Oil. Is it magic? - Page 5 - Renault Forums :: Independent Renault forum

LinkBack Thread Tools Display Modes
post #21 of 25 (permalink) Old 8th March 2007
Diamond member
espaced?'s Avatar
Join Date: Aug 2006
Posts: 499
Nominated 0 Times in 0 Posts
TOTW/F/M Award(s): 0
Thanks: 0
Thanked 0 Times in 0 Posts
Originally Posted by selwonk View Post
I second that. If you would be willing to knock up some notes, I'd be very pleased to turn it into a proper article in the FAQ!
you need to check the oil can if it says for e.g 'sf or cf'

the 'sf' means spark ignition 'f' grade the higher the order of the letter means a better grade oil eg. 'sh' is better than sf.

Diesel oil says 'cf' which means 'compression ignition' and the same applies about the letter eg 'ch' is better than 'cf'.
Currently in espaced?'s garage:
2001 espace 2.2 DCI VF8JEOK
espaced? is offline  
Sponsored Links
post #22 of 25 (permalink) Old 8th March 2007
Junior Member
Join Date: Dec 2005
Posts: 28
Nominated 0 Times in 0 Posts
TOTW/F/M Award(s): 0
Thanks: 0
Thanked 0 Times in 0 Posts
Part 1
Starting with a bit of a history lesson because it is needed to grasp the way oil is described and graded:
All engines require some form of lubrication, once it was by grease, then followed oil or grease that was manually pumped into the bearings as you went along, perhaps a couple of pumps on the old plunger every 1/2 miles or so until finally a mechanical oil pump was installed. This leap forward required a sump to keep the oil , pipe work to pick it up and pipe work to take it from the pump to the bearings. The manufacturer could get all his sums right but it relied on the oil to complete the equation; oil had to be graded so that its thickness could be specified. In simplistic terms early oil was graded by the time it took to flow a fixed amount through a hole of a given size. It was realised that temperature affected the oils ***8216;flowability***8217; (viscosity) so the measuring was carried out at 0degs and 100degs (not strictly true but you get the idea) So one oil of say 30 grade would flow at a certain rate when cold and at a certain , but much higher rate when hot . As manufacturers knew that a certain rate of flow was needed and that the grade of oil necessary to achieve this was different in winter to in summer you arrived at the situation when a car would require a different oil in the winter to the summer. In winter you might struggle to start the car as the oil of even a lighter grade was so thick when cold. Cars usually had a hand crank to turn them over as a final resort.
It was discovered that if you got a very light oil you could put in an additive called a viscosity improver (VI) which would stop the oil from thinning out so much as it got hot (most people think this is the other way around) This led to Multi grade oils that could even be left in all year around assuming that you didn't do much mileage as the oils could do with changing every 3,000 miles or so. This new multi grade oil required some rethinking in the way the oil was labelled as it certainly didn't fit in with the old classification system. This was done by giving the oil 2 numbers, the 1st followed by a 'w' which for ease should be considered to represent 'Winter' or the oils viscosity when cold (0 degs). The second number was the oils viscosity when hot (100 degs). This improvement in oil was limited by the fragility of the early VI's which would break down and leave you with the original thin oil incapable of maintaining its viscosity without the VI's when hot. The old ' oil like water' syndrome we all have seen. Over years these multi grade mineral oils improved tremendously, proper additive packages where introduced in an effort to counter rust, acids and the general by products of combustion, VI's became stronger but still the rule was that if the difference between the 1st number and 2nd was greater the strain on the VI' was more and the oil would be more likely to break down under strain, not so good. The performance of cars and their engines continued to improve, but the mineral based oils where reaching the limit of their development, Castor oils where used in high performance applications but still the lubrication was holding back engine development. High powered cars needed ever thicker oils to survive the strain of the pressure put upon them with regular changes to avoid the catastrophic effects oil degradation would have. It must be remembered here that Mineral oil is far from pure. In the oil will be components that even counteract the lubrication properties of the majority of the oil . A better way ahead was needed.
In 1972 Amsoil became the first synthetic motor oil in the world to meet American Petroleum Institute service requirements, But that as they say is another story.
Currently in amsoil's garage:

Last edited by amsoil; 8th March 2007 at 07:42 PM.
amsoil is offline  
post #23 of 25 (permalink) Old 8th March 2007
Veteran Member
Technical Supremo
Lagdti's Avatar
Join Date: Dec 2005
Posts: 40,429
Nominated 2 Times in 20 Posts
Nominated TOTW/F/M Award(s): 18
Thanks: 149
Thanked 1,103 Times in 942 Posts
This is great stuff,Amsoil!.I eagerly await the next installment.

I'd rather push my Alfa than drive a BMW....
Currently in Lagdti's garage:
2004 Saab 9-5 HOT Aero and a 2001 Audi A3 1.8 Turbo
Lagdti is offline  
post #24 of 25 (permalink) Old 21st March 2007
pyrogenius's Avatar
Join Date: Feb 2007
Posts: 85
Nominated 0 Times in 0 Posts
TOTW/F/M Award(s): 0
Thanks: 2
Thanked 3 Times in 3 Posts
is part two forthcoming?

I see a book and maybe film rights in this. We need a romantic lead to play the oil scientist who makes the synthetic break through and then his love interest.

Le- oil -nardo di Caprio for the main role?
Currently in pyrogenius's garage:
61 Grand Scenic 1.5
pyrogenius is offline  
post #25 of 25 (permalink) Old 21st March 2007
Technical Supremo

Join Date: Feb 2007
Posts: 42,940
Nominated 16 Times in 67 Posts
Nominated TOTW/F/M Award(s): 28
Thanks: 372
Thanked 5,201 Times in 4,712 Posts
Oil be loving you

You can talk about the properties of oil for ever - but I've never seen one yet that cleans itself or gets rid of its contaminants. Even the best filters won't remove any of the unwanted chemicals. In my opinion the only way to get the crud out of your engine is to change it. Overall I think its best to buy reasonable quality oil and change it often and don't put any so-called magic formula additives.
Oh Dear I feel a song coming on "Oil be loving you for ever"
Currently in madnoel10's garage:
Honda Civic 1.4l
madnoel10 is offline  

magic , oil

Quick Reply

Register Now

In order to be able to post messages on the Renault Forums :: Independent Renault forum forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Please enter a password for your user account. Note that passwords are case-sensitive.


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:


Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

For the best viewing experience please update your browser to Google Chrome