Drip lubricator question

[jgedde]

For my Farm Boy build, I made the cylinder drip lubricator per the print. It does work, but I don't get a nice steady drip, drip, drip. The first drip comes out normally, subsequent oil no longer forms a drip but clings to the side of the drip tube and moves upward... The oil then flows down the sides of the "drip viewer" bore and out the bottom as it's supposed to. This makes it hard to see if it actually providing oil...

Clearly the surface tension of the oil is causing me the difficulties. Any suggestions? I'm wondering if any of the following would help:

Make the drip tube a bit longer? Put a nice flat end on the drip tube? Taper the end of the drip tube? Make the oil hole smaller (or larger)?

Thanks,
John

 

[Rustkolector]

John,
I have larger engines that do the same thing. A larger oiler helped on one of them. For a model engine you can try a thinner weight oil. Thinner oils should exhibit less surface tension. You don't need a heavy weight cylinder oil, and you don't need a lot of oil. However, if the viewing port under the oiler is vented and has no glass, then the oiler flow rate when the engine is not running should continue at the same rate when the engine is running. I don't think changing the shape of the oiler drip tube will help. Engine vibration breaks the drop surface tension prematurely. You can also try a light oil/fuel mix and just use the oiler for looks. A 4 stroke doesn't need as much oil as a 2 stroke.

Jeff

 

[jgedde]

OK, per another member's suggestion, I remade the center section making sure there wasn't a chamfer in the drip tube hole. In addition, I made it slightly longer. While I still don't get drip, drip, drip, the oil now gets attacted to the bottom of the lubricator and I can see it's working. I really looks like the lubricator is simply too small to drip. The droplets are almost the size of the view port!

John

 

[Lew Hartswick]

How about a "sharp" edge on the bottom of the tube? That should provide less surface
for the drop to adhere to.??? Just guessing. not a fluid dynamics engineer.
...lew...