictates that the oil can neutralize more acid for a longer time than could an oil with a lower number and for oils intended
for 30-100kmi change intervals, numbers in the 11-12 range are usual. This is of less important since most diesel fuel available in the US
today has low or extra low sulfur content so the sulfur acid wastes are considerably reduced. If the oil is well filtered, even CF oils with
modest TBN can be entirely effective for many 10's of thousands of miles. These oils are most similar to the 229.x MB sheet oils. Oils with
TBN ratings of 6-8 are common for light duty diesel service (all passenger car and light truck diesels are light duty BY DEFINITION) where change intervals of 5-20kmi are common. Many CF oils do not advertise or even list on the spec sheets what the TBN rating is, as it's seldom challenged in light duty service when the engine is in good running condition and the oil is changed at the manufacturer's recommended intervals. Having an oil with a higher TBN is of course a waste if it's going to be discarded when only 20-30% depleted. More TBN is not better - enough is all that's needed and excess capacity is a waste and may well compromise some other quality or at least cost more without providing added benefit. There is no more need to have an oil with excess TBN than having cooling system that has a 5 gallon capacity when a two gallon capacity is what's required! There are factors related to content of metal anti-wear additives - some of which COULD poison or contaminate traps or CATS designed to reduce emissions.
The capacity to suspend soot is another MAJOR factor. API CF rated oils are not tested for soot suspension capacity (but many/most will handle
at least 2%). CF-4, CG-4 and CH-4 oils are rated for soot suspension and are certified to handle more (around 4%). This is largely irrelevant as
most analysis schemes suggest changing the oil before soot reaches 2%.
Most of the other characteristics relate to specific tests that measure qualities desirable in large, low rpm, high powered engines. There was
controversy about specifics of the the CI-4 rating because some lubrication and neutralization properties of the oil needed to be
compromised to achieve environmental and fuel efficiency requirements.
It was alleged that the CI-4 standard would result in an oil that did not meet some parts of the CH-4 standard and thus would NOT be backwards
compatible. I do NOT know how the final standard deals with these issues.
The API standards have been found by Mercedes to be inadequate for selecting oil. They recommend that oil be selected based on the specific
specification sheets that they publish (229.x class oil for gasoline and light duty diesel service - 228.x for heavy duty diesel service) and if approved oils are not available, that oil be selected using the ACEA standards. Only if oils meeting those criteria are unavailable should
API rating be used to select oil.
Thanks!
[ July 07, 2003, 03:34 PM: Message edited by: BOBISTHEOILGUY ]
In reading the MBZ diesel forum list, I found a few statements regarding oil choics for out indirect injection diesels that were quite informative. The first is very short, ad the second very long, but extremely well written. I just dont know enough to believe his comments on TBN, etc., and thus my reason why I am posting it here to see what everyone has to say. I would like to see what the experts here have to say about these posts (please note that these posts are written with regards to Indirect injection MB diesel engines, mopst from the late 70s to the early 90s):
I'd be MUCH more interested in seeing a B4-98/B4-02 spec than just a CF.
One of the major factors differentiating most CH-4 oils (somewhat similar to the MB 228.x rated oils) from CF rated oils (I haven't digested the final CI-4 standard yet - but the API CF rating is similar to the MB 229.x rating) is the increased TBN (that rates the oil's capacity to neutralize acidic combustion by-products). A high number(usually 11-12) dictates that the oil can neutralize more acid for a longer time than could an oil with a lower number and for oils intended
for 30-100kmi change intervals, numbers in the 11-12 range are usual. This is of less important since most diesel fuel available in the US
today has low or extra low sulfur content so the sulfur acid wastes are considerably reduced. If the oil is well filtered, even CF oils with
modest TBN can be entirely effective for many 10's of thousands of miles. These oils are most similar to the 229.x MB sheet oils. Oils with
TBN ratings of 6-8 are common for light duty diesel service (all passenger car and light truck diesels are light duty BY DEFINITION) where change intervals of 5-20kmi are common. Many CF oils do not advertise or even list on the spec sheets what the TBN rating is, as it's seldom challenged in light duty service when the engine is in good running condition and the oil is changed at the manufacturer's recommended intervals. Having an oil with a higher TBN is of course a waste if it's going to be discarded when only 20-30% depleted. More TBN is not better - enough is all that's needed and excess capacity is a waste and may well compromise some other quality or at least cost more without providing added benefit. There is no more need to have an oil with excess TBN than having cooling system that has a 5 gallon capacity when a two gallon capacity is what's required! There are factors related to content of metal anti-wear additives - some of which COULD poison or contaminate traps or CATS designed to reduce emissions.
The capacity to suspend soot is another MAJOR factor. API CF rated oils are not tested for soot suspension capacity (but many/most will handle
at least 2%). CF-4, CG-4 and CH-4 oils are rated for soot suspension and are certified to handle more (around 4%). This is largely irrelevant as
most analysis schemes suggest changing the oil before soot reaches 2%.
Most of the other characteristics relate to specific tests that measure qualities desirable in large, low rpm, high powered engines. There was
controversy about specifics of the the CI-4 rating because some lubrication and neutralization properties of the oil needed to be
compromised to achieve environmental and fuel efficiency requirements.
It was alleged that the CI-4 standard would result in an oil that did not meet some parts of the CH-4 standard and thus would NOT be backwards
compatible. I do NOT know how the final standard deals with these issues.
The API standards have been found by Mercedes to be inadequate for selecting oil. They recommend that oil be selected based on the specific
specification sheets that they publish (229.x class oil for gasoline and light duty diesel service - 228.x for heavy duty diesel service) and if approved oils are not available, that oil be selected using the ACEA standards. Only if oils meeting those criteria are unavailable should
API rating be used to select oil.
Thanks!
[ July 07, 2003, 03:34 PM: Message edited by: BOBISTHEOILGUY ]
