PCV parts verification

[40cpe]

I saw a late 60's 302 a while back that had the hose from the oil filler cap connected to the air cleaner housing, before the air filter. This connection does not provide filtered air for the PVC because it is not taken from the carburetor side of the filter. Would this be the correct location, or would a location INSIDE the air filter be preferred?

[JSeery]

The ones I have seen had a dedicated filter the fit into a clip on the side of the filter housing.

[old guy rich]

Originally Posted by 51 MERC-CT

Not to worry. On an 8BA engine a Mopar PCV oil filler cap can be used and a tube run to a remote filter or as in my case to the carburetor air cleaner plenum chamber just like Ford, Mopar and others did it.

51Merc, I like what you did, what year Mopar filler cap do you use? Rich

[40cpe]

Originally Posted by JSeery

The ones I have seen had a dedicated filter the fit into a clip on the side of the filter housing.

That makes sense. Thanks

[51 MERC-CT]

Originally Posted by old guy rich

51Merc, I like what you did, what year Mopar filler cap do you use? Rich

Mid 70's vintage.

[51 MERC-CT]

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Originally Posted by JSeery

The ones I have seen had a dedicated filter the fit into a clip on the side of the filter housing.

That is true. And if I were installing one on a different air filter than mine I would provide one. On the Ford filter it was nothing more than a flat piece of foam filter material that is slipped into a cage on the inside of the housing at the entrance point of the PCV hose.
In my case I am using the original '51 air cleaner. The point where the tube enters the lower plenum is filtered air.

[old guy rich]

Originally Posted by 51 MERC-CT

Mid 70's vintage.

51Merc,Thanks.

[Bader]

Same as britmans,valve is 455 pontiac,works great

[51504bat]

Originally Posted by Bader

Same as britmans,valve is 455 pontiac,works great

Correct me if I'm wrong but I thought you tried to use a pcv valve from an engine with a similar size displacement? One from a 455 Poncho seems a tad bit big for a 239 flattie but maybe a hopped up one needs one from a larger displacement engine.

[outlaw]

Originally Posted by Bader

Same as britmans,valve is 455 pontiac,works great

I kind of would be worried that that valve would be sitting too low on the valley & start suckn oil instead of vapors.

[scooder]

Originally Posted by 51 MERC-CT

Been there, done that and then decided to do it the correct way by using a sealed Mopar PCV filler cap and connecting to a neutral air pressure point on the carb. air cleaner as both Mopar and Ford did.

I'm sorry I don't get it,
I stated pulling in air via the mesh filtered oil fill cap, you say you decided to do it the correct way and pull from the air filter like Ford and mopar did. Later you show this air filter connection, this has the air being pulled from outside the filter! How is this unfiltered air source better than the mesh filter in the oil fill cap? Then it's stated that this outside the air filter connection used a small bit of foam in its factory installation. Again, bit of foam or a mesh filter, I'm going with the mesh filter, gotta be better unless I'm missing something here?
Martin.

[51 MERC-CT]

Originally Posted by scooder

I'm sorry I don't get it,
I stated pulling in air via the mesh filtered oil fill cap, you say you decided to do it the correct way and pull from the air filter like Ford and mopar did. Later you show this air filter connection, this has the air being pulled from outside the filter! How is this unfiltered air source better than the mesh filter in the oil fill cap? Then it's stated that this outside the air filter connection used a small bit of foam in its factory installation. Again, bit of foam or a mesh filter, I'm going with the mesh filter, gotta be better unless I'm missing something here?
Martin.

If you don't mind the hint of residual blow-by vapors wafting out of the wire mesh oil filler/filter then you certainly can use it if you wish. But by doing so you don't have a true PCV system. A true system is a closed system. The system is not always sucking air out of the crankcase. At times the valve is closed and the vapors are forced back towards the wire mesh cap and into the atmosphere. By placing the intake hose inside of the air cleaner it allows residual vapors to be drawn into the carburetor.
If you are referring to the plenum location on the original '49-'51 Mercury air cleaner as being unfiltered then you obviously do not understand the anatomy of the filter assembly. The location is after the air filter.

[scooder]

I was referring to the stock location on the Ford and mopar that were mentioned, the ones with a bit of foam (often missing, so unfiltered air) that were fitted outside the air filter element. I didn't look properly at your pics, didn't make um bigger, and thunk the first pic was one of the later Ford or mopar filters, and second pic was a Merc one. If it was a paper element type later filter style, the marked hole would be outside the filter element. I do know how the stock Merc filter works. Just made the pics bigger, and felt like a putz for assuming the first pic. Was looking at them on my phone. Sorry about that.
As yours does pull from the filtered air then your golden, and one of the better PCV flathead systems I've seen. Nice work.
My "don't get it" was aimed at the outside the filter element style, which in my mind is just stupid, pulling in often unfiltered air through the crankcase.
Martin.

[5851a]

The early 60's Ford PCV system just used the valve in place of the road draft tube and continued to use the horse hair open oil fill tube cap. Later the cap was sealed on the bottom with a wire mesh inside and a hose going to the air cleaner. My opinion was they were not cleaning the fill cap at service or it became cheaper to put the filter inside the air cleaner. When they started using the heated air intake system a side benefit is the air going into the PCV was also heated and really cleaned up the crankcases. This is just an opinion. Also had a question, has anyone ever hooked a vacuum/pressure gauge to the crankcase and seen a result of PCV verses road draft?

[51 MERC-CT]

Originally Posted by 5851a

The early 60's Ford PCV system just used the valve in place of the road draft tube and continued to use the horse hair open oil fill tube cap. Later the cap was sealed on the bottom with a wire mesh inside and a hose going to the air cleaner. My opinion was they were not cleaning the fill cap at service or it became cheaper to put the filter inside the air cleaner. When they started using the heated air intake system a side benefit is the air going into the PCV was also heated and really cleaned up the crankcases. This is just an opinion. Also had a question, has anyone ever hooked a vacuum/pressure gauge to the crankcase and seen a result of PCV verses road draft?

Has anyone hooked up a vacuum gauge?
As a matter of fact, see this thread----

https://www.fordbarn.com/forum/showthread.php?t=113816

[5851a]

That's great, thanks for the info.