SAE J300
[1] Key parameters for engine oil viscometrics are the oil's kinematic viscosity, its high temperature-high shear viscosity measured by the tapered bearing simulator, and low temperature properties measured by the cold-cranking simulator and mini-rotary viscometer.
[6][7] To assign winter grades, the dynamic viscosity is measured at various cold temperatures, specified in J300, in units of mPa·s, or the equivalent older non-SI units, centipoise (abbreviated cP), using two test methods.
To assign non-winter grades, kinematic viscosity is graded by ASTM D445 or ASTM D7042, measuring the time it takes for a standard amount of oil at a temperature of 100 °C (212 °F) to flow through a standard orifice, in units of mm2/s (millimetre squared per second) or the equivalent older non-SI units, centistokes (abbreviated cSt).
In addition, a minimum viscosity measured at a high temperature and high-shear rate (HTHS, ASTM D4683) is also required.
This single grade specification means that the oil must meet the SAE 30 requirements.
Otherwise, an oil not containing VIIs can be labeled as multi-grade or single grade.
Initially, there was skepticism surrounding these petroleum oils, seen as inferior to their animal and vegetable counterparts.
This practice of adulteration was frowned upon, prompting chemists and oil experts to develop tests to detect such fraud.
Often, specific test values were specified as requirements despite being irrelevant, unfairly giving the perception that Pennsylvania oil was inferior.
26 for "automobile engine light lubricating oil",[10] the first such formal specification.
These efforts were unsuccessful, since these names were tied up with the trademarks and advertising of the oil companies.
Beginning in 1920, the SAE began efforts to draw up a more extensive set of specifications.
[9] In the fall of 1925, a joint meeting of SAE and ASTM committee members (automotive and oil engineers) worked out a new standard.
The criteria were reformulated in 1967 to use kinematic viscosity in centiStokes and the cold-cranking simulator.
[19] The use of ASTM D7042 for determining low shear rate kinematic viscosity was added in 2021.
