O-360 break in oil consumption

Discussion in 'Firewall Forward & Fuel System' started by harleygaz, Jul 5, 2018.

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  1. Jul 5, 2018 #1

    harleygaz

    harleygaz

    harleygaz

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    Hi. I have 5 hours on my zero time HO-360 and in that time running 2500-2600 rpm for most of it I have used about a quart of straight 80. I have no idea if that is good or bad. I’m in N Mississippi and it’s been hot but mostly flying mornings in mid 80’s temps. What consumption should I expect when the engine breaks in? Cheers, Gary.
     
  2. Jul 5, 2018 #2

    TFF1

    TFF1

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    Kind of depends on the overhaul. If you see consumption go down per hour, it is breaking in. if it is using the same amount per hour, keep running it. If its still bad after 20 hours, you might need to do something. Straight 100 would be better. You need to run it hard. Full throttle; but watch the CHTs. Low power will glaze the cylinders and it will use oil until you hone it again and put new rings in. Don't do long ground runs.
     
  3. Jul 5, 2018 #3

    harleygaz

    harleygaz

    harleygaz

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    Keeping to 2500/2600 rpm as best I can but #3 is always high CHT even then. 480 or 490 and #4 is about 20 lower so can’t hit full power for too long. Plan to switch to 100 when I change the oil and filter. Overhaul was zero TSMOH with Superior cylinders. Hits 2500 static with a 72 x 56” pitch Sensenich so seems to be a good tight build.
     
  4. Jul 6, 2018 #4

    cwilliamrose

    cwilliamrose

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    "72 x 56” pitch Sensenich"

    Is that correct? Sounds like an O-320 prop.
     
  5. Jul 6, 2018 #5

    harleygaz

    harleygaz

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    My mistake, it’s 76x56. I had it repitched as a climb prop.
     
  6. Jul 6, 2018 #6

    cwilliamrose

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    I was hoping that was the case, thanks for the clarification.
     
  7. Jul 6, 2018 #7

    TFF1

    TFF1

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    Low power lowers the the combustion pressure. The pressure pushes the rings tight against the cylinder walls. You want the rings to knock the hone marks down. Built in grinder. Low pressures polish the tops of the hone marks and at a certain point there will not be able to put enough pressure on the cylinder to break it in all the way. With the cooling problem, I would takeoff, fly until you see 425 and land and let cool. You are going to have to hop it and not pleasure fly it for a while. Don't let it go 480. You might borescope the cylinders to see the cylinder walls.
     
  8. Jul 6, 2018 #8

    PittsDriver68

    PittsDriver68

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    Your high temps suggest that you should look for sealing issues with your baffles. There is too much air going around the cylinders and hot enough through them. When breaking in Lyco's I never saw temps as high as 400F. But I am a fanatic about making sure that there is no excess air below the engine impeeding airflow through the cylinders.

    Best of luck,

    Wes
     
  9. Jul 6, 2018 #9

    harleygaz

    harleygaz

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    Ad best as I can tell the baffle seals are a tight fit but I’ll do some more checking to see what gaps there are between cylinders etc. I’ll also work out the exit area of the cowling as I think I may not have enough differential pressure across the inlet/outlet boundary.
     
  10. Jul 7, 2018 #10

    Saber

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    I agree that 480 is way too hot. First W 80 is 40 wt. oil and too thin for your temps, so I'd change it right away. Usually we run about 25 hours on mineral oil and go to detergent. That is provided that it has stabilized in oil burn. This is just me but I do a oil change at 1-2 hours and check the screens or filter , then 5 more hours. Then 15 hours or so and if the burn is stab. Change to detergent oil. I like Shell w100. If your not flying a lot W-100plus.
    I think you are on the right track with the baffling, exit air restrictions many times is a problem. Good luck, it frustrating chasing this stuff but you will get it.
     
  11. Jul 7, 2018 #11

    jrs14855

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    480 CHT is WAY too high. You have likely already glazed the cylinders and the engine will continue to use oil. My target for breaak in is 425 max CHT. Aeroshell W oil is ashless dispersant N OT detergent
     
  12. Jul 8, 2018 #12

    Acrobum

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    I just went through this on my Pitts with a Superior EXP IO-360. I wasnt easy on it. I was told anything over 23" is where you needed to be on break in, that put me right at 2800 RPM. Two hours at 2800 then another hour at 2700. 5 hours in I have yet to add a quart and running strong. around 385 CHT in climb, dropped down to 320 CHT at 2800 RPM cruising around. 1050 EGT at 2800 RPM and 11oo EGT in climb at 2650 RPM full power. Oil temp has yet to go over 175. Really happy but you have to run them hard and have really good cooling.
     
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  13. Jul 8, 2018 #13

    Saber

    Saber

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    This isn't a blog about oil terminology, I was very clear what oil I use. AD is the only thing used and yes there is a difference that means nothing to the average guy useing aviation oil. It's either mineral or AD, straight or multi grade in AD.
     

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