Vlave cover breather vacuum pressure
04-09-2007, 06:46 AM
#1
Honda-Tech Member
Thread Starter
Join Date: Aug 2002
Location: repo.jackmoves., com, usa
Posts: 2,299
Likes: 0
Received 1 Like
on
1 Post
Vlave cover breather vacuum pressure
does anyone know exactly how much vacuum were looking at here? most people put a breather on this barb on their valve cover but does anyone know how much vacuum were looking at?
04-09-2007, 06:55 AM
#3
Honda-Tech Member
Thread Starter
Join Date: Aug 2002
Location: repo.jackmoves., com, usa
Posts: 2,299
Likes: 0
Received 1 Like
on
1 Post
Re: (pdiggitydogg)
im fairly sure its mostly vacuum hence the breather. If it was always positive pressure it wouldnt be necessary and you could just run a drain hose.
Ive seen a PCV diagram before and it showed it as incoming air vor the pcv system so that barb should be under vacuum. cant seem to find it at the moment.
Ive seen a PCV diagram before and it showed it as incoming air vor the pcv system so that barb should be under vacuum. cant seem to find it at the moment.
04-09-2007, 07:17 AM
#4
Honda-Tech Member
Re: (monicle)
Its built up pressure from everything moving so fast and the compression of the motor. Stock motors dont need this, 12.5 c/r dont really need this (block yes, head no). Anything after that i say tap the head. But everyone has there opinion on it.
04-09-2007, 07:31 AM
#5
Honda-Tech Member
Well, I just disconnected my breather hose (vc->intake) and air was coming out - positive.
Breathers arent always intakes, some are exits (breathing is a 2-parter
)
Come to think of it, if it were vacuum, there wouldnt be any point in running a catch can off the vc...
edit***
I have a boost gauge thats (-) and (+) pressures sitting here - I will connect it to the valve cover later tonight and get you a reading
(not a stock ls engine though)
Breathers arent always intakes, some are exits (breathing is a 2-parter
)Come to think of it, if it were vacuum, there wouldnt be any point in running a catch can off the vc...
edit***
I have a boost gauge thats (-) and (+) pressures sitting here - I will connect it to the valve cover later tonight and get you a reading
(not a stock ls engine though)
04-09-2007, 07:50 AM
#6
Honda-Tech Member
Thread Starter
Join Date: Aug 2002
Location: repo.jackmoves., com, usa
Posts: 2,299
Likes: 0
Received 1 Like
on
1 Post
Re: (pdiggitydogg)
heres the helms diagram Im looking at. shows clean air going in through to the valve cover. Im boosted though so I know that durring boost pcv emissions are definately coming out of that breather. Im just wondering in situations that it is under vacuum if anyone has measured the pressure. Im going to try to run a bypass valve with a breather and a can, when its under vacuum itll pull air through the breather, and when its under positive pressure itll push through the can.
Trending Topics
04-09-2007, 08:12 AM
#8
Honda-Tech Member
If you hold your hand in front of the breather port, you will feel air coming out. But if you put your finger directly covering the hole, you will feel vacuum. Air moves back and forth through the valve cover. It is not a constant vacuum, nor is it constantly under pressure.
You put a breather on so when it is sucking, it doesn't allow dirt in.
You put a breather on so when it is sucking, it doesn't allow dirt in.
04-09-2007, 08:20 AM
#9
Honda-Tech Member
Join Date: Feb 2003
Location: Nowhere Cali, Ca, USA
Posts: 1,693
Likes: 0
Received 0 Likes
on
0 Posts
Re: (pdiggitydogg)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by pdiggitydogg »</TD></TR><TR><TD CLASS="quote">Yeah, Ive seen that picture several times
dunno, perhaps my engines are just confused and blow out from the vc</TD></TR></TABLE>
thats true, remove the breather filter or hose while the engine runs and it blows out.
i always thought it was part of emissions because the air intake pulls it from the valve cover.
dunno, perhaps my engines are just confused and blow out from the vc</TD></TR></TABLE>
thats true, remove the breather filter or hose while the engine runs and it blows out.
i always thought it was part of emissions because the air intake pulls it from the valve cover.
