WZ507
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- Joined
- Dec 26, 2013
- Messages
- 553
At this point I think it has been well established through the present testing that there is little correlation between ZDDP content and performance in the scar test. This is presumably because we know nothing of the nature of the specific ZDDP molecules or additional additives employed in any given oil. Perhaps Comnoz said it best regarding ZDDP levels in consumer oils “Advertisers are going to talk them up, regulations and bean counters are going to hold them down”.
Regarding ZDDP and it causing corrosion, with the exception of the one line from Valvoline, I find no information in the literature I’ve searched that it causes corrosion, and in fact, without exception find exactly the opposite information, i.e., ZDDP is continually presented as a means of controlling oxidation and corrosion in oils and greases.
For example, the link below from Lubrizol, the likely supplier of the majority of ZDDP to the oil industry.
https://www.lubrizol.com/Sustainabi...c-Dialkyl-Dithiophosphate-Lubricant-Additives
And in this retrospective review of ZDDP development.
https://pdfs.semanticscholar.org/e2dc/da55f2a51bde3dabb2ef06543fc401d61ed4.pdf
Below is the link to Valvoline's comment about the corrosive nature of ZDDP "used above certain levels" (see 2nd to last bold bullet point).
https://www.valvoline.com/about-us/faq/racing-oil-faq
Valvoline makes the statement “zinc additives are corrosive above certain levels”, then follows-up with the suggestion to avoid 3rd party additives and instead use Valvoline VR1. What else we we expect from the Valvoline website? Valvoline provides no guidance whatsoever as to what “above certain levels” refers to. Should we use less than 1000 ppm, 2000 ppm, 4000 ppm? Perhaps they're trying to dissuade the backyard mechanic from dumping a qt of ZDDP additive in their engine? We only know that their recommended VR1 has 1300 ppm ZDDP, which presumably is less than “above certain levels”. I think the entirety of their presentation is a red herring rather than useful information for the end-user. I would think that if ZDDP were so corrosive, oil formulators wouldn't be employing it "above certain levels", whatever that means. In the end it is an individual decision as to whether you shy away from oils having certain ZDDP levels, especially those employing ZDDP "above certain levels".
If we are to be concerned about oil-induced engine corrosion occurring during storage then we also need to be concerned with the corrosion inhibition package used in the oil we employ, especially racing oils. Case in point, a few years back I queried Amsoil about their Dominator racing oil in a motorbike and was informed by their tech service line that it was not a good choice for routine use as it did not contain a complete corrosion inhibition package and was therefore suited only for short change intervals. This information from Amsoil is consistent with literature citations where it is acknowledged that certain additives "fight" each other, thereby degrading and rendering ineffective a key component of the oil. Such might be the case encountered with Amsoil where they chose to leave out certain corrosion protection components to assure the load carrying capacity of the oil was maintained. Perhaps the bottom line is that if we employ racing oils in our machines we might want to check with the manufacturer to see what they have to say about longer term storage and corrosion inhibition.
