Crankcase breather/oil separator


·   Environmentally Friendly

·   Keeps your oil on board, not overboard

·   Applies to most engines from 65 to 350 HP

·   Will retain the full 8 qts in your Lycoming

·   Returns breather oil discharge to the pan, not your cowling

·   Vents sludge inducing condensation overboard when properly warmed up

·   Lightweight, approximately 6 ounces.

·   Easy installation

·   ¾” inlet, ¾” outlet, ¼” return to crankcase

·   Mounts in-line, no hard mount required

·   Retained capacity increases engine life

·   Retained capacity means greater safety reserve

·   Reduced operating costs

·   Retained capacity means improved cooling

·   Made of high strength aluminum

·   TIG welded for strength and security


Do not let the low price or compact size mislead you.

The compact size is  important to the fit and function of the product.


What it does


Simply put, it keeps your cowl clean and your oil sump full.


But seriously, it keeps your cowl clean because it does its job of separating oil mist from crankcase breather gasses.

Another issue frequently brought up when talking about breather gasses is water vapor. This is the stuff you see pouring out of the tailpipe of the car in front of you in stop and go traffic.


After you shut your engine down, warm moist air condenses on the cooling metal and ends up in the crankcase in the form of water droplets.


Your engine should be allowed to warm up to the point where the water is heated past the boiling point for enough of a period of time to convert it back to water vapor, which will exit with the breather gasses.


How it does it


While it may appear to be cyclonic, the velocity is too low to benefit much from this. The offset intake helps the breather gasses contact as much of the internal surfaces as possible and the rest of the internal design optimizes flow, minimizes back pressure while keeping breather gas temperatures high enough to maintain the water in a vapor state. The internal baffling is very efficient in removing nearly all of the engine oil from the breather gasses.

Do you fly “Two Low”?


The typical flat four cylinder aircraft engine sump holds eight quarts of oil, yet when filled to capacity it will agitate and purge two of those quarts straight out the breather in the first two hours of running after filling to that level.


People typically manage the mess of oily breather gasses rather than the cause and consider this an acceptable loss.


Consider that you are compromising for 75% of your oil capacity.


Oil both lubricates and cools your engine.


You are giving up 25% of your engine lubrication.


That’s 25% of your oil reserve wasted on your engine cowling in the first two hours of flying.


Because your oil makes a significant contribution to your engine cooling this initial loss of oil reserve is a loss in cooling capacity as well.


Flying too low often implies poor Risk Management; flying “two low” is unnecessarily putting your engine’s longevity at risk.




The OIL MISERTM  should be installed as high as possible, within 15 degrees of vertical when in normal flight. The ¼” oil return should be in a constant downward attitude to a low pressure port into the crankcase above the oil level in the sump.


The OIL MISERTM  works by gravity, not pressure. The oil will not be able to flow back if it is going uphill, through a loop or against any backpressure be it higher ambient pressure or an accumulation of oil in the line.


The breather gas discharge line needs to exit the cowl into a low pressure area of the air stream. Pressures inside the engine cowling are generally greater than crankcase pressure which would prevent the breather from functioning properly.




At annual, remove the unit, inspect for damage, flush with neutral solvent and agitate. Pour out and repeat a few times. Blow out with shop air to remove excess solvent.


Blow in the inlet to ensure free flow through the unit and no back pressure. Air should be coming out the small discharge tube as well. If there is any back pressure, replace the unit.


This product will only operate as designed if recommended oil and filter service is performed at prescribed intervals.