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By Dennis C
#63202
What is synthetic oil?
The easiest way to define what synthetic oil is, is to define what it is NOT. Conventional motor oil as we have known it for the last 100 years or so is derived from crude oil that is taken from the earth with oil wells. Through a complex distillation process the crude oil is refined into many different liquids, or fractions, each having distinct characteristics. Some are very light and are used as fuel (gasoline, kerosene, diesel fuel), and some are heavier and are used as lubricants (motor oil, gear lube, grease). There are many molecular compounds present in crude oil and many of those compounds are still present in the refined product, detracting from the physical properties of that product. For instance, paraffinnic waxes are present in crude-based oil, but contribute nothing to the lubricative properties of the oil. Also, the size of the hydrocarbon molecules themselves are non-uniform in crude-based oils. Synthetic oil contains none of these contaminants and the hydrocarbon molecules are very uniform, giving the synthetic oil base better mechanical properties at extreme high and low temperature (see the sections below on physical properties). By contrast, synthetic oil is not distilled from crude oil. It is made through a chemical process known as the Fischer-Tropsch process, starting with raw materials like methane, carbon monoxide, and carbon dioxide. This process was developed by Germany in WWII, when that country's access to crude oil was very limited.
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By PeteF
#63207
"Synthetic oils are mineral oils"
Not necessarily Jefrs, they can be manufactured from other raw materials. If they are manufactured from mineral oils they are chemically modified, not just a different formulation.
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By PeteF
#63209
Sorry Dennis, didn't realise we were on to page 2 ;-)
By DUFFEL
#63285

I started to use Pentite 25/75W in my Meteor Minor Airflow really recommend it as the engine can run very hot in the Summer with the fairing especially in stop start traffic it seams to stay much more sticky on the dip stick when hot .I bought a 20 litre drum so will be using it next season on all my Enfield's faired and unfaired
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By Leon Novello
#63286
Duffel: I would be wary of such a thick oil, particularly in cooler months, could strip the teeth off the oil pump spindle on a cold morning.
By Bullet Whisperer
#63287
Just buy 1 can of decent 20/50 mineral oil and you can put it in the engine, chaincase [shares oil with the engine - do NOT use ATF], gearbox and even the forks of your 1965 Continental GT250. No harm will be done. Everything will work fine. Nothing can possibly go wrong.
By papasmurf
#63289
"What could possibly go wrong" I said when I arrived at a motorcycle rally with a flock of sheep in the next field.
By jefrs
#63294
Synthetic motor oil is made from modified petroleum components rather than crude oil. The petroleum components are refined from crude oil. The "mineral" in mineral oil means it comes out of the ground, crude oil, and the contents of this varies a lot depending on which hole it comes out of. "Full synthetic oils are derived from crude oil or byproducts through a chemical process rather than the distillation process used for conventional oil", these are the familiar "API" full synth motor oils.

Yes the germans developed several processes in WW2 to obtain liquid fuel and lubricants (& margarine) from other sources including coal because they did not have access to oil, if you delve into the history you'll find most of WW2 was actually fought over gaining control of the trans-Balkan and middle eastern oil fields. Different stuff, and yes we pinched the lot in army trucks back to research bases in blighty, the yanks got the scientists, the russians got the workers, we got the equipment.

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