I've seriously thought of installing one of those types of evacuation tubes.

Gary can you explain the air flow for this system?
And when the PCV should be working and what to expect?
Thanks!

Nos681 wrote:

Gary can you explain the air flow for this system?
And when the PCV should be working and what to expect?
Thanks!

I really can't. At idle and high manifold vacuum the valve should be almost closed as blow-by is at a minimum. At cruise and WOT the valve opens more as blow-by is at a maximum. If a backfire occurs it is suppose to close completely. Springs, crankcase pressure and manifold vacuum determine the flow. But what is the correct flow? The internet is full of questions about the flow rates and it seems none are published. I did find an adjustable unit but at $129 I'm not likely to try it. 

Yesterday at the local parts store they had nothing listed for the 67. The parts guy says we have a bunch of em in the back if you want to choose one that fits. No thanks, I'll keep looking. Napa has one so I think I'll drive the 32 miles round trip to get it. 

There are a lot of interesting discussion about PCV in forums and magazine articles to be found on the net. Flow rate matters.

Mike's suggestion of an orifice in the hose to cut down the flow is an option, but it is not the solution I am looking for.

I would like for someone to plug their PCV valve while idling and tell me the results. 

We had a big discussion on PCV valves a while back. You need them to work at idle and at WOT and at every point in between. Here’s a link to an article that opened my eyes on the subject:
http://mewagner.com/wp-content/uploads/2016/01/Hemmings-Muscle-Machine-Jan-2016-p64-67.pdf
I think you should look at the Wagoner valve again. I love the two I have on my cars and will never go back. Read the article if you haven’t already and give it another consideration.

Last edited by Muzz 66 (8/15/2019 1:08 PM)

GPatrick wrote:

There doesn't seem to be any problem as described in the original post.   This is pretty typical behavior for a PVC valve/system.  When you pull it, the engine goes lean and quits.  If you plug it, you don't have enough air, and it quits.  Can you plug it and increase the idle speed, yes, but then you are venting crankcase gases for no reason.  If it runs fine with it in, leave it in.  You can get different valves that have slightly different properties.  I think there is a HIPO 289 part number or a 428 Cobra Jet valve but I'd have to search again.  You can even buy adjustable units as has been discussed on here in the past.  Also, the PCV system is not intended to be closed.  In some cases people will block off the opposite valve cover where hopefully filtered air is brought in which can ultimately encourage blow-by as it pulls vacuum in the crankcase.  So, I guess my ultimate question is why are you trying to fix something that is working correctly and as designed? I'm with Ron!

The reason is because I don't think it is operating as designed. A snippet from the article Ron linked

For example, at low or idle engine speeds manifold vacuum is high. This pulls the plunger to the extreme forward position, or manifold end of the valve. Due to the shape of the plunger, vapor flow is reduced to a minimum. The low rate of the flow is adequate for ventilation purposes and will not upset the fuel/air mixture ratio.

The italics I put in. This is how I think the valve should work and not how my valve is working. I just wanted clarification that mine was not working correctly before I drove the 37 miles (1 hour) round trip to the NAPA store. 

I just returned from NAPA with a 6 cylinder PCV valve. The 8 cylinder valve they gave me was the plunger was stuck on the inside so they are delivering one tomorrow. I purchased both to see if there was any difference, curiosity only. 

Once the engine cools, I'll test the little 6 banger valve. 
 

Muzz 66 wrote:

We had a big discussion on PCV valves a while back. You need them to work at idle and at WOT and at every point in between. Here’s a link to an article that opened my eyes on the subject:
http://mewagner.com/wp-content/uploads/2016/01/Hemmings-Muscle-Machine-Jan-2016-p64-67.pdf
I think you should look at the Wagoner valve again. I love the two I have on my cars and will never go back. Read the article if you haven’t already and give it another consideration.

I am leaning toward the mewagner adjustable valve. The ability to fine tune the PCV to my engine is what I like about it. Not so the price. 
 

Thanks Muzz!  That may explain some issues I had in the past.

TKOPerformance wrote:

We did a group buy on the ME Wagner valve a while back.  The issue seems to be that replacement PCV valves are kind of one size fits all.  Originally these valves were different based on application, but now they just don't have the same level of engineering in them.

AND, once you start changing things in the engine the PCV valve for a stock engine, like a lot of stock parts, isn't necessarily up to snuff.  The ME Wagner valve solves this issue by allowing you to fine tune the valve for your particular combination. 

They are pricey, but they also work really well.  I've yet to hear of anyone who was unhappy with their purchase, and a lot praise it saying it solved issues they couldn't fix otherwise.  Plus, well made, and rebuildable, so its a lifetime purchase. 

What sort of price are we talking here TKO? I think I have a regular aftermarket one on mine and this post got me wondering.
If I get something like what you fitted, will I be looking at re-tuning the engine?

I just took a look at my pcv valve and wonder if it is the original. It has the brass bend fitting on the end with the pcv valve screwed into it.

Well crap, more money that I don't want to spend. OK, I'll buy one. 

The new PCV valves I bought, one for the 6 cyl and the other listed for all V8's do not work better than the one I have. The little 6 banger one vibrates while the engine is running. 
 

Nos681 wrote:

Thanks Muzz!  That may explain some issues I had in the past.

YW, Just passing it on. On my ‘92 the ME Wagner valve was working a little too well.  The PCV hole is at the back of the intake manifold.  There is no baffle to keep free oil from splashing up and getting sucked into the valve and into the intake, gumming things up. There is a “crankcase breather element” that slows some of that down. It’s just a wad of wire. I added an oil separator to the line to the intake. It pulls out about 1/3 cup of oil every 1000 miles.  Works great.

Muzz 66 wrote:

Nos681 wrote:

Thanks Muzz! That may explain some issues I had in the past.

YW, Just passing it on. On my ‘92 the ME Wagner valve was working a little too well. The PCV hole is at the back of the intake manifold. There is no baffle to keep free oil from splashing up and getting sucked into the valve and into the intake, gumming things up. There is a “crankcase breather element” that slows some of that down. It’s just a wad of wire. I added an oil separator to the line to the intake. It pulls out about 1/3 cup of oil every 1000 miles. Works great.

And that's why Ford put a filter below the PCV on the 5.0, which had the PCV in the rear of the intake.  I believe there was a baffle below the filter as well.  I'd pull the intake and fabricate something similar.  Shouldn't be too terrible tough.  You should be able to drill and tap the intake in that area so long as you avoid any coolant passages.