The reasons synthetic oils are better

[oilman]

I as a vendor will never recommend an oil that would wreck your engine. It\'s called reputation and I have a good one plus a wealth of knowledge and technical contacts in the business.

Cheers
Simon

[ro284]

Simon,  i like to run a premix, about 150-1, i use a mineral oil for high revving chain saws made by Sthil, i think after all the information posted on these two threads, Many thanks! i will use synthetic engine oil in future, in my standard engine, what decided it for me was the capability of synthetics to cope with very hot running rotary engines! plus Apex seal lube, & maybe less oil changes,
would you recomend a synthetic premix?
cheers Bob

[Adriansturgess]

Ok, to be fair here I can do what you ask but of course can only recommend the oils that I sell!

My recommendation would be as follows:

Highly modified / tracked etc = Silkolene Pro S 5w-40, Motul 300V 5w-40 or 10w-40

Mildly modified / street = Motul 8100 5w-40 or Fuchs Titan Supersyn SL 5w-40

Stock / street = Fully Motul 8100 5w-40 or Fuchs Titan Supersyn SL 5w-40
                    = Semi Silkolene or Fuchs XTR 10w-40 or Motul 6100 10w-40

Now we\'re beginning to make some progress - cheers Simon..... :chat

[clive]

I said in a very early post on here which Clive removed.

"Some will stick there heads in the sand and because Mazda used information thats now 25 years old, will say "if it\'s not broke don\'t fix it".


MRC does have to be carefull, Clive is also a vendor who sells 76 Oils, so to a degree has a vested interest in members buying mineral or 76, and has recommended that people who want to save money go to Asda and buy it. I know I wont put oil in my car that I can buy for £2.75 a drum. So cant see that in the clubs interest to recommend.

If a list has to be made, and MRC have to get involved, why not just put a list of oils that MAYBE (cause you will never prove it) wont harm, because it will be a hard job to list and state reasons why.
If MRC keeps out of recommending then it will be down to the vendors to recommend and face the outcome. If Clive wants to act as a vendor and put forward 76 Oils tech in a SHY thread thats cool, each can state there qualities, and let members decide but not to say the club recommends, as its not the club, its the club president and vendor telling all to use mineral.

If any of this upsets Simon then please remove, posted as a couple kinda asked about RP. Im not getting in to my oils better than yours.

Gary I am staggered there are a few things you are saying here that you of all people should not even need to question.

First of all the slightest implication that I would even consider trying to persuade the members of our club to buy mineral for my own financial gain is quite honestly damn right insulting and you should know better!.

Indeed I find your implications that you are trying to damage myself, my business and the club via your accusations disgusting!

So why have I been telling people to use mineral for all these years long before my company even formed, the reason is that up until now it has been the only sure fire way of NOT confusing members or even worse telling them to go and possibly buy synthetic that could damage their engine when I know as you should some synthetics CAN cause terminal damage through seal failure!.

Even over the last few months I know of a race rotary that has died now more than once due to this type of failure.

You also obviously resent the fact that I keep saying "if it aint broke don\'t fix it" surrounding oils at a time when you are trying so desperately to sell your own RP oil, but unbeknown to you I have spent two hours on the phone today with Mazda technical discussing oil types and myths and facts surrounding the Rotary engine and they whole heartedly support my stance about only telling our members to use mineral oil in their Mazda engines but also have said to say to our members consult your chosen engine builder if the engine is modified on their choice of oils so as not to invalidate a particular engine builders warrantees .

I have found today that The Mazda Corporation official 2006 stance on oil is that the Rotary has so few demands on its oil system that it feels that fully synthetic oil is totally unwarranted and before anyone says the RX-8 uses synthetic it was made clear today that this is only a semi synthetic (mineral based oil) which as we have all found on this thread to be a totally different oil to man made fully synthetic oils.
I did uncover today one interesting fact though that the RX-8 is equipped with all internal seals and gaskets that are compatible with ANY type of synthetic oil on the market.

However inspite of this official line from Mazda I fully welcome the fact that Simon started this thread not to sell oil but as a Rotary enthusiast himself to try and enlighten us all with the benefits of synthetic oils in Rotary\'s particularly with the fact that we have so many highly modified cars within the club.

