What's the easiest way to avoid pressure in the crank case?
09-25-2005, 09:07 PM
#51
1.5 BAR
Join Date: Aug 2003
Posts: 1,164
Re: What's the easiest way to avoid pressure in the crank case?
There was a thread on honda tech a while back and they tested several different setups. Basically a slash cut pre turbo or exhaust will create vacuum but its such a small ammount that it doesnt really help you. You have three options that really work.
A. Leave it the way it is and it will be fine (just make sure your breather is open and not connected to the charge piping).
B. Just unhook the valve cover breather and PCV
C. If you are a tree hugger you can do option B but hook them into a catch can so your not putting oily burnt gassy ---- into the atmosphere.
I like option B and guess what, its free. It also give you a nice place on the intake manifold to feed all your vacuum hungry turbo accessories(where the PCV used to be hooked up)
A. Leave it the way it is and it will be fine (just make sure your breather is open and not connected to the charge piping).
B. Just unhook the valve cover breather and PCV
C. If you are a tree hugger you can do option B but hook them into a catch can so your not putting oily burnt gassy ---- into the atmosphere.
I like option B and guess what, its free. It also give you a nice place on the intake manifold to feed all your vacuum hungry turbo accessories(where the PCV used to be hooked up)
09-26-2005, 01:55 AM
#53
0.0 BAR
Join Date: Dec 2002
Posts: 0
Re: What's the easiest way to avoid pressure in the crank case?
Originally Posted by highroller54
This is my last post in here because RS is the only other ------ guy in here that has any idea how an engine works, but no body is listning. :P
09-26-2005, 05:50 AM
#54
3.0 BAR
Join Date: Apr 2003
Posts: 11,058
Re: What's the easiest way to avoid pressure in the crank case?
every ------- body and their mother runs a valve cover breather, that's not the ------- cure all for crank case pressure 
i'd rather not listen to the guy that's had one boosted honduh and drove it around with broken ring lands the whole time. do whatever you want, but i'll never run a stock pcv system on a boosted honda.
i'd rather not listen to the guy that's had one boosted honduh and drove it around with broken ring lands the whole time. do whatever you want, but i'll never run a stock pcv system on a boosted honda.
09-26-2005, 07:14 AM
#55
0.0 BAR
Join Date: May 2005
Posts: 0
Re: What's the easiest way to avoid pressure in the crank case?
This should be the last ------- post here. There has been a whole ------- page of people bitching back and forth PVC this and breather that. First off it's PCV ********. PVC is plastic type tubing. PCV stands for positive crankcase ventilation. Some of you may even think it is a drug.
I will explain how the system works with both boosted and NA cars. If you don't believe what I have to say or think I'm wrong, you will remain forever ignorant on this subject.
The primary function of the PCV is to evacuate pressure in the crankcase back to the intake manifold to be burned and keep the tree-huggers happy. If we didn’t have emissions regulations then the breather hose would handle the ventilation. In the old days there was no PCV and the crankcase was ventilated straight from the valve cover by a little filter. If you just routed the breather hose to the intake manifold you would have issues with the AFR which are explained below.
This pressure comes from the combustion chamber blow-by. Yes, some pressure goes by the rings all of the time. ABSOLUTELY NONE OF THIS PRESSURE COMES FROM THE FACT THAT THE PISTONS ARE MOVING UP AND DOWN. It is composed of fuel and oil vapor. Fuel vapor in the crankcase will contaminate oil. Fuel contaminated oil will begin to break down and form sludge in the engine. This pressure is the highest at high engine loads. More power = more combustion pressures = higher blow-by.
NA motors
1) The PCV valve is usually located between an oil separator and the intake manifold. The separator is connected to the block. The separator separates oil and fuel vapors to keep oil in the crankcase. It also can be located in the valve cover. So that means that the blow-by goes from the crankcase up little passages to the head. These passages also drain oil back to oil pan from the head. It also means no oil separator.
