TOPIC: Another home-built Air Oil Separator

Hi tonite I made another air-oil-water separator. This one's goin' on my '85 Subaru GL wagon w/ it's new Weber carb and air filter. I already have 2 different OEM type AOS's in this engine. I tee'd output hoses from those to a single hose to the new Weber air filter's plastic breather nipple.

Now it's winter and this all aluminum engine generates more condensation, plus the Weber has free'd up a LOT of hidden power, as a result some oil mist/water is getting past my existing AOS's. ,getting into the air cleaner nipple.

So here's another AOS made outta a thrift store $1.00 aluminum water bottle, w/ a '72 -up Mopar valve cover breather filter, grommet, and 5/8" hose nipple w/ a 1/2" copper 90 deg. piece.

It's just like the one in the Index under home-built AOS that I posted last winter. I added 2 stainless scrubber pads inside to help condense more vapor. It's going to go inline after existing AOS's before air filt. breather nipple. Hopefully will remove oil/water crud for good! Took about an hour to make. I'll detail install after JB Weld around hose barb cures. Here's pics of this one, anyone ought to be able to copy this idea.

PS 1-13-2014 Its been in place 3 weeks now works Perfectly. I've drained a couple OZ. water w/ some oil in it twice. Could probably ignore it all winter will hold a LOT of liquid!

Tracy G

I like it very good job Tracy .

Thanks, Bill!

Today the JB around the brass nipple is almost cured. I stuffed 2 stainless scrubbers into top they sit above the brass nipple, to capture fine oil/water mist. Area below nipple is open, black plug is bottom drain. The Mopar breather has a baffle and stainless mesh inside. Combined this way the whole deal will capture blowby mist that gets past my existing vortexing air oil separators. Hopefully will get all of it. Again it gets installed w/ breather on top so gravity can participate.

My Subaru generates a lot of water condensate being all aluminum, and oil mist is getting past my AOS's. I've been getting a little oil into the white plastic breather hose nipple on the chrome box air filt. on the Weber.

Neighbor hot rodder buddy has suggested to just vent valve covers out down to atmosphere. I could do that--but that goes against the spirit of emissions control. We are working towards gains in all 3 areas- emissions, power and MPG. Ron's Groove discovery does just that, this AOS breather filter catch bottle supports better emissions control and a cleaner engine internally.

A final trick to this is to extend hose legnths that connect everything together, this slows airflow speed and encourages blowby mist and water vapor dropout. With stock hitachi carb/aircleaner I had driver side valvecover hose run around back of spare tire to the vortex-type AOS, about 4 ft. of hose. W/ Weber conversion I shortened hose. Each valvecover nipple has a hose to a separate AOS, w/ stock setup each went to its own nipple on stock aircleaner. Weber install, chrome box aircleaner has one nipple, so driver side was shortened, and both hoses tee'd together to one hose to air cleaner white nipple. And I'm seeing oil mist into aircleaner now (of course the occasional urge to floor it now CAN'T have ANYTHING to do w/ that, right? )

So here it is, a neat 'lil trick to help keep the crud monster outta the air cleaner!

Tracy G

Quick update on this blue bottle--it's grabbing water w/ a little oil and capturing it keeping it out of my air cleaner--it works Great!

Tracy G

Warning to all,

I just wanted to warn you of a potential problem concerning oil/air separators.
I recently had a terrible experience which could've ruined my engine!

I built and installed a device similar to Tracy's and it indeed cleaned up the PCV emissions.
However, since it's been sub freezing weathering where I'm at and my car has benn sitting for several days, the water in my oil/air separator and it's input & output lines froze solid!

It all started when I took the car out one freezing morning and I noticed the engine was running very rough! I soon started to smell burning oil and when I got out to fill up I noticed Oil had sprayed out of the hood and onto the front of the car a bit. Things were so froze that I couldn't even open my hood at the time to see exactly what happened. Later that night while lying in bed I thought to my self, "I bet the condensation in the oil/air separator froze and prevented my engine from breathing, The engine gasket must've blew!"

The next day I managed to open up the hood and see what happened. Oil had sprayed everywhere! Upon further investigation I noticed the oil dipstick was popped out! Hopefully that gave out first instead of the head gasket! I've been driving fine now for a few days so I think all is ok.

