Oil Recommendations here!
15 November 2004, 01:36 PM
#32
Originally Posted by Vegescoob
Oilman I'd hoped you'd answer my query ref competition oil in road cars.
It's a question of cost. Can you justify it or not?
They are perfectly fine for road cars and give higher levels of protection than normal oils because they are built of synthetics and have higher tolerances.
Oils like Silkolene PRO or Motul 300V are very popular (although expensive) for all types of cars. It's important to use the correct viscosity though as I've said on many occasions, stear clear of 0w-20's and 10w-60's and you'll be fine.
Cheers
Simon
15 November 2004, 04:34 PM
#33
Scooby Newbie
Join Date: Apr 2004
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
Simon,
With Redline Race Oils - In order to reduce the possibility of detonation , these race oils contain very few detergents and are therefore not recommended for road use.Your reply therefore confirms this is not case for Motul or Silkolene although suited for road or rally.
The other question on using an ester base oil for road use is their stability in the presence of water, and whether their ability to cling is actually better than the use of tackifiers?
The cST vis @ 40c for M1 0W40 is 80 compared to 125 for 15W50 would this not imply that there is better start up flow using a 0W rather than 10W or 15W?
Although against Castrol 10W 60 Motul offer 15W50 and 15W60 recommended for engines with power greater than original engines being pushed hard, very high temperature conditions and excellant for engines constantly on limit. At what point do you consider it necessary to change to a 50 or 60?
With Redline Race Oils - In order to reduce the possibility of detonation , these race oils contain very few detergents and are therefore not recommended for road use.Your reply therefore confirms this is not case for Motul or Silkolene although suited for road or rally.
The other question on using an ester base oil for road use is their stability in the presence of water, and whether their ability to cling is actually better than the use of tackifiers?
The cST vis @ 40c for M1 0W40 is 80 compared to 125 for 15W50 would this not imply that there is better start up flow using a 0W rather than 10W or 15W?
Although against Castrol 10W 60 Motul offer 15W50 and 15W60 recommended for engines with power greater than original engines being pushed hard, very high temperature conditions and excellant for engines constantly on limit. At what point do you consider it necessary to change to a 50 or 60?
15 November 2004, 07:27 PM
#34
Scooby Regular
Join Date: Feb 2001
Location: The Ghost Town. Drives RS6
Posts: 1,821
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by oilman
Hope this helps:
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 Viscosityand 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 oilsare 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.
Cheers
Simon
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 Viscosityand 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 oilsare 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.
Cheers
Simon
So is Castrol RS 10w60 any good for an Impreza engine with 250-260BHP, that has 100k and has had regular oil changes (more than recommended) all it's life (and a new short engine 50k ago, if that makes any difference)?
Thanks
16 November 2004, 03:27 PM
#36
Scooby Regular
Originally Posted by sulli
Phew.....cheers mate
So is Castrol RS 10w60 any good for an Impreza engine with 250-260BHP, that has 100k and has had regular oil changes (more than recommended) all it's life (and a new short engine 50k ago, if that makes any difference)?
Thanks
So is Castrol RS 10w60 any good for an Impreza engine with 250-260BHP, that has 100k and has had regular oil changes (more than recommended) all it's life (and a new short engine 50k ago, if that makes any difference)?
Thanks
What I don't quite get is how come 10w40 oil ranges from £18 for 4 litres to £30 for 4 litres.
16 November 2004, 03:32 PM
#37
Originally Posted by sulli
Phew.....cheers mate
So is Castrol RS 10w60 any good for an Impreza engine with 250-260BHP, that has 100k and has had regular oil changes (more than recommended) all it's life (and a new short engine 50k ago, if that makes any difference)?
Thanks
So is Castrol RS 10w60 any good for an Impreza engine with 250-260BHP, that has 100k and has had regular oil changes (more than recommended) all it's life (and a new short engine 50k ago, if that makes any difference)?
Thanks
Cheers
Simon
16 November 2004, 03:43 PM
#38
Originally Posted by JohnD
Ditto that Re- my post about Millers CFS & XFS
JohnD
JohnD
"It's really too thick and, even hot-running engines do not need SAE 60 oil these days. (by ‘hot’ I mean 120-130C). SAE 60 is heavier than most SAE 90 gear oils. If an oil is too thick, it de-aerates slowly, leading to cavitation in the oil pump, or the bearings being fed slugs of air along with the oil."
If you add this to the potential heat issues:
"A heavier visocosity oil will be more difficult to pump through the engine. More friction will be present than with a lighter viscosity oil. More friction means more heat. In other words, by going to a thicker oil you may actually be causing more heat build-up within the engine. You'll still be providing adequate protection from metal to metal contact in the engine by going with a high viscosity, but the higher viscosity will raise engine temperatures.
In the short run, this is no big deal. However, over the long term, when engine components are run at higher temperatures, they will wear out more quickly."