2) So from above THAT MEANS THAT THE PCV VALVE IS NOT A ONE WAY VALVE THAT IS OPENED BY INTAKE MANIFOLD VACUUM. It’s actually the other way around. Intake manifold vacuum actually forces the PCV valve to close, but not completely.
3) When there is high vacuum, at idle and deceleration, the engine has a light load which means there is little blow-by. This means that the PCV valve doesn’t need to be open very much.
4) When there is low vacuum, at high engine load, the engine produces the most blow-by. This means that the PCV valve needs to be fully open.
5) The breather in the valve cover is there to help the PCV valve when blow by is at maximum. This hose goes to the intake before the throttle body. The system is designed so that the PCV valve and breather hose work together to match the blow-by of the engine. Ah HARMONY!
So the PCV valve handles ventilation primarily at light to medium loads to vary the amount of ventilation needed and a little bit at heavy loads.
6) Another reason that you don’t want the PCV valve to be open very much at light load is the fact that the blow-by going into the intake manifold and then going into the combustion chamber will throw the air-fuel ratio off. At this load the AFR is very sensitive. Another thing that the PCV valve does is close completely if the engine backfires so to not ignite the blow-by in the crankcase.
Boosted motors
1) The system works mostly the same way as in a NA motor. The only difference is the fact that the breather hose is routed to the inlet of the turbo and the PCV functions less in boost or closes all together and lets the breather hose handle all of the blow-by. HOWEVER, THE MAIN FUNCTION OF THE PCV VALVE, WHICH IS TO HANDLE VENTILATION AT VARIOUS ENGINE LOADS, IS STILL BEING MAINTAINED. If the breather hose was routed to the charge pipe then the crankcase will be pressurized. The breather hose will have boost to it and the PCV will be restricted by boost. This will not adequately ventilate the crankcase blow-by gases at the high load, high blow-by situations of boost.
So now that everyone knows how the PCV system works I will explain what you can do to make it functional with a boosted car. Okay ready, carefully take off the breather tube from the intake pipe. Careful now, don’t hurt yourself. Now aim the breather hose carefully at the ground and you’re done. If you want to satisfy green-peace you can route the breather hose to the inlet pipe of the turbo. Or you could route it to a catch can and then to the turbo inlet or just let it vent to the atmosphere.
The main point that I am making here is that the PCV valve is there to function below boost because it is variable. In boost the breather hose handles the blow-by.
I will explain how the system works with both boosted and NA cars. If you don't believe what I have to say or think I'm wrong, you will remain forever ignorant on this subject.
The primary function of the PCV is to evacuate pressure in the crankcase back to the intake manifold to be burned and keep the tree-huggers happy. If we didn’t have emissions regulations then the breather hose would handle the ventilation. In the old days there was no PCV and the crankcase was ventilated straight from the valve cover by a little filter. If you just routed the breather hose to the intake manifold you would have issues with the AFR which are explained below.
This pressure comes from the combustion chamber blow-by. Yes, some pressure goes by the rings all of the time. ABSOLUTELY NONE OF THIS PRESSURE COMES FROM THE FACT THAT THE PISTONS ARE MOVING UP AND DOWN. It is composed of fuel and oil vapor. Fuel vapor in the crankcase will contaminate oil. Fuel contaminated oil will begin to break down and form sludge in the engine. This pressure is the highest at high engine loads. More power = more combustion pressures = higher blow-by.
NA motors
1) The PCV valve is usually located between an oil separator and the intake manifold. The separator is connected to the block. The separator separates oil and fuel vapors to keep oil in the crankcase. It also can be located in the valve cover. So that means that the blow-by goes from the crankcase up little passages to the head. These passages also drain oil back to oil pan from the head. It also means no oil separator.
2) So from above THAT MEANS THAT THE PCV VALVE IS NOT A ONE WAY VALVE THAT IS OPENED BY INTAKE MANIFOLD VACUUM. It’s actually the other way around. Intake manifold vacuum actually forces the PCV valve to close, but not completely.
