Oil Sight Glass?

[ossagp]

The oil's molecular structure is expanding due to heat, but since an engine doesn't get anywhere near the boiling point of oil, IMHO, the rise in volume will be extremely minimal.

I think the 'Viscosity Improvers' and 'pour point depressant' additives in multi-viscosity oil are changing the Viscosity of the oil and manipulating how the oil moves through the engine, giving different readings (on a dipstick or sight glass) as the temperature changes. Examples: Surface tension making the oil 'climb' the walls.

EDIT: Another thing I thought of as the engine heats up it expands as well. Could this possible cause the oil level to rise as the volume of storage decreases?
-BIG DAN

LOL so the volume of a pan gets smaller as the pan heats up? I know you are including the other components as well. I can believe you can see it change. I am still considering the tt that rez menioned and the hondas I am familiar with more frequently and how they maintain and oil level in coolers and and frame reservoirs and how it changes from sitting overnight to just run. It isnt heat affected enough to change the visible levels and certainly not on the 10 to 15% levels to make a sight glass on a system that is less than a quart and a half go up or down a quarter of the sight glass window.

 

[SRAD97750]

LOL so the volume of a pan gets smaller as the pan heats up? I know you are including the other components as well.

I figure, if we are counting the molecular structure of the oil, we can't leave it's container out of the equation!-BIG DAN

 

[ossagp]

Don't you think the volume of the space in the case expands with the case though?

 

[SRAD97750]

Don't you think the volume of the space in the case expands with the case though?

In terms of cases, I would imagine the aluminum expands in all directions equally.
Example, the sidewalls get 'fatter' from their centerline. Minuscule as it is, wouldn't the inner volume decrease as well?
This is certainly a concept I have never explored/discussed before. -BIG DAN

 

[ossagp]

seems like everything would grow. whether it all grows in equal proportions is the question. I never thought of it in this context before either. if the case walls grow every which way, as a tank does when heated then the question would be if the oil and the components extending into the oil grew more. I am still convinced that I/we are over looking something structural in how the oil is held in this case. In most case fill rigs (which is how I recall the rfs) the oil is held in the lower end, unlike the ones with a dry or semi dry sump that read higher after it has had a chance to bleed back down from the reservoir (back bones of frames are popular for this). In the case of some of my air cooled hondas you would look to see you had oil to start it, run it a few minutes, shutoff and check the level. It was always lower after the startup and recheck. As the one way valve that keeps the oil up in the reservoir aged it kept less and less up there. KTM just has a different variation on that and therefore gives the advice that they do.