Bravo oil consumption m20m -??? Bravo 1998

[pkofman]

My engine has about 450 hours and all compressions are in the mid to high 70's

Lately I have been burning more oil than I recall as normal

I have been doing allot of training flights ( ifr procedural stuff ), so not constant long haul flights but more on off power sort of flying

but I am burins more oil that I can recall

I am also plugging the plane in nightly now  as it is getting colder ( does that have an effect??) 

it may be a very very very broad question but from a 30000 ft perspective what would be considered "normal" oil consumption 

im sorry for asking such a big question , just looking for a general idea. I would say I  was getting  about 8 hours a qt. and now maybe 5

Thoughts  

Pete

[jlunseth]

I generally need to add one quart between oil changes in my 231, and oil changes are 35 to 50 hours. In the winter when I don't fly as much I change the oil at 25 hours and do not need to add a quart in between, so about 1 quart every 20-25 hours. Now, that's a Conti turbo.

[pkofman]

@jlunseth I get nothing like that at all. I use way more.   Lyc turbo 

[Bravoman]

I have almost 600 hrs on my factory reman and I add 2 quarts or slightly less between 25 hr oil changes. Your consumption is probably increased due to how you’re currently operating your engine. I would compare it to how it does on normal cross country flights. 

[jlunseth]

What I learned after the first couple of hundred hours, was that the "aircraft engines burn oil" mantra is a bit of a myth that went the way of the radial engine that really did burn oil. There are all kinds of sources of leaks. The quick drain, which is just a convenience for the mechanic in changing the oil, is one. The seal gets weak quickly and is susceptible to blockage by small particles in the oil. Rocker covers, gaskets that were sheared or misapplied when a cylinder was put on, etc., etc. My engine was IRANd at about 1200 hours when I was going through a quart every few hours, it is now at 1950 which is 150 over TBO for the TSIO360, and my oil consumption has gone up only marginally in that time. What I learned was that if the oil consumption changes markedly at some point, look for the leak. If you get a drop of oil on the ground or nose gear, look for the leak. It may be a drop when the engine is not running, but pressurize the engine and it is a different story entirely.

[Davidv]

If you're doing a lot takeoffs 5 hours/quart would not be too abnormal in my experience. When I'm flying 4-5 hours legs I go around 10 hrs between quarts and 6 hrs when I'm doing short flights around Florida.

[pkofman]

@Davidv bravo??

[FoxMike]

When I bought my Bravo (250hrs TT) the engine burned 1qt every 12 hours. by the time the cylinders hit 2000hrs the consumption hit 1qt every 4 hours.  To get a good trend check the oil in the morning before a flight.  Checking it after a flight will not allow enough time for most of the oil to flow back to the sump.  I have been told by engine shops that a properly broken in TIO 540 should do about 1qt in 16 hours while new.

[Davidv]

15 minutes ago, pkofman said:

Bravo??

Yes. About 400 hrs. I’m told our engines use more oil because of the wet heads.

[xavierde]

2 hours ago, jlunseth said:

What I learned after the first couple of hundred hours, was that the "aircraft engines burn oil" mantra is a bit of a myth that went the way of the radial engine that really did burn oil. There are all kinds of sources of leaks. The quick drain, which is just a convenience for the mechanic in changing the oil, is one. The seal gets weak quickly and is susceptible to blockage by small particles in the oil. Rocker covers, gaskets that were sheared or misapplied when a cylinder was put on, etc., etc. My engine was IRANd at about 1200 hours when I was going through a quart every few hours, it is now at 1950 which is 150 over TBO for the TSIO360, and my oil consumption has gone up only marginally in that time. What I learned was that if the oil consumption changes markedly at some point, look for the leak. If you get a drop of oil on the ground or nose gear, look for the leak. It may be a drop when the engine is not running, but pressurize the engine and it is a different story entirely.

What level do you keep your oil at? I burn more than that and the engine seems to "spit out" whatever oil is about the 5qts mark on the dip stick (TSIO360-MB).

[pkofman]

3 hours ago, xavierde said:

What level do you keep your oil at? I burn more than that and the engine seems to "spit out" whatever oil is about the 5qts mark on the dip stick (TSIO360-MB).

I try to keep my oil at eight it seems to use about 5 to 7 hours per quart but because of the flying I’ve been doing recently.  If I add more than eight I think she just spits it out. 

Edited November 24, 2020 by pkofman

[daytonabch04]

Mine seems to be happy around 7.  Anything more gets spit out...

