"1sttruck, how can you say that what goes on in aviation engines has any relevance to what happens in cars? Those oils must work under an entirely different set of circumstances than car oils. Not to mention the engines are low rpm, constant load.
Ever taken apart a Continental? "
No. The more modern air cooled small aircraft engines that I've seen look like bigger brothers to the VW, Porsche and Corvair air cooled opposed 4 and 6 cyl engines, and I have rebuilt a few VWs. Wear points in engines are similar, as they have in common journal bearings, valve trains, piston/ring/liner assemblies, and such. As I recall from some of the older VW specs in artic conditions one could have ended up with a 500 mile oil change interval, which at 25 mph on snow and ice means about a 20 hr oil change interval. Does that sound at all similar to aircraft engines that you're talking about ?
As far as more modern car engines go the 3L V6 in our Taurus in OD is running about 2000 rpm at 60 mph, obviously less at 55 mph, with 6 people, a full trunk, headwind, going up a grade, and the air on. Is that a load and rpm at all similar to smaller aircraft ? My truck is rated for about a 12k load when towing, and it's pulling about 2000 rpm at 65 mph.Being a water cooled engine the Taurus and Cummins can be set up with tighter tolerances in some areas than an air cooled engine, and before CAFE concerns it appears that at one time 40 weight oils may have been used in the Taurus, based upon references to the use of 'motor oil' for some assembly procedures. Single or multiple grade 50 weight oils seem common in aircraft, which seem similar to PCMO oils like 10W40 or 5W40, or HDEOs used in my truck like 15W40 or 5W40, 'ashless' requirements aside.
Finally, does a ball on a rotating disc have any relevance to a car engine or heavy duty diesel ? Most would say no, but there are lots of different bench top testers for various aspects of oil. See below.
http://iantaylor.org.uk/papers/Esslingen2002.pdf
A Screener Test for the Fuel Economy Potential of Engine Lubricants
SUMMARY A useful screener test for identifying engine lubricants which have good fuel economy potential is described. The screener test involves measuring the Stribeck curve of the fresh oil in a PCS Mini-Traction Machine, using operating conditions that mimic those found in the Sequence VI-B engine test. The lubricant is then oxidised in a Sequence IIIE laboratory screener test for a specified length of time, during which the viscosity increase of the lubricant is monitored (the TBN and TAN can also be monitored if required). The oxidised lubricant is then re-tested in the Mini-Traction Machine. Results are presented for a range of lubricants, including a 0W/20 fuel economy lubricant containining a Molybdenum based friction modifier. Results are also presented showing how the phosphorus content of the lubricant affects the Stribeck curve, and for heavy duty diesel engine lubricants showing how the soot content of the oil also affects the measured Stribeck curve.
Ever taken apart a Continental? "
No. The more modern air cooled small aircraft engines that I've seen look like bigger brothers to the VW, Porsche and Corvair air cooled opposed 4 and 6 cyl engines, and I have rebuilt a few VWs. Wear points in engines are similar, as they have in common journal bearings, valve trains, piston/ring/liner assemblies, and such. As I recall from some of the older VW specs in artic conditions one could have ended up with a 500 mile oil change interval, which at 25 mph on snow and ice means about a 20 hr oil change interval. Does that sound at all similar to aircraft engines that you're talking about ?
As far as more modern car engines go the 3L V6 in our Taurus in OD is running about 2000 rpm at 60 mph, obviously less at 55 mph, with 6 people, a full trunk, headwind, going up a grade, and the air on. Is that a load and rpm at all similar to smaller aircraft ? My truck is rated for about a 12k load when towing, and it's pulling about 2000 rpm at 65 mph.Being a water cooled engine the Taurus and Cummins can be set up with tighter tolerances in some areas than an air cooled engine, and before CAFE concerns it appears that at one time 40 weight oils may have been used in the Taurus, based upon references to the use of 'motor oil' for some assembly procedures. Single or multiple grade 50 weight oils seem common in aircraft, which seem similar to PCMO oils like 10W40 or 5W40, or HDEOs used in my truck like 15W40 or 5W40, 'ashless' requirements aside.
Finally, does a ball on a rotating disc have any relevance to a car engine or heavy duty diesel ? Most would say no, but there are lots of different bench top testers for various aspects of oil. See below.
http://iantaylor.org.uk/papers/Esslingen2002.pdf
A Screener Test for the Fuel Economy Potential of Engine Lubricants
SUMMARY A useful screener test for identifying engine lubricants which have good fuel economy potential is described. The screener test involves measuring the Stribeck curve of the fresh oil in a PCS Mini-Traction Machine, using operating conditions that mimic those found in the Sequence VI-B engine test. The lubricant is then oxidised in a Sequence IIIE laboratory screener test for a specified length of time, during which the viscosity increase of the lubricant is monitored (the TBN and TAN can also be monitored if required). The oxidised lubricant is then re-tested in the Mini-Traction Machine. Results are presented for a range of lubricants, including a 0W/20 fuel economy lubricant containining a Molybdenum based friction modifier. Results are also presented showing how the phosphorus content of the lubricant affects the Stribeck curve, and for heavy duty diesel engine lubricants showing how the soot content of the oil also affects the measured Stribeck curve.
