Exhaust Crankcase Evacuation

[guaynabo89]

Steve, this ones for you!


The dilemma was me making fun of Steve for his catch-can setup. I was telling him that it is a way, but not a very effective way, to relieve crankcase pressure.

.

wait wait wait......one second.......


Steve showed you his catch can!


damn it, he wouldnt even open the hood for me let alone show me anything.

[2drSE-i]

wait wait wait......one second.......


Steve showed you his catch can!


damn it, he wouldnt even open the hood for me let alone show me anything.

Haha, your just jealous because i didn't make fun of your catch can!

[guaynabo89]

lol


you couldnt find my catch can.

[Civic Accord Honda]

If you plug your pcv system you are going to use way more oil then you should, it's probably leaking out of every seal on the engine

its not completely plugged the valve cover has a breather on it which sprays my valve cover and sprak plug wires in oil but its only temporary until i can make myself a new catch can and hook it up that way, and it is burning less oil this way
i have around 273k on my engine so there is a lot of blow by
less blow by now that i adjusted the valves tho which is weird

[lostforawhile]

its not completely plugged the valve cover has a breather on it which sprays my valve cover and sprak plug wires in oil but its only temporary until i can make myself a new catch can and hook it up that way, and it is burning less oil this way
i have around 273k on my engine so there is a lot of blow by
less blow by now that i adjusted the valves tho which is weird

without the circulation through the crankcase, your oil is going to load up with sludge and acids formed from the sludge combining with water. the circulation is needed to remove water vapor, the valve cover breather isn't going to let the water escape. you aren't old enough to remember engines with road draft tubes instead of PCV systems, every one of those engines would be coated with sludge inside. The pcv is much more then emissions, it stops sludge formation inside of the engine

[Civic Accord Honda]

yeah which is why i plan to hook it back up with a catch can (one of them water sepraters or w/e there called from home depot and HF that go on air compressors) but for now i couldn't afford to keep dumping oil in her lol, ill get it fixed next month

[AccordB20A]

i got tired of my car severly smoking, when i took the intake off there was like puddles of oil in the runners. i stopped this and half of the smoking too by plugging the vacuum line from the intake and taking the pipe off that black box thing so now it just vents out to the air, i dont know how effective this is but at least now after 7000rpm accelerating heavily i can still look and see whats behind me in the rear view mirror, rather than a blue cloud of smoke screen

[Xaisk]

Interesting. So what your saying is that putting one of the breathers on the crankcase vent isnt the most promising way to do it? and that a catch can is what I need?

What exactly is a catch can and what does it do?

Also how much would one be and how hard would it be to set it up?

[2drSE-i]

Interesting. So what your saying is that putting one of the breathers on the crankcase vent isnt the most promising way to do it? and that a catch can is what I need?

What exactly is a catch can and what does it do?

Also how much would one be and how hard would it be to set it up?

A catch can is just a ventilated can that is tied into your crankcase and/or your valve cover, to catch excess oil vapors and/or blowby. I'm not sure where you have your breather filter connected, i assume on the side of the valve cover? if so, no sweat. As long as you didnt seal it your ok. Chances are, no oil will ever come out of there.

[Xaisk]

A catch can is just a ventilated can that is tied into your crankcase and/or your valve cover, to catch excess oil vapors and/or blowby. I'm not sure where you have your breather filter connected, i assume on the side of the valve cover? if so, no sweat. As long as you didnt seal it your ok. Chances are, no oil will ever come out of there.

I didnt seal mine and havent had any issues yet.

But I live in Mississippi and lost said that if you dont use a catch can, itll be more susceptible to water turning the oil more acidic and lowing your detonation power. Mississippi is RIDICULOUSLY humid so thats a very probable issue.

I would be wise to get the can.
Ill probally make one using that guide posted further down the page.

When making one Id pretty much route it from the crankcase to the can then to the breather on the valve cover right? then just put my little filter onto the can?