[jlunseth]

2 hours ago, xavierde said:

What level do you keep your oil at? I burn more than that and the engine seems to "spit out" whatever oil is about the 5qts mark on the dip stick (TSIO360-MB).

7-8 qts. The MSC I take it to for oil changes usually puts in 7, sometimes 8. I put in a quart as needed when it reaches 6. It does not seem to lose oil any faster at 8 than at 7 or 6.

[LANCECASPER]

13 hours ago, Davidv said:

Yes. About 400 hrs. I’m told our engines use more oil because of the wet heads.

They definitely may leak more oil because of all of the fittings on the wet head, but once the oil goes from the line into the cylinder head it just wicks away the heat around the exhaust valve guide area, cooling that area, prolonging the life of the "hot-section" or the exhaust valve guide material. Then it ends up in the drain lines and back to the sump. Part of the Bravo conversion on this engine was to increase the size of the drain lines due to the extra oil flowing through the system. No chance of burning the oil in that area since the oil cools the area but does not come near the combustion area. The least I fly with is 8 quarts in the sump.

[PaulM]

I burn about 1Qt/5 hours in my Bravo (1300hr) .

At the oil change it is filled to the 10Q line... I let it drift down to the 7qt line, add 1 Qt, and then let it drift down to 6qt.  then I'm at 25 hours, and we change the oil.    If I needed to do a long cross country near the end I would add another Qt. 

So, Although I only add one Qt between oil changes, one must be honest and admit that is using oil at 1Qt/5. 

The one time that I had much more than that (1Qt/2-3 hours) it was a leak in the wet-head fittings.   The external oil streaks and higher consumption were obvious.  My shop says that the 540 Lycs all ooze oil and there will always be some right below the engine on the center cowl.  Any oil marks elsewhere are an unexplained leak. 

[pkofman]

19 minutes ago, PaulM said:

I burn about 1Qt/5 hours in my Bravo (1300hr) .

At the oil change it is filled to the 10Q line... I let it drift down to the 7qt line, add 1 Qt, and then let it drift down to 6qt.  then I'm at 25 hours, and we change the oil.    If I needed to do a long cross country near the end I would add another Qt. 

So, Although I only add one Qt between oil changes, one must be honest and admit that is using oil at 1Qt/5. 

The one time that I had much more than that (1Qt/2-3 hours) it was a leak in the wet-head fittings.   The external oil streaks and higher consumption were obvious.  My shop says that the 540 Lycs all ooze oil and there will always be some right below the engine on the center cowl.  Any oil marks elsewhere are an unexplained leak. 

I did not think I was sweating or leaking  oil but to be honest I see allot of oily feeling stuff on the belly and  I thought   it was from the breather tube or just being spit out if overfilled.  My plane goes for annual this week so we will check all of these things out. To be honest the plane seems to run super well and oil pressure is dead solid when flying. I once had a full oil blow out f in a J ,so im hyper sensitive to oil indications, usage and seals...

[Danb]

PK I’ve had my Bravo basically since new, I’ve always had somewhat of a oily belly, my consumption is determined by the level of oil. When out of annual the MSC fills it up to ten quarts and the first quart disappears in six hours or so when I do the change it reads 8 1/2 on the line and usage is around eight hours per quart, I have 1000 hours on the new engine.

[carusoam]

Briefly... a summary of what I read above...

1) Lycomings like to expel the extra oil out the vent...

2) High power and high attitudes put the oil back towards the case vent, and blows it overboard...

3) Lots of T/Os and landings will show an increase of oil use...

4) Going back to long cruise flights, the oil use should return to normal...

5) Checking oil level...always a challenge as it takes time to drain from all the systems...

6) Check the oil level after the flight to see if it is foamy, or black... signs of blow-by if it is occurring... blow by aids in blowing oil overboard...

 

Go MS!

Best regards,

-a-

 

[alextstone]

PK I’ve had my Bravo basically since new, I’ve always had somewhat of a oily belly, my consumption is determined by the level of oil. When out of annual the MSC fills it up to ten quarts and the first quart disappears in six hours or so when I do the change it reads 8 1/2 on the line and usage is around eight hours per quart, I have 1000 hours on the new engine.

My usage also is one quart per 8 hours when the engine is healthy. Recently, that quickly went up to one quart every 3 hours and this sudden change was my early warning sign of a cylinder suffering from blow by of the rings and impending exhaust valve failure.