As many of you reading will have gathered I'm not in favour of thicker oils in modern engines, they are not recommended and not required. I am however in favour of lighter shear stable true synthetic oils as they have great benefits.
Cheers
Simon
16 November 2004, 03:46 PM
#39
Originally Posted by EddScott
So your oily bits have only done 50K then? Mine on 55K and I put 10w60 RS in it before but by the sounds of it 10w40 is better.
What I don't quite get is how come 10w40 oil ranges from £18 for 4 litres to £30 for 4 litres.
What I don't quite get is how come 10w40 oil ranges from £18 for 4 litres to £30 for 4 litres.
A word of caution – You get what you pay for!
Below is an article written by John Rowland, Silkolene/Fuchs Chief R & D Chemist for 40 years.
Quote:
Costs of synthetics vary considerably. The most expensive are the “Ester” types originally only used in jet engines. These cost 6 to 10 times more than high quality mineral oils.
The cheapest synthetics are not really synthetic at all, from a chemists point of view. These are in fact specially refined light viscosity mineral oils known as “hydrocracked”. These have some advantages over equivalent mineral oils, particularly in lower viscosity motor oils such as 5w-30 or other oils with a low “W” rating such as 5w-50 etc and they cost about 1.5 times more than good quality mineral fractions.
We use several different grades of this base oil, where appropriate. This is the “synthetic” which is always used in cheap oils that are labelled “synthetic”. Yes it’s a cruel world, you get what you pay for!
Now, you may ask, why are these special mineral oils called “synthetic”?
Well, it was all sorted in a legal battle that took place in the USA about ten years ago. Sound reasons (including evidence from a Nobel Prize winning chemist) were disregarded and the final ruling was that certain mineral bases that had undergone extra chemical treatments could be called “synthetic”.
Needless to say, the marketing executives wet their knickers with pure delight! They realised that this meant, and still does, that the critical buzz-word “synthetic” could be printed on a can of cheap oil provided that the contents included a few percent of “hydrocracked” mineral oil, at a cost of quite literally a few pence.
So, the chemistry of “synthetics” is complex and so is the politics!
The economics are very simple. If you like the look of a smart well-marketed can with “synthetic” printed on it, fair enough, it will not cost you a lot; and now you know why this is the case. But, if you drive a high performance car, and you intend to keep it for several years, and maybe do the odd “track day”, then you need a genuine Ester/PAO (Poly Alpha Olefin) synthetic oil.
This oil costs more money to buy, because it costs us a lot of money to make, very simply, you always get what you pay for!
Unquote:
Cheers
Simon
16 November 2004, 06:12 PM
#40
Scooby Regular
Join Date: Feb 2001
Location: The Ghost Town. Drives RS6
Posts: 1,821
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by oilman
TBH I would have said that 5w-40 or 10w-40 fully synthetic would be more suitable.
Cheers
Simon
Cheers
Simon
Following this, what would you reccomend as a good quality oil to go in my car every 3-4k?
Oh, and thanks
Last edited by sulli; 16 November 2004 at 06:18 PM.
16 November 2004, 06:24 PM
#41
Originally Posted by sulli
Well I have another 5 litres left of the RS 10w60, and it's due a change in the next few weeks, so i'll use that.
Following this, what would you reccomend as a good quality oil to go in my car every 3-4k?
Oh, and thanks
Following this, what would you reccomend as a good quality oil to go in my car every 3-4k?
Oh, and thanks
Cheers
Simon
17 November 2004, 10:17 AM
#45
Originally Posted by knap
The other question on using an ester base oil for road use is their stability in the presence of water, and whether their ability to cling is actually better than the use of tackifiers?
The types of esters (there are a lot of different types!) used in automotive lubricants are stable in the presence of water, even at high temps.
Tackifiers don’t ‘cling’ in the same way as esters. They are not polar, so there is little electrostatic adhesion. These very long chain polymers cling by physical effects; they form a sort of gel structure in an oil. They are very prone to shear effects, and the ‘tacky’ effect falls off rapidly at higher temperatures. (80C+.) Only really effective in low temperature total loss applications.
Originally Posted by knap
The cST vis @ 40c for M1 0W40 is 80 compared to 125 for 15W50 would this not imply that there is better start up flow using a 0W rather than 10W or 15W?
Absolutely correct as a thinner base oil is used.
Originally Posted by knap
Although against Castrol 10W 60 Motul offer 15W50 and 15W60 recommended for engines with power greater than original engines being pushed hard, very high temperature conditions and excellant for engines constantly on limit. At what point do you consider it necessary to change to a 50 or 60?
Motul offer a 15w-50 and a 20w-60 to be precise. Only in exeptional cases really where temperatures are a problem. A shear stable ester based 5w-40 is more than capable up to 130 degC so in extremes is the answer but even then an sae 50 will be fine instead of an sae 40.
