Bravo Oil Level

[Davidv]

For the Bravo owners out there, what oil level does your engine typically like?  As I’ve mentioned in a previous post, I’m a new owner it’s burning slightly more oil than I would expect and I’m curious if there is a common level where it does best.  Mine is a pretty low time engine. 

@mike_elliott was kind enough to give me his take when we flew together a few days ago but interested to hear from others as well!

[Steve Skinner]

I start at 10 liters/pints

By about 10 hrs I’m at 8.5

I add a pint and that gets me 25 hrs.

Apparently I run my engine at higher power levels than some at 31/2400 1600 tit (100rop) = 19.5-20g/hr

 the last engine made it to TBO without issue and still had compressions around > 73/80 

[LANCECASPER]

If I put 10 qts in it goes down to 8 within probably 6-8 hours and stays at 8. If I put 8 in, it stays at 8, so therefore I keep it at 8 .  . .lol

Only exception to that is with long range tanks if I was going to do a marathon flight I might add one extra quart for peace of mind, but usually even then when I land it's at 8 quarts and I have a quart of oil all over the belly.

[nfonville]

I put in 9 qts at oil change and let it go down to 7 qts with about 8 hours of flight.  Add 1qt.  Mine will throw anything over 8 on the belly.

[Davidv]

Thanks for all of the responses so far - May be a stupid question but anything wrong with letting it drift towards 7?  I’m at 8 at the moment but want to see if the consumption slows at 8.

[Steve Skinner]

  On 2/16/2019 at 1:19 AM, Davidv said:

Thanks for all of the responses so far - May be a stupid question but anything wrong with letting it drift towards 7?  I’m at 8 at the moment but want to see if the consumption slows at 8.

Expand  

It won’t stop at 8.

Some  engines throw oil on the belly over 9 quarts, mine doesn’t.

The logic of not going below 8 is about volume available to cool the engine.

The Bravo oil has a much larger task than most due to its requirement to cool exhaust valves. So between that and the turbo you get a 25 hr mandated oil change.

Personally I’d always top up at 8.

[Bravoman]

I put 9 quarts in at oil changes with about 10 ounces of camguard. That ends up reading as close to 9 quarts on the dipstick. For my plane, 8 quarts is definitely the sweet spot. I add about a quart and a half between oil changes which I do at 25 hrs.

[Awful_Charlie]

My old engine would blow anything over 8 out through the breather quite quickly so I would fill to 8 at oil change, and then top up when it was down to 7 (I measured and scribed lines for the odd numbers on the dipstick). Towards the end of it's life with me (at TBO +10%), the oil consumption got up to a quart each 5 hours or so, and I experimented with letting it go down to 6 to see it that made any difference to the oil consumption . No improvement on the consumption by letting it go down, and no detectable change in the oil temperature - the certification for the engine has a minimum safe quantity of 4 but I wasn't prepared to go down that far.

Currently holding the new engine at 8 and it seems happy there, but haven't got any good figures yet for consumption, having had to cope with a series of leaks caused by the exchange (which I think I'm just about on top of now, just need to go fly it more)

I'm afraid I don't get the argument for increased quantity increasing cooling - the extra oil just sits in the sump, and the sump is not a great cooling facility. The pumped oil is just a transfer medium from the hot spots (ie head and turbo) to the oil cooler - as long as the oil does not contain a significant amount of air  (due to the pickup being close to the surface, think of it like a bath plughole after you pull the plug out and the water level drops - it is only the last inch or two when it sucks air in with the water, and the last inch or less when there's not enough to fill the hole). The oil cooler has a oil heated surface area of something like four square feet, with thin walls, fins to increase the air surface area even more, and sits in an area of high air volume movement. Contrast this with the sump where the increased surface area of casing by raising the oil level from 6 to 8qts will be at a guess a few tens of square inches or less of thick aluminium, without the benefit of fins or a dedicated air flow

[AustinAir]

My ‘99 M20M likes to stabilize at 9 

[Rick Junkin]

Another 8 quart airplane here.

I put in 8 quarts of Philips X/C and a full 16oz of Camguard at oil change which registers at just over 8 quarts on the dipstick. Then add another quart of oil at about 13 hours when it gets to just over 7 quarts on the dipstick, and that carries me through to the next oil change at 25 hours. My engine has 800 hours SMOH.

Cheers,
Rick

[Danb]

Ditto start at 9 on stick add a quart at just under 8, agreed the extra oil above 8 goes on the belly..

[affricate]

I start at 10, after 6 hrs flight I'm at 8.5,

 

Oil on belly. 

 

Bravo lines not leaking 

[LANCECASPER]

On the Bravos I had I learned to start at 8 and it stayed there a long time. When I started at 10 it stayed on the belly a long time . .lol

[JohnB]

+1 on eight, as my prior engine would stay at 8 for a very long time, but would waste to 8 if I filled higher, so I just filled to 8 quarts when I need to and had very low consumption.

Interestingly to me, I just had a FRM engine put in a few months ago and the number seems to be 9 now.