Jump to content
iaw4

Low Oil and Instruments?

Recommended Posts

 

hi roger----I believe you that oil does not evaporate.  If it does not show under the airplane, it's likely mostly still in the engine.  :-).

will a functioning dynon d120  (oil pressure or temperature) give me good hints/advice when I need to pour more oil into the engine?

 

Share this post


Link to post
Share on other sites

Burping the engine and visually checking the oil in the tank is the only way to know. Most don't need oil between changes.

Share this post


Link to post
Share on other sites

IAW,

I agree with Tom.

Oil pressure is not a good indicator of oil quantity. It's a binary indicator. If there's any oil at the pickup then you'll see full pressure the oil pump outlet. If there's not oil at the pickup, then the oil pressure will be zero. In which case, you'll need to shut the engine down quickly to prevent it from seizing.

There might be some period of time when the pump would be dry and the gauge reading zero until another few drops of oil blow out of the engine, thorough the reservoir and into the pump, at which time the pump would again read full pressure momentarily, before dropping back to zero. So you might say that a indicator bouncing between full pressure and zero pressure is possibly an indication of low oil level. But it's still too late to save the engine.

Oil temperature would be no more useful in measuring oil quantity. There are at least four major paths for heat to flow out of our engines. The biggest is surely out the exhaust. Second is probably the heat lost to forced convection in the engine compartment. The third is probably the heat carried from the water at the radiator and the fourth is probably the heat carried from the oil at the oil cooler. All the paths are interrelated in that all provide some degree of oil cooling.

Among the heat lost to forced convection in the engine compartment is the heat from the oil reservoir, and it is a function of the amount of oil in the reservoir. However, this heat flow is a small percent of the total. And there are so many variables: outside air temperature, pressure altitude, air speed, angle of attack, throttle setting, mixture, combustion efficiency, timing, etc. It would be very difficult to detect the difference in oil temperature due to reduced oil quantity. At least up to the point where the oil is no longer moving, at which point, again, it's too late anyway.

Mike Koerner

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...

×
×
  • Create New...