BTW, Lycoming provides a formula for "normal" maximum oil consumption:

"Lycoming uses the following formula to determine maximum oil consumption: (. 006 x BHP x 4 )/ 7.4 = maximum quart/hour consumption. This means that...."

For the Bravo: (. 006 x 270 x 4 )/ 7.4 = .087 qaurt/hour consumption maximum!!!

I think the biggest takeaway is to know your engine and watch for trends.

Also, I'm going to go out on a limb here and say that Mike Busch's messaging has really more to do with condition based maintenance (for part 91 ops) rather than hours, time in service or arbitrary "swapology" of parts such as a full top overhaul just because one or two cylinders are in need of replacement.

Alex

Sent from my Pixel 3 XL using Tapatalk

[Guest]

On 11/24/2020 at 10:20 AM, pkofman said:

My engine has about 450 hours and all compressions are in the mid to high 70's

Lately I have been burning more oil than I recall as normal

I have been doing allot of training flights ( ifr procedural stuff ), so not constant long haul flights but more on off power sort of flying

but I am burins more oil that I can recall

I am also plugging the plane in nightly now  as it is getting colder ( does that have an effect??) 

it may be a very very very broad question but from a 30000 ft perspective what would be considered "normal" oil consumption 

im sorry for asking such a big question , just looking for a general idea. I would say I  was getting  about 8 hours a qt. and now maybe 5

Thoughts  

Pete

Peter,

Is your consumption calculation based on total engine running time or air time from the journey log book?

Clarence

[pkofman]

25 minutes ago, M20Doc said:

Peter,

Is your consumption calculation based on total engine running time or air time from the journey log book?

Clarence

Great question I have to think about that and by the way I sent your private email about the date for the annual I think basically though I simply take my total number of hours I’m flying. 
I don’t just use the flying air time

peter

[Steve2]

For the Bravo: (. 006 x 270 x 4 )/ 7.4 = .87 quart/hour consumption maximum!! - there was an extra zero in there.

[carusoam]

1 minute ago, Steve2 said:

For the Bravo: (. 006 x 270 x 4 )/ 7.4 = .87 quart/hour consumption maximum!! - there was an extra zero in there.

I didn’t do the math...

But rule of thumb for an O360 was a quart every 10 hours...

Steve, your math is showing near a quart every hour... there must be a zero missing..?

Best regards,

-a-

[pkofman]

2 minutes ago, Steve2 said:

For the Bravo: (. 006 x 270 x 4 )/ 7.4 = .87 quart/hour consumption maximum!! - there was an extra zero in there.

So the question was asked earlier , is thst total engine run time (start to stop) or flight time ? My quess .... total time ?!

[Steve2]

The formula alexstone posted is taken from Lycoming Service Instruction 1427 and details the maximum oil consumption limits Lycoming considers to be airworthy.  For the Bravo that's 0.87qt/hr or put the way we normally figure oil consumption 1.15hrs/qt.  For a 200hp IO360 it comes out to be 0.65qt/hr or 1.54hrs/qt - and yes, that's a heck of a lot of oil.  I think most owners would be freaking out well before these numbers.

As to pkofman's question regarding total run time or flight time (hobbs or tach) the SI doesn't address that, I'd say I wouldn't worry too much about the detail, if you were pouring a quart or 2 into your engine every hour however you calculate it, you need to investigate and determine the cause.  Regarding the OP of going from qt/8hrs to qt/5hrs, the change in typical flight profile could certainly be a reason; I guess taking some longer cruise flights would prove/disprove the theory. 

Oil exits the engine through either case/hose/fitting leaks, breather or exhaust.  Case/hose/fitting leaks can be identified with the mark 1 eyeball - is the engine case/inside of the cowling wet with oil?  Breather - some is normal, excessive can be caused by high internal crankcase pressure caused by either cylinder blowby (inspect lower sparkplugs for excessive wetness); usually oil goes black quickly / higher CHT on the offending cylinder(s) / higher than normal oil temp or I've heard mentioned leaking crankshaft seal pressurizing the case although I usually see this as oil leaking out at the front of the engine.  If it's coming out through the exhaust you may have a greasy tailpipe (wipe your finger around the inside to check) although often with a turbo it may just be so hot all greasy trace is burnt away.

Sorry for the slight thread drift from pkofman's original question, the 0.087qt/hr figure mentioned above needed correcting before people got excited that 11.5hrs/qt was the lycoming limit for a Bravo engine.

Edited November 26, 2020 by Steve2