3) When there is high vacuum, at idle and deceleration, the engine has a light load which means there is little blow-by. This means that the PCV valve doesn’t need to be open very much.
4) When there is low vacuum, at high engine load, the engine produces the most blow-by. This means that the PCV valve needs to be fully open.
5) The breather in the valve cover is there to help the PCV valve when blow by is at maximum. This hose goes to the intake before the throttle body. The system is designed so that the PCV valve and breather hose work together to match the blow-by of the engine. Ah HARMONY!
So the PCV valve handles ventilation primarily at light to medium loads to vary the amount of ventilation needed and a little bit at heavy loads.
6) Another reason that you don’t want the PCV valve to be open very much at light load is the fact that the blow-by going into the intake manifold and then going into the combustion chamber will throw the air-fuel ratio off. At this load the AFR is very sensitive. Another thing that the PCV valve does is close completely if the engine backfires so to not ignite the blow-by in the crankcase.
Boosted motors
1) The system works mostly the same way as in a NA motor. The only difference is the fact that the breather hose is routed to the inlet of the turbo and the PCV functions less in boost or closes all together and lets the breather hose handle all of the blow-by. HOWEVER, THE MAIN FUNCTION OF THE PCV VALVE, WHICH IS TO HANDLE VENTILATION AT VARIOUS ENGINE LOADS, IS STILL BEING MAINTAINED. If the breather hose was routed to the charge pipe then the crankcase will be pressurized. The breather hose will have boost to it and the PCV will be restricted by boost. This will not adequately ventilate the crankcase blow-by gases at the high load, high blow-by situations of boost.
So now that everyone knows how the PCV system works I will explain what you can do to make it functional with a boosted car. Okay ready, carefully take off the breather tube from the intake pipe. Careful now, don’t hurt yourself. Now aim the breather hose carefully at the ground and you’re done. If you want to satisfy green-peace you can route the breather hose to the inlet pipe of the turbo. Or you could route it to a catch can and then to the turbo inlet or just let it vent to the atmosphere.
The main point that I am making here is that the PCV valve is there to function below boost because it is variable. In boost the breather hose handles the blow-by.
09-26-2005, 11:58 PM
#56
0.0 BAR
Join Date: Jul 2004
Posts: 25
Re: What's the easiest way to avoid pressure in the crank case?
very nice^^^
i have been readin ALOT on this subject and had seriously considered doing something i heard that theoldone did one domestics back in the day.
By using an auxilary (sp?) vac source you can actually remove alot of the pressure in the crank case. Now without the thousands of $$$ the true race car drivers have we HMT people would be left with using a vac pump off an 80s chevy (can't remember the model and such). now by hooking up this electric vac pump, under load or pressure it would come on and effectivly vent the crank case. Now in domestics i read this can make as much as 30+ hp. So i figured that with our hondas and such we can see decent numbers too...
I was wrong. After talking to a friend and others i found out that the rate at which the chevy vac sucks it will actually suck out oil and cause problems. So, once again to support the man above me.
the BEST way to vent the crank case is with a $5K kit that is custom made. the best HMT way is a cross cut in your exhaust after the cat/resionator
i have been readin ALOT on this subject and had seriously considered doing something i heard that theoldone did one domestics back in the day.
By using an auxilary (sp?) vac source you can actually remove alot of the pressure in the crank case. Now without the thousands of $$$ the true race car drivers have we HMT people would be left with using a vac pump off an 80s chevy (can't remember the model and such). now by hooking up this electric vac pump, under load or pressure it would come on and effectivly vent the crank case. Now in domestics i read this can make as much as 30+ hp. So i figured that with our hondas and such we can see decent numbers too...
