Ash content corrolations to Pre-Ignition

[vex]

Originally Posted by Barry Bordes

VEX,

Third Paper
LUBRICANT DEVELOPMENT FOR THE
WANKEL-TYPE ROTARY ENGINE
page 4, top and bottom, Figs. 16 & 17.
their "prime candidate" oil Fig 17, has half the wear, and the "Typical Marine Cylinder Lubricant" in fig. 16 also shows extremely low wear data.

Unfortunately the CAT VOR info doesn't include sulfur in their testing!

Which Castrol 0w-30 are you referencing? There are a few listed. It would be great to find an oil that was stocked locally in stores.

Barry

I see. I don't know why I didn't see that before. From my reading of it, the oil to which they are referring appears to be "...the oil formulation which satisfies the preignition test (explained later) and at the same time gives
the best cold-wear performance contains magnesium at a total sulphated-ash level of 0.4 per cent by weight." My best guess for that would be an oil based off of magnesium rather than calcium. The calcium and magnesium when burned produce a portion of the sulphated ash (see above figure for more understanding regarding that; basically, the more calcium the higher the ash content--that is my understanding at least). So we'd need to find an oil that has a magnesium 400ppm rating. That should give similar if not the same results for which they were relating.

As for the Castrol 0w-30, that is all the distinguishing markings of the oil they tested. There's no further classification of it. On the CAT charts look for Castrol [Blank] 0w-30. That is the one I'm referencing. You can verify that by looking at the calcium readings.