From day one I pride MRC on being a forward thinking club and if Simon can offer the guidance about oils to further progress the Rotary community that I now believe he can offer after reading this thread, and providing I have a list of synthetics that I can honestly know will not damage a members engine I will willingly drop my safety net of telling people across the board "only use mineral in your Rotary"

Lastly there are two things,

First, NOT ONE OF YOUR POSTS WAS REMOVED BY ANYBODY least of all me as you have stated abve when this thread was split, and secondly I cannot understand why were you unable to honour this mans wishes of keeping away from another Vendors thread even after you apologised to him! and yet you have come back on yet again to hinder this thread with petty accusations toward me and think its O/K by saying "if this upsets Simon please remove!"
__________________

[Adriansturgess]

Clive, I don\'t think many, if any, on the forum would question your integrity to be quite honest.

[Mr J.T]

Clive, I don\'t think many, if any, on the forum would question your integrity to be quite honest.

i second that!!!!

[AndyGen3]

Eh yea thats kool lads...

I have another question for the Oilman...

What difference if any wud it make using a thicker or thinner oil in a Rotary or Piston engine...??

I know a main problem with a thick oil wud be clogging the oil pump!! But is there any others??

[oilman]

Rotary\'s in particular do not need thick oils but the consquences are as follows:

Lower bhp at the wheels due to oil drag
Poorer fuel consumption again due to drag
More friction, heat and engine wear in the long run

Finally the risk of aeration and cavitation leading to oil pump failure if oil temperatures are not high enough at high revs.

Cheers
Simon

[clive]

Hi All,

Further to the oil debate Simon sent me this yesterday after a phone call from me a couple of days ago asking him to clarify a few things surrounding the use of synthetics in Rotary\'s.

 I would like to share this information with you all as this is very good info to help us all understand the differences and effects of oil in general.

In particular it is worth noting that this details fully exactly what Semi Synthetic and full Synthetic oil actually is and particular note should be paid to the explanation of "ester" content, and "shear" qualities as these are particularly crucial areas for Rotary\'s.

Cive,
 
Futher to our telecon, here are some facts about oils that you will find very interesting.
 
The most important thing with oil is that it is shear stable (stays in grade when subjected to heat) as this means that the oil film is retained and not thinned causing the potential for metal to metal contact. As I have explained, synthetics do this the best as the basestocks are by design more thermally stable, an absolute essential in a modded or track car.
 
For stock road cars, something of a lesser quality will suffice, it will not give as good protection against wear in the longterm but I would still recommend for those who intend to keep their cars that they look at it as a better quality option.
 
Obviously semi-synthetics are better than straight mineral oils but it is a fact that semi-synthetics ARE NOT in fact synthetics at all, they are in fact MODIFIED MINERAL OILS (more highly refined that\'s all) and therefore will act the same in the rotary as a mineral oil except they can take more heat and generally have a better addative pack and will keep the engine cleaner, they however are NOT synthetic! Mazda cleary do not understand this fact either but then again they build cars, not oil thank god!
 
So to the gory details:
 
Oil bastocks are classified into Groups by API (American Petroleum Institute) and it is important to understand what it all means to comprehend why the word synthetic is so misleading and in fact meaningless unless the type of synthetic is defined.
 
The grouping is 1-5, 5 being the best, "ester" used in Aircraft engines for 50 years due to it\'s thermal stability.
 
Groups 5 and 4 are the only "true" synthetics, not dug out of the ground but man made in laboratories by chemists for the purpose for which they are intended. Petroleum or hydrocracked synthetics (Group 3) are merely highly refined mineral oils but do not have uniform molecules, only manmade Group 4 and 5 synthetics have these for obvious reasons, they are manmade!
 
Basestock categories and descriptions

 

All oils are comprised of basestocks and additives. Basestocks make up the majority of the finished product and represent between 75-95%.

 

Not all basestocks are derived from petroleum, in fact the better quality ones are synthetics made in laboratories by chemists specifically designed for the application for which they are intended.

 

Basestocks are classified in 5 Groups as follows:

 

Group I

 

These are derived from petroleum and are the least refined. These are used in a small amount of automotive oils where the applications are not demanding.

