Quote
NoCoast
Large amounts of blow by pressurizing the crankcase in a huge way.
Plus it was some POS Mitsu thing anyhow.

interesting....when I pulled my engine apart, I found a LOT of oil in the intercooler, turbo compressor, inlet pipes, etc.....I wonder if the same thing happened to me (just not as badly as yours)

Built engines, running forged pistons, loose tollerances, and high boost....make a good amount of blow-by.

It's very common on Subarus, and other turboed motors.

Your AOS will be handling all that oil that you found in the intercooler, pipes, etc when you took your motor apart. Run a BONE STOCK wrx hard, and you will be able to pour atleast a cup of oil out of the intercooler.


There is a reason that people run AOS's instead of a catch can.

Run a catch can, that holds a quart....i'll bet you it's full in half a rally (maybe less). Oil level is now down a quart, you toss the car into a corner, the engine starves for oil because it's now low, and your bearing goes SPIN.....CLACK CLACK CLACK....

That AOS is dealing with alot more OIL than you think.

I still have no clue what AOS means, but Chris just implied that it's the same as a catch can but it reroutes the oil back to the sump. You guys just teeing into the turbo return line to dump back in I presume?

AOS = Air/Oil Separator.

Yes...like a catch can, but designed to dump the oil back into the crank case.

I'm dumping it back into the middle crank case vent on the ej22. The turbo drain would be fine, but harder to get too.

Is that the one that's near the crank position sensor?
The previous owner on my car, which has a 2.2T swap from a Legacy, just had all of the breathers plugged together...

yes sir,

the one under the alternator on an EJ22T

finished up the bumper delete/replacement last night:





You can see where I replaced the Rad support and replaced the subframe brace and made a new skid plate mount. (I still can't find those pics of 'construction in progress).

Overall, the front end is quite a bit more solid now and about 32 lbs lighter.



Edited 1 time(s). Last edit at 08/21/2010 01:29PM by Jon Burke.

Quote
Jon Burke
besides, if you destroy your rings, wouldn't all your oil blow by and go out your exhaust? how'd you get all that oil in your crankcase ventilation lines when your pistons are pushing it out the exhaust valves? (serious question)

I got to drive a GLH (forgot whose it was, I guess its history was colorful) that had rings so bad that it kept blowing the dipstick out, despite a clever arrangement of hose clamps that were supposed to hold it in.

Last week, I pulled a sick engine from a Buick GN. Severe blowby. It wouldn't build any boost, but it would pressurize the crankcase so well that oily fox would come out of every gasket, seal, and breather. And pop the dipstick out.

I don't see how a bad seal between the crankcase and the combustion chamber could possibly result in oil going out the exhaust. It's going to be combustion gases entering the crankcase.

Evacuation systems that use the exhaust for vacuum at high rpm will put
oil in the exhaust, even with a AO seperator... An example of a nice set
of racing headers that will use crankcase evacuation...





The nipples in the collector gets a check valve, then hoses run up to the
AOS, which has a filter media inside it to hopefully catch most of the oil
fog, then has another pair of hoses to the front of the valve covers.

The system doesn't work very well at low rpm, only draws 1 or 2"hg,
but under load, at mid range and up, will pull upwards of 15"hg...

---

SteveL
This is the point in the killing spree when you really should turn the gun on yourself

I guess if y'all want to use extreme examples to prove your point,a feel free. I had a hairline crack and pulled my engine, I didn't want to risk damaging my heads.

Quote
Pete
I don't see how a bad seal between the crankcase and the combustion chamber could possibly result in oil going out the exhaust. It's going to be combustion gases entering the crankcase.

Pete....so that Buick, I'm sure the exhaust out the back was clear as sky, eh? All that combustion was just perfectly pushing back on the piston 100% of the time, 360 degrees around, keeping every drop of oil on the right side and not a single drop got by? Even on the exhaust stroke when there was no combustion (but yet enough pressure still in the crank case to blow out the dipstick, eh?)

Quote
Jon Burke
Pete....so that Buick, I'm sure the exhaust out the back was clear as sky, eh? All that combustion was just perfectly pushing back on the piston 100% of the time, 360 degrees around, keeping every drop of oil on the right side and not a single drop got by? Even on the exhaust stroke when there was no combustion (but yet enough pressure still in the crank case to blow out the dipstick, eh?)

Don't forget the exhaust manifold pressure, which would set a minimum cylinder pressure.

And yes, the exhaust WAS clear. I was, to be honest, surprised at this, given how poorly the engine was running.

The headers with the evacuaters are there to make more horse power at higher rpm.I guess they figure if the air in the case is under vacuum it's better then the crank beating that air around. When I rebuilt my first engine I blue the dipstick out the first time I jumped on the throttle. After it heat cycled it quit. All my other race engines had the dipstick hole plugged off. I have a plug on the side of the oil pan to check the oil.

Any pics Chris?
Seems like that empty space next to the alternator would be a great mounting location. Could fit about a 6" square in that area. Either catch can or a WRX coolant reservoir is what I was thinking. Though I also was thinking of putting the coolant reservoir over on the shock tower near where the stock wiper reservoir is.
My car is an Impreza with a swapped stock 22T and a 06 or so Forester Intercooler. Stock turbo but might grab a WRX turbo to toss on there. I'm sure I can find one for virtually free but for now I'm just focused on getting all the bullshit sorted.
What heads and turbo and all that fun shit are you running on yours Chris?
I was thinking maybe something like this, which would easily fit in that space.
http://www.merlinmotorsport.co.uk/p3381/OIL-CATCH-TANK-1-LITRE-BRUSHED/product_info.html
I kinda prefer a catch can is it lets you know if you're blowing by a ton of oil. I use a catch on the Merkur and end up with very little blowby. Tablespoons after around 100 competitive miles with it on. With a bad engine I was overflowing a 12 oz ghetto rigged 7-Up can within 3 miles.



Edited 1 time(s). Last edit at 08/23/2010 08:43PM by NoCoast.

Grant,

With the Ej22 there aren't many limitations, you can go as crazy as you want, or as simple as you want.

Most any DOHC Subaru heads will drop right on. You can use the AVCS heads from STi's, or whatever you want. There is alot of documention about compression ratios etc.

I'm using a GT28rs right now, which seems to work well. It's a bolt on turbo from ATP. But a VF39 from an STi is a good fit, and can be had for like $300.




With regards to an AOS on a Subaru...IMHO it's a neccessity. There is a reason that Crawford makes them, and others do as well. On a stock motor, you can do without it, but on a build motor when you start running big boost, forged pistons etc. You need the AOS.

I ran a catch can, ran a 20ish km stage, and the thing was FULL. The motor had no problems, great compression, leakdown within spec, etc.

I'm not joking that with a catch can you are down a quart of oil when your catch can is full.

With the catch can, i'd be topping up oil at every service, and emptying the catch can.

With an AOS, i can set it and forget it, and things work MUCH better.

I'm using this. http://www.ixizconcept.com/ixizaosep/ixizaosep_pd.htm

You running yours vented to atmosphere or rerouted back to the intake? We're talking about making one of these designed to mount where the AC condensor normally is and dumping back into the same place you mentioned.