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Oil pressure vs temp chart?

Kooshball

Well Known Member
The Lycoming manual for my AEIO 360 only lists maxim, minimum and target values for oil temp and pressure. Under the pressure relief adjustment section it only says ?warm up engine, run at 2000rpm and if the pressure is out of limits make an adjustment?. It does not define how warm the oil should be (should I use 185F?).

I am trying to establish the impact of oil temp on the pressure. For example if the oil temp is 206F, would it be ?normal? and acceptable to see a pressure of ~58psi at ~2350 rpm at that temp?

Thx
 
I don't have a chart like that, but my experience is that once the oil is over 150*, temps changes have a relatively small impact on viscosity / oil pressure. the 58* at 2300 is telling you that you have wear somewhere in the engine that is keeping the pressure low. I can't imagine it will be much higher at 180 vs 205*

Would be best to confirm that the relief is not the issue, as that is the easiest potential fix if it is the problem. I would set the pressure with the oil temp at 180.

Larry
 
pressure

58# is not an acceptable cruise power oil pressure. This subject was discussed extensively just a few weeks ago.
 
58# is not an acceptable cruise power oil pressure. This subject was discussed extensively just a few weeks ago.

I am guessing that you're referring to the thread: ECI-360 oil pressure problem solved

In fairness, I think it's safe to say that 58 psi is not a normal oil pressure for cruise flight, but it may be a stretch to say that it not an acceptable oil pressure. I believe the manual for the engine would tell you that the minimum oil pressure for the motor is 50 - 55 psi, depending on the specific motor we are talking about.
 
Pressure

The AE oil system is not an all attitude system and will loose oil pressure in certain attitudes. By setting the oil pressure high green the duration of the loss will be slightly less and the recovery quicker. Higher oil pressure also improves valve lubrication and reduces valve sticking.
 
I have made a typo...the engine in question is AIO-360 which gives 55psi as the lower limit. When the oil is 180-185F the pressure is showing ~75-80psi. Runs that way in cool air. Now that we have had a few warm days the oil temp is up at 200-206F and the pressure 58psi, still in limits but is that a normal drop due to temp? If so I should be working on baffling and oil cooler efficiency improvements.

Thx

From the LYCOMING OPERATOR?S MANUAL - AEIO-320, AEIO-360, AEIO-540 Series Engines, Page 4-10, Minimum Normal Operating Oil Pressure is 60 PSI:

i-97VSCTj-M.jpg


I wouldn't be happy with only 58 PSI in cruise.
 
high oil pressure

I have a high oil pressure situation in my RV7A/Aerosport 0-360 engine. Last long flight I made, the oil pressure as measured by the Dynon EMS-D10 (all original sensors - 14 years old) was in the red zone - at 100 psi. I landed enroute and talked to an A&P at an aircraft engine shop, before adding some oil and returning to home airport. I flew at a lower rpm than usual and oil pressure was then in yellow zone (90-95 psi).

I changed the oil/filter and switched to a slightly lower viscosity oil (15W-50 from 20W-50) and adjusted the oil pressure relief valve counter-clockwise two turns. After doing this the oil pressure is at the very high end of green in cruise, 88-90 psi, which after making these adjustments still gives me cause for concern. I have not changed out the oil pressure sensor but that was going to be my next step, if I need to take it.

Appreciate any advice. Thank you.
 
I have a high oil pressure situation in my RV7A/Aerosport 0-360 engine. Last long flight I made, the oil pressure as measured by the Dynon EMS-D10 (all original sensors - 14 years old) was in the red zone - at 100 psi. I landed enroute and talked to an A&P at an aircraft engine shop, before adding some oil and returning to home airport. I flew at a lower rpm than usual and oil pressure was then in yellow zone (90-95 psi).

I changed the oil/filter and switched to a slightly lower viscosity oil (15W-50 from 20W-50) and adjusted the oil pressure relief valve counter-clockwise two turns. After doing this the oil pressure is at the very high end of green in cruise, 88-90 psi, which after making these adjustments still gives me cause for concern. I have not changed out the oil pressure sensor but that was going to be my next step, if I need to take it.

Appreciate any advice. Thank you.

A sudden onset of high oil pressure should always be presumed to be the sensor for diagnostic purposes. They routinely fail (usually high) and the adjustable pressure relief system rarely drifts and even more rare to drift to the high side. It is wise to verify the oil pressure reading BEFORE adjusting your pressure relief.

Larry
 
Last edited:
high oil pressure

Thank you for your reply: "A sudden onset of high oil pressure should always be presumed to be the sensor for diagnostic purposes. They routinely fail (usually high) and the adjustable pressure relief system rarely drifts and even more rare to drift to the high side. It is wise to verify the oil pressure BEFORE adjusting your pressure relief."

What is the easiest way to verify the oil pressure independent of the existing system (Dynon EMS-D10)? If with a mechanical oil pressure gauge, where would this be inserted and where can one be procured?

Thanks

Andreas68
RV7A - 0-360 AeroSport
 
Thank you for your reply: "A sudden onset of high oil pressure should always be presumed to be the sensor for diagnostic purposes. They routinely fail (usually high) and the adjustable pressure relief system rarely drifts and even more rare to drift to the high side. It is wise to verify the oil pressure BEFORE adjusting your pressure relief."

What is the easiest way to verify the oil pressure independent of the existing system (Dynon EMS-D10)? If with a mechanical oil pressure gauge, where would this be inserted and where can one be procured?

Thanks

Andreas68
RV7A - 0-360 AeroSport

Easy method is to replace sender and see if pressure returns to previous normal. You can remove the 1/8" NPT sender and replace with a mechanicl PSI guage for confirmation. Can also install a tee to allow both mechanical gauge and sender to capture info. You can buy a cheap air pressure gauge (usually 1/8" NPT) for this test. Would not recommend using it for air after the test.

Larry
 
Oil pressure is the only engine gauge that I have a backup for.... Van's original and MGL. Two separate systems.

I will only go into panic mode if both gauges read low or high.
 
Consider having a permanently installed second mechanical oil pressure gauge. If you have a digital engine monitor, you should have room in the panel. I use my mechanical gauge
/sender to watch oil pressure on startup before the EFIS/engine monitor has booted up, to quickly identify an intermittent sender, or to confirm a true loss of oil pressure situation.

Bevan


Thank you for your reply: "A sudden onset of high oil pressure should always be presumed to be the sensor for diagnostic purposes. They routinely fail (usually high) and the adjustable pressure relief system rarely drifts and even more rare to drift to the high side. It is wise to verify the oil pressure BEFORE adjusting your pressure relief."

What is the easiest way to verify the oil pressure independent of the existing system (Dynon EMS-D10)? If with a mechanical oil pressure gauge, where would this be inserted and where can one be procured?

Thanks

Andreas68
RV7A - 0-360 AeroSport
 
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