PCV: Few questions in regards to removal.

[seq4x4]

I have a few questions about how the PCV works. Ihave figured out away to remove it. But it involves taking it out completely or removing the spring.

What the plan is to do is bung the top of the hole on the manifold. Below that tap in a barb fitting and run it to a oil catch can. But to do that i need to figure out how it actually works. Because of the spring, the plenum compresses it abit. Would the motor still work fine if: I took the spring out and leave the PCV in. Or does it need to back it pushed down so no gases/oil escapes past the valve?

[oscar03]

A crankcase ventilation system is a way for gases to escape in a controlled manner from the crankcase of an internal combustion engine. A common type of such system is a positive crankcase ventilation (PCV) system, the heart of which is a PCV valve—a variable-restriction valve that can react to changing pressure values and intermittently allow the passage of the gases to their intended destination (which nowadays is the engine's intake stream).

Internal combustion inevitably involves a small but continual amount of blow-by, which is when some of the gases from the combustion leak past the piston rings (that is, blow by them) to end up inside the crankcase. The gases could be vented through a simple hole or tube directly to the atmosphere, or they could "find their own way out" past baffles or past the oil seals of shafts or the gaskets of bolted joints. This is not a problem from a mechanical engineering viewpoint alone; but from other viewpoints, such as cleanliness for the user and environmental protection, such simple ventilation methods are not enough; escape of oil and gases must be prevented via a closed system that routes the escaping gases to the engine's intake stream and allows fresh air to come in.

in short yes the engine will still run ok but WILL develope oil leaks. that said some more modern engines also take into consideration this extra air flow in their tune which is why if you get a split or blockage in your pcv system it can cause the car to throw error codes.

[seq4x4]

Iv read that before. But what i plan to do is not bloke it so it cant escape. A breathable oil catch can will be hooked up to a barb fitting that will be put below the blocked of section of the manifold thus creating a different place for the gases/oil to go instead of into the plenum. The problem im enquiring about is about weather the spring needs to be attached to it so its operation or the valve can work fine without it?

Cheers for the info tho.

[oscar03]

you shouldn't need it what a lot of people do is just replace the oil filler cap with a breathable one to solve pressure problems. the sprung valve is there to prevent gas from flowing the wrong way i.e. from the intake side into the crankcase. if you are going to remove that link remove the valve as well.

[seq4x4]

So saying that, what i do is take out the valve and spring, block it and run the can? I havnt seen breathable oil caps for an ecotec before. The other thing is, with the oil splashing around the rocker cover, wouldnt it escape?

Iv attached my idea for a neat and tidy yet still trying to be legal plan.

[delcowizzid]

block it all together and fit the pcv into a grommet in 1 rocker cover then into catchcan and back into the plenum via a new hosebard threaded into the plenum

[GRPABT1]

#### it off entirely and run a hose from each rocker cover to a vented catch can. Nothing like fumes to get you excited

[seq4x4]

I might do the twin rocker cover one. Does it have to be vented back to the plenum tho?

[azkwazere]

I might do the twin rocker cover one. Does it have to be vented back to the plenum tho?

If you dont want to get done for emissions violation is does...

aZk.

[seq4x4]

So i guess then, no breather and run that to the plenum.

[delcowizzid]

you need an air inlet and then the pcv into plenum for it to work correctly.its not just there for emissions it also removes all the caustic shit that builds up in the crankcase and oil

[GRPABT1]

Basically without proper crank case "through flow" you will have moisture build up in the oil quicker. This creates no problem if you change your oil every 5000km's or more. Revving a motor hard with a shitty stock PCV system though is a sure fire way to blow oil seals on a Holden like the rear main, and also puke power robbing oil into the intake tract. I ####ed around for ages with elaborate PCV systems that "in theory" should have worked but still blew the dip stick out. Now I have a vented puke tank I don't have a drama (except for the fumes lol)

[Brett_jjj]

Years ago,most engines crankcases were just vented to the atmosphere,which caused pollution,so they came up with the system where it uses filtered air from the throttle body/inlet manifold to scavange the crankcase vapours,the air and scavenged vapours are then directed back into the inlet manifold where it then goes into the engine and is consumed in the combustion process.
If blowby is at a very high rate,(from either worn piston rings or when the engine is running under extremely high/heavy loads),and the blowby gasses generated exceed the capacity of the PCV valve,then these excess vapours will flow back through the engine vent hose to the throttle body,where its then drawn into the inlet manifold to be consumed.

[seq4x4]

Thanks for your input guys. Im going to do it properly. Take the plenum to an alloy welder and weld and smooth the hole like it was never there. Chuck 1 barb each into the rocker covers, route them to the catch can then another line back to the plenum.

Now saying what you said brett, im under the impression i can get away with a "T" piece to that vac line. Is this correct?

[Paul13pp]

Now I am curious as to how often the oil catch can will require servicing...

[GRPABT1]

Depends on the condition of the motor and the amount of abuse it cops.

[seq4x4]

I can assure you this car cops a flogging. Im just sick of replacing lid seals every time i clean the plenum. Not to mention all the money and work i put into the new intake system thats going on, i would like to keep it clean.