Magnesium Only Detergent

[Phishin]

Why doesn't anyone make a Magnesium only detergent oil?

Lots of people here believe that high calcium is bad for Turbo's. Lots of people of people here love HDEO's (lower calcium with Magnesium mixed in).

So, why doesn't anyone make an oil with ZERO calcium and say 2500ppm Magnesium?

 

[lubricatosaurus]

Great question, since I've noticed Castrol Edge has recently converted to Calcium Sulfonate detergents from Mg Sulfonates previously. Some reason for getting away from Mg I guess.

It could be that calcium sulfonates actually perform in antiWear as well as being a detergent. (More multi-functional than Mg.) This is more and more important as ZDDP levels drop. Take a look at "Oil Extreme" that markets Ca. And http://www.chempoint.com/products/catalo...lcium-sulfonate
And file:///C:/Users/Mark/Downloads/Sulfonates_fnWeb.pdf

 

[Rand]

Simply put:
You can replace some calcium additive with magnesium additive but not all. they are complementary but magnesium isnt a full replacement for it. ie it doesnt do Everything that calcium does.

There have been technical posts about it in the past.

 

[lubricatosaurus]

Rand, is that what https://www.oronite.com/pdfs/Sulfonates_fnWeb.pdf Chevron-Oronite refers to when they say "However there is still a need to neutralize harmful combustion acids, so the solution is to use several different types of sulfonates, those that are rich in soap to protect against engine deposits, and those that are rich in metallic base to protect against corrosive wear from combustion acids." ???

 

[wemay]

Castrol's direction varies by product i assume...

http://www.pqiamerica.com/June 2014/castrol.htm

Quote:
Calcium..........685
Magnesium...1530

Castrol Edge Synthetic (FST) Motor Oil API SN/GF-5, SAE 0W-20 motor oil
BP Lubricants USA
Purchased at: Advance Auto Parts, Weirton, WV
Date of purchase: 8-14-2014

 

[lubricatosaurus]

wemay, thats the old formulation. It was recently that Castrol switched over. That bottle PQIA got was from early 2014 or 2013, off the shelf. It was purchased in mid-2014, had been on the shelf or warehouse for months likely.

 

[wemay]

Ah, that is a valid point. Purchase date does not necessarily represent bottled date.

But what basis is there that a switch has been made, Lubricatorsaurus? Not being difficult, just untested in seeing it too.

You can't go by UOAs. That oil may have been in someone's stash for quite some time.
I guess current VOA's would suffice. If we knew when those were bottled as well.

 

[A_Harman]

I read a paper referenced on BITOG a couple of years back that said Magnesium-only formulations are better at TBN retention, but are not totally effective at neutralizing weak acids. The paper said that a combination of Calcium and Magnesium detergents was the most effective at neutralizing all acids while still giving good TBN retention.

 

[camrydriver111]

Originally Posted By: A_Harman
The paper said that a combination of Calcium and Magnesium detergents was the most effective at neutralizing all acids while still giving good TBN retention.


Makes sense. This would also help explain why TBN depletion is not linear.

There also might be different types of Mg and Ca based detergents. Who knows? It always depends on what they test and under what conditions.

 

[Jetronic]

since ZDDP also adds to TBN, how could retention be linear?

 

[weasley]

Originally Posted By: camrydriver111
There also might be different types of Mg and Ca based detergents. Who knows? It always depends on what they test and under what conditions.


There are many, many different detergents using calcium, magnesium and other metals. And it's not just sulfonates, there are phenates and salicylates and some more unconventional types. There are variations in overbasing and each type has benefits and drawbacks in different areas. Most engine oils will have a mix of different detergents. It is far more complex than is made out here.

 

[weasley]

Originally Posted By: Jetronic
since ZDDP also adds to TBN, how could retention be linear?


It does?!

 

[Joe90_guy]

Sorry for the late response (I've been on holiday) but there's absolutely nothing wrong with making an all-magnesium engine oil. Ten years ago, you could find these almost anywhere in the world (except for the US and Japan) if you knew where to look.

If you consider over-based sulphonates, generally speaking, it's easier to manufacture a 400 TBN Mg sulphonate than a 400 TBN Ca sulphonate (300 TBN Ca is the more normal grade). As a result, for a given oil TBN, you need less of the more concentrated Mg juice. This points to one thing that's probably an industry truism and that is that Mg tends to be focused towards the more price sensitive parts of the engine oil market (ie, not the US or Japan).

 

[BrocLuno]

Does the EPA/CARB have anything to say about metallics vs calcium...

 

[camrydriver111]

Originally Posted By: weasley
Originally Posted By: camrydriver111
There also might be different types of Mg and Ca based detergents. Who knows? It always depends on what they test and under what conditions.


There are many, many different detergents using calcium, magnesium and other metals. And it's not just sulfonates, there are phenates and salicylates and some more unconventional types. There are variations in overbasing and each type has benefits and drawbacks in different areas. Most engine oils will have a mix of different detergents. It is far more complex than is made out here.


That's what I was thinking. Yet people on BITOG read one scientific paper and magnesium = bad!

 

[Garak]

Originally Posted By: BrocLuno
Does the EPA/CARB have anything to say about metallics vs calcium...

That would be highly unlikely. But, formulators may find some advantage to one over the other depending on the specification they are attempting to meet.

 

[weasley]

Although it is less critical in PCMOs, when I was using detergents in formulations the Mg ones were avoided because they tended to exhibit worse hydrolytic stability and water wash-out. Conversely they showed faster acid neutralisation and exhibited softer, more friable ash. I was working on marine diesel and stationary gas power gen engine oils.