This ZDDP Article is Excellent! A Must Read!

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Originally Posted By: JohnBrowning
Long ago I commented on how the Asian OEM where concerned witht he drop in phos but could care less about the Z in ZDDP. No one got it at the time the article does a good job explaining why the P in ZDDP and the sulfur which I long ago said I missed where so important. ZDDP is just a an ends to a mean.A lot of Aisin OEMs still do not use rollers in their valve trains.


Yeah zinc is probably just there for bonding properties for the sulfur and phosphorus, and maybe anti-oxidant effect. What I found confusing was the article seemed to suggested sulfur was doing most of EP anit-wear effects, but then it went on about the phosporus level mostly. Onerthing I am confused about is does the sulfur creat a lot of sulfated ash? I use to hear about "ashless" oil, but don't all oils have some ash levels, and if they didn't they couldn't have zddp?

The article also says that weights heavier than 10W30 and dual rated HDEO are exempt from the zddp limits, but they are still SM rated. Can anyone verify if HDEO still have more zddp than non-HD SM oils?
 
Originally Posted By: mechanicx

The article also says that weights heavier than 10W30 and dual rated HDEO are exempt from the zddp limits, but they are still SM rated. Can anyone verify if HDEO still have more zddp than non-HD SM oils?


They do. CJ-4's phosphorous limit is 1200 ppm.

Likewise, a few name brand oils like Chevron Supreme in 10w-40 and 20w-50 have higher ZDDP then the fuel economy grades.
 
Originally Posted By: Drew99GT
Originally Posted By: JohnBrowning
A lot of Aisin OEMs still do not use rollers in their valve trains.


A modern bucket type OHC valvetrain probably has half the pressure exerted on the lifter/cam lobe interface as an OHV pushrod engine. Just like the article stated.



Well I think the article mentioned dynamic forces are high so a direct acting bucket without a rocker multiplying valve lift probably has much lower static and dynamic forces or finger follower that don't mulitply valve lift probably has lower static and dynamic dynamic forces, but of course you don't have the pushrod to damp them or maybe cause them either way. But if the finger follwer multiplies lift like on a 2 valve engine, then they had high wear. Usualy the direct acting follwers have a larger diameter for cam contact, than OHV but most of the time they just utilize a more aggressive lift when the follwer is bigger. For example, Chevy's had a .842 lifter diameter, Ford .875 and chrysler .904 and the lift each could obtain per cam duration increased respectively.
 
Originally Posted By: mechanicx
Originally Posted By: Drew99GT
Originally Posted By: JohnBrowning
A lot of Aisin OEMs still do not use rollers in their valve trains.


A modern bucket type OHC valvetrain probably has half the pressure exerted on the lifter/cam lobe interface as an OHV pushrod engine. Just like the article stated.



Well I think the article mentioned dynamic forces are high so a direct acting bucket without a rocker multiplying valve lift probably has much lower static and dynamic forces or finger follower that don't mulitply valve lift probably has lower static and dynamic dynamic forces, but of course you don't have the pushrod to damp them or maybe cause them either way. But if the finger follwer multiplies lift like on a 2 valve engine, then they had high wear. Usualy the direct acting follwers have a larger diameter for cam contact, than OHV but most of the time they just utilize a more aggressive lift when the follwer is bigger. For example, Chevy's had a .842 lifter diameter, Ford .875 and chrysler .904 and the lift each could obtain per cam duration increased respectively.




I should add that some finger follwers don't have the luxury of rotating and Japanese cars typically run a mechanical cam which allows for more aggressive valve opebning and can't adjust for wear, so valvetrain wear might be a bigger consideration for them.
 
Originally Posted By: mechanicx
What I found confusing was the article seemed to suggested sulfur was doing most of EP anit-wear effects, but then it went on about the phosporus level mostly.

Phosphorus level is a concern because of its effect on the catalytic converter.

Originally Posted By: mechanicx
Onerthing I am confused about is does the sulfur creat a lot of sulfated ash?

No, only metals contribute to sulfated ash. It is called sulfated ash because the test burns off the organics and reacts the ash with sulfuric acid.

Originally Posted By: mechanicx
I use to hear about "ashless" oil, but don't all oils have some ash levels, and if they didn't they couldn't have zddp?

Correct, an ashless oil does not have any metals. Motor oils are not ashless as the ZDDP and detergents contain metals.

Tom NJ
 
Quote:
Originally Posted By: Tom NJ
mechanicx said:
What I found confusing was the article seemed to suggested sulfur was doing most of EP anit-wear effects, but then it went on about the phosporus level mostly.

