Blocking off vaccum

[Turbizmo]

I just had i question I wanted to know if anything bad would happen if i block off the line comming out of the valve cover that conects with the Intake? I know people put oil catch cans but would it be safe to block it his a picture of the line im talking about im not talking about the PCVvalve.

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[BLINKY619]

do you meaN HAVING IT BLOCKED OFF WITH NO ARE COMING IN OR OUT...?????

 

[neoviper]

I'm gonna say no. While I'm not 100% sure about this I believe that that's part of the PCV system. When your car is either idling or decelerating and your IM sees vaccum you pcv valve uses that vaccum to suck the crankcase gases out of the head, meanwhile fresh air is pulled out of the intake pipe, which I believe is the line that youre looking to "block" off.

Check out this write up, it explains the pcv valve on a 4g63 motor but I'm pretty sure that it applies to the 420a as well:

Dsmtuners.com/forums/articles-engine-fuel/366890-4g63-pcv-system.html

 

[knochgoon24]

That line pulls a vacuum in your engine. It helps pull condensation and other vapor contaminants out of your oil. It's a good idea to leave it connected.

 

[Fotowntalon]

I had it kind of blocked off for over a year because i had a cheap SRI that had no port on it on the intake, so I just through a breather on the valve cover. Didn't have any problems. Now that I have an actually AEM SRI I use the vacuum port, but between the two cant say I noticed a difference.

 

[Glacius_01]

I agree with everybody else...it's a good idea to leave it hooked up...

 

[Locke]

It doesn't have to be hooked to the intake, BUT it cannot be plugged at the VC either. If you remove that hose, put a breather filter on the VC. Your PCV system won't function with it plugged.

 

[neoviper]

While a breather filter will function well its still better to hook it up to the intake, the reason being that your using air that's already been measured by the MAF. granted the amount of air we're talking about is fairly minimal, but, technically it can make you're car run a little leaner as you're adding air to the system that hasnt been seen by the ECU. But definately don't plug that line on your vc

 

[Locke]

Or, since the OP has a 420a engine which uses a MAP and IAT in the IM that provides data to the ECU which performs speed density calculations to determine mass air, he can put a breather on the VC and plug the port on the intake pipe if he wants to.

 

[neoviper]

He's also turbo'd though so it would be good to keep it hooked up to the intake so that he could utilize the vaccum that the turbo creates to help suck out the crank case pressure under boost.

 

[Locke]

No.

That pipe is hooked to the UICP which is exposed to pressurized air. Your reasoning is incorrect as well, this line is not for air to be pulled out from. We don't want vacuum to the breather. This is where air will return to the crankcase, allowing flow through the PCV hose. Without this flow, the PCV valve would not be pulled open. This is the same reason we cannot plug it. Air must be allowed to be drawn into the breather. This is the "P" in PCV. Otherwise, it would just be a crankcase vent.

Him being turbocharged causes even more reason for him to remove that tube, plug the port on the intake pipe and install a breather on the VC. With that tube hooked up, he is pressurizing his crankcase when boosting, which is bleeding off boost after the WGA signal branch. He is working the turbo more than needed, creating the possibility of popping out his dipstick, and potentially slowing the return of oil from the turbo to the pan.

 

[Turbizmo]

Well this is the reason y i want to block it off. Back then I had a breather on but under boost it spit out alot of OIL. so then i hooked it up to my intake pipe. wrong thing to do since it leaked oil under boost it caused me to burn oil and oil used to be all inside the pipes and made my pipes pop out. so then i decided to go with a oil catch can it worked well but then it melted . then for a while it just stopped trowing oil under boost and know all of a suden its trowing oil again so i guess best thing to do its built me anoher heavy duty Oil Catch.

Can anyone just tell me if this is normal to trow lot of oil i mean it filled up a gatorade bottle in like 4 hard runs. can i make it stop? my dip stick does pop out once in while too.

 

[Locke]

Excessive blow by, or a busted PCV valve. The PCV valve should be stopping the boost from entering the VC. If the PCV valve is functioning correctly (shake it to make sure its not stuck, blow/suck on it to make sure it seals) then you should consider adding a secondary check valve in line with the PCV valve.

Check your compression as well. Excessive blowby is generally paired with poor compression. (worn or damaged rings or ring-lands, glazed cylinders, incorrect ring end gap, &c...)

A catch can is always a good idea, though.

 

[Turbizmo]

thanks LOCKE I will buy me 2 new OEM PCVs today and hook them up and see if that helps it I doubt it mt piston rings since there Je and there new about 8 k on them but u never know hopefully its just the PCV ill let u know whats up

ok well i bought 2 new PCVs and now my problem is SMOKE is coming out of the line thats running to the oil catch can. Also My car feels weaker than before I changed my spark plugs and gaped them to 35. Any ideas please help?