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Quick PVC Routing Question

Started by 68CoronetRT, January 07, 2013, 10:38:40 PM

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68CoronetRT

Ok. So going through the new car(To me!) and noticed it has two "breathers" on the valve covers. 1 breather was hooked up to the carb with the 3/8ths (Or maybe 5/8's) line and the other didnt have any hook up for any line. Car was running real rough so we plugged off the line to the carb and walah! it's running alot better. Now tonight I'm looking at the breather with the hose hook up and the guy that owned it silicone the bottom side shut! Which after reading about PCV systems means it was trying to draw in air but it was blocked or vise versa and that is why im getting smoking from the non PCV sided breather (Pass side).

SO my question is this. Can I run two breathers? OR if I want to run a PCV system, do I leave the pass side as a breather and either A.) Get a new breather/PCV dealio and hook it back into the base of the carb. Or B.) Do I run a PCV valve in the cover and then run the line to the base of the carb?

Or do you hook that line into the intake? or the air cleaner?

So much different options on the net and it's confusing to me!! I just dont want all this smoke after getting on the gas for a few seconds which I assume is blowing oil out the pass side thanks to a clogged breather on the drivers side.

femtnmax

You can run one or two valve cover breathers.  But from the factory a pcv system was used and helps keep the engine crankcase clean.  Most carbs have pcv inlet fitting, meaning the carb has been tuned to include the air ingested by the pcv, so eliminating it will make the fuel air mixture richer.

PVC system draws air in from the air cleaner or valve cover breather into valve cover, then down thru crankcase and back up thru opposite valve cover, then thru PCV valve, then into the carb base or intake manifold.  Thus any piston ring blowby is ingested back into the engine and burned.   If piston ring blowby is within normal levels, there will be a slight suction at the "inlet side" of system (air cleaner or valve cover breather).  To check, remove the breather, and place a scrap of paper towel or such across the opening with the engine idling.  The suction will hold paper in place.  With excessive ring blow by the paper will be blown off the vavle cover.

IN the photo. at left side of air cleaner is the fitting for pcv hose to run to valve cover breather/filter element.  So inlet hose would run from the air cleaner to pass. side valve cover.  On the driver side valve cover will be pcv valve, then hose from that valve to the large open pipe at bottom center of carb.
Phil

Brightyellow69rtse

i was having some weird peressure issues on the new motor. i ended up scraping the pcv and just running 2 breathers. everthing was fine after that.

Dmichels

You NEED to have some type of PVC valve befor the carb conection to regulate the vacuum. The other breather needs to be an air filter. You are pulling clean air threw the motor. Some think this negitive preasur will let you make more HP. PVC is not really a bad thing it removes alot of crap from the crank case
68 440 4 speed 4.10

68CoronetRT

Ok so I think I got it. I'm running a standard PCV valve connected to the base of the carb, then the opposite side has a breather type deal plugged into the valve cover.

Another question, I noticed when I put the new rubber grommets in the valve covers they do not cover the entire hole up! these covers have holes that would require a twist lock type breather or PCV and I'm trying to run the standard rubber grommet and just stab the pcv in and breather in.  Will this setup leak oil like that?

Dmichels

Yes it probally will. You can find larger gromets that will work.
68 440 4 speed 4.10