Oil burn...What are your numbers?

The Lycoming engine owners here sure use a lot more oil than I see.
 
Lotta variables but this old Lycoming O320 can do about 5-10 hrs per quart. If I'm doing lotta touch & goes it seems to burn more than If I'm just cruising on a cross country.

This engine is old and three of 4 cylinders the lower plugs are usually pretty oily when pulling them for cleaning. Somehow it runs good and hasn't changed much over the 20 years we have flown it.
 
NealRomeoGolf said:
Well it is at 1850 hours. Was hoping it would go a bunch longer. No metal being made.
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That’s where I was, with about 3 hours per quart at best.

Two cylinders were wetter than the others, so I rolled the dice and replaced the wettest one with an overhauled jug. That wasn’t enough, so replaced the second one. It worked - 2300 hours now and 10 hours per qt. Still no metal in filter, and normal oil analysis in this big Continental.

I found that mechanics were inclined to overhaul, just because of hours and oil consumption when nothing else was wrong. “Wouldn’t you enjoy a new engine?” was one ploy. Well, it turns out I’m enjoying flying the old one just as much.
 
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Each of my GO435 engines on my Twin Bonanza go through about .3 to .5 quarts per hour. That's well under the engine manual's max consumption, which is 1.4qts per hour (per engine) at normal cruise power and 1.2qts per hour at economy cruise.

The ring wash is an interesting procedure. Might try that this winter, as my engines are pretty old overhauls.
 
bnt83 said:
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This engine is old and three of 4 cylinders the lower plugs are usually pretty oily when pulling them for cleaning. Somehow it runs good and hasn't changed much over the 20 years we have flown it.
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Have you tried hotter plugs on the bottom?
I'm thinking worn valve guides.
Also, if you are interested, there is an oil control ring flush (no tear down) technique to free coked up oil control rings.
www.dropbox.com

savvy-oil-control-ring-solvent-flush.r.pdf

Shared with Dropbox
www.dropbox.com www.dropbox.com
 
bradg33 said:
Each of my GO435 engines on my Twin Bonanza go through about .3 to .5 quarts per hour. That's well under the engine manual's max consumption, which is 1.4qts per hour (per engine) at normal cruise power and 1.2qts per hour at economy cruise.

The ring wash is an interesting procedure. Might try that this winter, as my engines are pretty old overhauls.
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Be very careful with those geared engines, could bend a rod.
 
Mikey52 said:
Be very careful with those geared engines, could bend a rod.
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Interesting thought. Are you thinking the extra force from the gearbox could apply more pressure the rods than in a non-geared engine?
 
The Lycoming O-360-A4M in my C-172 burns about 1 quart every 15-18 hours. At high power 2600 RPM cruise it burns a bit more oil than putting around at 2200 RPM. Same oil consumption rate since break-in was complete and it now has about 600 hours. I change oil at 50 hours or 6 months, whichever comes first (usually 50 hours). The rate of oil consumption is the same when fresh as it is approaching 50 hours. I fill to 7 qts and add a quart when it drops to 6, because anything over 7 qts blows out the breather and makes a mess. UOA shows oil at 50 hours is still serviceable, viscosity in range yet contaminants are increasing.

If a typical Lyco or Conti aircraft engine isn't burning at least a quart of oil every 20 hours, there might be a problem.

For those who see increasing oil consumption with hours, check the shape of the oil pan - if the sides taper toward the bottom then your oil consumption isn't actually increasing, but you're seeing reduced volume of oil as you get lower down on the dipstick.
 
Why 6 months when the mfgrs say 4 months?

Every engine I’ve owned consumes oil faster when the oil is old and ready to change. I change oil at 25 hours and filters at 50 hours. With that I don’t use much oil.

My Lycoming uses a crankcase vac system and oil-air separator so I’m not spitting out the oil slung from the accessory case. What oil I use in that engine gets burned, either in the cylinders or in breather fumes at the exhaust. I’ve never had oil on the belly of that plane.

The oil your Lycomings puke out isn’t all due to blowby. Increase the height of the breather hose and you’ll blow out less oil.
 
Stewartb said:
It means the blow-by is reduced. Blow-by is the primary source of contamination in our oil. XC reducing blow-by is easy to see. Watch how the drips from the breather line are reduced with XC. I've convinced a lot of guys to try that test and all have reported improvement. They all use XC now, too.
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I did not notice any reduction of oil dripping from the breather. Oil looked cleaner on the stick, but after draining at 31 hours for annual, I am not sure its any cleaner than 100. I am putting 100 back in, it will be interesting to see if I notice any difference after two oil changes with 20-50.
 
