Moly, MoS2, Molybdenum Disulphide

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RedLineR

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Hi guys! We are having a heated debate around oils on a BB here in SA that I frequent. You guys really know your stuff and I read a lot of your posts regarding synthetic oils, especially the Castrols, RP, Amsoils and Mobil. I have a couple of questions. When Moly is listed in oil sample analysis. Is it MoS2/Molybdenum Disulphide? Or in other words... Does RP engine oils (street and racing) contain MoS2/Molybdenum Disulphide? Are there any known negatives/disadvantages to MoS2? Besides the it falling out of suspension, which doesn't happen these days as I understand. If the MoS2 is "in suspension", that means that is did not dissolve as sugar in water does. So are they still solid particles, though very very small?
 
Thanks satterfi, From that I gather that MoTDC is what is used in motor oils including RP. The reason for the question was this quote, by Terry from Dyson Analysis,from this thread... http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=1;t=000010#000005 "Kalbri,Street RP is what I tested. RP has less MoS2 than both Schaeffers and Redline. Redline has 7 times the amount of the other 2. Mostly PAO base for RP.Schaffers is usually 120-150 ppm MoS2. Did as well and mostly better than say a Amsoil lubricant in Honda 4cyl engines on extended drains and cheaper. RP is as much Synthetic as any other primarily group 4 base. Call RP and ask about the founder. Alot of the components of the product are proprietary and as such can't be disclosed on a public forum. Hope this info helps clarify as much as possible"
 
I'll try to answer your first post: From http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000343#000000 Moly Disulfide Powders - CAS #1317-33-5, is a steel-green powder used for gear lubes as an EP additive. MoDTC, is oil solube moly or Molybdenum DialkylDithiocarbamate, which is made by reacting molybdenum with carbon disulfide acids; MoDTC is very stable against high temp decompostion and resists mechanical pressures or loads.. MoDTC is advantageous in motor oils as a Friction Reduction additive. Another form of MolyDTC is Molybdenum di-2-ethylhexylphosphorodithiolate (MoDPT) with a CAS number of 68958-92-9, but this moly additive is primarily used in hydraulic oils.
 
quote:
Originally posted by MolaKule: Moly Disulfide Powders - CAS #1317-33-5, is a steel-green powder used for gear lubes as an EP additive. MoDTC, is oil solube moly or Molybdenum DialkylDithiocarbamate, which is made by reacting molybdenum with carbon disulfide acids
Just to re-emphasize MolaKule's explanation, MoS2 is a suspended, non-soluble micro-powder. As such it can settle out in storage when used as an additive in motor oil. I was corrected over a year ago on that point and further informed that this compound is rarely if ever still used in motor oils (at least marketed in the U.S.). However, MoDTC is a fully oil soluble salt, will not settle out in storage, and, in solution, passes freely through the oil filter. (Since it's in solution, it can't "clump".) However, heat and pressure (of which there's plenty inside an operating engine at points of sliding metal-to-metal "contact") will allow the molybdenum to be deposited and "fused" with those sliding metal surfaces as an anti-wear, last-line-of-defense, extreme pressure agent micro-coating in the event the oil film is briefly disrupted.
 
Liqui-Moly (Lubro-Moly) is actively pushing its MoS2 oils and oil additive for many years. As I understand this type of Moly is far from to be perfect, if not to say more. But who is offering MoDTC additives and where to buy them ?
 
So this post: Schaffers is usually 120-150 ppm MoS2. Did as well and mostly better than say a Amsoil lubricant in Honda 4cyl engines on extended drains and cheaper. Is not true if they rarely use it in the US anymore right. [Confused]
 
The elemental readings in a VOA/UOA are of the element molybdenum only. You are not reading MoS2. The total sulfur readings one could only see in an advanced VOA/UOA, would be from sulfur contributed by ALL the additives that contained sulfur, in addition to the base oil if it were mineral oil.
 
Well, if you've been doing some reading, you will know that I'm a staunch supporter in moly. Not sure what type they use, but the oils that are known for having tons of moly in it, like Pennz. 5W-20, look at the bottom of the jug when you pour it out. You won't see any particles on the bottom. Means it's in suspension. Moly will not dissolve as it is an element. The element is very small and that's the key to this additive. Look under an electron microscope of metal surfaces and you will see numerous scars, kind of like the Grand Canyon. The moly will embed itself into these irregular surfaces and keep it smooth. That translates into less friction, which is the primary cadidate for heat production and mechanical failure.
 
Commercial Additive suppliers of soluble (MoDTC)moly are firms such as: R.T. Vanderbilt Lubrizol Ethyl Oronite (Chevron) Crompton Rhein Chemie Greta Lake Chemical Uniqema (ICI) Dover Ciba Infineum and about 20 other minor players.
 
And who says that Liqui Moly uses MOS2? Maybe Liqui Moly just say that on their products because that's what people generally know as moly additive. What regular consumer knows what MoDTC is?
 
Thanks for all the inputs guys! OK... From what I understand one cannot test for MoS2. You can only test for the presence of the Molybdenum atom. So you do not know in what kind of molecule it is bound in. So Royal Purple does contain Molybdenum atoms(That are bound to "something"), but it is unknown if they are actually MoS2 molecules. Are these statements correct?
 
quote:
Originally posted by moribundman: And who says that Liqui Moly uses MOS2? Maybe Liqui Moly just say that on their products because that's what people generally know as moly additive. What regular consumer knows what MoDTC is?
If it's written MoS2 on the can, it's MoS2 and not MoDTC. May be it contains both. Do you like to expriment ? L.-M. produces many other oils without MoS2 and they may contain MoDTC.
 
quote:
OK... From what I understand one cannot test for MoS2. You can only test for the presence of the Molybdenum atom. So you do not know in what kind of molecule it is bound in. So Royal Purple does contain Molybdenum atoms(That are bound to "something"), but it is unknown if they are actually MoS2 molecules. Are these statements correct?
Pretty much. In MoDTC, the moly atoms are bound to carbon and sulfur atoms; hence Molybdenum Dithiocarbamate. In chemistry, the Thio part refers to the fact that sulfur atoms replace the oxygen atoms in a reaction, and you don't necessarily have just 2 sulfur atoms per moly atom. In MoS2 powders, there is one moly atom bound to two sulfur atoms. In Royal Purple (or any main stream motor oil that uses moly) you can rest assured the moly is the soluble form of moly or MoDTC. To be technically correct, the soluble form of moly is Molybdenum Di-Alkyl dithiocarbamate. This is a stabilized and alkylated form of moly. An alkylated molecule is stabilized against acid production. I hope this explanation helps. [ August 06, 2004, 11:16 AM: Message edited by: MolaKule ]
 
quote:
Primus wrote If it's written MoS2 on the can, it's MoS2 and not MoDTC. May be it contains both. Do you like to expriment ? L.-M. produces many other oils without MoS2 and they may contain MoDTC.
I can't confirm either of those claims. Someone who cares enough should ask LM if they really mean MoS2, or if they use MoS2 as a generic term for moly, akin to people calling any 4WD car, anything from a Lada Niva to a Landrover, a "Jeep."
 
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