An Intelligent (I hope) question about ZDDP

[barryh]

Say you have two oils and all other things being equal, one has 800ppm of ZDDP and one has 1200ppm of ZDDP.

Assuming the oils are new, does the oil with higher level of ZDDP provide any immediate better protection or does it just last longer before the additives are depleted.

What I'm getting at is if you are doing a very low OCI is there any point fussing about particularly high ZDDP oils even on a flat tappet engine.

 

[69GTX]

On a flat tappet engine, especially an older one, the ZDDP probably matters a lot no matter how short your OCI. I'd be sure my engine was getting enough. Probably something in the 1000-1400 ppm range. Too much can be just as bad.

The higher ZDDP just means the potential (via blowby) for more contaminants to get into your Cats and shorten their lives. No Cats, then no problem. If your question pertains to a specific vehicle (1979 BMW?) then that should be part of the discussion.

 

[wsar10]

In short no....

You will get the "it destroys CAT's and emissions equip" response in some places. Most on here are intelligent enough to not spread that myth. Just in case there is one in the crowd that clings to it.... I will share my personal experience over the last half million miles of using Rotella Triple T, T5, T6. I have owned 4.0 inline 6 JEEP's for several years, so that is what got me into looking at and buying HDEO's. In the last half million (combined) miles using T5 and other oils with higher Zinc and Phosphorus (or ZDDP), I have never replaced any form of emissions equipment prematurely. The only difference in my experience is a happier healthier engine!

In fact I would prefer using a HDEO (Heavy Duty Engine Oil) in every motor if it was feasible.

 

[barryh]

I'm not concerned with cats or any specific application, the question is really about "how does ZDDP work"

I know it produces a sacrificial layer on the metal surfaces but does more ZDDP (within limits) apply a more protective layer or does it just last longer before the levels of ZDDP are depleted below some level where it no longer works.

You could ask the question another way by saying what is it at a scientific level that makes 1200 ppm of ZDDP better than 800 ppm.

The internet is awash with opinions about ZDDP and what you should use in a given application. I'm hoping someone here really knows how it works.

 

[Ohle_Manezzini]

When SL came, a lot of engine builders had flat tappets and camshaft wear problems in as soon as 1k miles for lack of zddp, specially at breakin.

 

[HerrStig]

I've used a lot of T6 in Camrys and if there isn't a blowby or valve seal problem the cat will die of other causes before the zinc gets it. It' also been my oil of choice for my airhead BMW bike which IS flat tappet.

 

[SonofJoe]

When I was playing around with ZDDPs, you would see a big difference between 800ppm and 1200ppm of ZDDP on tests that were in some way related to oil oxidation. Tests like the Sequence IIIF/IIIG which primarily looks at viscosity increase, the Sequence VG which looks at an oil's propensity to drop out sludge and the various Teost tests which measure the tendency to form deposits at high temperature all tend to improve the more ZDDP you have in your oil.

However it's not so easy to say what happens to wear when you up ZDDP. That's partly because the industry standard wear tests (the Sequence IVA in the US & the Peugeot TU3MS in Europe) were usually very easy to pass, even at very low levels of ZDDP. As a result, you never really looked to see how much further you could drop wear by upping ZDDP (half the time you couldn't increase it anyways because of spec constrainsts).

For what it's worth, my gut feel would be that ZDDP is to engine wear what Vitamin C is to human metabolism. Too little and you've got problems (wear or scurvy!). Too much, and your engine/body will absorb only what it needs to keep things healthy. On the SoJ Additive Dosage Scale, 500 ppm of Phosphorus is far too little, 800 ppm on the borderline, 1000 ppm the right amount and 1200 ppm probably too much.

 

[barryh]

Originally Posted By: Ohle_Manezzini
When SL came, a lot of engine builders had flat tappets and camshaft wear problems in as soon as 1k miles for lack of zddp, specially at breakin.


OK so if high levels of ZDDP were beneficial at break in and over the first 1000 miles then that suggests a higher ppm of ZDDP in some way builds a better protective layer even in new oil.

