Aussieflyer
Active Member
Thought I'd share my experience with running in my new YIO-390. I read the Lycoming material carefully. I used no power settings less than 82% power. Thanks to Van's design for the baffles, never had a temperature problem. At 40 hours the oil consumption appeared to have stabilised at around 1 quart for 22 hours operation. I changed the mineral oil out and used Shell 100W plus. Did a leak down test and got four 80/80's rings and valves nice and tight. Within two hours operation on ashless dispersant oil I started getting a puddle of oil on the floor after every flight. Examination revealed the oil was dripping out of the sniffle valve (intake manifold one way valve). I asked Lycoming what they thought and got no response (not impressed with their customer service).
A local Lycoming mechanic told me that I'd taken the run in oil out too early, he said the IO-390 should be run in up to 100 hours. I was instructed to take out the 100W plus and immediately replace it with run in oil (mineral oil) and to go and fly the aircraft for the next 50 hours at wide open throttle (WOT) not above 5000 feet (the lower the better). After the first 2 hour flight - bingo no more oil coming out of the sniffle valve and not a drop since.
I just finished reading a nice article in April's 2017 Kitplane magazine by Reinhard Metz on the IO-390, where at page 46 where he writes, "One thing that is not so well known about the IO-390: The typical approach to break-in is to run the engine hard in first flight(s) (and with power variations) to press the rings out and help them seat...... The IO-390 doesn't behave this way. According to Lycoming, and true to my experience, the IO-390 rings may take as long as 50 hours or more to seat and for the oil consumption to drop. Apparently they are made of harder material, which is responsible for the longer break-in and supposedly have a longer service life. Hmm, well see."
Hope this thread is useful for those following. Anyone got similar experiences?
Alan
A local Lycoming mechanic told me that I'd taken the run in oil out too early, he said the IO-390 should be run in up to 100 hours. I was instructed to take out the 100W plus and immediately replace it with run in oil (mineral oil) and to go and fly the aircraft for the next 50 hours at wide open throttle (WOT) not above 5000 feet (the lower the better). After the first 2 hour flight - bingo no more oil coming out of the sniffle valve and not a drop since.
I just finished reading a nice article in April's 2017 Kitplane magazine by Reinhard Metz on the IO-390, where at page 46 where he writes, "One thing that is not so well known about the IO-390: The typical approach to break-in is to run the engine hard in first flight(s) (and with power variations) to press the rings out and help them seat...... The IO-390 doesn't behave this way. According to Lycoming, and true to my experience, the IO-390 rings may take as long as 50 hours or more to seat and for the oil consumption to drop. Apparently they are made of harder material, which is responsible for the longer break-in and supposedly have a longer service life. Hmm, well see."
Hope this thread is useful for those following. Anyone got similar experiences?
Alan