Closed PCV System for my C69A

[third_edition]

I have been trying to design a closed PCV system for my 1946 C69A motor that has an older Navarro Super Dual Intake.

I have seen the hidden versions designed by several members, but I would prefer to have the valve serviceable and I don't like the idea of putting hose inside the engine.

Would either of the following work (if not where have I gone wrong)...

Thanks,
George

[OHV DeLuxe]

I would look at the WW2 Ford and Willys Jeeps for well functioning and era correct way to do it.

[JSeery]

Your first drawing looks similar to the original Ford setup. Remember you need to close off the road draft.

[51 MERC-CT]

First drawing is virtually identical to the set up on my 8BA.
And as stated, block off the oil pan draft tube.
Looks like both would work but don't understand the inclusion of a 'baffled tank'.

[third_edition]

Hi 51 Merc,

The baffled tank was one of those things which I was hoping to get opinions on. The purpose would be to stop the PCV from sucking up oil mist out of the Lifter Galley.

That would perhaps happen if there was typically a lot of aerated oil in that area of the engine - if not, I am good to go with the first version - cut a whole in the intake, put in a grommet and mount the PCV there.

thanks,
George

[blucar]

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Originally Posted by third_edition

I have been trying to design a closed PCV system for my 1946 C69A motor that has an older Navarro Super Dual Intake.

I have seen the hidden versions designed by several members, but I would prefer to have the valve serviceable and I don't like the idea of putting hose inside the engine.

Would either of the following work (if not where have I gone wrong)...

Thanks,
George

From my prospective you are over engineering a PCV system, the same is true of the common system that requires removing the intake manifold and the placement of a PCV within the engine.
A good functioning PCV system needs a good fresh air source. That can be achieved via the stock oil fill tube breather located on the top of the fuel pump stand on a '32-48 engine. The 8BA-8CM are slightly different due to the location of the fill tube.
If the engine in question has a crankcase breather located on the left front portion of the pan, the vent must be closed off.
A good source of vacuum must be supplied, via an area below the carb throttle plate.
When dealing with a flat-head Ford a location for a threaded type of PCV (Ford used this style for years on the 292 V8's and 240 6 cyln engines.) The port into the intake manifold has to be located away from the air intake end of the engine, making sure it is not into the vacuum chamber.
A baffle has to be fabricated on the bottom side of the intake manifold so the PCV can't suck oil into the PCV. The baffle is simply a small vented can or a U shaped plate attached to the bottom of the intake manifold casting.
I have not owned a vehicle, regardless of the year and/or engine style during the past thirty plus years that I have not fitted a PCV to.
I would not recommend a hose running to the air cleaner for a fresh air source, the volume would not be sufficient to provide good ventilation.

[51 MERC-CT]

Originally Posted by third_edition

Hi 51 Merc,

The baffled tank was one of those things which I was hoping to get opinions on. The purpose would be to stop the PCV from sucking up oil mist out of the Lifter Galley.

That would perhaps happen if there was typically a lot of aerated oil in that area of the engine - if not, I am good to go with the first version - cut a whole in the intake, put in a grommet and mount the PCV there.

thanks,
George

- The tank can't hurt and may give an insight to determine if excess oil is captured or not. (it can always be removed)
The hose to the air cleaner should not be an issue as I am running a Mopar oil filler cap with a hose to the air cleaner as you are proposing and there are no lack of flow issues.
Don't know if you have already cut a hole for the PCV grommet but there are PCV valves that can be threaded in such as this.

[third_edition]

I was looking at the Mopar breather caps also - they would do the trick. How did you attach it to the stand-off pipe? or did you use a stand-off pipe?

[51 MERC-CT]

Originally Posted by third_edition

I was looking at the Mopar breather caps also - they would do the trick. How did you attach it to the stand-off pipe? or did you use a stand-off pipe?

As I stated earlier I have the system on an 8BA style engine so I suppose that something will have to be fabricated to accept the same (5/8" dia hose I believe) that Mopar uses.

[Jack E/NJ]

Originally Posted by third_edition

I was looking at the Mopar breather caps also - they would do the trick. How did you attach it to the stand-off pipe? or did you use a stand-off pipe?

A Mopar filler/breather combo attached to the air cleaner provides adequate air for the PCV valve when at maximum throughput. It also serves to entrain crankcase fumes into the air cleaner when the valve is at or near minimum throughput. I use this kind of setup on my 21-studder's fuel pump stand. Jack E/NJ

[51 MERC-CT]

Originally Posted by Jack E/NJ

A Mopar filler/breather combo attached to the air cleaner provides adequate air for the PCV valve when at maximum throughput. It also serves to entrain crankcase fumes into the air cleaner when the valve is at or near minimum throughput. I use this kind of setup on my 21-studder's fuel pump stand. Jack E/NJ

So the cap fits into the filler pipe? That's a good thing. Don't have to fabricate anything.

[mumpsimus]

That sounds simple. I like it. But don’t the carb jets and the air filter eventually get covered in oil?

Originally Posted by Jack E/NJ

A Mopar filler/breather combo attached to the air cleaner provides adequate air for the PCV valve when at maximum throughput. It also serves to entrain crankcase fumes into the air cleaner when the valve is at or near minimum throughput. I use this kind of setup on my 21-studder's fuel pump stand. Jack E/NJ

[Jack E/NJ]

Yes, the Chrysler-style filler/breather on the pump standpipe is all I have on my 21-studder. GB Sisson also tried it on his smokey flathead.
https://www.fordbarn.com/forum/showp...26&postcount=7

The oil pan vent on the passenger side can be left open as-is or wrapped with screening if you're worried about keeping rocks & stones out of the crankcase. I was neither particularly worried about nor had problems with entrained oil fumes clogging the carb that's being continuously washed down with gasoline. Consider it like an upper cylinder lube 8^). You also have the option of running the hose after the air filter if you're worried about clogging it. I run mine before .

Jack E/NJ

[JSeery]

Originally Posted by mumpsimus

That sounds simple. I like it. But don’t the carb jets and the air filter eventually get covered in oil?

The original post (2017) drawing uses the air filter connection as the air inlet to the crankcase. The air flows from the air filter to the cap on the oil stand pipe into the crankcase. Then the air is drawn through the PCV valve and into a vacuum port on the intake manifold. If the original vents are left open unfiltered air will be drawn into the engine.

If you are going to use the air filter connection as a lower pressure source to draw air out of the crankcase you are going to have to provide a filtered air source into the crankcase. I don't think a PCV valve would work with this type of setup.

[Jack E/NJ]

I don't worry much about sucking air into the road vent because it's really a process of entraining crankcase fumes into the intake airstream before the carb, not really sucking them in with manifold vacuum after the carb. Blowby from most of these vintage engines probably overwhelms any minute low pressure created by intake airstream entrainment. Jack E/NJ