ZDDP 1

[mikesavannah]

I am a marine machanic and have received an oil report for a sample stating the ZDDP package has depleted in the diesel engine sample. I have never seen this on a report before. Can anyone tell me why this is important and what it is.

Thanks

 

[FoMoCoMoFo]

type zzdp in the google search of this forum ^
much discussion about zinc of late.

 

[FoMoCoMoFo]

sorry thats ZDDP

 

[romke]

zddp (zincdithiophosphates) are compounds that accomplish two things in an (engine)oil: it acts as an anti-oxidant and as an antiwear additive. the anti-oxidant prevents the oil from premature aging - and gets used up in the process. if the amount of usable zddp has decreased considerably two things can happen: excessive oxidation (thickening of the oil, formation of varnish and laquer at the hot parts where the oil is in contact with metal (ring belt area) and also premature wear at the heavily loaded engine parts (valve actuation mechanism, distribution gears and camshaft).

how was the depletion of the zddp measured? i am not aware of any method that reliably measure the decrease in effectiveness, although an atomic absorption emission measurements interpreted by a skilful engineer might accomplish that.

 

[dicer]

It's most likely depleted because many oil companys are cutting way back on it. There is alot of info on the net how flat tappets and cams are wearing out fast due to the lower quantities of it in motor oil. Things would change if they or whome ever is mandating it would have to pay for damages. And romke, that is how most outfits do check oil samples.

 

[franzh]

The ZDDP additives do decrease engine wear but zinc can cause rapid deterioration of the exhaust catalyst, the prime reason ZDDP has been minimized. Many builders of older, pre-catalyst vehicles, recommend the use of Diesel engine lubricants for the higher levels of ZDDP.

Franz

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Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[turbocohen]

There is a new standard for oil labeled as GF-4. GF-4 is not compatible with older engines not designed to operate with lowered phosphorous and zinc while newer models such as the ford v10 and all toyotas and more were revised to permit the new oil.

The pro is less cat and O2 sensor poisoning. Especially important during breakin. The con is less protection if the engine is not operated for long periods of time.

In the end, the new oil will prolong emissions durability and the net effect will be longer engine life since there will be less unburned fuel reaching the crankcase.

Next time you are at an auto parts store take a moment and look for GF-4 on the label. It is not so common but GF-3 is everywhere. Only a few weights of mobil one are GF-4. I run it in my GMC Denali and I would expect better fuel economy over the long haul since the 02 sensor is not likely to deteriorate as rapidly as is the case now.

 

[romke]

the amount of zinc and other inorganic compounds is reduced in oils designed for use in low-emission engines. that is not done for bringing down the cost of formulation but to meet the new specifications that have maximum limits for certain types of compounds as not to jeopardize exhaust aftertreatment devices. i think the vision as expressed by dicer in this respect may be somewhat biased, actually the formulation cost of these new types of engine oils is higher then hitherto.

most oil sample analysis programs use some form of emission spectography to detect wear debris - the most prominent type used being ICP, whereas AAS is far less used because of the fact that interpreting the results is rather difficult. Even if AAS is used it is difficult to discern between "fresh" zinc compounds and compounds that have somehow been used and therefore lost their effectiveness. So the question as how the loss of effectiveness was measured is still a valid one.

in most analysis programs the amount of zinc compounds is measured, which as such, give no clue to their effectiveness or the changes therein.

 

[drwebb]

"zinc can cause rapid deterioration of the exhaust catalyst" is a common misconception. It is phosphorus that may cause this, and that is what is limited in engine oil specifications. There are no limitations on Zn because it is is only a convenient delivery vehicle for the P which may be easily be supplied via a Zn-free chemical compound.

Depleted compared to what? If unit averages it probably means you used a low phosphorus specification oil while most of their database didn't. Low P formulations are usually supplemented with other AW chemistries, so this doesn't automatically mean inferior performance, but if you are concerned and your equipment doesn't recommend it then you may choose to stick with engine oil based on older, typically higher P specifications.