 

Group II

 

These are derived from petroleum and are mainly used in mineral automotive oils. Their performance is acceptable with regards to wear, thermal stability and oxidation stability but not so good at lower temperatures.

 

Group III

 

These are derived from petroleum but are the most refined of the mineral oil basestocks. They are not chemically engineered like synthetics but offer the highest level of performance of all the petroleum basestocks. They are also known as “hydrocracked” or “molecularly modified” basestocks.

They are usually labelled/marketed as synthetic or semi-synthetic oils and make up a very high percentage of the oils retailed today.

 

Group IV

 

These are polyalphaolefins known as PAO and are chemically manufactured rather than being dug out of the ground. These basestocks have excellent stability in both hot and cold temperatures and give superior protection due to their uniform molecules.

 

Group V

 

These special basestocks are also chemically engineered but are not PAO.

The main types used in automotive oils are diesters and polyolesters. Like the group IV basestocks they have uniform molecules and give superior performance and protection over petroleum basestocks. These special stocks are used in all aviation engines due to their stability and durability. Esters are also polar (electro statically attracted to metal surfaces) which has great benefits. They are usually blended with Group IV stocks rather than being used exclusively.

 

It is common practice for oil companies to blend different basestocks to achieve a certain specification, performance or cost. The blending of group IV and V produces lubricants with the best overall performance which cannot be matched by any of the petroleum basestock groups.  

 
So to expand upon the above, I will now explain what group 3, 4 and 5 are all about:
 
Group 3 = Hydrocracked synthetic, molecularly converted mineral oil.
 
“HYDROCRACKED” (HC) or MOLECULARLY CONVERTED (MC) BASESTOCKS

 

There are many petroleum oils available on the market that are so pure and refined, they can now be passed off as synthetics.

 

Petroleum oil basestocks can be put through a super-extreme refining process called

“hydrocracking”. These are extremely high performance petroleum basestocks, but they are not truly synthetic the way that most people understand the term and will not necessarily perform to the same level as a premium synthetic oil like PAO (poly alfa olefins) or Esters.

 

Hydrocracking involves changing the actual structure of many of the oil basestock molecules by breaking and fragmenting different molecular structures into far more stable ones. This results in a basestock which has far better thermal and oxidative stability as well as a better ability to maintain proper viscosity through a wide temperature range - when compared to a typical mineral basestock.

 

SYNTHETIC HYDROCARBONS or POA’s (Poly Alpha Olefins)

 

These are, in effect, very precisely made equivalents to the most desirable mineral oil molecules. As with esters, they work very well at low temperatures, and equally well when the heat is on, if protected by anti-oxidants. The difference is, they are inert, and not polar.

 

PAO’s work best in combination with esters. The esters assist load carrying, reduce friction, and cut down seal drag and wear, whilst the PAO’s act as solvents for the multigrade polymers and a large assortment of special compounds that act as dispersants, detergents, anti-wear and oxidant agents, and foam suppressants. Both are very good at resisting high-temperature evaporation, and the esters in particular will never carbonise in turbo bearings even when provoked by anti-lag systems.

 

Esters

 

All jet engines are lubricated with synthetic esters, and have been for 50 years, but these expensive fluids only started to appear in petrol engine oils about 20 years ago. Thanks to their aviation origins, the types suitable for lubricants work well from â€"50 degC to 200 degC, and they have a useful extra trick.

 

Due to their structure, ester molecules are “polar”; they stick to metal surfaces using electrostatic forces. This means that a protective layer is there at all times, even during that crucial start-up period. This helps to protect cams, gears, piston rings and valve train components, where lubrication is “boundary” rather than “hydrodynamic”, i.e. a very thin non-pressure fed film has to hold the surface apart. Even crank bearings benefit at starts, stops or when extreme shock loads upset the “hydrodynamic” film.

 
The best oils for a modded or tracked rotary are a combination of Group 4 and 5, the ideal and top quality ones being a blend of around 20% ester and 80% pao, not hydrocracked ones.
 
The likes of Silkolene Pro S and Motul 300V are the best European ones due to their high ester content.
 
These high ester contect oils are not only used in the aviation industry but also in F1 Cars and Superbikes for their superior thermal stability under stressed conditions.
 
