Oil consumption during break-in

[mluvara]

Originally Posted by Bsquared

I am running a stock 390 and have been following the recommended break in.....long flights At WOT and 2500 rpm. At 6500 feet that gives me about 72% power..... well above the 65% recommended min. I am right at 20 hours and my CHTs and oil temps are good but I am still burning about a quart of oil (AeroShell 100) every 4 to 5 hours. Is this common? I have heard that it can take over 50 hrs to break in the 390. The belly is clean so not going out the crankcase vent.

Curious - what CHT temp did the break in log at Lycoming record on the 15 min run at rated power?

Michael

[Bsquared]

15 min full power run CHT is recorded as 374. I assume this was the highest Cylinder

[mluvara]

Originally Posted by Bsquared

15 min full power run CHT is recorded as 374. I assume this was the highest Cylinder

Thanks. I'm involved with an IO-390 (not in an RV) that is in a similar predicament. This engine is at 50 hours and still consuming oil (~1 qt every 3 to 4 hours. Lycoming said the same thing. Continue running mineral oil and monitor consumption. Max CHT on this engine on the factory run in was 299, which seems low. We've been running it as recommended. Oil is pooling in cylinders and seems like the cylinders are glazed. Will see what happens. Figured it would be run in by now.

[Jimzim]

Originally Posted by Ironflight

More time on the run-in stand is a good thing to negotiate if you can - I have found that a couple hours pretty much breaks in a standard Nitrided Lycoming cylinder. Also make sure you have the airplane as slick as possible to get maximum cooling - wheel pants, fairings all complete.

Paul

Thanks Paul, all good advise. After contacting Lycoming directly, I won’t be able to add any test stand time. I was told that they don’t usually offer that option. Curiously, they also said that test stand CHTs routinely hit 450, at least on the 360 series of Lycoming.
After speaking to both the sales rep and the tech rep, I am pretty much left with proceeding with early morning flights, WOT, 2500 rpm and don’t throttle back unless CHTs exceed 450. They seem confident that I won’t have any problems.
I don’t mean to highjack the thread, but just wanted to post in case anyone was wondering about buying run in time from Lycoming.
Thanks, Jim

[Nova RV]

Just another current data point, I changed oil in Dec at 125.5 tach time and have added 1qt since then at 143.0 tach time so about a qt per 18hrs now. Oil consumption gradually has decreased since new and I think is pretty steady now. I fill to 6qts and add once it gets to 5. This is a Thunderbolt IO390.

[bmarvel]

Originally Posted by Nova RV

I have found that the -390 likes 6 quarts and no more. If you top off to 7-8 you will see horrendous numbers as you refill constantly back to 7-8. Leave it at 6 and it will last much, much longer before it goes down to say 5 qts. This is of course after actual break in is completed.

+1 on this post. I refill with 6 quarts and a new filter, and then wait to add a quart when the dipstick shows 5. With 721 hours on the 390, I average about a quart every 10 hours. I'm in Colorado and did my initial flying as low as I could safely fly at full throttle and 2600 RPM. CHTs were around 420 on the first couple of flights but then started dropping. In cruise flight these days here in the high west, I see CHTs in the low 300s running WOT, 2400 RPM, 8 GPH and 160 knots TAS.

[JDA_BTR]

My 390 in the 14A is a little better on the oil level. I fill it to 7 and it goes 15-20 hours before it hits six and adding a quart. Not sure why it hangs in there so well since some engines just can't keep the level up. My arrow was terrible; would dump to 6 no matter what you did, then sit at six a long time.