Tom F&L GoR
Enthusiast
The second of a new series in the VCA forums.... since I copy/paste from ***, the format may be awkward, as you may have to start at the bottom and work your way up. Sorry about that.
Many of you send me *** with oil questions. I will answer to you personally, but I think I will also put up my answers as a new thread. Feel free to send me ***, my User CP is set to bounce it to my email so I will respond more quickly to you than to a new thread. I'll hide/change the names to protect the innocent. I just hope it doesn't swamp me...
Another answer to another old question! Who would have thought that the Gov would cause us car guys to use Diesel oil to get the lubrication that we need for our cars???
Wonders will never cease.
Thanks,
tttt
Quote:
Originally Posted by Tom, F&L GoR
It's also that the gasoline engine manufacturers use catalytic exhaust treatment and rely on noble metals, while the diesel manufacturers use particulate filters that aren't affected by phosphorus. So there is a divergence of needs.
Detroit Diesel did get their act together and developed a foaming evaluation that is now an industry standard. Their diesel engines were used in Ford pickup trucks and the injector design used the engine oil in a clever hydraulic pressure accumulator to provide the high fuel pressures needed for better atomization. With foamy oil, the fuel pressure at the nozzle was too low and emissions/starting/driveability suffered.
It's interesting stuff.
-Tom
Quote:
Originally Posted by tttt
I had some knowledge of Cat and Cummins not agreeing that the new oils were "as good as the old G rated oils". This email pretty mich explains it.
Years ago I'd hear that the Diesel oils didn't have enough antifoaming addittives since they were a low rpm designed oil so the oils aerated too much in hp high revving engines.
tttt
Quote:
Originally Posted by Tom, F&L GoR
Quote:
Originally Posted by tttt
So the Diesel contains EP additiives that have been removed from our car oils (giving us the L and M ratings instead of G?)
tttt
Hi tttt,
Direct answer is yes, current diesel oils contain the level of additives that API SG oils used to have.
EP (extreme pressure) additives are one type of high aggressive surface chemistry used in gear oils. Engine oils don't have EP additives. Engine oils contain anti-wear additives, a sacrifical layer of additive formed by ZDDP (zinc-phosphorus) additives. The car companies believe phosphorus poisons catalysts, so the current level in API SM averages 800 ppm P in those oils that also claim to meet the fuel economy of ILSAC GF-4 (i.e. the starburst sympbol on the front of the bottle.) ILSAC oils are what the OEMs want for factory fill (i.e. best fuel economy and long catalyst life.) Thicker oils, such as the 0W40 or 15W-anything (such as diesel oils) can still claim API SM but don't have to meet the lowered ZDDP limits.
In API SG the level was around 1200 ppm phosphorus, so the use of ZDDP is not eliminated. However, the newest category will go into effect Oct 2010 and be called API SN. This will have an 800 ppm Phos maximum and 600 ppm minimum.
I'm not picking on you , but the nomenclature means different things to formulators. And the myriad of rules that apply sometimes to some viscosity grades and sometimes not to others makes it confusing.
I hope all that made sense. If not, let me know.
-Tom
__________________
Many of you send me *** with oil questions. I will answer to you personally, but I think I will also put up my answers as a new thread. Feel free to send me ***, my User CP is set to bounce it to my email so I will respond more quickly to you than to a new thread. I'll hide/change the names to protect the innocent. I just hope it doesn't swamp me...
Another answer to another old question! Who would have thought that the Gov would cause us car guys to use Diesel oil to get the lubrication that we need for our cars???
Wonders will never cease.
Thanks,
tttt
Quote:
Originally Posted by Tom, F&L GoR
It's also that the gasoline engine manufacturers use catalytic exhaust treatment and rely on noble metals, while the diesel manufacturers use particulate filters that aren't affected by phosphorus. So there is a divergence of needs.
Detroit Diesel did get their act together and developed a foaming evaluation that is now an industry standard. Their diesel engines were used in Ford pickup trucks and the injector design used the engine oil in a clever hydraulic pressure accumulator to provide the high fuel pressures needed for better atomization. With foamy oil, the fuel pressure at the nozzle was too low and emissions/starting/driveability suffered.
It's interesting stuff.
-Tom
Quote:
Originally Posted by tttt
I had some knowledge of Cat and Cummins not agreeing that the new oils were "as good as the old G rated oils". This email pretty mich explains it.
Years ago I'd hear that the Diesel oils didn't have enough antifoaming addittives since they were a low rpm designed oil so the oils aerated too much in hp high revving engines.
tttt
Quote:
Originally Posted by Tom, F&L GoR
Quote:
Originally Posted by tttt
So the Diesel contains EP additiives that have been removed from our car oils (giving us the L and M ratings instead of G?)
tttt
Hi tttt,
Direct answer is yes, current diesel oils contain the level of additives that API SG oils used to have.
EP (extreme pressure) additives are one type of high aggressive surface chemistry used in gear oils. Engine oils don't have EP additives. Engine oils contain anti-wear additives, a sacrifical layer of additive formed by ZDDP (zinc-phosphorus) additives. The car companies believe phosphorus poisons catalysts, so the current level in API SM averages 800 ppm P in those oils that also claim to meet the fuel economy of ILSAC GF-4 (i.e. the starburst sympbol on the front of the bottle.) ILSAC oils are what the OEMs want for factory fill (i.e. best fuel economy and long catalyst life.) Thicker oils, such as the 0W40 or 15W-anything (such as diesel oils) can still claim API SM but don't have to meet the lowered ZDDP limits.
In API SG the level was around 1200 ppm phosphorus, so the use of ZDDP is not eliminated. However, the newest category will go into effect Oct 2010 and be called API SN. This will have an 800 ppm Phos maximum and 600 ppm minimum.
I'm not picking on you , but the nomenclature means different things to formulators. And the myriad of rules that apply sometimes to some viscosity grades and sometimes not to others makes it confusing.
I hope all that made sense. If not, let me know.
-Tom
__________________
