Calcium VS Magnesium

[Revelate]

Hi all, long time viewer of BITOG, and excited for my first post! After reading and studying the topic here and in other research papers/books, I'm curious which detergent formulation could be considered better either in PCMO/HDEO applications?

Many threads here that i've looked at seem to be inconclusive or highly speculative, and i'm hoping to find more factual info and more references i can learn from. For instance i've read an article from machinery lubrication, along with the Oronite research paper on the subject with their ending conclusion being: "Each of the evaluated detergent types has strengths and weaknesses. , and in order to optimize a lubricant’s performance, it may be best to use a well balanced mixture of more than one detergent type."

http://www.machinerylubrication.com/Read/354/reserve-alkalinity-oil

http://www.oil-lab.com/downloads/TBN-1.pdf

I understand that various oil manufacturer's will develop different formulations based off cost effectiveness, efficiency, etc. with all passing appropriate API and other governing bodies requirements, but would u say any one would be a better formulation as a detergent package? Such as a Cal/Mag blend over Calcium alone?

I've looked at VOA/UOA's and found that when diesel oils are concerned many use a blend: Delo, Delvac, SRT 5W40, SuperTech, Napa, Car Quest, etc.

http://www.pqiamerica.com/March2013PCMO/HDEO SUMMARYrev2.html

But when compared to syn PCMO's only Castrol Edge and Mobil 1 used the blend (in the oils tested of course)

http://www.pqiamerica.com/March2013PCMO/Marchsyntheticsallfinal.html

Following PCMO's that are a standard petroleum oil with all of them only using Calcium with negligible magnesium content.

http://www.pqiamerica.com/Feb2014/consolidated5w20ALL.html

I understand that magnesium tends to cost more, and that it's not as effective at combating all forms of acid like calcium, with the possibility that it crystallizes more easily possibly leading to increased wear, and that it tends to maintain a higher TBN since it my not neutralize as many acids, but can any of u shed any more light on the subject or have any recommendations of other books/articles i can gather more info from?
Sorry for the long post and thanks for any and all info/replies!

 

[Gokhan]

All-calcium or mostly calcium with some magnesium (less than about 30%) formulations are the best.

Formulations with too much magnesium may not be effective at arresting the TAN (keeping it low), which may lead to increased wear during longer OCIs. This is because magnesium cannot neutralize certain kinds of acids (narrow spectrum), as opposed to calcium, which can neutralize almost all kinds of acids (wide spectrum).

 

[EricF]

How bad is it to have a very high Sodium level?

 

[Voltmaster]

As far as chemistry goes, they are both in group II so they will try to bound with similar compounds/molecules.

Mg and Ca have similar reactivity properties. Since Ca is heavier it will be better oxidized, making it a better reducing agent. Important factor in motor oil, that's for sure.

^ That was a scientific explanation of what Gokhan said.

 

[Voltmaster]

Originally Posted By: EricF
How bad is it to have a very high Sodium level?


Sodium can come from coolant and thats bad, very bad.

Some oil's use it as additive, but not in very high levels.

 

[Gokhan]

Originally Posted By: Voltmaster
As far as chemistry goes, they are both in group II so they will try to bound with similar compounds/molecules.

Mg and Ca have similar reactivity properties. Since Ca is heavier it will be better oxidized, making it a better reducing agent. Important factor in motor oil, that's for sure.

^ That was a scientific explanation of what Gokhan said.

Thanks!

 

[Gokhan]

Originally Posted By: Voltmaster
Originally Posted By: EricF
How bad is it to have a very high Sodium level?

Sodium can come from coolant and thats bad, very bad.

Some oil's use it as additive, but not in very high levels.

To be more clear, it's not sodium that's bad for the engine. It's ethylene glycol, which ruins the oil. Sodium is just an indication of the dangerous ethylene glycol, as most ethylene-glycol-base coolants also contain sodium (as sodium hydroxide or such) in the corrosion-inhibitor package.

Is this correct or am I missing something?

 

[SLATRON]

The only thing I would mention is that Valvoline/Ashland ie; Napa oils and many other house brands use a sodium add pack. In somewhat highish levels around 400+ppm IIRC.
some people don't like this, can make spotting coolant harder, but potassium normally also present. Although I've seen some great UOA's with synpower and maxlife is probably the most popular high mileage oil, at least first I believe

 

[buster]

Ashland is using a Lubrizol additive package which uses Na as part of it's detergent system.

Castrol and Mobil, and many other diesel oils use Mg/Ca combinations. That I'm pretty sure is an Infineum system. They are using Mg to lower the slufated ash.

Where Gokhan and Voltmaster are wrong, is their unscientific assumption that just because an oil has Mg it is therefore inferior. Not so.

Non-metallic detergents are being used that will not show up in a VOA. Also, the level of Mg being used is very small. Nothing to worry about at all. Let the industry tests prove how good the product is.

