[velostar]

What would be typical oil burn rate for a Lycoming 5 years/300 hours into engine life?

[Flyin'Dutch']

IIRC Lycoming has values for that in their guidance material and it is quite a lot from what I remember.

Important points are - how frequently is the engine used, what is it used for and has there been a significant change?

Quick Google found it:

This from SI 1427B:
"The maximum allowable oil consumption limits for all Textron Lycoming
aircraft engines
can be determined by using the following formula:
.006 x BHP x 4 / 7.4 = Qt./Hr. "

Plenty more interesting stuff here:

https://www.lycoming.com/content/oil-and-your-engine

and here:

https://www.lycoming.com/sites/default/ ... mption.pdf

[velostar]

Brilliant, thanks

[Flying_john]

I think that formula gives you worst case towards end of engine life, as it works out about a pint an hour for a 180 Lyc.

The oil consumption may be erratic for the first 25hrs from new - after that it should stabilise and my expectation is for there to be about a pint to a quart of oil used between 50 hr services up to about 500hrs of engine time. After that it may rise to one or two quarts between 50hr services.

Any large change in consumption at any time really, should be investigated by opening the oil filter and checking for large metal deposits/flakes.

At 300hrs (O.P engine) then anything more than three pints per 50hrs is starting to creep up. Was it a brand new Lyc from USA or was your old engine zero timed and was this the first zero timing since new ? Was it run in properly (65 - 75% pwr for first 25hrs), is it baby'ed or used harshly, is it in training environment of your pride and joy. All need to be taken into account.

[Gas Guzzler]

FWIW, FJ has the real world figures about right, my O360 has done about 150 hours a year for the last 10 years and has used 47 litres apart from refills at the services, at the 500 hour point it was using about 1.5 litres between each 50 hour check, now at 1600 hours this is nearer 2.5- 3 litres

[GolfHotel]

My O360 has done 200 Hrs since 0 time. It is using a lot of oil and has since I have owned it at about 100Hrs. I don't have the numbers to hand but its about a quart every 10/15 Hrs. It is still slowly reducing so there may be a possibility that it will drop to "normal" levels eventually.

One of the things that makes a real difference is keeping the oil level low. The lower the oil the less it uses. My plugs are clean and the breather is clean so I don't really know where it gets out. I think I need to be brave, read the handbook and keep the level as low as it allows.

One other point my last craft had a new o320. That used to go between 50Hr check with no oil added.

[ChrisRowland]

I'd love to know how Lycoming came up with a formula with one variable and three constants. Doubt they will say so.

[Flying_john]

Agree with GH, keep it low about 6qts on the dip stick, any more and it chucks it out of the breather pipe, can foul plugs etc. But keep a litre in the Aircraft as I would not let it fall below 6 especially if it has sat for a coupla days and all the all has drained into the sump.

[Paul_Sengupta]

I keep mine between 5 and 4...

[GrahamB]

I've run two Lycoming engines from zero-time overhaul to about mid-life. In both cases they started off being able tolerate 8 quarts of oil without excessive loss, but by the time they reached 500 hours or so, any more than 6 quarts gets blown out pretty quickly, Keeping them between 5-6 on the dipstick usually results in consumption of about 10-15 hours to the quart.

The only time I put more in is when I'm in France in the summer at 30 deg C +, and I always feel that extra couple of quarts helps keep the oil temp down on a long climb to cooler air.

[Flying_john]

Surprisingly, the minimum safe oil volume for an O-360 is just 2 quarts !

http://11hc.44rf.com/manuals/engine-pro ... manual.pdf

P3-11

[GolfHotel]

I keep mine between 5 and 4...

That's interesting for me, I have an ex bulldog engine. I take it you are having no problems as a result?

The owners manual gives no minimum, that I can find, but I run it at 6 or more. Maybe I can reduce that.

Why Lycoming don't give a minimum for the dry sump I have no idea. I was surprised to see only 2 quarts as a minimum for the o360!

[Paul_Sengupta]

No, no problems at that level. I don't let it drop below 4 though. 5 is what I normally aim for. 6 is ok, but it does seem to reduce faster than at 5. Anything over 6 and it seems to go down quite rapidly.

[Dodo]

another vote for between 1 and 2 litres per 50 hr check. (1300 hr lycoming 0320).

[cockney steve]

The owners manual gives no minimum, that I can find, but I run it at 6 or more. Maybe I can reduce that.

Why Lycoming don't give a minimum for the dry sump I have no idea. I was surprised to see only 2 quarts as a minimum for the o360

Most of the"surplus "oil is foe cooling an an endurance reserve for burning..
you need enough to prime the oil-pump, filter, galleries and enough to trickle down, after it's done it's job and keep the pump full . Had a BMC Mini in once, with a flickering oil-light.....it took 9 pints! (capacity awa 9 1/2 !....remarkably, there was no damage.