Interesting Oil Facts Part # 1

oilman

Member
To kick off Opie Oils new 12 part series of interesting oil facts we thought that we would address the statement “My oil has turned to water!”

Let’s be objective and look at the actual figures involved here, emotional expressions such as ‘turned to water’ just will not do. Engineering is supposed to be a science afterall!

So! Almost all modern jet engines run on 5cst at 100degC synthetic ester oil. Needless to say, some bearings will actually be running at a temperature of perhaps 200degC; so the true oil viscosity in these situations is in fact 1.5cst.

This is really thin, much thinner than any car or bike engine oil even in a race engine.

But is it as thin as water? NO!

At 20degC water has a viscosity of 1.0cst and at 50degC it drops to 0.55cst.

Just for comparison, a 0w-20 oil will have an approximate viscosity of 107cst at 20degC, 32cst at 50degC, 8.9cst at 100degC and 2.3cst at 200degC.

So there you go, it may look like water but it certainly isn’t!

Cheers.
Guy & The Opieoils.co.uk Team

Note:
Centistokes (cst) is the measure of a fluid's resistance to flow (viscosity). It is calculated in terms of the time required for a standard quantity of fluid at a certain temperature to flow through a standard orifice. The higher the value, the more viscous the fluid.
 

jjs

Member
hi with regards to the note ie, the higher the number the more viscous the fluid, i thought the oil got thinner with the temperature going up, so more viscous, but in the note cst number gets lower ?
 

oilman

Member
Indeed, oil like all fluids thins with heat

For example a 10w-50 will have the following cst values at varying temps

0degC..........................1034
10degC,,,,,,,,,,,,,,,,,,,,,,,,..537
40degC,,,,,,,,,,,,,,,,,,,,,,,,..116
100degC,,,,,,,,,,,,,,,,,,,,,,....18

Cheers
 

Jon Olds

Well-Known Member
On a related subject, I know which make oil the best jets use, and having little oil knowledge I copy them by using Mobil 1 motorsport. Not knocked a bigend bearing out since. Thought i'd share that.

PS. Can you beat halfords prices for this oil?
 

youngsyp

Active Member
oilman said:
Indeed, oil like all fluids thins with heat

For example a 10w-50 will have the following cst values at varying temps

0degC..........................1034
10degC,,,,,,,,,,,,,,,,,,,,,,,,..537
40degC,,,,,,,,,,,,,,,,,,,,,,,,..116
100degC,,,,,,,,,,,,,,,,,,,,,,....18

Cheers
Out of interest, could you tell us what would a 5w40 oils viscosity be at the same temperature levels ?

And what would the minimum 'safe' viscosity level be, for a road cars engine ?

Paul
 

oilman

Member
for 5w-40

0degC..........................874
10degC........................440
40degC..........................91
100degC........................14


Cheers
 

youngsyp

Active Member
oilman said:
for 5w-40

0degC..........................874
10degC........................440
40degC..........................91
100degC........................14


Cheers
That's great.

What would you say the maximum engine temperature, the 5w40 could provide sufficient protection up to ?

Paul
 

youngsyp

Active Member
oilman said:
It depends totally on the quality

We have ones that can take 120degC

Cheers
How about the Silkolene Pro S ?

And whay would the viscosity be of that oil, at 120degC ?

Paul
 

steve963

Active Member
so what are the min and max temps for the silkolene 10 50 you sell for the R, where its giving good protection? 80-110?
 

youngsyp

Active Member
steve963 said:
so what are the min and max temps for the silkolene 10 50 you sell for the R, where its giving good protection? 80-110?
It would seem that the 5w40 would offer the same level of protection at those temperature levels but, be better for cold starts.

Paul
 

steve963

Active Member
hmmm, think I may change to thinner oil then, as I use my car more for short journeys and I always keep an eye on the oil temp
 
Top