04-09-2007, 09:13 AM
#10
Honda-Tech Member
Thread Starter
Join Date: Aug 2002
Location: repo.jackmoves., com, usa
Posts: 2,299
Likes: 0
Received 1 Like
on
1 Post
Re: (built562)
ok so now that we all know that sometimes its under vacuum and sometimes its under positive pressure...
anyone actually measured how much vacuum its is/can be under? if its not enough for the cracking pressure of the valve it wont do me any good to buy one. Someone has got to have a magnahelic or something that could test it for me real quick.
anyone actually measured how much vacuum its is/can be under? if its not enough for the cracking pressure of the valve it wont do me any good to buy one. Someone has got to have a magnahelic or something that could test it for me real quick.
04-09-2007, 09:23 AM
#11
Join Date: Oct 2004
Location: kazakhstan, DC, US and A
Posts: 1,550
Likes: 0
Received 0 Likes
on
0 Posts
again bakeoff is correct. Even the frickin PCV valve will reverse its self. How do I know this? because i run just a drain tube with a hollowed out PCV valve. The hose was near the ground, and when I went to go add a breather to the PCV hose, there was all sorts of dust/dirt and mud up inside the hose (not chocolate milk, clumps of mud and grease from my busted up axle)
The valve cover will inhale and exhale depending on pressure and engine loads. I had a clear hose connected to the intake from the VC, and without a PCV valve/system, oil would enter the intake arm.
WIth vacuum, it would hardly go into a positive form, so the intake/VC breather would be bringing in fresh air.
Either way, I say rip out the PCV and add breathers
about 20hg of vacuum. But have you played with the PCV valve, im sure that cuts it almost down to nothign. Id rather vent, my Idle thanks me as well.
The valve cover will inhale and exhale depending on pressure and engine loads. I had a clear hose connected to the intake from the VC, and without a PCV valve/system, oil would enter the intake arm.
WIth vacuum, it would hardly go into a positive form, so the intake/VC breather would be bringing in fresh air.
Either way, I say rip out the PCV and add breathers
about 20hg of vacuum. But have you played with the PCV valve, im sure that cuts it almost down to nothign. Id rather vent, my Idle thanks me as well.
04-09-2007, 09:40 AM
#12
Honda-Tech Member
Re: (YoungKadafi)
A valve cover breather on a street car is a red flag indicating "ricer". Those little filters fill up with oil very quickly, then you start getting oil forced out around the valve cover gasket usually at the distributer seal or the VTEC solenoid if the person even has a VTEC motor.
Not to mention that making your ecologically friendly Honda run dirty is just ******* retarded. I mean, if it's a dedicated race car, then yeah; throw out and defeat the emissions equipment. But for the street? That just makes you a goddamn wanna be. Maybe a domestic would better suit your personality. Hondas have been ULEVs since the early 90's. But I guess if you don't care about anything in this world except yourself, then making your Honda run dirty is JDM yo.
You can actually get a small performance boost by creating a vacuum in the valve cover. The easiest method is to put a catch can inline with the tube and then put a slash cut pipe pre-turbo (as this is usually done on turbocharged engines) or in the exhaust stream.
Not to mention that making your ecologically friendly Honda run dirty is just ******* retarded. I mean, if it's a dedicated race car, then yeah; throw out and defeat the emissions equipment. But for the street? That just makes you a goddamn wanna be. Maybe a domestic would better suit your personality. Hondas have been ULEVs since the early 90's. But I guess if you don't care about anything in this world except yourself, then making your Honda run dirty is JDM yo.
