Discussion in 'General Discussion' started by stevron, May 19, 2013.
What is a acceptable oil disappearance for a lycoming engine?
Email Lycoming. Not being funny here, but they will have done the testing, and they will also have the data coming in from their service outlets. Much more accurate than "Mine's fine" etc.
As a general comment you could expect a little more than normal while the engine is running in (50hrs or so). The bulk of the running in should be complete after the usual 25 hrs or so, with oil consumption tapering off after that. It does not magically arrive at its end point oil consumption at 25 hrs.
Do the basics, have a GOOD look around to see if there are any leaks, run it up with the cowl off to see if there are any leaks under pressure.
As above, contact Lyc to see what that "normal" consumption is. If the 233 is anything like other GA derived engines (as distinct from smaller LSA type engine, Rotax etc) then you can expect more oil consumption that you would expect as being "normal" from a smaller engine.
IF your rings haven't bedded in properly it will show as blow by. You can examine what amount of fumes are coming out of the breather. Has the engine been sitting for a long period out of use since it was put into operation?. If so do a boroscope examination of the bores for corrosion. Nev
Stevron, Facthunter has probably had the most experience in this engine class. It might help him if you could tell us how much it is using.
The engine is using 1.5 quarts per 5 hours, there seems to be a drip at the end of the breather pipe. Stevron
What's its run in history? You might find someone who will measure the rate of blow by. The engine can take quite a while to bed in the rings especially if there is no dust and it's not working very hard. I'm still a little concerned about whether it has been sitting idle for say a month. Don't give it a short run then put it away . It should be fully warmed up and this may take an hour.. I wouldn't be worried about that rate of oil consumption if it has still got say 50 hours up. Are your oil and head temps good? Nev
Have you got the new prop yet Steve? When speaking with you at Thurgoona you indicated it is under propped. I believe that can lead to low cylinder pressures which is not good for bedding in rings. Cheers, Laurie.
And work it hard...don't baby it. Ly comings do better at higher revs and you will avoid glazing the bore.
I can't remember what Lycoming say oil consumption should be, will try to find the info. Yours is high from what I remember of lycoming info.
The main cause of high oil consumption, other than leaks is blow by and this can be caused by poor break in procedures. Get a leak down test done and that should show if you have blow by or leaking valves. the drip at the breather points towards blow by, but a leak down test is your best bet. O.M.E had a tester for sale cheap recently. but you still need 80 psi compressed air.
It can be done with the engine running. I think it works on the same principle as an Argon gas flow meter. I'm not sure that engine has been in service that long and if it hasn't I would be prepared to give it a bit more time as long as there is no cylinder damage due rust. That's why the boroscope. Some oils have a tendency to vent off some solvents as soon as they are heated a bit so after they are topped up the oil consumption stabilises at what it really is. Nev
That is almost 1.5 litres every 5 hrs...seems a lot to me
To cut a long story short ( As in how to run in a new lycoming engine ,that could be a huge thread in itself as there is so many opinions on the subject) the formula for the maximum allowable oil consumption is
0.006 x BHP x 4 divided by 7.4 = quarts per hour. according to Lycoming
PS- I reckon most of the "Run in" is done in the first hour, but the engine has to be run IAW the engine manual for the first 50 hours to make sure that the rings have bed in properly.
Also Lycoming run brand new engines on a test bench I believe, so a lot of the Run in procedure is done by them. Well the initial part. Off the top of my head, they must be run hard for the run in period, I'm thinking about 80 percent throttle for 90 percent of the time for the first few hours. To me a few hours would be at least 10 hours. Not really a problem in a draggy plane but could be a real problem in something like a RV4 as a example.
No experience with the 0-233, but lots with the 0-235 which I ran for 2400hrs, (full TBO), in a C152. My consumption was between 75 and 100 mls per tacho hour. With the new engine, I flogged it for the 1st hour or 2, probably anywhere from 2700 to 2550 RPM - then ran it at 75% - about 2500 RPM I think for another 5 hrs, Plenty good advice already - perhaps run it really hard for an hour or two again and see if that helps.
Lycomings generally need really hard running to get everything bedded down, and then they seem to be very low oil users. The IO-360 that I have in my RV9A was run really hard for 5 hrs, but exceptionally hard in the 1st hour. Result is that it uses less than you'd believe - around 60-80 mls /hr depending on the type of operation.
Same as poteroo for our Rv9a. Our low compression 0-235 on our latest trip (2600 nm) consumed one pint of oil. The motor now has 270 hrs Tach time and 240 hrs Hobbs time. We got heaps of conflicting instructions on how to break in a Lycoming. We finished up going with Lycomings manual and tied the aircraft down and flogging the sh!t out of it for an hour. This was done in several sessions on the same day so there was no waiting for oil temps to come up and it was full throttle untill cylinder head temps got over 400*, we then brought it back to a high idle for a couple of minuts to allow temps to drop and then shut it down to cool. Then apart from first flight flogged it for the first ten hours. I used the first ten hours to do full throttle climb and speed tests etc. Our breather hose always has a drip sitting on the end of it so I don't think that is excessive blow-by unless there is oil splatted around the breather hose.
Agree with you RR - except that it's probably better to do the hour in flight so that you can check the individual cylinder CHT's under flight conditions. I'd be worried that in ground running you might have uneven heating which wasn't reflected under in-flight conditions. We've broken in about 10 Lycomings here, mostly 0-320 and 0-360 variants - and have done the same for them all. One special point was to not go too high on the 1st flight so that power was high for everything except the last bit of the approach and of course taxying. You need to avoid any rapid cooling because the CHT's tend to be higher in these early hours. On my own IO-360 there's barely a drop from the breather. It's now 130TT.
Some model Lycomings have nitrided cylinders and others don't. Generally the low compression motors don't. This would have a bit of an effect on the bedding in. Getting a new motor really hot is not advised. If the fits are critical you may get binding and seizure. A new motor runs hotter already than it will after bedding in. Heat is the problem during the run in period. Shock cooling has always been a problem with these engines so avoid it if you can. Also the rings don't seal as well as they will after a few hours If there are local areas where blowby is excessive the ring may warp and never perform right. Why not do a boro inspection of the bores? It's not rocket science.> Nev
I can confirm that the formula Dazza gave is correct for all Lycoming engines.
My new Lycoming O-320 had an initial run in at the factory as follows.
1500rmp for 5 min
1800rpm for 10 min
mag check 1800rpm for 1 min
2200rpm for 10 min
Rated power 2682.8rpm for 15 min
Idle for 4 min
The sum total is less than the break in for a 2 stroke Rotax and I don't ever want to do that again.
After this the recommendation is to fly, take off full power and shallow angle.
reduce to climb power as per aircraft POH. At cruise altitude reduce to 75% power for 1 hour, then vary between 65% and 75% for the second hour, then full throttle for 30 min. land and check everything.
After that fly at 65 to 75% for total of 50 hours.
All well and good, but if you are flying a new plane with a new motor there have to be some changes.
The break in formular that Yenn stated is correct. I just looked up my engine log book and that was the procedure we followed as ours was a complete rebuild.
I can remember flogging the hell out of the engine, but that formular was the procedure we went by.
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