 

[FCD]

1000ppm at least is what i would want in a flat tappet engine rebuilt or not, doing short oil change intervals won't really change anything, in fact when you change the oil the old oils' antiwear film is washed away, and it takes a few heat cycles to establish that new film, atleast from what i've read.
In the 70s some tests found that camshaft wear was the least when the oil contained around 1200ppm of Zinc and Phos, and research has also shown that anything more than about 1500 provides no greater protection and at 2000 it starts to chemically corrode the camshaft.

I'm sure that BMW would not mind a 20w50, Valvoline VR1 is a great oil with 1300 or so ppm of Zinc which should keep you out of any zinc related problems, you can get it from OpieOils for not too much money.

 

[MolaKule]

Originally Posted By: barryh
Originally Posted By: Ohle_Manezzini
When SL came, a lot of engine builders had flat tappets and camshaft wear problems in as soon as 1k miles for lack of zddp, specially at breakin.


OK so if high levels of ZDDP were beneficial at break in and over the first 1000 miles then that suggests a higher ppm of ZDDP in some way builds a better protective layer even in new oil.


It doesn't suggest that at all.

You need high levels of ZDDP during breakin to reduce wear and excessive heat.

After break-in high levels of ZDDP resulting in over 900 ppm of zinc and phos don't give you any added wear protection.

The later versions of ZDDP that are included in current additive packages have lower volatility which is why we can lower ZDDP levels and still maintain wear protection.

ZDDP isn't the Messiah when it comes to wear protection. There are other AW chemistrys' out there but ZDDP is still cheaper than those.

 

[SonofJoe]

Originally Posted By: Ohle_Manezzini
When SL came, a lot of engine builders had flat tappets and camshaft wear problems in as soon as 1k miles for lack of zddp, specially at breakin.


I don't want to be overly pernickety but SL was never the problem. GF-4, which came in around 2003/2004 was the spec that first restricted Phosphorus to 800 ppm max in the ILSAC viscosity grades (0W20, 0W30, 5W20, 5W30, 10W30). The equivalent low viscosity grade API SL oils could go up to 1000ppm max but many companies just read-across their 800 ppm formulations. All of the SL grades (10W40 and heavier) weren't restricted at all on Phosphorus (although many oil companies imposed internal limits if 1000 ppm max).

 

[barryh]

Thanks Molakule, that's what I was looking for.


The other thought process I'd had was that if ZDDP or any other anti wear additive gets used up during an OCI then if for example you start an OCI with 1200ppm it must be at some lower level at the end of the OCI and hopefully that lower is still effective. That in itself suggested to me that it can't be as simple as "you must have 1200ppm"

 

[aquariuscsm]

How about in roller cam engines,is zddp even needed at all?

 

[Jetronic]

Originally Posted By: SonofJoe
When I was playing around with ZDDPs, you would see a big difference between 800ppm and 1200ppm of ZDDP on tests that were in some way related to oil oxidation. Tests like the Sequence IIIF/IIIG which primarily looks at viscosity increase, the Sequence VG which looks at an oil's propensity to drop out sludge and the various Teost tests which measure the tendency to form deposits at high temperature all tend to improve the more ZDDP you have in your oil.



That reflects my observations with Mid-saps oils in petrol engines, lots more deposits on the same oil change intervals compared to A3/B4 oils. Despite mid-saps oils alledgedly having more stable base oil mixes.

 

[Ohle_Manezzini]

Originally Posted By: SonofJoe
Originally Posted By: Ohle_Manezzini
When SL came, a lot of engine builders had flat tappets and camshaft wear problems in as soon as 1k miles for lack of zddp, specially at breakin.


I don't want to be overly pernickety but SL was never the problem. GF-4, which came in around 2003/2004 was the spec that first restricted Phosphorus to 800 ppm max in the ILSAC viscosity grades (0W20, 0W30, 5W20, 5W30, 10W30). The equivalent low viscosity grade API SL oils could go up to 1000ppm max but many companies just read-across their 800 ppm formulations. All of the SL grades (10W40 and heavier) weren't restricted at all on Phosphorus (although many oil companies imposed internal limits if 1000 ppm max).


