Open Crank IC Engines

Discussion in 'General Engine Discussion' started by neil_1821, Jul 13, 2018.

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  1. Jul 13, 2018 #1

    neil_1821

    neil_1821

    neil_1821

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    I just have a quick general question regarding open crank engines. As some will have seen i've completed my Hoglet V Twin and usually after running i get fuel/oil (black mess) on the flywheel which gets flung everywhere. It's not excessive but I do have to clean the flywheel after it's ran.

    I've adjusted the fuel so it's not running rich, but is this perhaps a symptom of loose O rings? Or is it perfectly normal? I can't imagine the O rings being too loose otherwise it wouldn't fire.

    If it's normal then no worries!
     
  2. Jul 13, 2018 #2

    Brian Rupnow

    Brian Rupnow

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    If you at running any kind of oil with the fuel, you will always have mess to contend with. These little engines seldom get hot enough to burn the oil in the combustion chamber, so it passes tight thru and out the exhaust. If the hoglet has a sealed bottom sump and this is happening, then your oil control rings aren't doing their job.---Brian
     
  3. Jul 13, 2018 #3

    neil_1821

    neil_1821

    neil_1821

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    Thanks for your reply Brian

    Yeah the Hoglet is open as per the design, I just wanted to make sure that it was classed as 'normal' which I thought it may be given there is only 1 O ring. I'm used to having an oily mess to clean given I spend a lot of time running steam locomotives but since it was my first IC engine I thought I'd check.
     
  4. Jul 13, 2018 #4

    Jasonb

    Jasonb

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    As I said on ME on an open crank engine you will always get some much coming out of the bottom of the cylinder particularly on a new engine that is bedding in the rings and may well have been flooded a bit while trying to first get it to start.

    Have a look at this engine I finished recently, you can see a small pool of black liquid sitting in the well below the crank.

     
  5. Jul 13, 2018 #5

    neil_1821

    neil_1821

    neil_1821

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    That’s a nice engine Jason, is it a hit and miss?

    I see what you mean by the puddle, so I’m relatively happy that’s it’s perfectly normal
     

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