So be aware anyone who uses a homemade oil/air separator in a freezing climate!
Bad things can happen to your engine! Especially if both your PCV & Breather lines connect together into the device prior to the air intake.

After that catastrophe, I bypassed the device and won't use it until the weather returns to normal.

I dont know why eveyone is trying to get rid of the moisture and crankcase oil vapors.
This vapor and water vapor will burn as fuel with the right equation.
It can actually be used to gain mpg,as we all know water injection will increase power.

The oil vapor can actually be cracked into burnable molecules to produce fuel with the moisture
to gain power and to promote oxidation also key in cracking to a burnable fuel.

Anyone doesnt believe this needs to study how they crack fuel at the refinery stage,we can take it even further.

Ive been doing this for along time,the groove inhances the vaporization process,remember vaporization and cracking are two different processes though they are related and work smooth together.So before you separate the muck think how to utilize it.

Dan Merrick

JV, it might help to use larger diameter hoses/hose nipple fittings for your air oil separator. That bad incident shows that there's enough water going thru it to freeze up in the size of hose lines used. But I'm glad you warned of what can happen! The dipstick acted as a crankcase pressure relief valve. Might be good to look at where the ice formed in it, and go from there. Might put the container in a warmer location. I had not considered the freezing aspect, I have 5/8" I.D. hoses on my setup. Hasn't been so crazy cold here.

Dan, I agree w/ you, if a way to use the water and hydrocarbons as a fuel/fuel enhancer can be shown. I first came up w/ this as a way to deal w/ the water and oil glop that aspirated thru the redirected PCv and breather hoses on my Subaru. Ron spoke when I first put this up, of making a "bb jar". I think Bruce McBurney has shown something like that too. My car had a bad incident one cold rainy night last winter, the glop had found its way into the carb, and caused a bad misfire.

This issue is the side effect from the PCV re-route mod which enhances the Groove. It's a serious one, and deserves deliberate attention.

The Condensator device and others are designed to partially do as you describe. I wasn't trying to turn the water oil and HC's in blowby gasses into fuel, just stop them from crudding things up. How would you go about making this stuff useful? Is there a simple way, how complex would it be?

Tracy G

Yes I've been thinking about that these days Dan. My conscious tells me the natural occurring moisture may be a good thing.

I've tried both methods, using the oil/air separator and without. I can't recall noting any significant changes in performance/economy if anything. I too, along with TracyG was looking to keep my intake cleaner assuming a better burn. But due to the extreme weather causing ice blockage I'm not willing to attempt that again for a while.

This reminds me of the following info. I've gleaned from MPG Mike Holler.
See these videos on utilizing the PCV blow-by waste as an enhancement.

PCV Gases System


Cal Cat - Fuel System


Anyone have experience with these?

Wow, JV, good info score there!

This afternoon I dumped out my AOS bottle, and the 2 smaller catch bottles on the valve cover hoses. The smaller ones were full of oily water, the big blue one had prob. 2 Oz in it. Hasn't been that cold here, but started getting rainy past few days.

I'm not at all surprised to see these from Mike Hollar, he's a serious Brainiac! nice guy and very helpful, a Gadgetman too. He's been in a few other programs, and does his own stuff too. These look like a better way to treat crankcase residue than just throwing away...

JV where did you find this info?

Thanks!

Tracy G

Today I re-connected the crankcase breather and PCV hoses back to stock type config. Removed homemade AOS and one of the 2 European type ones. Kept the black BMW OEM one in PCV hose. Had just too much water condensation in crankcase w/o active ventilation.Subaru is all aluminum engine, crankcase was just too "wet" even w/ 3 AOS'es. However the 3 AOS'es DID capture ounces of water and crankcase effluents. Passive like w/ the PCv re-route style is basically OK in warmer weather, but I am re-thinking winter configuration.
W/ just a few miles driven this way, the Subie seems happy, maybe even more power. Never had PCV active w/ the Weber carb till now. Will see how it does like this. Researching other ways of working w/ the PCV system.

Tracy G

go to fuel savers # 4 bruce mc burney has a air oil separator i have one works great

Milton any info or pics of your AOS is it from Bruce McBurney? Can you elaborate pls?

Tracy G