Yes, you're totally right, I said that because its Api the most applied ratings around the world at the time, even though SL also came with emission control hardware in mind, So 5w30 5w20 0w30 0w20 (most used) maybe even 10w30 engine ols all came restricted to 800ppm of P max. The trend came with SJ that restricted to 1000ppm, as in GF3. So SL7 sure gave problems. SL and Gf4 came up with one or two years appart.

 

[Ohle_Manezzini]

Originally Posted By: aquariuscsm
How about in roller cam engines,is zddp even needed at all?



Not bad when the bearing starve at lugging or under viscosity for the temp.

 

[Solarent]

Originally Posted By: barryh
Thanks Molakule, that's what I was looking for.


The other thought process I'd had was that if ZDDP or any other anti wear additive gets used up during an OCI then if for example you start an OCI with 1200ppm it must be at some lower level at the end of the OCI and hopefully that lower is still effective. That in itself suggested to me that it can't be as simple as "you must have 1200ppm"


I would also add to Molakule's comment that your original question stipulates that "all other things being equal" isn't a true reflection of reality - for example if you were to take a formulation and using the same species of ZDDP and increase from 800 to 1200 ppm phos and change nothing else, you will likely see several different interactions with the synergistic components in the formula. Not only the benefit of less volatility in the ZDP from the newer species, but also other benefits from ashless dispersants and other components that go in the additive package. You aren't going to see this unless you are the one formulating the oil though.

Worrying about phosphorus levels is ridiculous in my opinion. I've seen plenty of low phos formulas that outperform high phos options in every available test. And before someone says something like "go tell that to Ford"... maybe I already have

 

[barryh]

Thanks everyone,

I've learnt enough to see it's not remotely simple.

 

[SonofJoe]

The thing to worry about is that phrase 'every available test' because despite what a lot of people would have you believe, 'every available test' does not equate to reality. It never has and probably never will.

If I could only have one additive in oil, it would be ZDDP. It may have been knocked off its pedestal because of concern over cats but in my mind, it's still THE additive which all other oil additives hang off. I don't think I've ever met a serious oil formulator who would actively choose to restrict the amount of ZDDP in PCMO. Seventy years worth of positive automotive reality with ZDDP should not be blithly dismissed.

 

[SR5]

Good Question OP, I have often wondered the same thing myself, does more ZDDP give more protection or the same level of protection for longer ?

Some great replys from people who know more than me. But I'm still a little confused.

Does the ZDDP get depleted during the OCI and at what rate ?

Does more ZDDP create a thicker or stronger or more continuous protective layer on the metal surface ?

Is there a maximum size / strength / thickness of protective layer created by ZDDP beyond which more can not be added ? And what level of ZDDP create this saturation point. ?

I'm just asking out of chemical curiosity.

I also note, that some 30 grade oils that are not chasing GF-5 go above the GF-5 Phos limit. Two examples off the top of my head is Castrol Edge 5W30 (API SL, A3/B4, BMW LL-01, MB 229.5) it clearly states on their PDS that it meets all the quality requirements of SN, but has more Phos than the chemical limit and so is SL.

Also Valvoline SynPower FE 5W30 it's SL, A5/B5 and Ford WSS-M2C913-D. I assume the major difference between this oil and Valvoline SynPower DX1 5W30 (SN, GF-5, Dexos1) is the Phos / Zinc level. They also say this is a good oil for bio diesel (passes MB Bio Oxidation test).

Given how good ZDDP is in protection oil from sludge formation and oxidation. Is there a correlation between reduced ZDDP levels forced by GF-5, and the difficulties some modern oils are having to pass recent Euro ACEA specs ? I hear they pass the petrol side easy (A3 or A5) but it's the diesel (in particular Bio-Diesel) side (B4 or B5) that they have difficulty passing.

Are the above formulations from Castrol and Valvoline saying that the Phos and Zinc limit needs to be increased ? I hear from local Castrol techs that the Oz Edge 5W30 A3/B4 has about 1000 ppm Zinc.

Sorry for more questions than answers.

Merry Christmas Everybody !!!