Valve cover breather?
#1
Valve cover breather?
Hey im a newbie to all this but I recently bought a EK Hatch Off my buddy. It has a B16A with a Type R manifold, Headers, Aem Fuel Rail, and a CAI. I noticed a tiny breather looks like an intake on my valve cover. He said when he bought the valve cover it came with it already attached. I know a hose from the valve cover should run to the intake but this breather is in place of that hose. The entry for the hose on the intake is open. I know its for ventialtion purposes but i was reading that on engines that rev to high RPMs its best to keep it on instead of a hose. Just want to Know if its true or not. I checked other similar threads but its really just a bunch of people going back and forth saying yes and no towards its functionality. Should I keep it on and plug that entry on the intake? or just run a hose?
#2
Re: Valve cover breather?
Run the breather hose on the valve cover to the intake, or add a filter. You don't want dirt and debris getting sucked into the head and crankcase. Also make sure the PCV hose and valve are connected to the IM and oil breather chamber.
#3
Re: Valve cover breather?
From what I understand, it's best to return to stock setup and run the hose from the intake to the valve cover. This pressurizes the PCV system which in turn reduces blow-by to some degree. If you wish to reduce oil going into your intake for the high rpm it's best to add a quality oil catch can in between the breather box and the entry point into the intake. Your choice if it is before or after the PCV valve itself.
Also, having an open hole in the intake tube itself is foolish as it allows dust and dirt to be sucked straight into the engine. Sort of negates the purpose of an air filter if you ask me.
Also, having an open hole in the intake tube itself is foolish as it allows dust and dirt to be sucked straight into the engine. Sort of negates the purpose of an air filter if you ask me.
#4
#5
Re: Valve cover breather?
Hmmm, now I have to find that thread that discussed this. Need to see if I misread, it was incorrect or if it just contradicts that.
Found it, came from Team Integra quoted in this post:
https://honda-tech.com/acura-integra.../#post44350017
Found it, came from Team Integra quoted in this post:
https://honda-tech.com/acura-integra.../#post44350017
Originally Posted by SufferX @ Team-Integra.net
The honda crankcase breather is a POSITIVE pressure ventilation system.The air from the intake blows into the valve cover. It is NOT a negative pressure ventilation system...it does NOT suck air from the valvecover to the intake.
Breathers remove the source of positive ventilation that repressurizes the POSTIVE CRANKCASE VENTILATION (PCV) valve.
There is less pressure in the crank when you add a breather at the valve cover. The consequence of this is you get more positive blow-by from the combustion chamber past the piston rings and into the crankcase. More blow-by means less cylinder pressure...less cylinder pressure means the burn is slower and less complete...the result is more emissions and less power.
If you want to do this right and remove oil vapor from the circulating crankcase before it goes into the intake valve then, get an oilcatch can and put a breather on the catch can. Then place the catch can in between the valve cover breather and the PCV valve.
Disconnecting the breather tube, which blows fresh intake air into the valve cover, and placing a breather on the valve cover just creates more blow-by and emissions. Eventually you have so much blow-by, you lose power.
Breathers remove the source of positive ventilation that repressurizes the POSTIVE CRANKCASE VENTILATION (PCV) valve.
There is less pressure in the crank when you add a breather at the valve cover. The consequence of this is you get more positive blow-by from the combustion chamber past the piston rings and into the crankcase. More blow-by means less cylinder pressure...less cylinder pressure means the burn is slower and less complete...the result is more emissions and less power.
If you want to do this right and remove oil vapor from the circulating crankcase before it goes into the intake valve then, get an oilcatch can and put a breather on the catch can. Then place the catch can in between the valve cover breather and the PCV valve.
Disconnecting the breather tube, which blows fresh intake air into the valve cover, and placing a breather on the valve cover just creates more blow-by and emissions. Eventually you have so much blow-by, you lose power.
#6
Re: Valve cover breather?
Hmmm, now I have to find that thread that discussed this. Need to see if I misread, it was incorrect or if it just contradicts that.
Found it, came from Team Integra quoted in this post:
https://honda-tech.com/acura-integra.../#post44350017
Found it, came from Team Integra quoted in this post:
https://honda-tech.com/acura-integra.../#post44350017
#7
Re: Valve cover breather?
The tube from the intake tube to the valve cover blows air to pressurize the crank case and aid pushing gases into the breather box, through the pcv valve into the intake manifold plenum as well as provide some positive pressure to the back side of the piston rings reducing some blow by.
This one here:
Notice the breather filter and the empty/plugged hole in the intake tube where the tube should be to the breather filter spot.
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#8
Re: Valve cover breather?
That doesn't make sense. Why would the gas go from the crank case, up the oil return holes through the valve cover into the intake tube to enter the throttle body. That would also pull pressure from the breather box, pcv valve and fight the draw from the plenum of the intake manifold.
You and the quote at the link are saying pressure from the intake is pushing air out of the crankcase into the IM. This is wrong. Instead, it's vacuum from the IM pulling gases from the crankcase, with the breather hose simply allowing for continuous air flow out of the crankcase, without creation of a vacuum.
The tube from the intake tube to the valve cover blows air to pressurize the crank case and aid pushing gases into the breather box, through the pcv valve into the intake manifold plenum as well as provide some positive pressure to the back side of the piston rings reducing some blow by.
#9
Re: Valve cover breather?
Where did I say this^?
You and the quote at the link are saying pressure from the intake is pushing air out of the crankcase into the IM. This is wrong. Instead, it's vacuum from the IM pulling gases from the crankcase, with the breather hose simply allowing for continuous air flow out of the crankcase, without creation of a vacuum.
