To all,
I see that Mobil really seems to like to use Mag in most of its oil. I think it was Ken2 and BITOG that stated magnesium produced abrasive deposits. Anyway my questionis, this, are we going to see problems from oil with magnesium or not? ANy views appreciated. his goes back to the FM post about Jap car makers not liking Mag.
GregH
Magnesium- good or bad??????
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Patman
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quote:Actually they have reduced the level of magnesium considerably. Trisynthetic Mobil 1 had a lot of it, but the Supersyn formulation has very little.
Originally posted by GregH: To all, I see that Mobil really seems to like to use Mag in most of its oil.
Yep, Mobil 1 with SS has very little Magnesium. I'd say a lot of Magnesium may tend to cause sludge, especially in a high revving engine.
M1 SS and Castrol Syntec have little to no Magnesium, but higher Calcium levels.
I'd say it's not a good thing. I prefer to see the higher Calcium levels.
MolaKule
Staff member
The magnesium in discussion is usually magnesium sulfonates and succinimides. This is used primarily as a dispersant.
The older Magnesium adds had a low TBN (metallic-based BASE).
The newer Magnesium adds are "over-based" adds which have a very high tbn/milliter, so less is needed.
You will notice that the calcium levels are way up, and this is due to overbased calcium carbonate detergents now in adds, that also function as AW adds.
AT one time, high doses of Mn adds would cause gelling in older formulations that experienced low temperrature operation. The newer Mn adds don't do that.
I've noticed that Amsoil's oils have a lot of Mg in them compared to other synthetics. I would guess this is to aid in extended drain capabilities(?). Is there any downside to an oil having over 500ppm Mg in its formulation?
Amsoil changed their detergent/dispersant mix with their last re-formulation in mid 2002.
Their previous SJ/CF chemistry was approx this:
Ca, 3000 ppm
Mg, 300 ppm
Their current SL/CF chemistry looks like this:
Ca, 2200 ppm
Mg, 800 ppm
They've increased the level of dispersants to deal with the fuel/moisture related, solids accumulation you get from short trip and stop and go driving....
One thing I've noticed is that this newer chemistry in the 0w-30/5w-30/10w-30 seems to be doing better in resisting thickening over long drain intervals ....
quote:I've noticed this as well and have been paying attetion to Amsoil's viscosity retention. About a year ago their oils would thicken more or so it seemed. Interesting regarding the formulation change. Higher levels of calcium seem to be the way things are going so I'm surprised they went in the other direction.
One thing I've noticed is that this newer chemistry in the 0w-30/5w-30/10w-30 seems to be doing better in resisting thickening over long drain intervals ....
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I'm not sure Mg has anything to do with sludge...
We have seen some higher wear numbers in oils with certain levels of Mg, ie maybe the Mg:Ca ratio is tilted more toward the Mg than the Ca....but is this purely because of the Mg or is the Mg organo compound selected
Insufficient information.
Isn't there a paper published on this, Molecule?
Insufficient information.
Isn't there a paper published on this, Molecule?
MolaKule
Staff member
quote:Not with their formulation. Each manuf. formulation is different and commensurate with their slection of base oils and additive components.
I've noticed that Amsoil's oils have a lot of Mg in them compared to other synthetics. I would guess this is to aid in extended drain capabilities(?). Is there any downside to an oil having over 500ppm Mg in its formulation?
Not meaning to beat a dead horse but I noticed that the diesel formulations of Mobils oils still have about as much mag as ever. Do diesels indeed have some unique requirements. The more I learn, the more I realize I have more to learn.
Thanks for all the info and patience
GregH
So would the same capability that aids soot-mitigation also help against whatever deposits are generated by a turbocharger on a gasoline engine? I've noticed that my 9³'s oil is jet-black when compared to the oil in the n/a engines I've got.
MolaKule
Staff member
quote:The problem here is not soot per se, although Turbo engines do run a bit richer, but I suspect that the Turbo is oxidizing the oil, i.e., attempting to cook it. I would use a good synthetic and change according to severe service intervals.
So would the same capability that aids soot-mitigation also help against whatever deposits are generated by a turbocharger on a gasoline engine? I've noticed that my 9³'s oil is jet-black when compared to the oil in the n/a engines I've got.
Yes I believe Mg helps keep things clean.
M1 has about 20 ppm of Mg, whereas GC has 120 ppm; in my experience GC keeps things a little bit cleaner in BMWs. Then again, it could be the esters.
BMW's synthetic has only 10 ppm of Mg and it really tends to leave a mess.
Now I'm really tempted to run D1 in my SAAB turbo, with its whopping 450 ppm of Mg! Hmm...
MolaKule
Staff member
Right.
Diesels need a lot of dispersant (Mg) to keep soot particles from turning real ugly and thickening up the oil too much.
Originally Posted By: MolaKule
The magnesium in discussion is usually magnesium sulfonates and succinimides. This is used primarily as a dispersant.
The older Magnesium adds had a low TBN (metallic-based BASE).
The newer Magnesium adds are "over-based" adds which have a very high tbn/milliter, so less is needed.
You will notice that the calcium levels are way up, and this is due to overbased calcium carbonate detergents now in adds, that also function as AW adds.
AT one time, high doses of Mn adds would cause gelling in older formulations that experienced low temperrature operation. The newer Mn adds don't do that.
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