PCV System Removal?

[Maxx Mazda]

Can I not jsut cap the intake manifold nipples and plug the hole that the PCV valve goes into and leave a breather on the side of the valve cover?

Basically, isn't the PCV system just for emmissions?

 

[Maxx Mazda]

Btw, I know how the system works and all that, and rather than put in a catch can, I'd like to remove the system all together.

 

[Kooldino]

PCV system consists of:

1-side vent (stock routes back into the intake, but many people use a breather).


2-the PCV valve at the rear center of the valve cover that goes into the intake mani

3-the lines that run to the intake mani.

So if you did what you described, you'd just have a big gaping hole at the rear center of your valve cover.

 

[Maxx Mazda]

...and plug the hole that the PCV valve goes into...

 

[yashart_mp3]

The PCV System isn't killing or even hurting performance, so why remove it?

BUT

I cannot see it causing any harm if you were to remove it...

 

[ChopstickHero]

i'm not saying Wiki has correct information ... but:

As an engine runs, the crankcase (containing the crankshaft and other parts) begins to collect combustion chamber gases which leak past the rings surrounding pistons and sealing them the to the cylinder walls. These combustion gases are sometimes referred to as "blow by" because the combustion pressure "blows" them "by" the pistons. These gases contain compounds harmful to an engine, particularly hydrocarbons, which are just unburned fuel, as well as carbon dioxide. It also contains a significant amount of water vapor. If allowed to remain in the crankcase, or become too concentrated, the harmful compounds begin to condense out of the air within the crankcase and form corrosive acids and sludge on the engine's interior surfaces. This can harm the engine as it tends to clog small inner passages, causing overheating, poor lubrication, and high emissions levels. To keep the crankcase air as clean as possible, some sort of ventilation system must be present.

 

[yashart_mp3]

Nice find.

I wonder if simply using a breather on the side vent that usually connects to the intake, is enough to relieve the pressure.

I somehow doubt it...

 

[ChopstickHero]

Nice find.

I wonder if simply using a breather on the side vent that usually connects to the intake, is enough to relieve the pressure.

I somehow doubt it...

I used to have a breather on my P5 for a few years. I took it off one day and decided to cut it in half. i didn't notice any oily residue inside it.

 

[Maxx Mazda]

The PCV System isn't killing or even hurting performance, so why remove it?

BUT

I cannot see it causing any harm if you were to remove it...

Cause I dont want my shiny new engine inhaling oil vapor lol!

The vacuum created by the engine opens the PCV valve, and sucks air in through the breather filter, through the valve cover, and into the manifold. It's mostly emmissions related from what I understand, I just don't want it there. I'm trying to find out what defecit there is to taking it off, if any. Edwin?

 

[TheMAN]

where you put the breather filter on the valve cover (what a lot of ricers do) is actually the intake part of the system... fresh air is drawn into it in order to displace what has gotten sucked out of the engine through the PCV valve... if that didn't occur, the crankcase would build up vacuum and that would cause oil seals to get sucked in, etc...

now during full throttle or under boost, it will go in reverse because the pressure in the intake system is forcing the PCV valve closed, so in that case, all the blowby could do is escape through the breather tube... and being that this happens in a continual state while the engine is under that condition, pressure equilibrium inside the crankcase is maintained

to understand all this better, you MUST read the PCV valve thread *carefully*

 

[Maxx Mazda]

where you put the breather filter on the valve cover (what a lot of ricers do) is actually the intake part of the system... fresh air is drawn into it in order to displace what has gotten sucked out of the engine through the PCV valve... if that didn't occur, the crankcase would build up vacuum and that would cause oil seals to get sucked in, etc...

now during full throttle or under boost, it will go in reverse because the pressure in the intake system is forcing the PCV valve closed, so in that case, all the blowby could do is escape through the breather tube... and being that this happens in a continual state while the engine is under that condition, pressure equilibrium inside the crankcase is maintained

to understand all this better, you MUST read the PCV valve thread *carefully*

Right, so if I remove the PCV system (check 2 posts up, I think my understanding of how it works matches your description) and jsut leave the breather filter, I should have no problem, correct? Since the breather would equalize pressure inside the crankcase.

 

[TheMAN]

you'd have to disconnect both ends and have something to catch the oil or have it spit straight out to the ground

 

[Maxx Mazda]

you'd have to disconnect both ends and have something to catch the oil or have it spit straight out to the ground

But why? If there's no engine vacuum sucking the oil out of the crankcase, it would jsut stay in there, wouldn't it?

 

[TheMAN]

because blowby still happens and the s*** will always find the path of lease resistance to get out

the vacuum system is only there to help *efficiently* get rid of the blowby from the engine to increase oil life

 

[Maxx Mazda]

That's what I don't get. If the blowby is confined to the valve cover instead of being drawn out into the intake, is there any deficit? It would just condense on the valvetrain again, no big deal, right?

 

[TheMAN]

blowby is air, oil, and fuel vapors
mixing gas with oil over time = turning the s*** acidic, breaking down oil, and sludging it up

 

[Maxx Mazda]

So am I to understand then that with a catch can, the catch can will see boost, right?

 

[Tzar177]

bump! Any answer on this?

 

[br289165]

New question old thread

My motors an NA, high compression, built. ANyways I have a custom CAI with no bung for the valve cover side vent hose to mount to on the CAI, so i ran the cover side vent hose to a fitting normally used for the pcv valve on the intake manifold and the pcv valve to the other fitting on the intake manifold. After reading info on this thread, I assume I can't just circulate the vented side hose directly back into the intake manifold, it must be ran to the intake tube before the throttle blade, or not?

 

[Jordysoso]

Not to bring back an old thread, but I need to shorten my intake so it's not rubbing the top radiator hose anymore. My idea was cut just above the breather tube and remove it and install a breather filter. Do I need to do anything else besides that with the PCV system?