Excessive oil from the breather??

·         PHILIP BIRD

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I now have 40 hrs on my engine and I would have thought the rings should be bed in by now but I am having to put in perhaps 50mil of oil per hr. This has been the same since new. I try to keep the oil in the middle of the dip stick (deep sump 2200). It was making a mess on the bottom of the plane so I now have a catch bottle on the firewall. The engine is running fine, all the temps if anything are to low. I can also hear air coming out of the breather pipe if I turn the engine over by hand.
I thought I might do a leak down test at the 50hr mark.
Any suggestions
Thanks
Phil

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·         Doug Smith

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Hi Phil,
That's 40 hours from new? Have you been using run-in oil the whole time? It does sound like it's not bedded in as well as it could. You might find that a few hard sessions of circuits will help. your leak down results would be interesting too.

Ultimately it might just be the way that particular engine is. Mine has always been a bit like that (particularly on a cross country flight) but it's oil use is within limits and it otherwise runs like a top so I've left it alone... And of course I (we) made it out of leftovers and floor sweepings so a few quirks are to be expected!

Depending what you find, fitting an oil condenser / return might address the symptom (oily belly).

Regards,
Doug.

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·         PHILIP BIRD

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Thanks Doug
Yes 40hrs from new (well 0 hr solid lifter engine). I used Aeroshell run in oil for the first 25hrs and now its Phillips 25-50 multigrade. I deliberately
tried not "babying" the engine from day one although the prop I was using A Sensenich 60x46 from Jabiru probably wasn't really loading up the engine.
Anyway I will see how things go but like I say "touch wood" the engine is running great and pulls the Sonex along with ease.

Phil

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·         Doug Smith

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Ah, fair enough. Well as I'm sure you know, if the prop is a little on the fine side then don't be scared to let it rev a bit higher during normal ops. A 2200 that revs out to say 3400 at full power straight and level can typically cruise at around 3000 happily enough. Your EGT will tell you once you're above the "step" in the needle (I.e. Above normal continuous power) or the other hint is fuel usage - about 15 lph should be loading the engine about right.
But all that's optional really, if it's behaving then theres no reason to do anything drastic 🙂
D.

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·         PHILIP BIRD

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Thanks again Doug

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·         PHILIP BIRD

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Update on this Engine of mine for you Doug and anyone who might be interested.
A couple of weeks ago I did a 50hr service.
Compression 140,135,130,135
Leak down 80/76, 80/74, 80/73, 80/76, All of which I figure is very good.
The oil consumption over the 25 hr period worked out to be 30 mil/hr all I suspect lost down the breather into the catch bottle. I now think perhaps this is not excessive, annoying perhaps but as you say it is what it is.
I have also been trying a Thompson 56x48 prop, cruise is great, 120knots at 2900. Climb is not as good, cht's are up a little in climb.

Regards Phil Bird

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·         Doug Smith

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Hi Phil,
That all sounds pretty good.
Horizontally opposed engines do tend to be a bit oil-hungry, but 30m/hr isn't bad in the scheme of things 🙂
Regards,
Doug.