I was wrong. After talking to a friend and others i found out that the rate at which the chevy vac sucks it will actually suck out oil and cause problems. So, once again to support the man above me.
the BEST way to vent the crank case is with a $5K kit that is custom made. the best HMT way is a cross cut in your exhaust after the cat/resionator
09-27-2005, 12:44 AM
#57
0.0 BAR
Join Date: Dec 2002
Posts: 0
Re: What's the easiest way to avoid pressure in the crank case?
Originally Posted by MADMAX
So now that everyone knows how the PCV system works I will explain what you can do to make it functional with a boosted car. Okay ready, carefully take off the breather tube from the intake pipe. Careful now, don’t hurt yourself. Now aim the breather hose carefully at the ground and you’re done. If you want to satisfy green-peace you can route the breather hose to the inlet pipe of the turbo. Or you could route it to a catch can and then to the turbo inlet or just let it vent to the atmosphere.
isnt that what everyone here has been saying but there is one douche bag that won't listen?
Im also pretty sure most of the hondas we're dealing with on this website only have the valve cover breather attached to the air inlet pipe and the pcv is attached to the intake manifold.
Question: What is the purpose of the PCV valve and what are the symptoms when it goes bad?
Answer: PCV means positive crankcase ventilation. This valve uses vacuum from the intake manifold to draw the fumes from the crankcase.
Answer: PCV means positive crankcase ventilation. This valve uses vacuum from the intake manifold to draw the fumes from the crankcase.
It is called positive since there is a positive force that removes the combustion vapors from the crankcase. That force is vacuum - just like the vacuum that sucks the dirt out of your rugs and furniture only this vacuum is derived from the engine, not from a Hoover. Vacuum derived from the engine is a rather sensitive resource, that is you don't want to steal any vacuum from the intake manifold when the engine is idling. However, when the engine is running at highway speed the engine can afford to allow a "vacuum leak" to occur via the PCV Valve. It is a metered flow of air, controlled by a needle valve inside the PCV Valve. When the engine is at idle and vacuum is high the force of the vacuum overcomes the force of a spring inside the PCV Valve and it is closed down to allow a flow of about three cubic feet per minute. When the throttle is opened and the intake manifold vacuum is reduced (closer to atmospheric) then the spring in the PCV Valve forces the valve to open allowing up to six cubic feet per minute of flow to occur.
09-27-2005, 03:15 PM
#58
0.0 BAR
Join Date: May 2005
Posts: 0
Re: What's the easiest way to avoid pressure in the crank case?
Question: What is the purpose of the PCV valve and what are the symptoms when it goes bad?
Answer: PCV means positive crankcase ventilation. This valve uses vacuum from the intake manifold to draw the fumes from the crankcase.
Answer: PCV means positive crankcase ventilation. This valve uses vacuum from the intake manifold to draw the fumes from the crankcase.
It is called positive since there is a positive force that removes the combustion vapors from the crankcase. That force is vacuum...
This part is wrong. The crankcase pressure forces itself out. The vacuum created by the engine at idle or high load is simply used to suck the crankcase vapors into engine to be reburned.
09-27-2005, 05:47 PM
#59
0.5 BAR
Thread Starter
Join Date: Jul 2005
Posts: 134
Re: What's the easiest way to avoid pressure in the crank case?
Awesome, I get it now.
But why does my vavle cover vent breather hose Y out, bigger tube going into intake before throttle body, while a smaller tube goes into the manifold peice that leads into the idle control valve?
But why does my vavle cover vent breather hose Y out, bigger tube going into intake before throttle body, while a smaller tube goes into the manifold peice that leads into the idle control valve?
09-27-2005, 08:27 PM
#60
0.0 BAR
Join Date: May 2005
Posts: 0
Re: What's the easiest way to avoid pressure in the crank case?
Originally Posted by progress
Awesome, I get it now.
But why does my vavle cover vent breather hose Y out, bigger tube going into intake before throttle body, while a smaller tube goes into the manifold peice that leads into the idle control valve?
But why does my vavle cover vent breather hose Y out, bigger tube going into intake before throttle body, while a smaller tube goes into the manifold peice that leads into the idle control valve?
