Thread: OILS 101- THE ANSWERS

Thanks, but its got some errors and self contraditcions in it, in some areas it covers the opening principles but doesnt go into the depth required.

ITs mostly right but I'd treat that pretty much as a glorified wiki entry..

little things

This is OK as long as we have a minimum of pressure to move the oil.

Most believe that pressure = lubrication. This is false. Flow = lubrication.

flow is what moves the oil, pressure is the resistance to that flow... the resistance to the flow should be the clearances in the bearings. which is where you need to get the pressure from

later on when dealing with oil temp increase and the fall off of pressure he lists that as acceptable because youve got more flow to provide the lubrication.

In reality if the oil thins out when its hot the pump pressure relief valve will close up to allow a better flow to the bearings keeping the pressure constant. If the oil pressure is dropping when the engines at running temp and speed then the oil is too thin ( or the pump does not displace enough oil) to provide protection for the application but more importantly you probably already have excessive clearances (or the wrong pump setup) and I dont care how well you understand oil, the issues are a bigger problem.


the bulk of the work explaining what the oils doing and whats happening to it is about right but the working application is where it gets a touch one leggy.

The explanations of the various standards is very well presented but remember the last question on his exam...

20- I am (single best answer):
A- Surgeon
B- Biochemist
C- ‘Halfass mechanic
D- Absurdly interested in motor oils
E- All of the above
The correct answer is E- All of the above

Yeah, I did pick that. It's only looked at from a petrol based perspective also.
With a diesel in mind, there are a number of other factors that are missing such as oil jets. Start losing too much pressure and the jets can start to lose distance and fail to cool the underside of the crown effectively.
Detergent rating differences were also missed and relative differences between air and liquid cooled engines and fundamental differences of oil between the two.

However it does dispell the myths a lot of people have had about oil for years.

Using Capitals, the difference between helping your Uncle Jack off a horse or helping your uncle jack off a horse...

Originally Posted by LOVEMYRANGIE

Yeah, I did pick that. It's only looked at from a petrol based perspective also.
With a diesel in mind, there are a number of other factors that are missing such as oil jets. Start losing too much pressure and the jets can start to lose distance and fail to cool the underside of the crown effectively.
Detergent rating differences were also missed and relative differences between air and liquid cooled engines and fundamental differences of oil between the two.

However it does dispell the myths a lot of people have had about oil for years.

Using Capitals, the difference between helping your Uncle Jack off a horse or helping your uncle jack off a horse...

turbo petrols can have oil squirters in them... and at the level hes looking at it, whats going on above the crown is largely irrelevant.


That said, If i was only allowed to point someone at one URL to explain oils (and nothing to do with the mechanicals) I could do a lot worse than send them there.