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API TC: No longer a valid rating; there no longer exists an agency to oversee this standard, so you could put this label on a jug of rendered bear lard if you wanted to.
JASO FA: (Japan Auto Standards Org) weakest standard, applies generally to a mineral (dinosaur bones) oil with a very basic metallic detergent added.
JASO FB: a little better with some quality control aimed at smoke and deposit control; generally by increasing additives and closer control over choosing particular isomers
JASO FC: generally a semi-synthetic product. The FC standard is largely about smoke control and deposits also; better lubrication is a benefit achieved along with the use of synthetics
JASO FD: Newest standards, most likely contain group IV and V synthetics along with metallic detergents, anti-wear agents, etc.
ISO L EGB, EGC, EGD: similar to above, except overseen by International Standards Org.
Metallic detergents: generally highly polar compounds like Calcium or magnesium sulfionate
are used in air-cooled engines. They actually act as antiwear barriers at temps that break down oil films as well as prevent deposits from forming thick layers by increasing the liklihood that the oil will burn and be carried away in the exhaust. Outboard-grade oils contain hydrazine and phosphate additives that chosen to keep partly decomposed oils moving on through and out because 350 deg cylinder-wall temps aren't hot enough to burn the oil away.
The reason not to use outboard oils in an air-cooled motor are that combustion heat may strip some of the hydrogen atoms from the oil chains leaving producst that resemble waxes, tars, and plastics. being that there are no friction-modifying metallic salts to aid in lubrication and that the phosphate detergents aren't able to mobilize the thick black residue, life will be short. Air-cooled oils in an outboard are similarly bad because the low-molecular wieght oils will only partly burn, but the remaining heavier oils won't be. Black sticky carbon deposits will ensue, as well as ring-groove packing and subsequent loss of seal. Soon blow-by will destroy the oil film and we all know what comes next.
Both types of oils may contain Zinc antiwear agents, anti-oxidants (shelf-life" pour-point modifiers, etc).
Group I oils: Highly saturated (hydrogen) solvent extraction or possibly hydrocracked "synthetics" (some countries disallow the term here) with fairly high sulfur content
Group II oils: (similar, except low sulfur)
Group II: similar, low-sulfur, but high molecular weight oils
Group IV: mainly polyalphaolefins. These are very useful as an additive to control temperature-induced
changes in viscosity and lubricity; they are "flexible" and resist shear.
Group V: Esters, Di-esters, Glycols, etc.
Group I, II, and III are highly refined products but these molecules do exist in nature. IV and V are lab creations designed to have specific properties; they are very expensive and are probably never used alone, rather to enhance products made of less expensive base stocks.
The Pennz air-cooled multi=purpose oil is either the best of both worlds, or the worst, depending on your POV. It is basically a mineral oil with a heavy dose of botn air and water-cooled additives. It is throughly "adequate", but not anywhwere near optimal.
JASO FA: (Japan Auto Standards Org) weakest standard, applies generally to a mineral (dinosaur bones) oil with a very basic metallic detergent added.
JASO FB: a little better with some quality control aimed at smoke and deposit control; generally by increasing additives and closer control over choosing particular isomers
JASO FC: generally a semi-synthetic product. The FC standard is largely about smoke control and deposits also; better lubrication is a benefit achieved along with the use of synthetics
JASO FD: Newest standards, most likely contain group IV and V synthetics along with metallic detergents, anti-wear agents, etc.
ISO L EGB, EGC, EGD: similar to above, except overseen by International Standards Org.
Metallic detergents: generally highly polar compounds like Calcium or magnesium sulfionate
are used in air-cooled engines. They actually act as antiwear barriers at temps that break down oil films as well as prevent deposits from forming thick layers by increasing the liklihood that the oil will burn and be carried away in the exhaust. Outboard-grade oils contain hydrazine and phosphate additives that chosen to keep partly decomposed oils moving on through and out because 350 deg cylinder-wall temps aren't hot enough to burn the oil away.
The reason not to use outboard oils in an air-cooled motor are that combustion heat may strip some of the hydrogen atoms from the oil chains leaving producst that resemble waxes, tars, and plastics. being that there are no friction-modifying metallic salts to aid in lubrication and that the phosphate detergents aren't able to mobilize the thick black residue, life will be short. Air-cooled oils in an outboard are similarly bad because the low-molecular wieght oils will only partly burn, but the remaining heavier oils won't be. Black sticky carbon deposits will ensue, as well as ring-groove packing and subsequent loss of seal. Soon blow-by will destroy the oil film and we all know what comes next.
Both types of oils may contain Zinc antiwear agents, anti-oxidants (shelf-life" pour-point modifiers, etc).
Group I oils: Highly saturated (hydrogen) solvent extraction or possibly hydrocracked "synthetics" (some countries disallow the term here) with fairly high sulfur content
Group II oils: (similar, except low sulfur)
Group II: similar, low-sulfur, but high molecular weight oils
Group IV: mainly polyalphaolefins. These are very useful as an additive to control temperature-induced
changes in viscosity and lubricity; they are "flexible" and resist shear.
Group V: Esters, Di-esters, Glycols, etc.
Group I, II, and III are highly refined products but these molecules do exist in nature. IV and V are lab creations designed to have specific properties; they are very expensive and are probably never used alone, rather to enhance products made of less expensive base stocks.
The Pennz air-cooled multi=purpose oil is either the best of both worlds, or the worst, depending on your POV. It is basically a mineral oil with a heavy dose of botn air and water-cooled additives. It is throughly "adequate", but not anywhwere near optimal.