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Hello John and others: This is from Wikipedia: Zinc dithiophosphate
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Structure of a monomeric zinc dialkyldithiophosphate
Zinc DialkylDithioPhosphates (often referred to as ZDDP) are a family of coordination compounds developed in the 1940s that feature zinc bound to the anion of a dialkyldithiophosphoric acid (e.g. ammonium diethyl dithiophosphate).[1] These uncharged compounds are not salts. They are soluble in nonpolar solvents, and the longer chain derivatives easily dissolve in mineral and synthetic oils used as lubricants. They come under CAS number . In aftermarket oil additives, the percentage of ZDDP ranges approximately between 2–15%.[2] Zinc dithiophosphates have many names including ZDDP, ZnDTP, and ZDP. Applications[edit]The main application of ZDDPs are as anti-wear additives in lubricants including greases, hydraulic oils, and motor oils. ZDDPs also act as corrosion inhibitors and antioxidants. They are almost ubiquitous in lubricants and treatment rates are usually between 600 ppm for modern, energy conserving low viscosity oils to 2000 ppm of this additive in some racing oils. It has been reported that zinc and phosphorus emissions may damage catalytic converters and standard formulations of lubricating oils for gasoline engines now have reduced amounts of the additive due to the API limiting the concentration of this additive in new API SM and SN oils, however this only affects 20 and 30 grade "ILSAC" oils, 40 and higher grades have no regulation regarding the concentration of ZDDP except for diesel oils meeting the API CJ-4 specification which have had the level of zddp reduced slightly, although most diesel Heavy Duty Engine oils still have a higher concentration of this additive.[3] Crankcase oils with reduced ZDDP have been cited as causing damage to, or failure of, classic/collector car flat tappet camshafts and lifters which undergo very high boundary layer pressures and/or shear forces at their contact faces, and in other regions such as big-end/main bearings, and piston rings and pins. Roller camshafts/followers are more commonly used to reduce camshaft lobe friction in modern engines.[4] There are additives, such as STP(R) Oil Treatment, and some racing oils such as PurOl, Brad Penn and Valvoline VR-1, which are available in the retail market with the necessary amount of ZDDP for engines using increased valve spring pressures. Also look at this article on ZDDP
https://shop.advanceautoparts.com/r/advice/car-maintenance/zddp-motor-oil-additive-engine-oil-additives-that-work Zinc DialkylDithioPhosphate
In addition to generic structure shown by Wikipedia above, the chemical name itself also shows that the ZDDP molecule - and there may be several variants, depending on the length of the "alkyl" ( carbon/hydrogen) chains involved - also contains Sulfur (the thio- part) and Phosphorus (phosphate) Ray Melton Las Cruces, NM 1957 Chrysler 300C cvt On 10/12/2018 8:03 AM, John Grady
jkg@xxxxxxxxxxxxxxxxx [Chrysler300] wrote:
__._,_.___ Posted by: Ray Melton <rfmelton@xxxxxxx> To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to bob@xxxxxxxxxxxxx or go to https://groups.yahoo.com/neo/groups/all/manage/edit For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/search.htm#querylang __,_._,___ |
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