Mineral or Synthetic?

Mineral oils are based on oil that comes from dear old Mother Earth which has been refined. Synthetic oils are entirely concocted by chemists wearing white lab coats in oil company laboratories. For more info, see the section on synthetics further down the page. The only other type is semi-synthetic, sometimes called premium, which is a blend of the two. It is safe to mix the different types, but it's wiser to switch completely to a new type rather than mixing.


Synthetics

Despite their name, most synthetic derived motor oils (ie Mobil 1, Castrol Formula RS etc ) are actually derived from mineral oils - they are mostly Polyalphaolifins and these come from the purest part of the mineral oil refraction process, the gas. PAO oils will mix with normal mineral oils which means Joe public can add synthetic to his mineral, or mineral to his synthetic without his car engine seizing up. The most stable bases are polyol-ester (not polyester, you fool). When I say 'stable' I mean 'less likely to react adversely with other compounds.' Synthetic oil bases tend not to contain reactive carbon atoms for this reason. Reactive carbon has a tendency to combine with oxygen creating an acid. As you can imagine, in an oil, this would be A Bad Thing. So think of synthetic oils as custom-built oils. They're designed to do the job efficiently but without any of the excess baggage that can accompany mineral based oils.

Pure synthetics

Pure synthetic oils (polyalkyleneglycol) are the types used almost exclusively within the industrial sector in polyglycol gearbox oils for heavily loaded gearboxes. These are typically concocted by intelligent blokes in white lab coats. These chaps break apart the molecules that make up a variety of substances, like vegetable and animal oils, and then recombine the individual atoms that make up those molecules to build new, synthetic molecules. This process allows the chemists to actually "fine tune" the molecules as they build them. Clever stuff. But Polyglycols don't mix with normal mineral oils.


http://www.carbibles.com/engineoil_bible.html

Now how about dispelling some myths here? I hear that synthetic oil is not good on the rotary because it burns it. Truth or not, I will just stick to dino oil.

OMP removed, 2 stroke premix in the gas now, problem solved. I now run 10w30 Royal Purple.

If anyone has any good information on oil choices and rotarys, please post in here. I noticed there were no hardcore Oil based threads after searching, nor in the archives.

 

Personally, I use a mineral oil that is approved for aircraft engines. To meet such qualifications, it must either A) be fully combustable or B) any deposits left from combustion must be soft, to easily flake away.
I still have the OMP hooked up, but also add 1/2 OZ 2 stroke oil per gallon of gas. While many will say that's too much oil entering the combustion chambers, the white coating in my exhaust ports and on the plugs tells a different story.
That's just me, though.

 

I run Idemitsu synthetic simply because I like synthetics and there is still some, (though small) argument about the rotary/synthetic issue.
Far as Im concerned,there are enough people over the last 10 or so years since synthetics have become commonplace,that have and do,run synthetics in their rotary,thats its pretty much a dead issue.If Idemitsu rotary oil didnt exist,Id probably run Royal Purple with no hesitation.But,if there is a syn. oil MADE specifically for rotaries,that has been around for some 15 years,why not run it?

 

Synthetics are just fine for a rotary and anyone that says different is miss-informed or just plain ignorant. I used Royal Purple in the FB with great results and once the motor is rebuilt it will be the only thing that goes in it

 

Now with the title stating the key search terms, Synthetic and Mineral. There are some related threads at the bottom of the page. :-)

 

Just tryin to get an oil thread started here

 

I use idemitsu synthetic in the oil resivour and I run idemitsu premix in my oil tank for my omp and I run protek-r in my tank. You know run sounds like rum... I like rum... for that matter I like whiskey too.

 

No omp used here. Synthetic oil for the motor and 2 stroke in the gas tank. Regular motor oil wasnt meant to be burned. BTW MMO works great to if you cant find a good quality 2 stroke oil!

 

Mineral oil. I don't see a point using synthetics.

 

With the cost of synthetics, and the frequency of oil changes, I don't see a point in using them either.

 

This topic has been debated too many times in the past. The problem is that the threads have gotten out of hand. So I am going to do like all of the mods before me and close it. Leaving the reference to one of the longer recent threads done on the subject.

https://www.rx7club.com/rotary-car-performance-77/mineral-vs-synthetic-new-bulletin-mazda-588321/