ASTM D4857 Standard Test Method for Determination of the Ability of Lubricants to Minimize Ring Sticking and Piston Deposits in Two-Stroke-Cycle Gasoline Engines Other Than Outboards
1. Scope
1.1 This test method evaluates the performance of lubricants intended for use in two-stroke-cycle spark-ignition gasoline engines that are particularly prone to ring sticking. Piston varnish and spark plug fouling are also evaluated.

1.2 The values stated in SI units are the standard. The values given in parentheses are provided for information only.

1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

2. Referenced Documents
2.1 ASTM Standards:
B 152 Specification for Copper Sheet, Strip, Plate, and Rolled Bar
D93 Test Methods for Flash-Point by Pensky-Martens Closed Cup Tester
D235 Specification for Mineral Spirits (Petroleum Spirits) (Hydrocarbon Dry Cleaning Solvent)
D445 Test Method for Kinematic Viscosity of Transparent and Opaque Liquids
D874 Test Method for Sulfated Ash from Lubricating Oils and Additives
D2270 Practice for Calculating Viscosity Index from Kinematic Viscosity at 40 and 100°C
D2622 Test Method for Sulfur in Petroleum Products by Wavelength Dispersive X-ray Fluorescence Spectrometry
D4052 Test Method for Density and Relative Density of Liquids by Digital Density Meter
D4629 Test Method for Trace Nitrogen in Liquid Petroleum Hydrocarbons by Syringe/Inlet Oxidative Combustion and Chemiluminescence Detection
D4858 Test Method for Determination of the Tendency of Lubricants to Promote Preignition in Two-Stroke-Cycle Gasoline Engines
D4859 Specification for Lubricants for Two-Stroke-Cycle Spark Ignition Gasoline Engines-TC
D4863 Test Method for Determination of Lubricity of Two-Stroke-Cycle Gasoline Engine Lubricants
D4951 Test Method for Determination of Additive Elements in Lubricating Oils by Inductively Coupled Plasma Atomic Emission Spectrometry
E 230 Specification and Temperature-Electromotive Force (EMF) Tables for Standardized Thermocouples
G 40 Terminology Relating to Wear and Erosion

2.2 ANSI Standard:
ANSI MC 96.1 American National Standard for Temperature Measurement Thermocouples

3. Terminology
3.1 Definitions:
3.1.1 cold sticking - of piston rings, a condition in which the ring is free in its groove while the engine is running but stuck when the piston is cold, normally indicated by the absence of varnish or other deposits on the outer face of the ring and of signs of blowby on the piston skirt.

3.1.2 combustion chamber - in reciprocating internal combustion engines, the volume bounded by the piston crown and any portion of the cylinder walls extending above the piston crown when in the top dead center position, and the inner surface of the cylinder head including any spark plugs and other inserted components.

3.1.3 hot sticking - of piston rings, a condition in which the ring is stuck in its groove while the engine is running, normally indicated by varnish or other deposits on the outer face of the ring, by signs of blowby on the piston skirt, or both.

3.1.4 lubricity - a qualitative term describing the ability of a lubricant to minimize friction between and damage to surfaces in relative motion under load.

3.1.5 preignition - in a spark-ignition engine, ignition of the mixture of fuel and air in the combustion chamber before the passage of the spark.

3.1.6 scoring, n - in tribology, a severe form of wear characterized by the formation of extensive grooves and scratches in the direction of sliding.

3.1.7 scuff, scuffing - in lubrication, damage caused by instantaneous localized welding between surfaces in relative motion which does not result in immobilization of the parts.

3.1.8 seizure - in lubrication, welding between surfaces in relative motion that results in immobilization of the parts.

3.1.9 spark plug fouling - deposition of essentially nonconducting material onto the electrodes of a spark plug that may, but will not necessarily, prevent the plug from operating.

3.1.10 spark plug whiskering, or spark plug bridging - a deposit of conductive material on the spark plug electrodes that tends to form a bridge between them, thus shorting out the plug.

3.2 Definitions of Terms Specific to This Standard:
3.2.1 benchmark reference oil - an oil whose performance in this test method is compared with the performance of the non-reference oil.

3.2.2 major preignition - preignition that causes a temperature increase of 10°C (18°F) or more measured at the spark plug gasket.

3.2.3 minor preignition - preignition that causes a temperature increase of more than 7°C (13°F) and less than 10°C (18°F) measured at the spark plug gasket.