PCV System
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Joined: Mar 2007
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From: middletown, RI, U.S.
PCV System
One of my good friends is finishing my swap due to the cold weather and said i need a valve cover with the pcv valve in the middle instead of on the side he said its important because when u really step on it the piston rings expand and scrapes the cylinder walls of excess oil is this true? or can i juss use the ls valve cover? this is for a b20 and hes been doin hondas since 96 hes like 30 so i dnt think hes yankin my chain but he insists i get it before he finishes?
Honda-Tech Member
Joined: Feb 2002
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From: MIAMI
Re: PCV System (grey_ghost)
" Purpose of the PCV system
During each compression stroke a small amount of gas seeps past the piston rings. These gasses comprise of an unburnt fuel/air mixture which contaiminates your engine oil and corrodes your internal parts. The purpose of the PCV system is to remove these gasses while maintaining emissions standards.
The PCV valve tested is known as a variable-flow PCV valve. This valve allows the crankcase to evacuate gasses into the intake manifold even at high load conditions.
The problem Honda engineers had was the following:
They needed to find a vacuum source which provides a variable vacuum with less draw at idle and more vacuum pressure pulling gasses out at high load (WOT) conditions. The dilemma is that at Idle and low load conditions the vacuum present inside the Intake manifold is the greatest and at WOT the vacuum in the intake manifold is the lowest(almost none). This is the exact opposite of what is needed because their is more blowby gasses needed to evacuate at WOT (high load) then at Idle!
So they designed a special spring loaded pintle valve(PCV valve) which does the following:
Idle, Low load--- high vacuum pressures fully retract the pintle causing only a small vacuum draw on the crankcase.
Mild load conditions--- vacuum present in the intake manifold is not as strong so the pintle sits in the middle of the pcv valve allowing more vacuum to evacuate the crankcase.
High load + WOT conditions--- their is almost no vacuum present and the pintle is almost completely extended allowing the most amount of gasses to be drawn into the intake manifold.
Engine backfire--- the pintle fully extends and seals to eliminate any gasses from flowing from the intake manifold to the crankcase.
Under acceleration and high load situations blowby is extremely high and consequently the PCV valve/purge hose cannot supply enough vacuum to remove all the gasses needed. This is when the flow reverses from the valve cover to the intake. Their is so much blowby present that both the PCV valve/purge hose and the Valve cover breather/hose have to both vent excess pressures created. The PCV is working at its best but can't keep up with the demanding pressures created. "
-Dasher*
please use search: catch can
https://honda-tech.com/zerothread?id=1674798
Modified by gringo7718 at 4:18 AM 12/4/2007
During each compression stroke a small amount of gas seeps past the piston rings. These gasses comprise of an unburnt fuel/air mixture which contaiminates your engine oil and corrodes your internal parts. The purpose of the PCV system is to remove these gasses while maintaining emissions standards.
The PCV valve tested is known as a variable-flow PCV valve. This valve allows the crankcase to evacuate gasses into the intake manifold even at high load conditions.
The problem Honda engineers had was the following:
They needed to find a vacuum source which provides a variable vacuum with less draw at idle and more vacuum pressure pulling gasses out at high load (WOT) conditions. The dilemma is that at Idle and low load conditions the vacuum present inside the Intake manifold is the greatest and at WOT the vacuum in the intake manifold is the lowest(almost none). This is the exact opposite of what is needed because their is more blowby gasses needed to evacuate at WOT (high load) then at Idle!
So they designed a special spring loaded pintle valve(PCV valve) which does the following:
Idle, Low load--- high vacuum pressures fully retract the pintle causing only a small vacuum draw on the crankcase.
Mild load conditions--- vacuum present in the intake manifold is not as strong so the pintle sits in the middle of the pcv valve allowing more vacuum to evacuate the crankcase.
High load + WOT conditions--- their is almost no vacuum present and the pintle is almost completely extended allowing the most amount of gasses to be drawn into the intake manifold.
Engine backfire--- the pintle fully extends and seals to eliminate any gasses from flowing from the intake manifold to the crankcase.
Under acceleration and high load situations blowby is extremely high and consequently the PCV valve/purge hose cannot supply enough vacuum to remove all the gasses needed. This is when the flow reverses from the valve cover to the intake. Their is so much blowby present that both the PCV valve/purge hose and the Valve cover breather/hose have to both vent excess pressures created. The PCV is working at its best but can't keep up with the demanding pressures created. "
-Dasher*
please use search: catch can
https://honda-tech.com/zerothread?id=1674798
Modified by gringo7718 at 4:18 AM 12/4/2007
Thread Starter
Junior Member
Joined: Mar 2007
Posts: 253
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From: middletown, RI, U.S.
Re: PCV System (gringo7718)
well um damn...thanks for all the info i only read one link so far but appreciate the response i searched pcv not catchcan thanks alot hopefully i conclude to the right answer do i need a catchcan or not...so far im leaning towards no
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