Best Practices for Reducing Oil Consumption

[ghostofme]

I will make note of the oil pressure and temperature when I fly today starting from 5.5 quarts, and then use those numbers as a control when running at lower oil levels. I would also be happy with slightly higher oil temperatures as that usually sits around 170F and I read here that it should be 180F plus to burn off moisture.

I'm changing oil every 50 hours on the tach, and just recently had it changed. The oil burn was the same as I've always seen it. I actually run at low RPM in cruise (around 2100rpm), and that's mainly because I got sick of looking up at the sky trimming to hold altitude at 2000rpm haha.

At the plane today I'll poke around and try to get some pictures to answer some of the other questions above.

[PACERGUY]

You can change oil temp by using metal tape on the front of the oil cooler. 1 inch high is usually go for 20 degrees change, adjust as needed. You still get rid of moisture at 170 just not as fast as 180 degrees. Properly leaned at 2100 that thing should be getting great fuel burn.
DENNY

[ghostofme]

You can change oil temp by using metal tape on the front of the oil cooler. 1 inch high is usually go for 20 degrees change, adjust as needed. You still get rid of moisture at 170 just not as fast as 180 degrees. Properly leaned at 2100 that thing should be getting great fuel burn.
DENNY

That's very interesting to note! I will keep that in mind, thank you. Yes, at 2100 leaned properly I can get the fuel burn to around 4-5 an hour and still cruise at a decent clip.

[ghostofme]

Hi all, I took some pictures at the plane and I'm going to have to admit my ignorance on basically everything. I learned my lesson regarding saying I know something when I actually don't. A humbling experience with SoCal controllers where I said "roger" because I didn't want to admit to completely missing the call taught me that. I've got some pictures; if anyone could help diagnose the oil consumption question from these pictures alone that would be much appreciated! If not, I'll probably bring this up with my mechanic next oil change and keep the level high by pouring quarts in. During my flight yesterday, I started at 4.5 quarts and it was down to 4.0 quarts when I landed an hour later, so that's still going out at a rate of 1 quart every 2 hours even at the lower levels. Let's see if I can figure out how to attach the images

[Steve Pierce]

Doesn't look like the typical excessive oil coming out the crankcase vent to me from an O-290. Did a pre-buy on a Pacer in Lake Havasu many years ago with an O-290-D2. Owner said it didn't blow oil and when I got there the plane was clean as a whistle. After doing a run up to warm up the engine it had oil dripping off the gear leg and all down the belly. Have seen it many times.

[Jspey]

I think I remember seeing something on here about the O290D2 camshafts being made a tiny bit too long and flinging oil into the front breather fitting. Was there any truth to that or was it an OWT?

[ghostofme]

I have some other images I was trying to share last night, but the site wasn't working. I'm surprised the belly pictures got in there. I'll add the others now:

IMG_20240131_202106.jpgIMG_20240131_202114.jpgIMG_20240131_202118.jpgIMG_20240131_202123.jpgIMG_20240131_202125.jpgIMG_20240131_202127.jpgIMG_20240131_202129.jpg

[ghostofme]

Doesn't look like the typical excessive oil coming out the crankcase vent to me from an O-290.

Just to clarify, you mean what's happening looks atypical, right?

[PACERGUY]

Belly looks normal for a plane that is flying a lot. Is the orange scat tube in the last picture supposed to be connected to that vent or did you take it off for the picture? When you pull your bottom plugs are they wet with oil?
DENNY

[Gilbert Pierce]

Based on your pictures I think you are burning the oil. I was using a quart an hour with good compressions. I removed an exhaust stack and looked up the exhaust with a bore scope camera. All of four ports showed a large amount of carbon.
We pulled a cylinder and found the oil control stuck on all four. Valve guides were worn. I believe exhaust blow-by past the exhaust guides was contaminating the oil and plugging up oil control rings.
The intake ports and intake valve had excessive carbon seen with my bore scope. On the intake stroke oil was pulled down worn intake valve guide and burned.
The symptoms I missed was the inside of the valve covers on the exhaust side were black as was the exhaust rocker arm. The oil on the dipstick was turning darker quicker than I was used to after an oil change.
Remove the rocker arm covers and take a look.

I have an oil filter and change oil every 25 to 35 hours.