breather with PCV tube or PCV valve?

[Jack E/NJ]

Any thoughts on using a filtered breather cap with an integrated PCV valve vs. one with a simple PCV tube to the air cleaner? Thanks.

Jack E/NJ

[51 MERC-CT]

Breather cap lets air in, crankcase vent tube is where the PCV valve should be located. ( to vent crankcase) PCV tube to intake or carb base vacuum.

[Jack E/NJ]

Thanks for comments. On OHV-v8s, PCV valve is on the back of one valve cover, and a breather cap with a PCV tube to the air cleaner on the front of the other valve cover to achieve crankcase ventilation. My understanding is that the breather cap lets air in from the air cleaner only when the crankcase is under vacuum (PCV valve opens at low throttle). And lets air out into the air cleaner when the crankcase is under pressure (PCV valve closes high throttle).

But on a flathead, the crankcase vent is on the pan where it's not easy to locate a PCV valve. So I was thinking that maybe a simple breather cap with a PCV tube to the air cleaner might be about the best you can do to clear the crankcase of a flathead with the vent in the pan.

Comments?

Thanks

Jack E/NJ

[51 MERC-CT]

In the OHV engine, the tube you speak of in the air cleaner is located in a low vacuum portion of the air cleaner and generally has it's own little air filter to provide filtered air thru the non vented oil filler cap (if so disigned )
The vacuum is still pulled from the carb base or a vacuum plate under the carb.
The 59A and the 8BA flathead venting systems are different and each one has its own solution to the problem.

[296 V8]

I run the valve under the intake ( not attached yet in photo)
And let it pull air in the oil filler cap
Sheet metal shroud attached to gasket covers it to keep from sucking up oil.

[36tbird]

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296, I'm too distracted by the bug on my monitor to make out the plumbing you have there. Can you post another pic close up of the middle? Also, do you block off the vent on the oil pan? Thanks, Lou

[Jack E/NJ]

To 51 Merc: Agree with you on the OHV setup. PCV valve to high vac carb base. Breather PCV tube to low vac air cleaner.

To 296v8: Related to what 36tbird asked, how is your crankcase being positively-vented if a lot of air is pulled into the oil filler cap instead of the crankcase vent?

To 36tbird: Does this distract you too?

[296 V8]

It’s a little confusing to try and explain but ill give it a shot. That is the only photo I have (59a is buttoned up and running)

The first way I tried it was.
I plugged the breather at the pan gasket with shim stock and drilled a ½’’ hole into the breather galley behind the cam gear (like a 8ba is stock).
I then caped the breather tube in the valley with a ¼’’ or 3/8’’ pipe coupler and put the pcv valve there. It was connected to the barbed fitting in the photo with hose.
This setup didn’t work, it sucked up oil from I presume the bleed off from the front cam bearing.

So I pulled the intake and put the valve right on the intake pluming extended forward as far as possible and shrouded.
Pan breather remains plugged …. don’t want unfiltered air coming in from there.

My thinking is
The oil filler tube go’s all the way down so im actually pulling air / blow by up from the cam and crank area threw the oil drain holes in the valley.
I just had to find a valve that was treaded on the right end (the out side)
Works fine and best of all no modern stuff showing.
Same basic idea as any modern engine ……..air needs to go in to come out.


Ok hotrod the bug is gone………..now you guys can complain that I made you hungry(:

[Kahuna]

Here's how I did mine. This is on a 59 type block. Essentially, I added a threaded tube to the pan vent area and added a small filter to it. It's located just behind the block drain in the pic. Next, I added a 1 1/2" copper cap to the fuel pump area where the original tube (now removed) is/was located. To that cap, I soldered a barbed hose fitting that then connects to the PCV valve located on the bottom of the manifold with a hose, similar to the way 289V8 did it. My thinking is that the air enters through the filtered tube, moves around the crankcase, picking up blowby gases, then is sucked up through the PCV valve to be burned.
Jim

[1952henry]

Originally Posted by 296 V8

It’s a little confusing to try and explain but ill give it a shot. That is the only photo I have (59a is buttoned up and running)

The first way I tried it was.
I plugged the breather at the pan gasket with shim stock and drilled a ½’’ hole into the breather galley behind the cam gear (like a 8ba is stock).
I then caped the breather tube in the valley with a ¼’’ or 3/8’’ pipe coupler and put the pcv valve there. It was connected to the barbed fitting in the photo with hose.
This setup didn’t work, it sucked up oil from I presume the bleed off from the front cam bearing.