So, finally I talked at the beginning about shear stability (the oils stay in grade capability) and many people do not understand that the average mineral 10w-40 will in fact be a 5w-30 after 1000 miles of hard driving (including town, stop/starts etc which is also hard on oil) and more like a 5w-20 after 3000 miles, believe me I\'ve tested them and seen the results!
 
On the otherhand a proper 5w-40 synthetic will still be a 5w-40 after 8000 miles or 10 track hours! and these are the reasons why:
 
Why do oils lose viscosity with use?

 

Viscosity Index Improvers.

 

An oils viscosity will decrease as the engine temperature rises. Viscosity Index Improvers are added to reduce this thinning. They are a key addative in the production of multigrade oils.

 

VI Improvers are heat sensitive long chain, high molecular weight polymers that minimise the viscosity loss of the oil at high temperatures. They work like springs, coiled at low temperatures and uncoiling at high temperatures. This makes the molecules larger (at high temps) which increases internal resistance within the thinning oil. They in effect "fight back" against the viscosity loss in the oil.

 

"Shearing"

 

The long chain molecules in VI Improvers are prone to "shearing" with use which reduces their ability to prevent the oil from losing viscosity. This "shearing" occurs when shear stress ruptures the long chain molecules and converts them to shorter, lower weight molecules. The shorter, lower weight molecules offer less resistance to flow and their ability to maintain viscosity is reduced.

 

This shearing not only reduces the viscosity of the oil but can cause piston ring sticking (due to deposits), increased oil consumption and increased engine wear.

 

Like basestock quality, VI Improvers also vary in quality. As with many items the more you pay, the better the finished article and more expensive, usually synthetic oils are likely to incorporate better VI improvers. All other things being equal the less VI improver an oil contains, the better it will stay in grade by resisting viscosity loss.  

 

Which oils require more VI Improvers?

 

There are two scenarios where large amounts of these polymers are required as a rule.

 

Firstly in "wide viscosity span" multigrades. By this I mean that the difference between the lower "W" number and the higher number is large for example 5w-50 (diff 45) and 10w-60 (diff 50) are what is termed as "wide viscosity span" oils.

 

Narrow viscosity oils like 0w-30 (diff 30) or 5w-40 (diff 35) require far less VI Improvers and therefore are less prone to "shearing".

 

Secondly, mineral and hydrocracked (petroleum synthetic oils) require more VI Improvers than proper PAO/Ester (Group IV or V) synthetic oils as they have a higher inherent VI to begin with, this is due to differences in the molecular structure of the synthetic base oils compared to mineral oils.

 

It is a fact that many synthetics require significantly less VI Improver to work as a multigrade and are therefore less prone to viscosty loss by shearing.

 



Finally, I use a Fully Synthetic in my RX8 (Motul 8100 5w-30). It improves my fuel consumption by 10% and decreases my oil consumption by 40%. The car is more responsive and there are far less of those annoying deposits on my exhaust................because synthetic DO burn more cleanly leaving less deposits!

 

Hope this helps,

 

Regards

Simon Barnard

Partner

Opie Oils

[clive]

Very supprised that there are no questions relating to the above  :2Rolleyes

[Smifta]

I haven\'t sat down with a cocoa and read it all through yet!

[oilman]

It may be comprehensive enough, there are too many myths and old wives tales surrounding oil. Hopefully this explodes the myth rather than creates more confusion.

If there are any questions than I would be happy to address them or call me personally if that\'s what you prefer or PM me.

Cheers
Simon

[ro284]

Brilliant, got that, thankyou for taking the time to give us such a comprehensive detailed technical explanation. will be in touch shortly with my order,
Bob

[kev-yorks]

Simon is there a database or website we can access that lists all the uk oils giving there types and contents?
Kevin

[oilman]

Afraid not Kev although I have a lot of data of my own due to chemical testing of many companies oils.

Now you have the info, ask the oil company yourself if you wish but 90% will duck the question or give a wooly answer, testing is the only sure way to find out.

If you are asking, by all means try me first because I may have the data but make sure you ask which API Group basestocks are used and do not accept answers like our oils only contain synthetic basestocks as there are real ones and petroleum ones!

If I can be of help please ask.

Cheers
Simon

PS. Wish I had started this debate 12 months ago but no one here seemed interested in knowing about the subject.