Two-stroke oil
Two-stroke oil (also referred to as two-cycle oil, 2-cycle oil, 2T oil or 2-stroke oil) is an engine oil intended for use in two-stroke engines. Since these lightweight engines do not have a closed crankcase like 4 cycle engines, as they use the crankcase as part of the induction tract, oil must be mixed with the gasoline, for distribution throughout the engine for the purpose of lubrication. The two-stroke oil is ultimately burned along with the fuel resulting in exhaust emissions with blue smoke and/or a distinctive odor. When the oil is mixed with gas before being put into the tank it is often refered to as "pre-mix".
The oil base stock is either petroleum, vegetable, semi-synthetic or synthetic oil and is mixed with petrol/gasoline at a fuel:oil ratio ranging from 16:1 to as low as 100:1.
Comparing regular lubricating oil with two stroke oil, the relevant difference is that two stroke oil must have a much lower ash content. This is required to minimize deposits that tend to form if ash is present in the oil which is burned in the engine's combustion chamber.
Injection Systems[edit | edit source]
Engine Original equipment manufacturers (OEMs) introduced pre-injection systems (sometimes known as "auto-lube") to engines to operate from a 32 : 1 to 100 : 1 ratio. Oils must meet or exceed the following typical specifications : TC-W3TM, NMMA, API TC, JASO FC, ISO-L-EGO. These type oils are often called "injection oil".