So I pulled the intake and put the valve right on the intake pluming extended forward as far as possible and shrouded.
Pan breather remains plugged …. don’t want unfiltered air coming in from there.

My thinking is
The oil filler tube go’s all the way down so im actually pulling air / blow by up from the cam and crank area threw the oil drain holes in the valley.
I just had to find a valve that was treaded on the right end (the out side)
Works fine and best of all no modern stuff showing.
Same basic idea as any modern engine ……..air needs to go in to come out.


Ok hotrod the bug is gone………..now you guys can complain that I made you hungry(:

Your pcv is threaded to the plumbing on the forward side of the manifold?

[296 V8]

Yes the ¼’’ tubing is almost the same as in the photo, just extended forward from the 90 a bit with a pcv valve threaded on the end.
I recall I used a small valve from some import………picked it out of the parts book at napa.

[36tbird]

Jack, I can deal with that rotary motor. Just curious, can you make it into a WWI recip with the crank stationary?

296, is that steak on there for today's holiday? I like mine medium rare. Please put your bug back on later, I really think it is mind blowing and at my age I need all the stimulus I can get.

Also, 296, it is OK that you will not remove your intake for us to get another pic. I found some things on the HAMB, see below. Sorry, I lost the name of whoever did this work to give credit.

Kahuna Jim, I should have know that you already worked this. Does it have any correlation to that mod you made to the pressure relief? I don't remember the details of that. Thought that when I get to that point I would talk to you about it then.

Ryan, should this be the first Fordbarn tech archive? Put it under 59A PCV?

Thanks, all. Lou

[1952henry]

Originally Posted by 296 V8

Yes the ¼’’ tubing is almost the same as in the photo, just extended forward from the 90 a bit with a pcv valve threaded on the end.
I recall I used a small valve from some import………picked it out of the parts book at napa.

Duh, now I see it, on the tee at the center.

[296 V8]

No not for the holiday just my girl friend and me ( 1 ½’’ thick NY) for some reason it looked so good I decided to take one of it.

That setup is on my dads 40 that’s not here but as soon as I do the one on mine I will keep track of what I did and show.
Mine is painted now and just waiting for me to bolt on all the goody’s .

[1952henry]

Originally Posted by 296 V8

No not for the holiday just my girl friend and me ( 1 ½’’ thick NY) for some reason it looked so good I decided to take one of it.

That setup is on my dads 40 that’s not here but as soon as I do the one on mine I will keep track of what I did and show.
Mine is painted now and just waiting for me to bolt on all the goody’s .

So to pester you once more, I see:

2-- 90s that screw into the bottom of the intake. Pipe thread/compression
Tubing connecting the whole thing.
1--Tee in the middle pipe/pipe/compression?
1--90 threaded to the tee
How does the threaded PCV connect to the 90??

[296 V8]

Originally Posted by 1952henry

So to pester you once more, I see:

2-- 90s that screw into the bottom of the intake. Pipe thread/compression
Tubing connecting the whole thing.
1--Tee in the middle pipe/pipe/compression?
1--90 threaded to the tee
How does the threaded PCV connect to the 90??

[QUOTE=296 V8;39355]Yes the ¼’’ tubing is almost the same as in the photo, just extended forward from the 90 a bit with a pcv valve threaded on the end.
QUOTE]

[1952henry]

Is the PCV similiar to the pictures posted by 36 Tbird? Or internal threads. Sorry it is taking me a bit to get this into my brain!!

[Chris Nelson]

As there is more than one way to skin a cat, here is how I did it on both of my flatheads. Using a Borg Warner #382 PCV valve and a Ford Grommet for a 75 through 94 PCV Valve. It fits into the galley breather opening and is connected by hose to the carb base on the manifold. The pan breather is plugged with shim stock. The reason for the particular Borg Warner PCV valve is the specs. It is; Closed at idle, 16 to 18 in hg; Floats at 8 to 16 in hg; Open at 1 to 6 in hg. Granted, it doesn't hide the fact that you have a PCV valve as is pictured previously, but it is easy to do and does not have any adverse dffect on the operation of the motor. It also keeps the underside of the engine/transmission clean.

[296 V8]

On the second attempt (after the photo)
I removed the barbed fitting (at the center 90) and installed a nipple and coupler then a male threaded pcv valve (threads on the outgoing side)

Moved forward so its suckin blow by as far as possible from the breather / incoming air.

[1952henry]

Thanks! I think I have it now!