You can actually get a small performance boost by creating a vacuum in the valve cover. The easiest method is to put a catch can inline with the tube and then put a slash cut pipe pre-turbo (as this is usually done on turbocharged engines) or in the exhaust stream.
04-09-2007, 09:48 AM
#14
Join Date: Oct 2004
Location: kazakhstan, DC, US and A
Posts: 1,550
Likes: 0
Received 0 Likes
on
0 Posts
^^the exhaust scavanging doesnt work, at all if you have a muffler. So doing it that way is more rice because if you did have that setup, you would be running an open pipe exhaust.
I dont know who started this whole valve cover breather hating, but really there is nothing wrong with it, at all. There is 0 proof that it will do harm, find me proof, and I will cancell my account with H-T.
Oh and maybe people like to have their engines simple and efficient. The emissions systems are NOT efficient, and if you do enough thoughtout research and trial and error, the PCV system is flawed, and bogus. Its only to satisfy the tree huggers.
The PCV system bypassed probably puts out less toxic gasses than 1 single cow in their lifetimes. Read up on it, its not ricer, i have like 5 breathers in my engine bay. 3 on the Valve cover, which have not filled up with oil, 1 on the PCV hose, and 1 on the Power steering catch can I made.
Not rice, its called being smart and beating something most other people are to scared to beat, and you can only beat it if you understand it, which you clearly dont. And dont bring up that stupid helms picture, that means nothing. And unless you have a vacuum pump to pull out ALL of the pressures with 0 restriction, then I having the system vent with 0 restriction is probably the most efficient setup.
I dont know who started this whole valve cover breather hating, but really there is nothing wrong with it, at all. There is 0 proof that it will do harm, find me proof, and I will cancell my account with H-T.
Oh and maybe people like to have their engines simple and efficient. The emissions systems are NOT efficient, and if you do enough thoughtout research and trial and error, the PCV system is flawed, and bogus. Its only to satisfy the tree huggers.
The PCV system bypassed probably puts out less toxic gasses than 1 single cow in their lifetimes. Read up on it, its not ricer, i have like 5 breathers in my engine bay. 3 on the Valve cover, which have not filled up with oil, 1 on the PCV hose, and 1 on the Power steering catch can I made.
Not rice, its called being smart and beating something most other people are to scared to beat, and you can only beat it if you understand it, which you clearly dont. And dont bring up that stupid helms picture, that means nothing. And unless you have a vacuum pump to pull out ALL of the pressures with 0 restriction, then I having the system vent with 0 restriction is probably the most efficient setup.
04-09-2007, 10:34 AM
#15
Honda-Tech Member
Thread Starter
Join Date: Aug 2002
Location: repo.jackmoves., com, usa
Posts: 2,299
Likes: 0
Received 1 Like
on
1 Post
Re: (YoungKadafi)
umm yeah so noone here has an answer to my question is basically whats happening here eh?
basically what Im trying to do is get rid of the cheap oem plunger 90degree pcv valve because they only work if mounted vertically. I would rather not just vent my pcv because of the oily film that gets all over the engine bay because of it. if youre just running breathers and you have no oil on your breathers then congratulations you have no blow by gasses. I however am boosted and create quite a bit of blow by under decent boost.
I want to run an aftermarket vacuum check valve between the catchcan and the intake manifold, and a bypass valve between the valve cover/catchcan/breather, but it wont work if the pcv system doesnt generate more than the cracking pressure of the valves. Hence the question.
I respect everyones opinions but this thread has nothing to do the the pros/cons of breathers nor requesting info about other methods of pcv ventillation.
basically what Im trying to do is get rid of the cheap oem plunger 90degree pcv valve because they only work if mounted vertically. I would rather not just vent my pcv because of the oily film that gets all over the engine bay because of it. if youre just running breathers and you have no oil on your breathers then congratulations you have no blow by gasses. I however am boosted and create quite a bit of blow by under decent boost.
