Open Crank IC Engines

[neil_1821]

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!

 

[Brian Rupnow]

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

 

[neil_1821]

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.

 

[Jasonb]

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.

 

[neil_1821]

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