ASTM D4859 Lubricants for Two-Stroke-Cycle Spark-Ignition Gasoline Engines-TC
4. General Requirements
4.1 This specification covers only specific aspects of the performance of the lubricant in an engine under the conditions of test. Requirements additional to those of this specification, such as miscibility with gasoline, may be agreed between the purchaser and the supplier.
4.2 Performance testing of each batch of lubricant shall not be required. The supplier shall certify that the product supplied meets the requirements of this specification and that it conforms in all significant respects to a batch of lubricant that has met the requirements of this specification. The supplier shall provide on request the batch and test number and the date and place of qualification of this previously qualified batch of oil, and such additional information on the physical and chemical properties of the lubricant as shall enable the purchaser to detect contamination or substitution of product.
4.3 Ring Sticking and Piston Deposit Test - The performance of the candidate oil shall be equal to, within the specified tolerances, or better than that of the benchmark reference oil when run under the conditions required by this specification and by the test procedure. The benchmark reference oil used when testing to this specification is ASTM 600.
4.4 Lubricity Test - The performance of the candidate oil shall be equal to, within the specified tolerances, or better than that of the benchmark reference oil when run under the conditions required by this specification and by the test procedure. The benchmark reference oil required by this specification is ASTM 600.
4.5 Preignition Test - Not more than one major preignition may occur when running the candidate oil. Minor preignitions shall be reported with the temperature increase and the time of occurrence in running hours to the nearest 0.1 h. The benchmark reference oil used when testing to this specification is ASTM 601.
NOTE 1 - Find a general description of these benchmark reference oils in Annex A1.
5. Summary of Test Methods
5.1 Ring Sticking and Piston Deposits-Test Method D4857 - This test is run in a 347 cm3 Yamaha RD-350B twin-cylinder air-cooled motorcycle engine for 20 h, set up with number one cylinder supplied with a fuel mix containing the benchmark reference oil and number two cylinder with a fuel mix containing the candidate oil, both at 50:1 fuel to oil ratio by volume. The test is normally run twice, exchanging the oils between cylinders for the second run, unless the performance of the candidate oil exceeds that of the benchmark reference oil by the margins specified in 6.2.7, in which case the second run need not be made.
5.2 Lubricity-Test Method D4863 - The procedure is a development of CEC L-19-T-77, for which test engines are no longer available. It is run in a Yamaha CE-50 49 cm3 single-cylinder air-cooled engine supplied with a 150:1 by volume fuel to oil mix. The engine is brought to equilibrium at 4000 r/min wide open throttle (WOT), and the cooling air flow adjusted to give a spark plug gasket temperature of 169 to 171°C (336 to 340°F). The cooling air to the cylinder is then cut off and the output torque recorded when the plug gasket temperature reaches 200°C (392°F) and again when it reaches 350°C (662°F), when the cooling air flow is restored. The smaller the reduction in torque output at constant engine speed during this interval, the better the ability of the oil to lubricate the piston. Tests are run alternately on the benchmark reference oil, ASTM 600, and on the candidate oil. This test does not normally damage the engine.
5.3 Preignition-Test Method D4858 - This is run in a Yamaha CE-50 engine. For the purposes of this specification the engine is run for 50 h at 4000 r/min at wide open throttle (WOT) using a 20:1 volumetric fuel to oil ratio. The number of incidences of preignition, as determined by an increase in the temperature of the combustion chamber over the normal running level, is observed.
