Oil - A slippery topic!

[andrewrx7]

Hey! There\'s never too much detail!!

Thanks for the comprehensive reply, though!


Do you have any opinion on non-named brands, such as Halfords, for example? I guess most people have shopped in places like this, and used their products. They obviously do not make their oil themselves, but buy it off of someone.....is there anyway to tell the quality of it?

[BlitzBoy]

Hey OILMAN I have a question, what are your views on using "Castrol R" on a high HP Rotary engine?
Do you know of its qualities as I have no clue but heard its quite good, and apparently it gives off a unique smell when the car is running, is this a myth?

[oilman]

Originally posted by andrewrx7
Hey! There\'s never too much detail!!

Thanks for the comprehensive reply, though!


Do you have any opinion on non-named brands, such as Halfords, for example? I guess most people have shopped in places like this, and used their products. They obviously do not make their oil themselves, but buy it off of someone.....is there anyway to tell the quality of it?

I really don\'t like commenting on things like this as my views are normally biased towards quality oils.

How does made to a budget sound;)

Or if that\'s not clear enough

CHEAP:rolleyes:

If it\'s any consolation my knowledge of the industry is extensive and I wouldn\'t use them in my cars.

Cheers
Simon

[wiggy]

hows about Motul 4100? would you comment on this

I think I\'ll be buying some this weekend so an experts view would be first class m8

Cheers

[BlitzBoy]

So Oilman are you able to answer the question on "Castrol R" then?

[oilman]

Originally posted by BlitzBoy
Hey OILMAN I have a question, what are your views on using "Castrol R" on a high HP Rotary engine?
Do you know of its qualities as I have no clue but heard its quite good, and apparently it gives off a unique smell when the car is running, is this a myth?

I presume you mean the Castor based oils?

Yes they do have a nice smell!

However, they are all monogrades and will not suit the rotary.

Cheers
Simon

PS. The next post is usually someone who says they use them and they\'re fine:confused:

[BlitzBoy]

ahhh damn I would have loved to have used that oil if it did smell nice.

So what is a monograde?? sorry for the ignorance

[oilman]

Originally posted by wiggy
hows about Motul 4100? would you comment on this

I think I\'ll be buying some this weekend so an experts view would be first class m8

Cheers

We like Motul and Silkolene here as they are brands that we sell and are top oils.

4100 is fine but the best (although not necessarily for the Rotary depending on who you listen to) are the Motul 300V oils, these like the Silkolene PRO Oils are truly 1st division!

Cheers
Simon

[oilman]

Originally posted by BlitzBoy
ahhh damn I would have loved to have used that oil if it did smell nice.

So what is a monograde?? sorry for the ignorance

OH NO, I feel a long post coming on now!

Monogrades are single viscosity oils meaning that unlike a multigrade that operates at two viscosities, one when cold labelled "W" and one when hot (i.e. 10w-40 is 10w cold and 40 when hot) monogrades which are usually sae 30, 40 or 50 remain as this viscosity when cold or hot.

Have a read of this, it will explain:

What is this thing called viscosity?

It’s written on every can of oil and it’s the most important visible characteristic of an oil.

The viscosity of an oil tells you how it reacts in certain circumstances and how it performs as a lubricant.

When a oil is subjected to external forces, it resists flow due to internal molecular friction and viscosity is the measure of that internal friction. Viscosity is also commonly referred  to as the measurement of the oils resistance to flow.

There are two methods of viewing an oils resistance to flow. Firstly there is Kinematic Viscosity which is expressed as units indicating the flow of volume over a period of time and this is measured in centistokes (cSt).

An oils viscosity can also be viewed by measured resistance. This is known as Apparent Viscosity and it is measured in centipoises (cP).

However in the real world an oils viscosity is also referred to in such terms as thin, light and low etc. This suggests that the oil flows or circulates more easily. Conversly, terms such as heavy and high etc suggest the fluid has a stronger resistance to flow.

The reason for viscosity being so important is because it is directly related to the oils load-carrying ability - The greater an oils viscosity, the greater the loads that it can withstand.  (It must be added when new not over a period of time as all oils “shear down” with use)

An oil must be capable of separating the moving parts in your engine at the operating temperature. On the basis that an oils viscosity is related to its load carrying ability, you could be fooled into thinking that “thicker” oils are better at lubricating but, you’d be wrong in this assumption.

The fact is that in the wrong application a high viscosity oil can be just as damaging as using a low viscosity oil.

The use of an oil that’s too “thin” can cause metal-to-metal contact, poor sealing and increased oil consumption and conversely, an oil that’s too “thick” can cause increased
friction, reduced energy efficiency, higher operating temperatures, and poor cold starts in cold temperatures.

It is very important that you select the correct oil, not too “light” or too “heavy” and your Owners Handbook is a very good place to start as it lists the temperatures and options.

