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The A.S.A. Oil Separators

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4 Cylinder6 Cylinder
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Polished MirrorWhite Powder Coat
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“THE ASA OIL SEPARATOR” Is a solution to the oil consumption and collection of oil on the belly of your aircraft. The breathers kick out oil mist that collects on the belly that in turn grabs all the dust and dirt.

For years we have been making this type of product used in automotive racing engines so the leap to a light weight aircraft unit was a small one. After many hours on the dynamometer many changes and hours of flight testing the effort was well worth it. “ASA Oil Separator” that in our tests out performs most of the competition at a fraction of the price.

We are convinced our unit is the most logical, simple and inexpensive device that can be manufactured and installed in an effort to address these breather oil issues. This great little unit installs in minutes and will pay for itself in oil savings alone. The product allows the engine to function and breath as designed without interfering with its dynamics or operation in any way. The oil separator simply removes the oil from the blow-by stream and vents off the moisture and acids that can potentially harm your engine.

Full installation and maintenance instructions will be included.
California Prop 65 Warning Symbol

WARNING: Cancer and Reproductive Harm -


  • The four cylinder unit is intended for 210HP or less and the six cylinder unit is intended for 210 HP to 475HP.
  • Weight is 11 oz


In The Box

  • Mounting Clamp
  • Bracket for the firewall
  • Frequently Purchased With
  • Customers Also Viewed


No where in the aircraft spruce ad did it say it was for experimental aircraft only. so I purchased it. I could not get an STC so had to return it. and purchase another unit which is in back order at this time. I talked to Alan the owner of the unit I returned and He said you took his ad and shorted the ad and removed that it was for experimental only. This is not the first time I have run into a problem with spruce advertising or a product I could not use. I purchased a set of spark plugs and 1 was bad I returned it You said it was good did I want to pay shipping back to me for the Bad plug you determined was good. I said No. I told the lady to shove it into her airplane and take her kids for a ride. It was just a massive plug 30 bucks but really pissed me off. Your lucky I am still a customer. The resistance when I measured it was way out and not usable. I bet you will not put this on your web site because it does not favor you. Have a nice day Peter Cheney EAA chapter #489 Young eagle and eagle coordinator Statesboro Ga.

Peter C
February 1, 2021

I usually would loose about 1/2 quart every 2 to 3 hours of flight time. All compressions are good but just seem to have a lot of oil out the breather. I am flying behind a Lycoming 0-320 160 hp. I must say I am amazed...I maybe have one drop out the breather in 5 hrs so far. Nothing on the belly or in the cowl. I am very impressed!! Quality construction and polished as well. Highly recommend this...

August 31, 2020

Very nice construction and welding on the oil separator and with a high polish finish. Looks great and the vendors web site showing internal construction is helpful to understand its design features.

Gary K
August 28, 2020

Fast Shipping, Product is bilt with quality !!

Ricacrdo A
July 9, 2020

Very nice product

Grant R
December 20, 2019

Nice unit, and easy to install.

Brian D
December 4, 2019

This looks like a great kit and of superb quality! I’ll be back after 50 hrs to rate it more accurately

June 14, 2019

Worked incredibly well I used to see a steam of oil on cowling after each flight. Now there is zero oil passing by separator very impressive, Installed on my Velocity IO-360. Also quality is excellent!

Jeremy B
April 14, 2019

It simply works! Always had a wet belly and dripping after shutdown from IO540. Installed the 6 cylinder version and after 4 flights belly is dry and not a single drop of oil out of tube after shutdown.

Lane H
September 21, 2018


Please note,'s personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Are the A.S.A. oil separators nit PMA'd or STC'd?

No. This unit is experimental and is not STC'd or PMA'd.

Q: 1. What size are the inlets/outlets? (both air and oil) 2. Can the body be opened for inspection, or are both ends welded on?

The push on fittings are 5/8" OD. The oil return is a male AN4 threaded fitting. Each end is welded closed.

Q: What are the dimensions of both 4 and 6 cylinder units, diameter, height of can and inlet/outlet port lengths?

4 cyl. 2" dia X 4" height and 6 cyl. 2-1/2" dia X 7" height. 4 cyl model has 5/8" in & out, 6 cyl has 3/4" in & out.