[Accordtheory]

Stock

In stock Hondas, including our old school beaters, the PCV (Positive Crankcase Ventilation) system is designed to relieve crankcase pressure, which builds and causes poor ring seal, increases blow by, robs power, and puts excessive tension within the crankcase.It does this by pulling a vacuum on the crankcase (See giant black box on the rear of our motor). The way that our vehicles (and many others) do this is by connecting it to the intake manifold. While this is a very eco-friendly model of doing things, its not very effective.


Why? Because you are literally sucking in oil vapors into your intake air. Oil is a very effective octane lower-er. By sucking in oil vapors, you promote detonation, lower power, and a much dirtier engine. Not to worry, our vehicles were designed to handle this (very effectively i might add, these motors last forever).

So whats a good alternative? Heres the lowdown.

I'll do this write up like many others have done on this subject

Power - Poor
Eco-friendliness - Excellent
Reliability - Good

I just want to clarify a few things. First, the factory pcv system is not designed to "pull a vacuum" on the crankcase, it is designed to dilute the blow by in the crankcase with fresh air under part throttle (like 95% of normal) driving. Huge difference there. The difference is literally thousands of miles in the oil change interval. You say "a much dirtier engine", well I sure would rather have my intake manifold dirty than my oil.

2drSE-i, what are you trying to do? a slash cut tube in the exhaust with a 1 way valve is a horrible pcv system for a street car. You won't have enough vacuum to make it work most of the time, and the blow by will not be diluted, and will end up exiting through the breather.

When you say you need your pcv system most during full throttle, well, maybe, but since the car only spends a tiny percentage of its time under full throttle, it doesn't have a huge overall effect on oil life.

I suppose you could modify the pcv system on a car to extend the oil change intervals, I'd probably do it by starting with a larger, higher flowing pcv valve, and then do whatever else was needed to support that higher flow rate, like maybe a bigger breather box too.

[Accordtheory]

Not \Pulling vacuum from the intake manifold is very limited; it pulls the most vacuum at idle and NO vacuum at all at WOT, \

the PCV valve is nothing but a glorified one way valve

It is actually a little more complex than that. It is designed to have a non linear flow rate vs vacuum. In other words, at part throttle cruise, you have less vacuum than at idle, but still need a lot of flow. At idle, you have maximum vacuum (oem cam anyway) but don't need a lot of airflow through the valve. So they designed it to where that higher vacuum actually pulls the valve more shut. Of course, at full throttle the valve is closed, not that it would be doing anything anyway, except the possible failure mode of bleeding boost into the crankcase on a turbo car. I always make it a point to tell people with forced induction to check their pcv valves and make sure they actually seal. The oem metal ones are really good quality, unlike the cheap auto parts store crap.

[lostforawhile]

let me explain this one more time, air enters the crankcase at the breather on the valve cover, thats why it's hooked to the air cleaner, so it doesn't pull dirty air through the entire engine, the air is circulated and pulled down through the engine by vaccume caused by the pcv valve, while it's doing this, it picks up water vapor and combustion byproducts, if it wasn't working, these would end up in your oil, and form sludge and acds. the vapors are picked up at the back of the oil pan, and travel through the hose at the back of the pan. they enter the oil seperator box, (the black box at the back of the engine) all this box is, is an empty metal box, with a baffle in it. they travel towards the top of the box, as they do this, residual oil condenses out, and travels through a tube pushed into the back of the block, yes it has three openings, you can't see this one, unless you remove the box. This oil travels back to the pan through the oil return passage from the head. Thevapors are picked up at the top of the box and pulled through the pcv valve,to be burned in the engine. The pcv on this car is actually excellent compared to a lot of other Hondas, The only thing you might want to do on a non turbo car, is add another seperator before the intake manifold. A lot of people use oil/water seperators from Home depot or Lowes. Don't remove the system, or try to modify the rest of it, it's fine the way it is. Check your hoses for cracks or leaks and replace as needed.