Oils thicken at low temperatures and thin as the temperature increases. The actual rate of change is indicated by their viscosity index (this number normally listed on the oils technical data sheet indicates the degree of change in viscosity of an oil within a temperature range, currently 40-100 degrees centigrade)

An oil with a high viscosity index, will normally behave similarly at these two temperatures but an oil with a low viscosity index will behave quite differently. It will become very fluid, thin and pour easily at high temperatures. A higher index is better!

Multi-grade oils are designed to perform at high and low temperatures by adding polymers to a base oil (5w,10w, 15w etc) which are heat sensitive and “uncoil” to maintain the higher viscosity sae 30,40,50 etc. This means that the oil can be used “all year round” rather than using different oils for summer and winter.
 
It is important to understand that the selection of the correct oil for your car is not just guesswork, you must consider the temperatures at which you need the oil to operate a 0w, 5w oil is better for cold starts as the oil circulates more easily when it’s cold and is able to flow around the engine more easily and quickly, offering protection at the critical moments following cold engine start-up. These oils are also known to give better fuel economy and engine performance.

Finally, all oils “shear” or thin down with use and this means that an oil that started life as a 10w-40 will with use become a 10w-20. The period of time this takes depends on the type and quality of the oil. The most “shear stable” oils are proper Synthetics, either PAO (Poly Alph Olefins) or Esters which have very high thermal stability.

They are in general of the more expensive variety but last longer and give the best levels of protection.

Don\'t say I didn\'t warn you! All clear now?

Cheers
Simon

[wiggy]

I did originally plan to use Motul 300V but was put off by yout first post about esters etc being bad and possibly causing seal shrinkage :rolleyes:

Ahh well 300V it is then, what harm can in do in 3000 miles anyway, I always was one for trying things

ATF in the gearbox this weekend too

[andrewrx7]

After your discussions above, would you be brave enough to list your, say, top 5-10 brands/specs that you\'d recommend for use in a rotary ?!;)

[oilman]

wiggy,

This is my opinion and my opinion only. I think 300V will be fine as it\'s a double ester and pao formulation. (Remember esters swell seals and pao\'s shrink them)

Even though we deal with Motul, I can\'t find out the percentages of each as oil companies treat their formulations with great secrecy, however as long as it\'s not 100% pao (which it\'s not) then they should counteract each other with regards to seals.

The Vicosities of 300V are 0w-20, 5w-30, 5w-40, 10w-40, 15w-50 and 15w-60. I would recommend 300V Chrono 10w-40.

I noticed you are a founder of GT4OC, have you read my posts on synthetics over there?

Cheers
Simon

[wiggy]

Hi Simon

Its been a while since I\'ve been active on the GT4OC forum, I just stayed in touch with friends from there via e-mail, messenger etc.

I have had many a debate on there though about oils etc it just seems simpler on a std 4 stroke engine to rotaries :confused:

Did you ever read the barnies I had with people over ATF in the gearbox.....was funny after about 50 posts....not

I am going to do the same with the Rex though as it made a big difference on the GT4 in terms of losses through the gearbox. and the gear change seemed to improve.

Loads of car manufacturers now recommend ATF in manual boxes and its a better oil anyway by all accounts??

Know anything about this to shed some light on the matter??

[oilman]

Originally posted by andrewrx7
After your discussions above, would you be brave enough to list your, say, top 5-10 brands/specs that you\'d recommend for use in a rotary ?!;)

Hell, that\'s one difficult question! Please don\'t let me get on my soapbox otherwise you\'ll never hear the last of me:o

Viscosity would be 10w-40 or 10w-50.

Brands in no particular order and based on quality alone would be

Silkolene
Motul
Fuchs
Castrol
Royal Purple
Amsoil

U.S. Oils sold in this country are too dear IMO and top European oils more than match for them so I recommend them as being better value for money as well.

Tin hat on and ready for a flaming, I\'ll get me coat:D

Cheers
Simon

[oilman]

Originally posted by wiggy

I am going to do the same with the Rex though as it made a big difference on the GT4 in terms of losses through the gearbox. and the gear change seemed to improve.

Loads of car manufacturers now recommend ATF in manual boxes and its a better oil anyway by all accounts??

Know anything about this to shed some light on the matter??

I\'ll agree to disagree with you on this one. I would use an ester based fully synthetic 75w-90 in your box and diff. A good competition GL4/GL5 gear oil will outperform the ATF any day as it will be surface-active. On a decent one it will be GL4 but will have the superior GL5 load carrying capability.

There are two that spring to mind.

Silkolene SYN 5 75w-90
Motul Synthetic Gear 300 75w-90

Bear in mind these are competition oils so they\'re not cheap!

Cheers
Simon