Fairly high oil pressure? Concern?

RickWoodall · #1 04-29-2012, 05:20 PM

Just did my annual and oil change. Also, dynon added voice alerts now.
So, a few flights since, the CAUTION OIL PRESSURE warning come on.

It is on for the first 5-10 minutes..and in straight and level as it warms up, adjusts and is fine. Oil temps are always in spec.

When I say high, the default io320 pressure warning is squawking at me at 85-90psi. Oil temps are say 170 and slowly climb to around 185 for cruise. A few minutes into the flight, oil pressure lowers to the yellow zone and is mid 70PSI

Flew several times today and twice on the roll and climb out the alarm went off, always just in the 86-90 range and short term. Never higher, and always fell back in line later in the flight as all seemed to warm up. I am running shell100+

Any ideas, is this pressure no big deal and I should adjust the default YELLOW ZONE up a few degrees so she stops yelling, or can this be something else. Any ideas on what to check?

Adequate oil, gauges work, temps are fine, just higher than green zone oil pressure?

Any ideas?

Walt · #2 04-29-2012, 06:46 PM

Pressures look good to me, adjust the alarm setttings.

RickWoodall · #3 04-29-2012, 07:12 PM

Appreciate the comments Walt. Been doing some research since I posted and it seems Lyco's are ok with 55 to 95 psi oil pressure. I will bump my warning levels up to not squawk until 95.

A little scary to the passengers but need to fix that asap. Cheers, Rick

jrs14855 · #4 04-29-2012, 07:16 PM

The new Cessna 172's produced since restart of production measure the oil pressure at the front of the oil gallery. If the oil pressure in this case were measured in the old location it would read approximately ten pounds higher. There are some well qualified people that feel this was done so that the valve train, especially the guides would get better lubrication. The change in the oil pressure pickup was done to keep the pilot happy. Some years ago Lyc raised the red line from 100 to 115#. High green oil pressure will not hurt a thing and may in fact be very beneficial for thje valves.

RV10inOz · #5 04-29-2012, 09:09 PM

While we are on the topic of GRN/YEL/RED zones, I wonder how amny folk have their CHT zones set wrong.

I said set wrong, not as per the Lycoming data

I firmly believe that the green should finish at 380, where it becomes yellow to 400-420 (your choice) and red thereafter.

Plenty of good reasons for this.........one is your safety in the case of a preignition event.

Just sayin............Let the cats and dogs fly!!