Good morning fellow C3 Folks,

Heard a discussion at one of our local Cruise Ins about running a SBC/350 with the PCV port to the carb plugged and have the valve cover PCV piped to free flow to the atmosphere?????

Kinda made me put this out to the forum to find out if there is any credibility to this story...........

Cordially,

Mk's 78/Mike

 

What are you asking? Disconnecting/plugging the PCV negates the PCV. If the cruise-in crowd was crowing about added horsepower by disconnecting the PCV, hang with another crowd.

 

What about venting the PCV to an aftermarket air cleaner with a port manufactured into it instead of to a vacuum port on the carburetor?

 

when it comes to PCV and breathers, I've found the way GM designed the system is always the best way to have it installed and fuctioning

 

If I understand what you mean, you will have a nice oily film all over your engine compartment.

 

What about putting a catch can in the system so that oil doesn't get introduced back into the carb or the intake? They make them for modern systems (still need to put one on my Ram)...

 

Someone has Gerry-rigged their PCV system to resolve some other underlying problem. Now, they are trying to profess that change as something 'beneficial'.

Baloney!

The PCV system (as GM/Chevrolet implemented it) works fine, absorbs no engine power, reduces engine compartment fumes/vapors/crud, and is almost maintenance-free. Tell your 'buddy', "Thanks...but no thanks."

 

If he plugs the PCV outlet on the valve cover it gets more interesting. If he leaves the PCV port on the front of the Q-Get open he will have a massive vacuum leak. Interesting post.

 

I have to agree not a good Idea on newer corvettes since I am guessing you have a 1978 by you screen name. Many early engines pre 1960s did not have the Positive Crank Valve and had breathers on both sides of the valve covers. While you can remove it on the valve cover and plug the hole on the carb it is not a good idea unless your running a pre 1960s engine. Even then it will suck dirt into the top end of the engine unless you filter it properly.

Here is a little history on the PCV

This is where crankcase ventilation comes in -- a certain amount of that mixture of air and gasoline is pulled down by the piston and slips through the piston rings into the crankcase, which is the protective cover that insulates the crankshaft. This escaping gas is called blow-by and it's unavoidable. It's also undesirable because the unburned gasoline in it can gunk up the system and produce problems in the crankcase. Until the early 1960s, these blow-by gases were removed simply by letting air circulate freely through the crankcase, wafting away the gases and venting them as emissions. Then, in the early 1960s, positive crankshaft ventilation (PCV) was invented. This is now considered the beginning of automobile emission control.

Conclusion unless you are running a full race engine and do not care about sucking dirt into the valve covers or rebuild the engine often then probably not a good idea The engine has to breath and the Positive Crankcase Valve pulls air on most older cars the Passenger side Valve Cover thru a filter then sucks it thru the crankcase into the carburetor to re-burn the excess fuel and oil fumes that blows by the rings on the Drivers Side Valve Cover into the Carburetor.