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what exactly is the pcv valve meant for and the guy that had the car before me plugged it off. what effect does that have on the car
 

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Full tilt boogie !!
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I believe it's: Positive Crankcase Ventilation..........If yours is blocked off, you need to fix it asap......do you have any oils leaks?:D
 

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Discussion Starter #3
well i went to a shop to get some valve springs thrown on because my valves are wantin to float and the guy noticed that the pcv wasnt connected. ive heard people talk about them but i have never actually knew what they were. it actually doesnt leak a drop of oil.
 

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mine is blocked off, but I have breathers on the valve cover. I would rather have it, now my car smells like oil from the oil vaports coming out threw the breather.

I had to plug mine becuase the pcv was sucking oil from below the intake into the intake tract and burning it.
 

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Positive Crankcase Ventilation

It keeps the crankcase from getting pressurized, which will spew oil out of every orifice there, like the dipstick tube, any small leak in the valve covers, oil pan, etc. That pressure comes from the little bit of blowby that's in all engines, plus the internal pressure changes from the pistons moving up and down. It's a good thing to have. You can block it off and put breathers on, but like BJ said, it will smoke from there and leave a mess. The PCV ducts that to the intake so that those fumes / smoke are run back through the engine and burned.
 

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duh...duh....duh
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Danny said:
The PCV ducts that to the intake so that those fumes / smoke are run back through the engine and burned.

Is that bad for the engine or would it decresase HP? Or is it so little that it means nothing in the daily operations of the engine?

Thanks,
 

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ceyko said:
Is that bad for the engine or would it decresase HP? Or is it so little that it means nothing in the daily operations of the engine?

Thanks,
Nope, you won't lose HP and it's not bad for the engine.

You may actually GAIN some HP since the pistons aren't trying to force their way down into a pressurized crankcase. Take a look at any serious race car and there will be a crank evacuation system that actually supplies vacuum to the crankcase. This helps ring seal as well.

As for being bad for the engine, nope. You'll have a little extra carbon and soot downstream from the PCV valve and that's about it.
 

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Without a functioning PCV system you oil will have a short life. If your really worried about the oil vapor in the intake, install an oil-air seperator.
 

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For what is is worth, Hot Rod or Carcraft was goofing around with a Chevy 454 on a dyno. They took an electric air pump from a Cobra, wired it backwards for suction instead of pressure and hooked it to a valve cover hole.

Made 5 more horses.

Land speed racers will hook up lines from crankcase to header collectors and get PCV from the venturi effect.

Really big HP dragsters have belt driven vacuum pumps for PCV.

Crank case ventilation is a good thing. Don't plug it up.
 
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