What I like about Philips 25w50 is using the same oil year round, no worries about summer vs. winter. And easier cold starts on cold winter days. One potential drawback is it's not as thick at ambient temperatures, so after the engine stops, the oil that coated the cam during flight will drip off a bit sooner than straight weight 40 or 50, leaving the cam less protected. This should not be a concern if you fly every week. If this is a concern, use Camguard.
 
Camguard: I've posted this elsewhere, but perhaps some will find it useful.
Juicing oil with CamGuard:

1.6 ounce/quart is 47.4ml Camguard per quart of oil.

Each 16 oz bottle of CamGuard will treat 10 quarts of oil.

When I get a new case of Phillips X/C 20W50 oil, I pretreat each quart with CamGuard. Open the quart bottle and use a needleless 50 ml syringe to squirt CamGuard into the bottle neck, reseal, and mark each treated bottle with a black felt-pen 'C'. That way I never need to think about it and the few quarts of oil I carry in the plane are ready to drink. And it's not rocket science, 45-50ml is fine.
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Domenick said:
Camguard: I've posted this elsewhere, but perhaps some will find it useful.
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Great suggestion, Dom. Thanks!

I’m using XC 20-50 with Camguard in my Lycoming O-360. Consumption varies a bit depending on how I’m flying (cruising at max throttle vs poking along low and slow), but is typically 8 to 10 hours per quart.
 
I had to replace my oil cooler back in Feb. My oil has stayed noticeably cleaner since. I imagine the old cooler was holding a lot of crud.
 
RyanB said:
What haven't we discussed by now? Curious what everyone's average oil burn is like. 10hrs/qt? Less, more? I notice as the oil ages and breaks down, the engine uses more of it, when compared to a fresh oil change, which seems to go 10+ hours before ever needing to add any.
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Depends on how much oil I keep in the crankcase, more so in my 500 hour TTSN IO-360 than my old 1,200 hour TSIO-360. For local and regional flights, the sweet spot for fill in my IO-360 is 4.5 quarts. More than that ends up on the belly in an hour. With a 4.5 quart fill, I estimate my burn to be 1Qt/25 hours. I say, "estimate" because I check and maintain 4.5 quarts with each flight.
 
FlyBoyMcCall said:
Depends on how much oil I keep in the crankcase, more so in my 500 hour TTSN IO-360 than my old 1,200 hour TSIO-360. For local and regional flights, the sweet spot for fill in my IO-360 is 4.5 quarts. More than that ends up on the belly in an hour. With a 4.5 quart fill, I estimate my burn to be 1Qt/25 hours. I say, "estimate" because I check and maintain 4.5 quarts with each flight.
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That (4.5 quarts) sounds low, though it's above the absolute minimum from the engine manual (which seems to be 2-4 quarts depending on the engine variant and installation). But since the amount of oil in the sump affects operating oil temperatures, I try to fill as high as possible before causing excessive blow-off. Does the IO-360 have the same sump size, shape, capacity as the O-360?
 
Domenick said:
O-320-D3G in Warrior II, about 12 hrs/qt. After oil change, I had 6 quarts and let the level settle. It usually settles at 6.5 quarts. At 5.5 quarts I add a quart. At 7 and above it blows oil out the breather tube.
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I have a similar situation with my IO-360 in my 64 Mooney. It throws oil out if over 6 qts, and it does it very quickly. I fill to about 5.75 qts and add 1/2 qt at about 5.25. I am getting about 8 hrs/qt. My AI now fills to 6 qts during annual and I drain oil for new every 25 hrs. I also use camguard.
 
O-470R. Change oil every 25 hours. We toss in about 3 quarts between every change of Aeroshell 100W. Unknown how much is blow out and how much is actually burning.
 
My Lycoming IO-360 with 1047 hrs burns a quart every 8-9 hours.
 
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56 hours on factory new Lyc180HP, 2 oil changes. Added one quart for first 25 hours, likely was not needed.
Old engine was very good 2300 TSOH, maybe 1 qt every 7-10 hours.
If I stay happy with 5-6 qts showing on the stick, I bet those times would be longer, for both engines.
 
MRC01 said:
The Lycoming O-360-A4M in my C-172 burns about 1 quart every 15-18 hours. At high power 2600 RPM cruise it burns a bit more oil than putting around at 2200 RPM. Same oil consumption rate since break-in was complete and it now has about 600 hours. I change oil at 50 hours or 6 months, whichever comes first (usually 50 hours). The rate of oil consumption is the same when fresh as it is approaching 50 hours. I fill to 7 qts and add a quart when it drops to 6, because anything over 7 qts blows out the breather and makes a mess. UOA shows oil at 50 hours is still serviceable, viscosity in range yet contaminants are increasing.