Broadly speaking, modern race engines can maintain oil pressure (which ensures hydrodynamic bearing lubrication) at an oil viscosity between 5 and 15 cSt. So, at 100C, this means from less than 20 SAE to 40SAE. With modern high-speed oil pumps, exceeding these limits by using, for example, an SAE xW/60 oil with a viscosity of 24cSt can lead to cavitation and a slower rate of oil flow.
Hope this helps
Cheers
Simon
17 November 2004, 01:03 PM
#46
Scooby Newbie
Join Date: Apr 2004
Posts: 29
Likes: 0
Received 0 Likes
on
0 Posts
Simon,
Not looking at performance issue just whether for start up and say long term winter storage which type of oil provides best protection.
If looking for a vis at 100deg between 5cST and 15cST then 0W at 40c of 80 for M1 would provide fastest flow without loss of any protection, for a road car why recommend a 10W or 15w?
At 13Oc what are the vis of various options say Silkolene M1 15W50 and Castrol 10W60 or Motul 15W60.
With the Castrol 10W60 which maybe not a true synth although likely to contain esters, how quickly would this shear anyway to a lower weight.
Not looking at performance issue just whether for start up and say long term winter storage which type of oil provides best protection.
If looking for a vis at 100deg between 5cST and 15cST then 0W at 40c of 80 for M1 would provide fastest flow without loss of any protection, for a road car why recommend a 10W or 15w?
At 13Oc what are the vis of various options say Silkolene M1 15W50 and Castrol 10W60 or Motul 15W60.
With the Castrol 10W60 which maybe not a true synth although likely to contain esters, how quickly would this shear anyway to a lower weight.
17 November 2004, 01:13 PM
#47
My preference would be a 10W40 oil for a moderately tuned impreza. Although I use 15W/50 Motul, I always allow a few minutes for the engine to warm up before even moving, and I monitor oil temperature and will not drive with any boost until oil is at least 60ºC and then not full throttle until 80ºC.
The thinner oil also warmed up more quickly, as the lower viscosity will allow for better heat transfer.
Paul
The thinner oil also warmed up more quickly, as the lower viscosity will allow for better heat transfer.
Paul
18 November 2004, 01:54 PM
#52
Scooby Regular
Join Date: Mar 2002
Location: Berkshire
Posts: 33
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by oilman
Impreza 2.0i Sport 1996-00
Motul 5w-40 or 10w-40
Silkolene 5w-40 or 10w-40
OATS 10w-40
etc etc
Cheers
Simon
Motul 5w-40 or 10w-40
Silkolene 5w-40 or 10w-40
OATS 10w-40
etc etc
Cheers
Simon
...so thats just a typo then?
19 November 2004, 10:16 AM
#57
A good 5w-40 will be OK for trackdays (Silkolene/Motul) as it will handle much higher temperatures than a petroleum based oil. The main reason for moving to a 10w-50 for track days would be higher temperatures.
If temperatures are not an issue then stick with 5w-40 as this will give better BHP, power delivery, fuel economy etc due to less oil drag.
Cheers
Simon
If temperatures are not an issue then stick with 5w-40 as this will give better BHP, power delivery, fuel economy etc due to less oil drag.
Cheers
Simon
19 November 2004, 10:34 AM
#58
Scooby Regular
Join Date: Oct 2004
Posts: 4,249
Likes: 0
Received 0 Likes
on
0 Posts
Bit off thread so apology first. Oilman I really appreciate your prompt replies to all the oil enquiries but am interested in how many other car/bike?boat boards you post on? Or is it just us Scooby owners who exhibit this oil fetish?
I hope all your efforts reap rewards too.
I hope all your efforts reap rewards too.
19 November 2004, 11:25 AM
#59
Scoobynet is a bit of an odd one really as it's not a Club as such, merely a Forum.
Most of our dealings are via owners and enthusiasts clubs and we use their forums with the Club's permission to give advice to members. There are over 100 Clubs that we deal with in this way.
I'm afraid that oil fetish's are not confined to "scooby" owners, it seems to be one of the hottest topics in all clubs from classic and vintage onwards!
Rewards vary I'm afraid but at least we assist in dispelling some of the myths and misinformation that abounds which more importantly helps owners to make informed choices rather than misinformed ones.
Cheers
Simon
Most of our dealings are via owners and enthusiasts clubs and we use their forums with the Club's permission to give advice to members. There are over 100 Clubs that we deal with in this way.
I'm afraid that oil fetish's are not confined to "scooby" owners, it seems to be one of the hottest topics in all clubs from classic and vintage onwards!
Rewards vary I'm afraid but at least we assist in dispelling some of the myths and misinformation that abounds which more importantly helps owners to make informed choices rather than misinformed ones.
Cheers
Simon
19 November 2004, 12:06 PM
#60
Scooby Regular
Well I ordered oil yesterday lunctime from Opie Oils and it turned up about an hour ago
Many thanks to Simon for his advice and info. I went for Motul 10W40 and really like the shiny can it comes in (eh?)
Many thanks to Simon for his advice and info. I went for Motul 10W40 and really like the shiny can it comes in (eh?)