Best Practices for Reducing Oil Consumption

[ghostofme]

Hi all, I'm back from getting my CPL and CFI. I intend to get my CMEL this summer when work slows down. For now, I'm home working during the day and flying long cross countries at night and on the weekends. I've fallen in love with the Tripacer. It was definitely intimidating to fly at first having done most of my training in low wing light sports or glider-like Diamonds. But recently I've been greasing the landings, and there's just a lot of joy sitting in such a spacious plane alone with my thoughts and the beautiful views. I even noticed and began to appreciate how pretty the Tripacer is as I rested on a bench at one of my stop-offs, looking out to where I had parked near the fuel island.

With my finance job financing my time building, I realistically see it being possible to put around 800-1000 hours into my logbook this year alone. One question I had is how can I best reduce the oil consumption of my PA22-135? The engine is a Lycoming O-290D2. It consumes around a quart of oil every 2 hours, which seems like a lot from my very basic understanding and research I've done. Is this normal? I may as well buy the 55 gallon barrel advertised on websites two times over! I'm currently running Aeroshell Aviation Oil W100+ and flying around 4 times a week, 5 hours per day. I'd appreciate any feedback. Thanks!

[Steve Pierce]

Is it coming out the crankcase vent? O-290-D2s are known for that with the front mounted crankcase vent.

[smcnutt]

Had similar issues so heres some questions for you. How many quarts are you filling it to? Do you have an oil separator installed? Does the crankcase vent line routing go under the engine or over the top?

[Old3pacer]

Ditto the above ???s
If I put 5-6 qts in the oil filler tube it will quickly come out as noted on the belly and around the oil breather /separator.
It stabilizes around 4 and 1/2.
I accept that my oil pressure is on the low end of the green arc.

[ghostofme]

Hey all, thank you for the responses. I'll have to do a bit more research and a walk-around to answer some of your questions. For now, I can answer the easy one. I fill it to 6 quarts. I'll follow-up with the answers to the other questions soon.

Are there any factors/ramifications I should be aware of letting it stabilize around 4 and 1/2 quarts beyond lower oil pressure? If nothing significant, I'd be okay letting it settle there and adding oil less frequently. Additionally, what should I be looking for to be able to answer the question of whether or not the oil is coming out the crankcase vent?

[Jim]

Hi,

While you're looking around see if your breather that exits out the bottom has a whistle hole to relieve the vacuum in that hose/pipe down there. It's also good to have one in case the end of the tube freezes and plugs on its end. If you can slow the suction you may save some oil. If you decide to run your vent hose over the engine be certain that it will drain condensates without freezing and plugging while parked, especially between the cylinders which is often a low spot. If that tube freezes and plugs your front crankshaft seal will blow out shortly after you start it.

[Gilbert Pierce]

I run 4.5 to 5 qts. in my O-320. Never noticed an oil pressure change or temperature problem from when I used to run 7 quarts.
The belly is sure cleaner.

[ghostofme]

Thanks, I'll look for that whistle hole as well. I did some reading in the POH and it says the minimum safe quantity of oil for the O-290D2 is 3.5 quarts. I'm curious what others think about this. My goal is to take my engine at least 30% past the 1500 hour TBO safely.

Did some research using Steve's ingenious search technique of "oil site:shortwingpipers.org" on Google, which turned out to be significantly more effective than the search function on the forum itself and found some tangentially related discussions that were useful.

[smcnutt]

Additionally, what should I be looking for to be able to answer the question of whether or not the oil is coming out the crankcase vent?

What I did was put the end of the vent tube into a coke can and safety wired it there. Just make sure that you're not constricting the airflow out of the vent. Then I flew a few laps around the airport and then checked it. Originally was convinced it was coming out of the exhaust until this test confirmed the vent instead. Then we concentrated on solving the vent issue. Routing the line, installing an oil separator, how far it hangs into the airstream, whistle hole, etc.

[PACERGUY]

The life of your engine is usually affected by greatly by its early years not so much if you are flying it weekly. DENIAL is not just a river in Egypt, if you are making metal you may be in for a rebuild sooner or latter. Keep looking for where the oil is going. Blow by/valve guides/piston rings, sometimes something as simple as running 5 quarts vs 6 makes a difference. You should not see lower oil pressure just because you use a quart or two of oil. Oil temp will make a difference but difference between 4-6 quarts in the sump not so much. How often are you changing oil and does your oil burn drop for a bit after an oil change? If your oil rings are clogged you can do a cylinder flush. RPM will also affect oil burn so do some testing and see what RPM the engine likes best from an oil burn use, a little slower flight just gives you more time toward your goal.
DENNY