If a typical Lyco or Conti aircraft engine isn't burning at least a quart of oil every 20 hours, there might be a problem.

For those who see increasing oil consumption with hours, check the shape of the oil pan - if the sides taper toward the bottom then your oil consumption isn't actually increasing, but you're seeing reduced volume of oil as you get lower down on the dipstick.
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Mine drops from 7 to 6 pretty fast, 6-5 takes a lot longer. Have you watched closer to see if maybe 5-6 indicated is a happy place?
 
At oil change I add 10 qts oil + 2 cans Avblend which brings it near the full line.
At about 15 hours it shows about 1 qt low and at 25 hours it shows 2 qts low which is when I change it.

The only time I add oil between changes is when I'm on a long x-country, like when I was in Alaska when I hit the 25 hour mark. I added one qt and came home to Florida to have it changed. First and last time I went over 40 hours between changes but I figured it was ok because of the frequent long legs.
 
4RNB said:
Mine drops from 7 to 6 pretty fast, 6-5 takes a lot longer. Have you watched closer to see if maybe 5-6 indicated is a happy place?
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I never checked that because I don't operate it below 6 qts (though Lycoming says you can). As the amount of residual oil in the sump decreases, overall oil temperatures go up slightly. When it takes 15+ hours to go from 7 to 6, it's not burning or losing much oil I and see no reason to letting it go below 6.
 
At 10 qts in my IO-550, I go a long time before it gets down to 9 where I throw in the next quart.
 
Both IO-470 run happy at 10 qt / side, XC20-50 w/ CamGuard. I’ve put 400 hours on this airframe, with 400 hours on #1 engine, and 600 hours on #2 engine. I don’t burn a drop in 25 hour oil change intervals, ruling LoP. 99% cross country flying - a trainer this is not. I always thought I was supposed to burn oil. Must be an anomaly. :eek:
 
kep5niner said:
Both IO-470 run happy at 10 qt / side, XC20-50 w/ CamGuard. I’ve put 400 hours on this airframe, with 400 hours on #1 engine, and 600 hours on #2 engine. I don’t burn a drop in 25 hour oil change intervals, ruling LoP. 99% cross country flying - a trainer this is not. I always thought I was supposed to burn oil. Must be an anomaly. :eek:
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Wow indeed. I thought these engines were "designed" to burn some oil. Put differently, the clearances in valve guides, piston rings, etc. when set properly pass a tiny bit of oil to ensure reliable lubrication over their entire operating temperature range. And at high power, some crankcase oil mist going out the breather. Net result is a healthy engine should burn a quart every 10-20 hours.

Maybe not? :dunno:
 
MRC01 said:
Wow indeed. I thought these engines were "designed" to burn some oil. Put differently, the clearances in valve guides, piston rings, etc. when set properly pass a tiny bit of oil to ensure reliable lubrication over their entire operating temperature range. And at high power, some crankcase oil mist going out the breather. Net result is a healthy engine should burn a quart every 10-20 hours.

Maybe not? :dunno:
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As I noted in post # 4 ... I fly an experimental with a Corvair conversion (air cooled flat six) and generally change oil at 30-35 hours. I do not add oil between changes.
 
I'm about 12hours and still yet to add on my 1600 hour o-360

My dads io540...dammit if I can get him to stop adding whenever the stick gets anywhere close to 9, so I've got no idea how much is puked out or burning up. Lucky for him he's got a deadbeat that doesn't pay hangar rent and washes the belly for him. Lucky for me it's a black belly.
 
I am at about a qt every 20-30 hours or so.
Lycoming mentioned to me that it is totally reasonable to see a 1qt per 10 hours!
The main thing to look for is trends; is she burning more or less.
I add it to my pilot log and tach time to investigate trends up or down and correlate that to time of year.
ps this I have pertains to IO360CIC/arrow-ii
oh one more thing, take your cowling off and see if you see oil down the intakes that can mean a blown gasket, this would also make your engine run more rough at idle (only) (if you have that)
the other thing is to put a sand basket underneath your nose gear and watch for spots next time flying, there is always a potential of over pressure taxi oil spillage but it should be minimal, it could however accumulate up to the oil loss you're seeing.
ps2 low oil pressure reading != necessarily low oil quantity (hot day, low rpm on cosntant speed prop can attribute to all that also).
xander
 
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