Suppose this has come up before and I missed it but how often do those on the group actually change the engine oil? I can go first: I use Phillips 20 50XC (blue can) and change about 25 hours but I have a hard time getting more than 40 hours a year on so it usually winds up being probably closer to 20 hours (last time was 22) and twice a year mostly because I want to drain out any sludge and moisture from my prolonged sitting. I always check the screen although I have a full flow filter (which I also change). I haven't been using oil analysis up to this point as I figure I should catch any excess metal in the screen.....although that doesn't tell the whole story either.
I bring this up because I was just reading an article that states the 3000 miles oil change for autos and light trucks is wasting oil. The article contends that with the new oils (and unleaded fuel)
it's not necessary but then the car/truck runs a lot more than my plane. I think my car recommends a 7500 mile oil change and actually has an 'oil life indicator' built into the dash system....not that I necessarily follow it. I'm usually about 70% or so when I change
Mike, I change my oil at 50 hrs. I normally fly more than 50 hrs per year. I use Aeroshell 100w plus oil year round. In the winter I install a cover over the bean shaped air inlet under the prop. I have a spin on oil filter on my C85 that I change at each oil change. I also have a mini Air Wolf air/oil separator that has a separate collection bottle for the sludge that exits the bottom of the separator. Over the last 120 hours since the engine was overhauled, I have collected and saved a total of about a pint of pretty yucky looking sludge from the separator. The standard installation recommendation for the air/oil separator is to return the sludge back to the crankcase, but I obtained a field approval to install the separate collection bottle. I have a 6 quart oil sump and maintain between 5 and 6 quarts of oil.
John Propst
313 Hickory Grove Ln
Elizabeth, WV 26143
cell 304 588 3690 j.e.propst@ieee.org
N3129E 2WV3
I use Aero Shell and also have the Wolf Remote Mounted Oil Filter on my C-90-8 and a case mounted oil filter on my C-85-12. The STC says 50 hours, but to be on the safe side I change it around 35 - 40. I put about 200 hours a year on the C-90 and 100 on the C-85.
My cars also recommend 7,500 miles between oil changes and my mechanic puts the ticker on for the next one to be at 3,000, which I use to gauge when I will be at 5,000 which is when I have them done.
Robert P. Kittine, Jr.WA2YDV
West Nyack Aviation, L.L.C.
New York, New York 631-374-9652 rkittine@aol.com
I have 'slowly' began extending the oil changes on my car and pickup to somewhere around 4000 miles or so but I have a hard time doing it on my aircraft engines I guess mostly because I don't get enough hours on so maybe twice a year isn't so bad. I know most recommendations are for 50 hours with a filter or every three months but at the present price of AV oil it's pretty hard to change the oil with 10-15 hours. I just changed oil on my L16/0200 conversion and the oil and screen were both clean. I'd attribute that to lack of combustion gases (blowby) getting past the rings with the new cylinders unlike the old 65 on which the oil seemed to get dirty in 15 hours or so although the leakage tests were still in the 70's.
I'm not a fan of the oil separators that return the sludgy oil back to the crankcase. John's that puts the sludge in a container makes more sense. Mine (without) just blows out of the crankcase vent during operation although I see a lot of 'snot' on the floor after the engine shuts down. I was flying yesterday (temperature about 45 degrees) and even with the nose oval cover on and a partial block on the lower pressure cowl outlet I had a hard time raising 150 degree oil temp after 30 minutes of operation which doesn't to a lot to boil off the water vapor inside the engine.
I like to change it every 25 hours or so, along with the filter, but between all the flying this year its been about 30-50 hours or so, but i have put a hundred and fifty hours on the engine sense July, so i figure the longer wont hurt it. Im using 15-50 Aeroshell
Since purchasing my Chief in midsummer, I have been pondering this question. I started composing a " Maintenance plan" for it shortly after and using input from this forum, local A&P's, and some minor research online have decided to use a 25 hour cycle with
Phillips 20W50 XC. The engine is only 200 hrs tach since major and thus far running fine.