I want to run an aftermarket vacuum check valve between the catchcan and the intake manifold, and a bypass valve between the valve cover/catchcan/breather, but it wont work if the pcv system doesnt generate more than the cracking pressure of the valves. Hence the question.
I respect everyones opinions but this thread has nothing to do the the pros/cons of breathers nor requesting info about other methods of pcv ventillation.
04-09-2007, 10:50 AM
#16
Join Date: Oct 2004
Location: kazakhstan, DC, US and A
Posts: 1,550
Likes: 0
Received 0 Likes
on
0 Posts
but the point is, there is no spec. vacuum that breather is pulling in, since your boosted, your asking an NA question.
The IM should be around 20/hg's like I said
The IM should be around 20/hg's like I said
04-09-2007, 11:05 AM
#17
Honda-Tech Member
Thread Starter
Join Date: Aug 2002
Location: repo.jackmoves., com, usa
Posts: 2,299
Likes: 0
Received 1 Like
on
1 Post
Re: (YoungKadafi)
ughh yeah. just cause Im boosted does not mean that Im running positive crank case pressure at all times.
I know theres no spec because its generally not an important factor, they designed their own pcv valves for the purpose. But I need to know what pressures its actually seeing to see if it will open the valves that Im wanting to use.
its apparent that Im just going to have to go get a magnehelic myself and check it out.
I know theres no spec because its generally not an important factor, they designed their own pcv valves for the purpose. But I need to know what pressures its actually seeing to see if it will open the valves that Im wanting to use.
its apparent that Im just going to have to go get a magnehelic myself and check it out.
04-09-2007, 11:24 AM
#18
Join Date: Oct 2004
Location: kazakhstan, DC, US and A
Posts: 1,550
Likes: 0
Received 0 Likes
on
0 Posts
Im sorry dude, but really what are you trying to find out? you need to post up the engine this is on.
For off boost, your should be around 21-20 in. hg of vacuum. However this is only in the intake manifold. The breather on the valve cover will change depending on pressures in the engine block. If there is positive pressure, the breather will have 0 vacuum, but the IM vacuum will remain @ 20 in. hg untill something like the EVAP system opens up.
Again, you cant look at these little diagram pictures, because its all variable. If there is vacuum in the block, its just like connecting a vacuum cleaner to a box, any holse in that box it will have air sucking, common sense.
The engine is usually not the one causing the vacuum, its the intake manifold. The engine is usually pressurized because of the piston movement and other things. The intake manifold is what sucks the pressures and vapors out, to help with windage losses and create a more semi-efficient system.
The engine (including valve cover) never creates its own vacuum, its the vacuum from the PCV/Intake manifold that creates the vacuum inside the engine. So it would be hard to register the vacuum on teh valve cover barb because its not directly related to the IM
Im sure if you put a gauge on the valve cover barb, it would not be correct, and if you put one on the IM ports, it would read 20 in. hg.
The PCV system just acts like a vacuum cleaner to suck out pressures and blow by. With out it, the engine and valve cover (whole engine including oil pan) would be under great pressures.
This is why I reccomend just having a good venting system, because the PCV "valve" is very shitty, and really sucks if you ask me, creates a lean mixture because its really just a controlled vacuum leak. And @ high positive pressures, its more of a restriction.
Having the system just vent ensures 0 restrictions if done correctly, so you can get some good sleep at night instead of dreaming how to evacuate pressures and gasses with the low efficient pcv valve.
For off boost, your should be around 21-20 in. hg of vacuum. However this is only in the intake manifold. The breather on the valve cover will change depending on pressures in the engine block. If there is positive pressure, the breather will have 0 vacuum, but the IM vacuum will remain @ 20 in. hg untill something like the EVAP system opens up.
Again, you cant look at these little diagram pictures, because its all variable. If there is vacuum in the block, its just like connecting a vacuum cleaner to a box, any holse in that box it will have air sucking, common sense.