You and the quote at the link are saying pressure from the intake is pushing air out of the crankcase into the IM. This is wrong. Instead, it's vacuum from the IM pulling gases from the crankcase, with the breather hose simply allowing for continuous air flow out of the crankcase, without creation of a vacuum.
The air rushing towards the tube to the valve cover is going to create a positive pressure. Which in turn will create a positive pressure in the crank case.
Removing the hose from the intake and the valve cover removes that positive pressure.
I am not saying the IM doesn't create a vacuum, I'm just saying there is a positive pressure in addition to the vacuum of the IM when the system is set up as Honda designed with the tube in place.
If you take a look at the full post on team integra, you will see even the diagram in the helms manual shows the tube from the intake is a positive pressure system pushing fresh air into the valve cover thus pushing fresh air to the crank case:
Team Integra Forums - Team Integra - View Single Post - Valve Cover Breather Debate
From the 92-95 FSM
#10
Re: Valve cover breather?
I don't believe the tube from the intake is negative pressure. The amount of air rushing towards that tube would prevent "continuous flow" from the crank case when the IM isn't producing sufficient vacuum. The pressures would be fighting each other, the pressure from the intake vs the blow by from the crank case.
The air rushing towards the tube to the valve cover is going to create a positive pressure. Which in turn will create a positive pressure in the crank case.
Removing the hose from the intake and the valve cover removes that positive pressure.
I'm just saying there is a positive pressure in addition to the vacuum of the IM when the system is set up as Honda designed with the tube in place.
#11
Re: Valve cover breather?
Not even a matter of feels right, is displayed in the helms manual as the flow of air as can be seen on page 11-140
#12
Re: Valve cover breather?
You say that the air flow direction is determined by air pressure pushing from the breather into the crankcase. This is incorrect.
I am telling that air flow in the system is instead determined by vacuum from the IM pulling air/gases from the crankcase and that the breather hose has a passive role in the process. There's no push. There's only pull.
#13
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Re: Valve cover breather?
intake manifold sucks through the valve cover. Those filters don't do jack but make your car look pretty. Not sure but I believe there is another diagram for the b-series that shows something similar. Gotta look it up after walking the dog.
edit: my bad, reverse what i said. There's also a discussion on H-T already on this but its an old one
https://honda-tech.com/forced-induct...tended-697498/
edit: my bad, reverse what i said. There's also a discussion on H-T already on this but its an old one
https://honda-tech.com/forced-induct...tended-697498/
Last edited by tony_2018; 05-28-2015 at 05:03 AM.
#14
Re: Valve cover breather?
You don't realize that we both agree on the direction of air flow. What we disagree about is what is the underlying cause of the direction of flow.
You say that the air flow direction is determined by air pressure pushing from the breather into the crankcase. This is incorrect.
I am telling that air flow in the system is instead determined by vacuum from the IM pulling air/gases from the crankcase and that the breather hose has a passive role in the process. There's no push. There's only pull.
You say that the air flow direction is determined by air pressure pushing from the breather into the crankcase. This is incorrect.
I am telling that air flow in the system is instead determined by vacuum from the IM pulling air/gases from the crankcase and that the breather hose has a passive role in the process. There's no push. There's only pull.
I know you are painfully aware of my not understanding what you meant by continuous air flow as well as a couple of other things.
Just as my mind was about to wander into never never land, the light bulb goes off. What I see is the IM is pretty much constantly drawing air but basically at different degrees. Without a breather tube it would likely cause a significant negative pressure in the crank case as the blow by doesn't likely get to the same levels as the draw from the IM. The breather tube allows for continuous fresh air from the intake tube to keep that negative pressure down to as close to zero as possible.
Like you said, on both counts, the flow is correct in the diagram and the error is in the interpretation that the breather tube is a positive pressure. I understand now. It IS a negative system, the breather tube is to prevent the pressure from becoming overly negative as the ideal would be a zero pressure condition but just is not possible in the real world.
So if anything the only real slight negative to having a breather filter instead of the breather tube is the filter might pose a slight restriction to the fresh air flow from the negative pressure pull of the IM through the breather box etc thus causing a slight decrease in efficiency of the vacuum.
Thanks for clarifying that as we can see it's very easy to misinterpret the air flow diagram and get the wrong conclusion of the breather tube as can be seen with the post I quoted and the threads I referenced.
Last edited by TomCat39; 05-28-2015 at 08:33 AM. Reason: grammatical corrections
#16
Re: Valve cover breather?
You don't realize that we both agree on the direction of air flow. What we disagree about is what is the underlying cause of the direction of flow.
You say that the air flow direction is determined by air pressure pushing from the breather into the crankcase. This is incorrect.
I am telling that air flow in the system is instead determined by vacuum from the IM pulling air/gases from the crankcase and that the breather hose has a passive role in the process. There's no push. There's only pull.
You say that the air flow direction is determined by air pressure pushing from the breather into the crankcase. This is incorrect.
I am telling that air flow in the system is instead determined by vacuum from the IM pulling air/gases from the crankcase and that the breather hose has a passive role in the process. There's no push. There's only pull.
#18
Re: Valve cover breather?
All 101 classes I've ever seen introduce physics in a vacuum only. :p
#19
Re: Valve cover breather?
First-year college Physics 101 principles are generally taught in two consecutive semester courses, such as Physics I and Physics II. The Venturi effect would be covered in the second half. Any advanced high school student would also be exposed to the principle.
#20
Re: Valve cover breather?
I stand corrected.
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