MolaKule
Staff member
In case you missed this topic, here is a write-up on two-cycle oils:
While this may be your first set of analyses for 2-C oil, there is really nothing controversial or strange about the analysis.
There are different strokes for different folks - pun intended. There are various approaches to formulations for each type of application.
In a two cycle oil you want the least amount of organo-metallic components in order to keep the ash deposits to a minimum.
A one-pass lubricant must provide a lubricating oil film with a sufficient film thickness to keep parts wear at a minimum, yet the lubricant must not leave sticky deposits that will gum-up the rings and exhaust ports.
This requires a mix of base oils that will not only burn clean (since the lubricant is mixed in with the fuel), but also lubricate sufficiently. The base oils must be the purest of base oils, so in the early years, highly refined Group I and Group II base oils were used.
Today, and in order to get the lean mixtures required for clean exhaust gasess, a minimum of Group III through Group V base oils must be used.
Now to the additives. As others have stated, no low-cost analysis will tell you all of the chemical components included, only the basic organo-metallic components that can be detected.
The calcium and the magnesium combo is a mild friction reducer but primarily serves as a detergent that minimizes carbon deposits, but not all deposits. In modern 2C oils, this is up to the synthetic base oil mix, usually comprised of one of more ester base oils.
One anti-wear component seen is the low treatment level of ZDDP, the zinc and phosphorus. This is a special ZDDP ester with a low level of sulfur. A cold-start anti-friction/anti-wear additive containing a boron compound may be added.
The Tin is usually tin napthenate or Tin dithiocarbamate (DTC), another anti-friction component. Mobil uses a Titanium DTC for the same reason.
A high-flash solvent is incorporated to keep all of the components in solution and to make it miscible ("mixable") with the fuel. Now if higher ester levels are used, less of this solvent is needed.
Another anti-wear/anti-galling component, that also is used to thicken the film, is a polyisobutylene Group V base oil.
A small amount of a sodium compound is used to inhibit rust on the steel components. Not seen is something called a dimercapto 1.3.4thiadiazole compound, an anti-corrosion additive.
The last component that is used that does absolutely nothing is the Blue organic dye.
With respect to using motor (PCMO) oils in modern 2C engines, I wouldn't because the organo-metallic additive levels are too high (too much ash deposits, as on the valves and or ports and spark plugs), the base oils will tend to form sludgy deposits, and the PCMO does not really have a sufficient level of solvents to keep the rings and exhaust ports void of deposits in an air-cooled 2-cycle engine.
From the combustion temperature profiles of pistons from the crown to the bottom skirt, the piston wrist pin location is at about 320F. So this thermal energy will Conduct down from the Gudgeon Pin (wrist pin), down the connecting rod, and then to the crank, bearing, and pin bearings at that approximate same temperature.
We have to keep the big picture in mind: This is a "once-through" lubrication system. No oil sump, no oil cooling, only a thin film of lubricant passing through with approximately the same viscosity as gasoline, about 0.6 cSt@100C.
I would not use two-cycle oils in any 4-stroke engine because the additive package in two-cycle oils was not designed to protect 4-stroke engines.
While this may be your first set of analyses for 2-C oil, there is really nothing controversial or strange about the analysis.
There are different strokes for different folks - pun intended. There are various approaches to formulations for each type of application.
In a two cycle oil you want the least amount of organo-metallic components in order to keep the ash deposits to a minimum.
A one-pass lubricant must provide a lubricating oil film with a sufficient film thickness to keep parts wear at a minimum, yet the lubricant must not leave sticky deposits that will gum-up the rings and exhaust ports.
This requires a mix of base oils that will not only burn clean (since the lubricant is mixed in with the fuel), but also lubricate sufficiently. The base oils must be the purest of base oils, so in the early years, highly refined Group I and Group II base oils were used.
Today, and in order to get the lean mixtures required for clean exhaust gasess, a minimum of Group III through Group V base oils must be used.
Now to the additives. As others have stated, no low-cost analysis will tell you all of the chemical components included, only the basic organo-metallic components that can be detected.
The calcium and the magnesium combo is a mild friction reducer but primarily serves as a detergent that minimizes carbon deposits, but not all deposits. In modern 2C oils, this is up to the synthetic base oil mix, usually comprised of one of more ester base oils.
One anti-wear component seen is the low treatment level of ZDDP, the zinc and phosphorus. This is a special ZDDP ester with a low level of sulfur. A cold-start anti-friction/anti-wear additive containing a boron compound may be added.
The Tin is usually tin napthenate or Tin dithiocarbamate (DTC), another anti-friction component. Mobil uses a Titanium DTC for the same reason.
A high-flash solvent is incorporated to keep all of the components in solution and to make it miscible ("mixable") with the fuel. Now if higher ester levels are used, less of this solvent is needed.
Another anti-wear/anti-galling component, that also is used to thicken the film, is a polyisobutylene Group V base oil.
A small amount of a sodium compound is used to inhibit rust on the steel components. Not seen is something called a dimercapto 1.3.4thiadiazole compound, an anti-corrosion additive.
The last component that is used that does absolutely nothing is the Blue organic dye.
With respect to using motor (PCMO) oils in modern 2C engines, I wouldn't because the organo-metallic additive levels are too high (too much ash deposits, as on the valves and or ports and spark plugs), the base oils will tend to form sludgy deposits, and the PCMO does not really have a sufficient level of solvents to keep the rings and exhaust ports void of deposits in an air-cooled 2-cycle engine.
From the combustion temperature profiles of pistons from the crown to the bottom skirt, the piston wrist pin location is at about 320F. So this thermal energy will Conduct down from the Gudgeon Pin (wrist pin), down the connecting rod, and then to the crank, bearing, and pin bearings at that approximate same temperature.
We have to keep the big picture in mind: This is a "once-through" lubrication system. No oil sump, no oil cooling, only a thin film of lubricant passing through with approximately the same viscosity as gasoline, about 0.6 cSt@100C.
I would not use two-cycle oils in any 4-stroke engine because the additive package in two-cycle oils was not designed to protect 4-stroke engines.
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