The engine is usually not the one causing the vacuum, its the intake manifold. The engine is usually pressurized because of the piston movement and other things. The intake manifold is what sucks the pressures and vapors out, to help with windage losses and create a more semi-efficient system.
The engine (including valve cover) never creates its own vacuum, its the vacuum from the PCV/Intake manifold that creates the vacuum inside the engine. So it would be hard to register the vacuum on teh valve cover barb because its not directly related to the IM
Im sure if you put a gauge on the valve cover barb, it would not be correct, and if you put one on the IM ports, it would read 20 in. hg.
The PCV system just acts like a vacuum cleaner to suck out pressures and blow by. With out it, the engine and valve cover (whole engine including oil pan) would be under great pressures.
This is why I reccomend just having a good venting system, because the PCV "valve" is very shitty, and really sucks if you ask me, creates a lean mixture because its really just a controlled vacuum leak. And @ high positive pressures, its more of a restriction.
Having the system just vent ensures 0 restrictions if done correctly, so you can get some good sleep at night instead of dreaming how to evacuate pressures and gasses with the low efficient pcv valve.
04-09-2007, 11:53 AM
#19
Honda-Tech Member
Thread Starter
Join Date: Aug 2002
Location: repo.jackmoves., com, usa
Posts: 2,299
Likes: 0
Received 1 Like
on
1 Post
Re: (YoungKadafi)
wow not sure where to start. the vacuum is created by the expansion of volume while the intake valve is open on any given cylinder while the cylder is moving in a direction away from the valve. the manifold just happens to be included in that area of volume that is increasing. so the manifold doesnt create anything at all.
I know that the intake manifold is where the vacuum is most easily accessable, but pressure is determined by the ammount of air in a given space. the same ammount of air (or lack of air{vacuum}) trapped in the intake manifold will not have the same pressure (or vacuum) as the same ammount of air trapped in the crank case. so knowing how much pressure is in the intake manifold will not help me out.
I think we can both agree that the vacuum on a barb actually on the intake manifold with not have the same suction as the barb on the valve cover.
The motor Im using is a b18c but vacuum should not differ a meaningfull degree between a 1.6 to a 1.8 itll be close enough for me to have a good idea. Id take an actuall pressure reading from either and be happy. seeing as putting a gauge on the valve cover could only read what was actually there and could in no way be "incorrect", it is what it is. and thats the reading that i need.
I know I could vent to 0 pressure but then it would only actually be evacuating oil/fuel particles physically puched into the can, however once pressure is relieved oil and fuel particles remain in the crankcase while it should be being pulled out by vacuum. THIS is what Im wanting to acchieve.
I know that the intake manifold is where the vacuum is most easily accessable, but pressure is determined by the ammount of air in a given space. the same ammount of air (or lack of air{vacuum}) trapped in the intake manifold will not have the same pressure (or vacuum) as the same ammount of air trapped in the crank case. so knowing how much pressure is in the intake manifold will not help me out.
I think we can both agree that the vacuum on a barb actually on the intake manifold with not have the same suction as the barb on the valve cover.
The motor Im using is a b18c but vacuum should not differ a meaningfull degree between a 1.6 to a 1.8 itll be close enough for me to have a good idea. Id take an actuall pressure reading from either and be happy. seeing as putting a gauge on the valve cover could only read what was actually there and could in no way be "incorrect", it is what it is. and thats the reading that i need.
I know I could vent to 0 pressure but then it would only actually be evacuating oil/fuel particles physically puched into the can, however once pressure is relieved oil and fuel particles remain in the crankcase while it should be being pulled out by vacuum. THIS is what Im wanting to acchieve.
Thread
Thread Starter
Forum
Replies
Last Post
Momentum
Honda Civic / Del Sol (1992 - 2000)
8
10-13-2011 12:54 PM
pwrofdrm
Honda CRX / EF Civic (1988 - 1991)
4
03-21-2005 07:06 PM