Advanced additive technologies such as salicylate detergents,
enhanced low S/P anti-wear and new antioxidant technologies are being used.

 

[dave1251]

Originally Posted By: buster
Ashland is using a Lubrizol additive package which uses Na as part of it's detergent system.

Castrol and Mobil, and many other diesel oils use Mg/Ca combinations. That I'm pretty sure is an Infineum system. They are using Mg to lower the slufated ash.

Where Gokhan and Voltmaster are wrong, is their unscientific assumption that just because an oil has Mg it is therefore inferior. Not so.

Non-metallic detergents are being used that will not show up in a VOA. Also, the level of Mg being used is very small. Nothing to worry about at all. Let the industry tests prove how good the product is.

Advanced additive technologies such as salicylate detergents,
enhanced low S/P anti-wear and new antioxidant technologies are being used.


So in layman's terms. The whole formulation is what is important. No just one or two additives. The sum of the parts is greater in this case.

 

[buster]

Quote:
The results demonstrate that the use of a combination of magnesium salicylate and calcium salicylate in Lubricant 1 gave better wear performance in an accredited engine test than use of calcium salicylate alone in Lubricant A, to the extent that Lubricant 1 passed the Test whereas Lubricant A failed.


http://www.freepatentsonline.com/8470751.html

 

[buster]

Originally Posted By: dave1251
Originally Posted By: buster
Ashland is using a Lubrizol additive package which uses Na as part of it's detergent system.

Castrol and Mobil, and many other diesel oils use Mg/Ca combinations. That I'm pretty sure is an Infineum system. They are using Mg to lower the slufated ash.

Where Gokhan and Voltmaster are wrong, is their unscientific assumption that just because an oil has Mg it is therefore inferior. Not so.

Non-metallic detergents are being used that will not show up in a VOA. Also, the level of Mg being used is very small. Nothing to worry about at all. Let the industry tests prove how good the product is.

Advanced additive technologies such as salicylate detergents,
enhanced low S/P anti-wear and new antioxidant technologies are being used.


So in layman's terms. The whole formulation is what is important. No just one or two additives. The sum of the parts is greater in this case.


Bingo. This happens all the time and even I get caught up in it. Oils are complex chemistry. To narrow it down to one or two things is missing a lot.

 

[kr_bitog]

So does this means mixing different weight of oils probably is not good idea since their add packs may be different ?

 

[dave1251]

Originally Posted By: kr_bitog
So does this means mixing different weight of oils probably is not good idea since their add packs may be different ?


If all the oil's are API certified, I would not worry about it. The oils will be compatible it may or may not be optimal but it is nothing I would lose sleep over.

 

[Revelate]

Originally Posted By: Gokhan
Originally Posted By: Voltmaster
As far as chemistry goes, they are both in group II so they will try to bound with similar compounds/molecules.

Mg and Ca have similar reactivity properties. Since Ca is heavier it will be better oxidized, making it a better reducing agent. Important factor in motor oil, that's for sure.

^ That was a scientific explanation of what Gokhan said.

Thanks!


Thank you both for your responses! Considering the Mack T-9 testing, it's interesting that the all magnesium oil outperformed the all calcium reference oil in every testing procedure except for the total AN test. Even though the all calcium oil had a lower AN than the all magnesium oil, the magnesium oil had the higher TBN (apparently because it couldn't neutralize as many acids as the all calcium oil), along with having lower test results of lead content and oxidation.

Gokhan, did you arrive at the conclusion that 30% or less magnesium formulations are more useful because the low BN Ca/Mg performed better than the all magnesium oil at a ratio of 3:1/33%? During my search here I came across your review of Oronite's report; indeed a thorough summarization!

Buster, I didn't mean to infer that the Ca/Mg concentrations were the most important factors of a fully formualted oil, as i'm sure everyone here can agree that it is the overall formulation of base stocks and additives that lead to a successful lubricant. I'm merely interested in any more research comparing the two detergents, and the positives and negatives of both.

 

[Gokhan]

Originally Posted By: Revelate
Thank you both for your responses! Considering the Mack T-9 testing, it's interesting that the all magnesium oil outperformed the all calcium reference oil in every testing procedure except for the total AN test. Even though the all calcium oil had a lower AN than the all magnesium oil, the magnesium oil had the higher TBN (apparently because it couldn't neutralize as many acids as the all calcium oil), along with having lower test results of lead content and oxidation.

Gokhan, did you arrive at the conclusion that 30% or less magnesium formulations are more useful because the low BN Ca/Mg performed better than the all magnesium oil at a ratio of 3:1/33%? During my search here I came across your review of Oronite's report; indeed a thorough summarization!

