Jump to content

Crankcase vent filter


Kklim
 Share

Recommended Posts

Ok, the breather is mean for the cylinder head. The PCV is directly from the crankcase and is slightly pressuried

↡ Advertisement
Link to post
Share on other sites

where is the airflow sensor located? If before, then doesn't make any difference at all. [nod] I noe from Mazda cars, this hose is after the airflow sensor, the ECU will make adjustment and u will probably loose some horsey. No benefit from adding this vent filter. [shakehead]

Works for older cars to prevent fouling of carb and throttle body. [nod]

That's why I put oil-catch tank instead. [thumbsup]

Edited by Normal_aspirated
Link to post
Share on other sites

this hose SHOULD be after airflow sensor...and isnt airflow sensor suppose to sense if there are enough air coming in?? i thought ECU will sense air and fuel mixture at intake??... i think all car are of such nature...like E68 "injecting" more air but later compensate by ECU...

 

 

..and AGAIN the filter is not going to make your car run faster or such..it just help prevent more alien materials from entering throttle body..the benefit is what you are trying to achieve with oil catch tank..not make your car run faster...

 

and oil catch tank is place after PCV valve area which blow-by enters intake mainfold and this is place at air hose leading to throttle leh...different place but trying to serve the same pupose...just that oil catch tank blow-by are "deadly" hence need to be burn up if not your car cannot come in singapore la...having oil catch tank is not going to make you car faster...just cleaner...same same concept...

 

AGAIN this mod is not trying to make your car run faster...just trying to make it cleaner...

Edited by Victorhoo
Link to post
Share on other sites

u misunderstand me , mah. [blush]

From the diagram u posted, plugged the nipple at intake hose and put a vent filter at crankcase, show me that will not help at all. dun mind saying. [wave] Put it at the PVC, worse, as now no fresh air come into throttlebody the ECU now see richer mixture so pump less fuel and result u feel lesser horsey, mah. My S$0.02. [:p]

Hv used that vent filter before with my car, and juz share with u my findings. [nod]

u still want cleaner engine, recommend u to use oil-catch tank. [thumbsup]

Edited by Normal_aspirated
Link to post
Share on other sites

..its only neg pressure that will cause air to be suck in crankcase..whereas most of time its positive..hence air is going into throttle body ..not the other way round...and when its neg , air can still be suck via filter...

 

 

i dun know about PVC but if its PCV valve you toking about...its leading directly to the intake manifold...it has nothing to do with fresh air at all...again...CANNOT put at PCV area la..those gases are harmful...its that filter or called a "breather" that is drawing the air...again like i say most of the time its not drawing ..its releasing...

 

cannot agreed with the part you toking about no frsh air into throttlebody..makes no sense at all..

 

to plug in the filter is exactly to prevent some oil escape going back into the throttle body...

Edited by Victorhoo
Link to post
Share on other sites

a interesting way of ending this discussion..anyway i am not a expert..it is just what i have understand from the many literature that i have came across...sorry if i have offend you in any way

Link to post
Share on other sites

There seems to be a bit of misunderstanding between cylinder head breather and crankcase PCV ventilor.

The space between cylinder head and cover the pressure is negative due to the rapid movements of the rocker armes and other rotating components and therefore fresh atmopheric air will be suck in. To prevent dirt from entering the breathing hose is normally located at the air filter housing or after.

The crankcase area receives alot of cylinder blow-by gases and therefore the space is pressureised. To prevent damage to the crankcase end seals and other seals, the pressuired gase must be allowed to escape. The pressurise gases are collected and pipe right into the cylinder head casting and connected by hose via a pcv to the intake manifold. The whole idea is to subject the blow-by gases to combustion temp and hopefully render the gases harmless.

Link to post
Share on other sites

Neutral Newbie
where is the airflow sensor located? If before, then doesn't make any difference at all. nod.gif I noe from Mazda cars, this hose is after the airflow sensor, the ECU will make adjustment and u will probably loose some horsey. No benefit from adding this vent filter. shakehead.gif

Works for older cars to prevent fouling of carb and throttle body. nod.gif

That's why I put oil-catch tank instead. thumbsup.gif

Last time I remember hor .... my twin carb Toyota Celica got this ley unsure.gif But dun know for what also laugh.gif

Link to post
Share on other sites

Last time I remember hor .... my twin carb Toyota Celica got this ley [:/] But dun know for what also [laugh]

Same oso for my old faithful Fiat 124S, every few months, must clean the carb. Until i started complaining, my mech introduce this vent filter thingy and divert it away from the air-intake. [:p][sweatdrop]

Since then no prob with dirty carb. Car oso more powderful and idling stable. [thumbsup] Dun worry, those days dun hv emission control regulations yet. [rolleyes]

 

Paiseh, u mean the vent/bleeder-filter or the oil-catch tank? [blush][blush]

Edited by Normal_aspirated
Link to post
Share on other sites

ah ..you see...PCV allows blow-by to go into intake (one-way)...the cylinder head breather is 2 way......not as what you have say of just sucking in of fresh air only....

 

thats is why the dirty carb...some of the escape air is channel back into the throttle body...its 2 way and not what you say its 1 way only...not forcing you to believe...but thats how its work....

 

I am quite sure of this...PCV valve 1 way, Breather 2 way.. [:)]

 

even when i check with my mech(he is very experience acknowledge by many) he also say it will go back to throttle although must depends on the speed that you are in..

Edited by Victorhoo
Link to post
Share on other sites

thats right...even though most of the alien blow-by will be channel back to intake to be burn off..some of them will still escape...

 

having it channel back to the throttle(closed system) is for better emmission control...

 

hence, bying adding of a filter, it will prevent some of the escape alien material from going back to throttle to be burn off...but bad for emission control

 

thats is the vent filter(breather)..the oil catch tank is after the PCV valve area before intake mainfold..

Edited by Victorhoo
Link to post
Share on other sites

Physically a carb and EFI engine to a layman is almost like twin but technically they are world apart from engine management to fuel vapour recovery system.

For a carb engine the breather air flow can be bi-directional depending on the air flow speed at the air intake duct. Intake air with some oil droplets will not seriously affect the carb in its performance. The only problem is the oil and dirts will untimately coat the throttle plates and choke the acceleration power jet.

For a EFI, clean air is a must in order for the MAF ( mass air flow)sensors to monitor air temp and volume. If the cylinder head breather is allowed to discharge oil mist into the air intake plenum (air duct after the air filter ) what will happen if these oil droplets start to coat the hot wire or termistors ? The result is erractic engine idle and accleration speed.

PS The surface bore of the MAF is normally coated with telfon so that the incoming air with dirts and abrasive will not cause extensive scratches on the surface. A heavily dirt coated surface will cause air flow to be uneven and slow down - all these will greatly affect the perfromance of the MAF sensors.

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...