What are the sizes (in microns) of soot particles found in the motor oil of a dino-diesel?

In the motor oil of a gas engine?

Don't use dead dinos for fuel:
let 'em rest in peace!

Enola: good question, and I don't have a direct answer. Here's what I do have though, from SAE J1858, that may give you an idea: Oil filters for both gas and diesel engines are tested for their ability to capture particles greater than 10, 15, 20, 25, 30, and 40um (microns). The assumptions are that smaller particles don't cause significant wear, and bigger particles are from parts failing.
Diesels are expected to have more soot (partially burned fuel) and fuel-dilution in the oil, but fewer other combustion contaminants than gasoline engines. Gasoline has more and different additives than diesel, so stranger chemical combinations show up in the oil.
A lot of truck shops offer oil analysis. Perhaps you could ask one of them if they've noticed any trend, or if they can put you in contact with the testing laboratory.
JohnO

UEO FILTERING -- Reading a bit about soot, (amazing amount of research on it on the net) The soot particals can be as small as 1 nanometer, I beleive this is 1/1000 of a micron. This explains why we can't filter it all of of the ueo. Diesel soot is also almost completely amorphous carbon, c-6, with tars and resins. I don't know what this means exactly but there is also a lot of info on the net about "diesel soot filters" or catalytic converters. they indicate that they burn the soot completely on the surface of the ceramic converter element. My laymens logic here is that - SOOT BURNS. It seems logical that as long as you filter the ueo the soot particals will be smaller than your filter size, this ensures that nothing will be clogged up by the soot, As long as you can get the soot onto the cylinder it - WILL BURN. These are the assumptions I am proceding on, anyway. Will someone confirm/correct this ??

I don't know much about soot particles, but bearing in mind that a Carbon atom is almost one fifth of a nanometer across, I can't see that many soot particles being only five times this size.

Will happily stand corrected if anyone knows better.

Hi Tim

An important aspect of "research & info" on the net is working out what's fact and what's fiction?

Also my logic tells me that "soot" is partially burnt diesel. Why didn't it burn properly and completely the first time and remember that diamonds (the world's hardest material) are Carbon as well. What are the abrasive qualities of "soot"? - hopefully not like diamonds!

One of the purposes of engine oil is to remove those abrasive substances and then dump them when you change your oil. Putting it all back into your fuel is just WRONG whether you are a layman or a professional.

Another thought - just because an abrasive substance is so small that it passes through your fuel filter does not make it OK. WHat a fuel filter does is remove any substances that could possibly be in the fuel in the first place that are larger then the rating of the fuel filter medium. Nobody ever expects used engine oil to be in your fuel!

Diamonds are crystals, soot is amorphous-big difference in properties. Graphite is one of the best known lubricants. So when you make the connection between soot and diamond and say both are abrasive, you could also make the connection between graphite and soot and say they are both very good lubricants.

Good point Habanero, but isn't the lubricating aspect of graphite the fact that at microscopic size it consists of perfectly flat flakes? and apparently only dry - when liquid it might be different?

Otherwise all oil manufacturers would produce graphite oil wouldn't they?

There is more to a good lubricating oil than just the actual lubricant properties. Using graphite as a lubricant would require a stable suspension, which is very difficult given the conditions an oil must perform under.

I am not going to say having soot in your fuel is necessarily good for your injection system, I was just wanting to point out the flaw in your diamond comparison.

I am also, by the way, not going to say having a little soot in your fuel is bad for your injection system either.