Buster, I didn't mean to infer that the Ca/Mg concentrations were the most important factors of a fully formualted oil, as i'm sure everyone here can agree that it is the overall formulation of base stocks and additives that lead to a successful lubricant. I'm merely interested in any more research comparing the two detergents, and the positives and negatives of both.

As far as I remember, the only reason why the all-calcium oil performed poorly in the Chevron Oronite paper was that it had a very low initial TBN.

Shell believes in all-calcium oils, even for HDEO. Other oil blenders experiment with magnesium now and then.

 

[gpshumway]

Originally Posted By: Gokhan
Shell believes in all-calcium oils, even for HDEO. Other oil blenders experiment with magnesium now and then.


Um, have you seen RT6 lately? 800+ PPM of Mg.

http://www.bobistheoilguy.com/forums/ubbthreads.php/ubb/showflat/Number/3332796/gonew/1/%2713_Ford_6.7L_Powerstroke_T6_5#UNREAD

RT6 hasn't been an all Ca oil since ~2008.
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/2627460/35k_Mi_of_UOA_-_2007_WRX_GC,_R#Post2627460

 

[JAG]

This is old but still interesting:
"Some Effects of Zinc Dithiophosphates and Detergents on Controlling Engine Wear"
Quote:
The modern crankcase oil should prevent wear in both gasoline and diesel engines. This paper addresses the effects of zinc dithiophosphates (ZnDTP) and detergents on wear control in both applications. The authors find a need to properly balance detergent and ZnDTP types in order to obtain optimum wear performance for gasoline valve train wear. In addition, high levels of magnesium sulfonate produce higher bore polishing and/or ring wear than calcium detergents in three different diesel engine tests. Finally, a proper balance of sulfur-containing components and ZnDTP is necessary to prevent corrosive attack of the bronze pins in some diesel camshaft roller followers. Film and metallurgical analyses of used engine test parts are presented.

Also see: http://books.google.com/books?id=d6kPqVN...utput=html_text

When API SN and CJ-4 oils came about, which often had less sulfated ash than the previous specs' oils, many of them adopted the MG/CA combination detergents instead of all CA. This was particularly true of the CJ-4 oils.

 

[A_Harman]

Originally Posted By: gpshumway
Originally Posted By: Gokhan
Shell believes in all-calcium oils, even for HDEO. Other oil blenders experiment with magnesium now and then.


Um, have you seen RT6 lately? 800+ PPM of Mg.

http://www.bobistheoilguy.com/forums/ubbthreads.php/ubb/showflat/Number/3332796/gonew/1/%2713_Ford_6.7L_Powerstroke_T6_5#UNREAD

RT6 hasn't been an all Ca oil since ~2008.
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/2627460/35k_Mi_of_UOA_-_2007_WRX_GC,_R#Post2627460


I was going to point that out, but RT5 had an all-Calcium adpak the last time I checked. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1791357

AMSoil has all-Calcium adpaks in all of their oils.

 

[Gokhan]

Originally Posted By: A_Harman
Originally Posted By: gpshumway
Originally Posted By: Gokhan
Shell believes in all-calcium oils, even for HDEO. Other oil blenders experiment with magnesium now and then.

Um, have you seen RT6 lately? 800+ PPM of Mg.

http://www.bobistheoilguy.com/forums/ubbthreads.php/ubb/showflat/Number/3332796/gonew/1/%2713_Ford_6.7L_Powerstroke_T6_5#UNREAD

RT6 hasn't been an all Ca oil since ~2008.
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/2627460/35k_Mi_of_UOA_-_2007_WRX_GC,_R#Post2627460


I was going to point that out, but RT5 had an all-Calcium adpak the last time I checked. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=1791357

AMSoil has all-Calcium adpaks in all of their oils.

If that's the case, Shell has completely changed their detergent philosophy. This is what they used to say:

Question: What's better: a calcium, a magnesium or a calcium-magnesium combination detergent?

Answer: For heavy-duty engine oils, we think calcium is the best, and that’s what we use in Rotella T®. Magnesium detergents allow oils to pass gasoline-engine wear tests easier, but magnesium-based detergents can give higher wear in the critical ring-belt area of diesel engines.

We use an all-calcium detergent because, according to our tests, calcium performs best in controlling wear in the ring-belt area.

http://www.shell-lubricants.com/truckquest2b.htm#29

Again, my own conclusion is that all-calcium or mostly calcium with some magnesium detergents -- in any case with a high initial TBN -- are the best.

My other important conclusion is that TBN - TAN (TBN minus TAN) is the critical measure. When TBN - TAN becomes negative or too negative, wear starts to increase exponentially.

This means that any detergent pack with high initial TBN will work up to a certain OCI. TAN increases more rapidly with magnesium than with calcium. However, some magnesium could be helpful in keeping TBN higher. So, chances are that 10 - 30% magnesium with high initial TBN is the best.