ZDDP activation temperature?

[berlyn]

Hello all,

please could you provide some info about it. I searched among the threads, I could not answer if ZDDP activation temperature and respective function is related

a) to the temp of the point contact where no oil film is present and let's say its 'close neighborhood',
or
b) to the avg oil temp of the oil in the sump,
or
c) none of the above (to which factor then?)

thank you for your feedback.

 

[krismoriah72]

"My test data is the real deal, it exactly matches real world experience, and it is the best and most complete motor oil comparison data you will ever find anywhere."

"A high level of zinc/phos is simply no guarantee of providing sufficient wear protection. And to make matters even worse, excessively high levels of zinc/phos can actually "cause" DAMAGE your engine, rather than "prevent" it. Motor Oil Industry testing has found that motor oils with more than 1,400 ppm ZDDP, INCREASED long-term wear. And it was also found that motor oils with more than 2,000 ppm ZDDP started attacking the grain boundaries in the iron, resulting in camshaft spalling (pitting and flaking). The ZDDP value is simply the average of the zinc and the phosphorus values, then rounded down to the nearest 100 ppm (parts per million).

I tell them to forget all that high zinc nonsense and look at my Wear Protection Ranking List. And to select any high ranking oil there, no matter how much zinc it has, because zinc quantity simply does NOT matter. The only thing that matters regarding wear protection, is the psi value each oil can produce in my testing. The higher the psi value, the better the wear protection. I recommend they use the SAME highly ranked oil for break-in and after break-in. It's that simple."

From this guy..

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/

 

[y_p_w]

This is a pretty good explanation. I recall that ZDDP has to activate first, then apparently it forms a protective film where it's being mashed together.

https://www.bobistheoilguy.com/foru...effectiveness-vs-engine-temp#Post2474803

I remember a discussion with the guy (he knows his stuff) on another forum where he was saying that ZDDP oils often showed increased wear after an oil change because the ZDDP needed to oxidize to activate.

 

[benjy]

from this forum its noted there are several types of ZDDP with varying activation temps

 

[69GTX]

Originally Posted by krismoriah72
"My test data is the real deal, it exactly matches real world experience, and it is the best and most complete motor oil comparison data you will ever find anywhere."

"A high level of zinc/phos is simply no guarantee of providing sufficient wear protection. And to make matters even worse, excessively high levels of zinc/phos can actually "cause" DAMAGE your engine, rather than "prevent" it. Motor Oil Industry testing has found that motor oils with more than 1,400 ppm ZDDP, INCREASED long-term wear. And it was also found that motor oils with more than 2,000 ppm ZDDP started attacking the grain boundaries in the iron, resulting in camshaft spalling (pitting and flaking). The ZDDP value is simply the average of the zinc and the phosphorus values, then rounded down to the nearest 100 ppm (parts per million).

I tell them to forget all that high zinc nonsense and look at my Wear Protection Ranking List. And to select any high ranking oil there, no matter how much zinc it has, because zinc quantity simply does NOT matter. The only thing that matters regarding wear protection, is the psi value each oil can produce in my testing. The higher the psi value, the better the wear protection. I recommend they use the SAME highly ranked oil for break-in and after break-in. It's that simple."

From this guy..

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/


This 540Rat blog testing has been debunked many times. While it has some potentially useful application to circle track racing engines utilizing flat tappet cams....it generally has little application to general wear in your passenger car or truck drive train. Rat's testing to determine "wear protection" utilizes questionable testing methods not utilized by auto manufacturers. And the Rat testing does nothing to determine ZDDP protection in the transition from a cold to warmed up engine....where most passenger car wear actually occurs.

 

[berlyn]

Hi benjy,
Temp on the spot or average sump temp? This I can not find in the forum.

 

[FCD]

Originally Posted by krismoriah72
"My test data is the real deal, it exactly matches real world experience, and it is the best and most complete motor oil comparison data you will ever find anywhere."

"A high level of zinc/phos is simply no guarantee of providing sufficient wear protection. And to make matters even worse, excessively high levels of zinc/phos can actually "cause" DAMAGE your engine, rather than "prevent" it. Motor Oil Industry testing has found that motor oils with more than 1,400 ppm ZDDP, INCREASED long-term wear. And it was also found that motor oils with more than 2,000 ppm ZDDP started attacking the grain boundaries in the iron, resulting in camshaft spalling (pitting and flaking). The ZDDP value is simply the average of the zinc and the phosphorus values, then rounded down to the nearest 100 ppm (parts per million).

I tell them to forget all that high zinc nonsense and look at my Wear Protection Ranking List. And to select any high ranking oil there, no matter how much zinc it has, because zinc quantity simply does NOT matter. The only thing that matters regarding wear protection, is the psi value each oil can produce in my testing. The higher the psi value, the better the wear protection. I recommend they use the SAME highly ranked oil for break-in and after break-in. It's that simple."

From this guy..

https://540ratblog.wordpress.com/2013/06/20/motor-oil-wear-test-ranking/


Oh don't get me started on the 540rat guy....

 

[FCD]

I don't recall ever reading what temperature is needed to activate Zddp.

But what it does need is a few hundred miles of driving to begin working, what happens when you change the oil in an engine is that the tribofilms which the previous oil had already created are washed away by the new oil, and it takes x hours of engine running time for the film to start building back up again.

One thing that is counter intuitive is that wear is highest right after an oil change when the oil is brand new, and steadily goes down from there and stabilizes at x ( ofcourse wear starts creeping back up again if you go too long between oil changes to the point where the oil begins to break down ! )

 

[claluja]

https://link.springer.com/article/10.1007/s11249-016-0706-7

 

[JAG]

From the link above:

"At very high temperatures, typically above 150 °C, ZDDPs react slowly to form films on solid surfaces even in the absence of rubbing and such films are termed "thermal films" [6]. However, when surfaces rub together in a ZDDP-containing lubricant, ZDDP films are generated rapidly and at much lower temperatures, at least as low as 25 °C [6, 7]."

 

[LeoStrop]

So changing your oil often will not increase wear since tribofilm "are generated rapidly and at much lower temperatures" on parts that aplly shear stress (where it matters).

And when someone says that "ZDDP will only activate at high temperatures", that is not entirely incorretc because if shear strees is not presented, only thermal films will be created >150°C

 

[berlyn]

Hi claluja,

Thanks a lot for the very interesting link!

 

[Solarent]

I would add that at the contact point, shear stress causes localized temperatures to be >150C (not the bulk fluid temperature discussed in the paper) this starts the production of the ZDP glass films.