View source for Oil Separator for Crank Case Vent Line

Aircraft engines don't use tightly fittet pistons as they are old air-cooled designs with large temperature spread. Therefore there is a lot of blow-by past the pistons ending in the crankcase. The stock solution is to use a 1 inch hose and just dump those fumes out the bottom of the engine compartment leading to oil and dirt accumulating on the bottom of the fuselage.<br>
There are designs that separate the oil and return the oil into the oil sump and only dump the cleaned fumes out the bottom. Drawback is that not just oil condensates in the separator but also water and therefore water is returned back into the oil pan. This happens when the oil separator is cold in the beginning and potentially during the entire flight if installed in vented/colder area of the engine compartment. See this [https://www.youtube.com/watch?v=2_pRXfPp5wQ video] about how much water accumulated in a catch can.<br>
To further clean the remaining fumes coming out of the separator, some opt to feed them into the exhaust pipe. Because the exhaust is very hot, burnt residues build up at the adapter which needs to be cleaned out at every oil change. To rule out clogging, it is necessary to also install a bypass valve that opens should the exhaust feed close up.<br> 
There are other designs that just use a reservoir (with overflow hole) to hold the separated oil / water for manual dump during oil change.

See this [https://www.danhorton.net/Articles/Separator-or-Condenser.pdf Kitplane article by Dan Horten]<br>
See this [https://vansairforce.net/community/showthread.php?t=209922 VAF Thread]<br>
See also this [https://vansairforce.net/community/showthread.php?t=209226 VAF Thread]<br>
See also this [https://vansairforce.net/community/showthread.php?t=198443 VAF Thread] (with pictures of clogged exhaust adapter)<br>
See also this [https://www.facebook.com/groups/vansrv10/posts/5684489401672112 FB Thread]

==== Vendors providing oil separators for the crank case vent line ====
* [https://www.aircraftspruce.ca/categories/aircraft_parts/ap/menus/ep/airoilseparators.html All Products at Spruce]
* [https://antisplataero.com/products/the-asa-oil-separator AntiSplat]
* [https://www.amazon.com/dp/B09B1QMS8G Cheap but heavy (1 lb) Amazon solution]
* [https://www.aircraftspruce.ca/catalog/eppages/enginecrank.php 3/4 inch reservoir type at Spruce]<br>

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