Oil flow pressure?

[Camprunner]

I was not quite sure what term or topic to search on this one so....

Does oil flow inside an engine stay the same at say 2,000 rpm and say 7,000 rpm? Or does it go up with speed / rpm?

 

[Chris142]

Depends if the oil pressure relief valve is open or not

 

[FCD]

Shannow should be here soon with his scientifical papers and graphs explaining it

 

[bullwinkle]

Goes up, especially since the rod & main bearings have a tendency to pull more oil & spray a LOT more at high RPMs, plus hotter oil=thinner oil, easier to push through the galleries, etc.

 

[BrocLuno]

A lot depends on the condition of the engine... But, assuming a sound engine, the flow will increase as the journal bearings surface speed increases (rods, mains, cam, etc.). As said, they sling the leakage a lot more forcefully.

RPMs were the reason to go to pumped oil in the first place. Lots of older designs with lower speed motors did fine with dippers and splashers in the old days. But as the speed went up, these devices tended to "splash" the oil out of the crankcase and lower the level until they were starving themselves of supply. Pumped oil solved that problem. Tends to occur above 3,500 RPM ...

 

[Shannow]

Originally Posted By: Camprunner
I was not quite sure what term or topic to search on this one so....

Does oil flow inside an engine stay the same at say 2,000 rpm and say 7,000 rpm? Or does it go up with speed / rpm?


Originally Posted By: FordCapriDriver
Shannow should be here soon with his scientifical papers and graphs explaining it


LOLing at FCD...BUT...

More RPM is always more oil flow, but the reasons are different.

More RPM on a journal bearing means that it leaks more oil and draws more from the galleries...that's the mains.

Premise is shown here for rod bearings as well...more RPM is more flow.

Cams spin at half speed, so go into high shear later in the RPM range, so will have a step increase in flow depending on size a little later than the mains.

If squirters/sprays are fitted, then they will flow more based on the pump discharge pressure, so once the pump is on relief, they will be maxxed out and not changing with RPM.