Are you using an Oil Screen in the engine or a Spin on or remote mounted Spin on oil filter? I think that Continental Recommends 25 hour intervals with the screen only, while the STC for, at least the remote mount I have, recommends 50, though I do not go that far.
Bob
Robert P. Kittine, Jr.WA2YDV
West Nyack Aviation, L.L.C.
New York, New York 631-374-9652 rkittine@aol.com
The least expensive way to assure the engine lasts is to change the oil often.....20-25 hours. These little engines don't hold that much oil so it's not that expensive. My. 85 HP had no filter other than the screen and I changed the oil every 25 hours. I used straight 40 in summer, variable viscosity in winter. I never filled it up. I usually kept it about half a quart low as it just blew it out. I usually added about 4 oz. MMO to the gas each fill up, or every other one for sure. The spark plugs are important !. I've seen a lot of OLD plugs being used in engines. This is false economy too. I always used recent plugs in good condition.. I burned 100 av. Gas always. Never had any valve problems. Not too long ago Toyota recommended a 7000 mile oil change. Many of the engines went bad and Toyota admitted it was a bad call. These little aircraft engines are many years old and need all the help they can get! I drive a Prius which recommends 10,000 miles. I change it at 5000. Hope this helps, JP
I suspect I will catch flack over my oil change intervals but here goes.
I change oil in my autos about every 50,000 miles give or take. Or when the oil level drops 2 to 3 quarts. All my autos go about 175,000 miles then I sell them. I have never had an engine failure or repair. If I drove in dusty conditions i would change the oil more often. I may change plugs twice during this time period. Usually when I detect a significant change in gas mileage. To me, a vehicle is just a commodity that I want as little invested in it as possible. My old vette however does not fit in the commodity category.
My attitude is a little different for my aircraft engines because I view it as an investment and I can not pull over to the side of the road if the filter clogs. I change it and the filter every 50 hours plus I have the oil analyze. As far as the plugs are concerned, I check the ohmic value and if within specs, I use them.
Let me toss this question into this conversation. How long after an oil change does your oil go before it starts getting dark? By 3 or 4 hours mine is dark and by 25 hours, the point where I change it out, it's like my Mom's coffee and that's a whole other shade of black.
Larry H
Sigourney, IA
Formally N84619, N84149 & N84069 - all1946 7AC's; also N57430 a 7ECA
Currently N91RA 7GCAA (Still a Champ, just grown up some)
Mine starts lookng dirty at about 150 hours, but not real dirty at that point.
I had a friend who claimed it took a couple of thousand miles to break down the hydrocarbon's in new oil and he never changed his oil except to top up, when he changed the filter, which he did every 3,000 miles.
I know of other people that will do 50,000 between changes on cars, but only with synthetic oil. Mobil 1, recommended that when it first came out, but I think they have cut that way back as they did the price.
Robert P. Kittine, Jr.WA2YDV
West Nyack Aviation, L.L.C.
New York, New York 631-374-9652 rkittine@aol.com
This just a guess but I think the tendency for oil to go 'dark' is a side process of blowby. In other words the more blowby you have the more likely it is for the oil to get dark due to the carbon being blown by the rings. As noted above my 'new' 0200 oil stays clean up and through 20+ hours but my A65 oil would go dark around 10-12 hours even though the compression leakages were all in the 70's. Also I think the combustion by products of unleaded (auto) fuel are darker nature than 100LL. The exhaust pipe outlet tells that as they're normally dark and sooty with auto fuel but nice and white with 100LL.
I have only the oil screen arrangement native to the A-65 Continental engine. I just changed the oil recently (twenty five tach hours from its' last change) and there was only a small amount of carbon crumb in it. The A&P who did the annual a week later said that was a normal thing for the type of engine.
interesting topic: I will add a note, I use marvel mystry oil, in Washington I used bardall, 8 oz to 10 gallons of fuel, and 15 to 20 hours OC on a screen A-75. Non detergent only, 100 in summer and 80 in the winter. I worked at a flight school 45 aircraft. totally different enviroment, and we had 80/87 red, but we ran the ND no multi viscosity there. all my engines are old, Even in the military I never remember multi oils, Just my 2 cents, A fellow Aviator Sunny
