Adjustable PCV valve

66Valiant528

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I haven't been running a pcv valve on my street dual quad 440 because I don't want to suck oil into the intake. I've considered a catch can and a pcv valve. But I know different valves function differently and your best guess is to find the pcv that was used from the factory with a similar cam/set up. Great except most pcv are now 1 size fits all. Before I jump into a 130 dollar adjustable one I was looking for suggestions. What are you running for a set up?
Screenshot_20220424-201150_Chrome.jpg
 

AJ/FormS

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If your engine is making that much blow-by as to concern you about sucking oil into the intake, wouldn't it concern you more about the blow-by in the first place?
Remember, at WOT, the PCV goes to minimum flow, the breather vents the CC gasses to the atmosphere, and the whole thing wants to run backwards. This doesn't happen only at WOT either, but at anytime the pressure in the CC exceeds the flow capability of the PCV.
Lets say you are just speeding up normally at PT and a vacuum of 8 inches, and say over 2400rpm . In this condition; If the engine is making more blow-by pressure than what the PCV is designed to deal with, then the excess will depart the CC thru the breather.
So yeah, at high manifold vacuum the PCV is running wide open, trying to create a vacuum in the CC. But as soon as the vacuum drops, the spring-loaded pintle inside the PCV, due to loss of vacuum, also drops; back to it's calibrated minimum flow. This protects your engine from excessive ingestion of oil-laden blow-by gasses.
 

66Valiant528

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I have no blow by. I just haven't been running a pcv . I've seen intakes with ports for the pcv and some have been discolored with oil residue. I understand how a pcv system works and understand that my chain store pcv is probably not right for my engine combination. Just wondering who has done what. I like the idea of a fixed system as I see the adjustable one can be set up for if that's what your combination needs. Thanks for the input.
 

AJ/FormS

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I've seen intakes with ports for the pcv and some have been discolored with oil residue.
The PCV has to be connected to the proper port on the front of the carb, just below the butterflies; so IDK what you have been seeing.
If your engine has no blow-by, then just hook up any old PCV that fits and routs easily. This is not rocket science. Your carb will need readjusting. Just make sure you start with a properly adjusted transfer-slot exposure, and modest idle-timing.
As mentioned ; make sure your valve covers are properly and adequately baffled, and every thing will be fine.Don't forget the breather has to work in BOTH directions.
 

66Valiant528

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The M/P covers are baffled. I have 14 inches at hot idle and like 20 cruising. It's pretty amazing considering it's a 520/540 282S solid cam with dual 450s. I hooked up a generic parts store one because those numbers are pretty "stock"and yes I need to jet up a little according to my O2 sensor. Again just wondering what people have been doing with there pcv systems and input on the adjustable one.
 

mderoy340

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I run a wagner adj and a $25 amazon catch can. Zero oil suck in the carb. It takes a little while for the old TRW forged slugs I run to expand and this setup works for me.
 

Bewy

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At idle, your average PCV pintle valve opening is equivalent to about a 7/64" hole. So what I have been doing for a loooong time is cutting open factory PCVs, gutting them, & brazing in a steel disc. In which I drill a 7/64" hole.....
Now have a working PCV at idle & not dependent on idle vacuum for reliable operation.
 

Rat Bastid

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Just buy the Wagner and don’t look back. Any fixed orifice PCV is limited at best. You can drill holes, put brass in line and dick around and it’s still not adjustable.

I have now used a dozen of them. They all have been different engines with different levels of performance. Not once has one not been far better than the junk they took off.

The guys who are telling you to screw around with OE style stuff have either never used the Wagner valve or are too cheap to see the value of it.

Buy it and tune it. You won’t be sorry.
 

weedburner

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Pretty easy to make a $6 NAPA pcv valve like this adjustable...

pcv2f.png


Just drill a hole in the plastic elbow and add a long screw to hold the pintle off the low flow position. Here's an exploded view of what's inside the above valve...

evacpcv3.jpg


Here's where to add the screw...

evacpcv5.jpg


Here's the view of the screw from inside the valve...

evacpcv4.jpg


I pulled the plastic elbow off the above valve and installed it on a valve that had not been cut apart. Been using the same modified valve since May of 2013 with no issues, it draws 15"Hg of vacuum in a sealed crankcase @ 2500rpm cruise. I run 12lb oil rings on the street with 5W-20 Mobil1, without crankcase vacuum it went thru a qt in about 250mi. After sealing up the crankcase and adding the modified pcv valve, I might add 1 or 2 qts all summer. Lack of oil leaks is a huge upside as well.

Grant
 

66Valiant528

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Pretty easy to make a $6 NAPA pcv valve like this adjustable...

View attachment 1715918219

Just drill a hole in the plastic elbow and add a long screw to hold the pintle off the low flow position. Here's an exploded view of what's inside the above valve...

View attachment 1715918220

Here's where to add the screw...

View attachment 1715918221

Here's the view of the screw from inside the valve...

View attachment 1715918222

I pulled the plastic elbow off the above valve and installed it on a valve that had not been cut apart. Been using the same modified valve since May of 2013 with no issues, it draws 15"Hg of vacuum in a sealed crankcase @ 2500rpm cruise. I run 12lb oil rings on the street with 5W-20 Mobil1, without crankcase vacuum it went thru a qt in about 250mi. After sealing up the crankcase and adding the modified pcv valve, I might add 1 or 2 qts all summer. Lack of oil leaks is a huge upside as well.

Grant
Impressive!
 
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