Phosphorus level is a concern because of its effect on the catalytic converter.


Right, but the article seemed to be also discussing phosphorus levels in the context as the needed anti-wear additve when earlier it said sulfur was doing most of the anti-wear, and sulfur was mentioned again.


Quote:
Originally Posted By: mechanicx
Onerthing I am confused about is does the sulfur creat a lot of sulfated ash?

No, only metals contribute to sulfated ash. It is called sulfated ash because the test burns off the organics and reacts the ash with sulfuric acid.


OK, but besides from the fuel doesn't the sulfur in ZDDP raise the sulfuric acid level? Isn't zinc considered a metal additive? Where are all the metals additives coming from (OK I think you answer that below from zddp and other additives).

Quote:
Originally Posted By: mechanicx
I use to hear about "ashless" oil, but don't all oils have some ash levels, and if they didn't they couldn't have zddp?

Correct, an ashless oil does not have any metals. Motor oils are not ashless as the ZDDP and detergents contain metals.

Tom NJ


OK so for an oil to be ashless it would have to not contain zddp and certain degterents? I don't know what the article I read was talking about with reccomending using ashless oil in a smb Chevy. So higher levels of ZDDP can contribute to sulfuric cid, suflated ash? What is so bad about ash and why does it always become sulfated?
Click to expand...
 
Last edited:
Hi Mechanicx,

The sulfuric acid does not come from the fuel or ZDDP, it is added in the laboratory when performing the sulfated ash test.

In the lab, a sample of oil is heated and ignited, then allowed to burn until all organic matter is gone, leaving only carbon and metals (as oxides). This ash is then reacted with sulfuric acid, and heated again in a furnace until the carbon is gone and the metal oxides are converted to metal sulfates. This final ash is weighed and expressed as a percent of the starting oil weight. The number gives an indication of the total metals present in the oil. The common metals that may be found in motor oils are zinc (from ZDDP), calcium, magnesium, and barium (from detergents), and molybdenum (from anti-wear).

Excessive sulfated ash content can lead to deposits, especially in the pistons/cylinders/valves. Ashless lubricants are used in applications where the oil tends to get burned off and the machines are very sensitive to residual ash deposits, such as 2-stroke engines, jet engines and some industrial applications such as recip compressors and oven chains. Some car and diesel engines are also sensitive to ash deposits, but the metals are essential and cannot be avoided, so limits are set.

Tom NJ
 
OK Tom NJ, I think that clears it all up for me. Basically, the sulfur and sulfuric ash in the engine isn't reall an issue, the sulfuric acid is just used in the test to "bleach out" the metals from the carbon. I assume these metal particles cause wear and are hard for the oil to clean off from where they cling too. It seems like ironically the very additives that reduce wear and deposits, can also create some deposits and wear too, but I guess it's a much better trade off.
 
The deposits from ash are usually on piston tops and valves, so not likely to cause wear, but can cause preignition or valve seating problems. Most motor oils limit sulfated ash to about 1%, and you are right it is not really an issue at these levels.

Tom NJ
 
OK. It' been a long time since I skimmed through that article and maybe they said something more like, "...Low ash (not ashless) 30-weight detergent oil..". Maybe my recollection was bad. Anyway, thanks for clearing that all up for me.
 
SAE Technical Article 2004-01-2986 "How Much ZDP is Enough" is fascinating, I paid $15 to download it, unfortunately it's copy protected so I can't attach it. It basically says 600ppm P is enough for all except hot rod flat tappet engines, particularly if not broken in.
I use this oil in my Unimog
http://www.mobil.com/Egypt-English/Lubes/PDS/GLEGENCVLMOMobil_Delvac_1_SHC_5W-40.asp
It has 1.8% ash, 1100 ppm P. Mercedes very highly recommends it for my particular engine.

Charlie
 
It seems that the end result of the ZDDP on the cam is the same as gear lube with sulfur on gears.
Iron sulfide - the time tested EP remedy.
 
I wonder if this some of the iron that we often see on Redline or Mobil 1 UOA's are coming from what ther article stated concerning chemical wear that is a result of the zinc/phos/heat reaction that puts on the protective layer he was talking about...
 
If the industry (factory and especially the aftermarket) would permanently phase out flat tappet lifters and go to roller lifters, this wouldn't be an issue.
 
Originally Posted By: pavelow
If the industry (factory and especially the aftermarket) would permanently phase out flat tappet lifters and go to roller lifters, this wouldn't be an issue.


LOL! that won't happen to the general automobile public here in NA for they are the slowest to adapt/change when it comes to technological process.

Q.
 
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