Two-cycle engines are among the most abused engines on earth. Because they have a high power-to-weight ratio and are relatively simple and inexpensive, they're used in applications ranging from weed wackers to motorcycles -- applications where they work hard and too often die young.
Two-cycle engines are simple and have no lubricant distribution system to speak of. In pre-mix engines, oil is mixed right into the fuel, and in injector systems, oil is added to the fuel and air at a rate appropriate to conditions as the fuel and air enter the engine. In either case, the oil is simply mixed with the fuel to lubricate the engine parts.
The reason two-cycle engines work so hard is simple: every stroke is a power stroke. In a four-stroke engine, the piston rises and is driven down by combustion (a power stroke), but the next time the piston rises it simply pushes out exhaust gases. In two-cycle engines, exhaust gas is driven out by the incoming oil-fuel mixture as the piston forces the mixture into the combustion chamber -- on each and every stroke.
These factors combine to place tremendous demands on lubricants:
Burn, and burn cleanly - - Since the oil is mixed with the fuel, it must also be burned with the fuel, and burned cleanly. If you've seen the tell-tale blue smoke coming from an outboard boat motor, chainsaw, or motorcycle, you've seen a case where oil isn't burning cleanly -- environmental regulations, concern for the environment and just plain common sense make that kind of scene unacceptable.
A more subtle danger when oil doesn't burn cleanly is what happens to the engine itself. Deposits in a hard-working two-cycle engine can cause scuffing and ultimately engine failure. Even exhaust outlets can become plugged, and when that happens, engine efficiency drops and wear increases.
Resist volatility - - Two-cycle engines run hot. But while the oil must burn cleanly at combustion temperatures, it must not burn at the hot temperatures found outside the combustion chamber. If an oil is not highly resistant to this volatile evaporation, deposits can begin to form and cause engine damage.
Lubricate - - Two-cycle oils must lubricate effectively under these severe conditions. Failure to lubricate properly can quickly result in excessive wear and finally engine failure.
Assist in cooling - - Two cycle engines are either air-cooled (hotter) or water-cooled (cooler). In either case, the lubricant must take on a major portion of the cooling duties.
The Conventional Answers
Conventional petroleum lubricants use bright stock, a heavy cut of petroleum, to add lubricity and anti-scuffing properties. Unfortunately, bright stock doesn't burn cleanly. In addition, petroleum basestocks are more prone than synthetics to volatile evaporation, and when they volatize, they tend to form hard carbon deposits that cause extreme engine damage.
To solve the contamination problems caused by dirty-burning bright stock, conventional two-cycle oil manufacturers use solvents to keep engine parts clean.
When using low-grade solvents, however, there may be drawbacks to this approach. Low-grade solvents help with dispersency, but they can hurt film strength and ultimately detract from lubrication performance. Manufacturers of two-cycle oils that treat two-cycle oil as a commodity are likely to use bargain-basement solvents instead of the more costly ones that perform better.
Finally, to deal with hotter temperatures, conventional two-cycle oils used in air-cooled applications must employ metal-containing (ash) additives to overcome weaknesses in their basestocks. Since ashed additive packages can cause fouling problems, these companies then formulate a separate oil for cooler water-cooled applications.
The AMSOIL Solution
The most striking thing to most customers about AMSOIL Saber Synthetic 100:1 2-Cycle Oil is the 100:1 mix ratio. It's unique, impressive and right in the products title.
Why can AMSOIL Synthetic 100:1 2-Cycle Oil be mixed at 100 parts gasoline to just 1 part oil (1.3 oz. AMSOIL 2-Cycle Oil to 1 gallon of gasoline) while other products are mixed at anywhere from 50:1 to 32:1? It's no mystery. The answer has to do with solvents, or in this case a lack of them.
Solvents often comprise as much as 20-30 percent of a conventional pre-mix two-cycle oil. However, AMSOIL 100:1 2-Cycle Oil uses a proprietary ashless formulation that makes use of esters - - and no solvents. This technology actually delivers solvency characteristics while improving lubricity.
Since AMSOIL is 100 percent active, it can be mixed at the economical 100:1 rate.
But the high-performance features of AMSOIL Synthetic 100:1 2-Cycle Oil don't stop with the mix ratio:
The unique synthetic formulation used by AMSOIL is clean burning. The lower emissions you can expect are much more in line with what current and pending lubricant standards and environmental regulations demand - - not to mention what our environment deserves.
Due to the absence of solvents, fire and flash points are dramatically higher. These higher flash and fire points help AMSOIL products resist volatile evaporation and allow a single, non-ash formulation to be used in both water-cooled and air-cooled applications.
AMSOIL products provide enhanced lubricity. This high lubricity, in turn, aids in engine cooling (since much of the heat generated by an engine comes from friction) and promotes faster response, greater efficiency and improved overall performance.
Ashless formulation has been shown effective in water- and air-cooled applications. AMSOIL Synthetic 100:1 2-Cycle Oil is perfect for both kinds of applications.
The benefits of using AMSOIL Synthetic 100:1 2-Cycle Oil are clear: economical mix ratio, reduced emissions, less engine fouling, cleaner combustion, reduced smoke, greater efficiency, cooler running, lower volatility and improved performance.
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