PCV valve orientation?

Short version: does the orientation of the PCV valve matter? They seem to be installed within a few degrees of vertical in nearly all OEM applications. I would like to mount one horizontally... will the valve
still operate correctly? Will any problems result?
Longer version: I have a modified Ford smallblock (302 block, 347 stroker) that has cast aluminum valve covers. The covers have no breather or PCV holes, so I'm adding a breather to the left one and a PCV valve to the right one - more or less factory configuration.
The covers are quite tall and there is plenty of room to put the PCV valve port on the side of the cover, near the top. It will be well above the valve gear and oil splash, baffled of course, and will actually be higher from the head surface than a stock mounting would be.
I'm not 100% clear on the details of how PCV valves work, but it doesn't seem to me that there would be much difference between "vertical and being rattled around like hell by the engine" or "horizontal... [ditto]."
I am planning the setup around the stock valve used for a 1968 smallblock - if there is another model intended to work horizontally, please let me know!
Answers and comments appreciated.
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It works off vacuum, not gravity. Maybe in vertical the check valve ball falls back down into the closed position to prevent suction of fumes back into the engine. Who says the valve has to be "on" the engine anyhow. It could be anywhere in line it seems.
: Short version: does the orientation of the PCV valve matter? They seem to : be installed within a few degrees of vertical in nearly all OEM : applications. I would like to mount one horizontally... will the valve : still operate correctly? Will any problems result? : : Longer version: I have a modified Ford smallblock (302 block, 347 : stroker) that has cast aluminum valve covers. The covers have no breather : or PCV holes, so I'm adding a breather to the left one and a PCV valve to : the right one - more or less factory configuration. : : The covers are quite tall and there is plenty of room to put the PCV : valve port on the side of the cover, near the top. It will be well above : the valve gear and oil splash, baffled of course, and will actually be : higher from the head surface than a stock mounting would be. : : I'm not 100% clear on the details of how PCV valves work, but it doesn't : seem to me that there would be much difference between "vertical and : being rattled around like hell by the engine" or "horizontal... [ditto]." : : I am planning the setup around the stock valve used for a 1968 smallblock : - if there is another model intended to work horizontally, please let me : know! : : Answers and comments appreciated. :
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Tom Line
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James Gifford wrote:

IIRC, Ford Escort 2.0 is horizontal.
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On Thu, 12 Aug 2004 00:59:12 -0000, James Gifford

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I don't know what state you live in, but fooling around with the emission control system can land you in major trouble here in California and probably other states too. I'm sure you feel your modification is a good one, but the average bureaucrat isn't interested in hearing about your excellent engineering. He'll just pull out his little book and start writing.
Food for thought.
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Since the car in question is a '68, it falls off the back of the California smog regs.
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On Fri, 13 Aug 2004 01:58:01 -0000, James Gifford

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No, I don't think so. ANY factory-installed emission control hardware can not be altered in California. Even the old stuff. I remember when the first crankcase vents came out and lots of guys wanted to plug them up. They were told ABSOLUTELY NOT! I don't believe the rules have changed since then. If I'm wrong, someone please correct me.
I suspect you're thinking about the ones which are exempt from the testing requirement. That's a different issue.
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Bill Turner wrote:

If you're not required to test then what's to stop you from running any set up you choose. Exempt, it seems to me, means...... exempt.
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I believe current law is that all 1973 and prior vehicles are exempt from testing, both regularly and at transfer. You're correct in that the law says the smog gear must be left intact... but I guarantee you there are few 1960s-era vehicles with all the little valves and hoses on them. :)
The flap over California's AB2683 has nothing to do with restoring currently exempt vehicles to testing, only to prevent the smog exemption from rolling forward... which I don't think is a good idea. The pre-cat cars have little difference in emissions between no controls and the pathetic vacuum switches and air injectors, and most older cars still on the road are either beaters headed for the junkyard or collector's cars that are better maintained than new. Once catalysts got into the act, though, the reductions were significant. Disabling these smog systems should not be permitted, although the laws should be flexible about motor swaps etc.
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wrote:

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Exempt from testing does not mean exempt from tampering. The original issue was whether a pre '73 car could legally have the emission control system modified. The answer is still no.
As to "what's to stop you"... mostly your own conscience, I suppose. It's not likely any official would notice you have your PCV valve installed differently from a factory install. But if they do notice and they're in a bad mood, you're toast.
Your choice.
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Ford Focus 2.0 is sideways.
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I would not recommend the PCV installation on the side of your aluminum valve covers. Correct placement requires a flat plate, secured by four screws, be installed under the PCV, inside the valve cover. The plate prevents splashing oil from being sucked into the PCV valve and into the intake. You will have to shield the PCV valve from splashing oil if you have to install the valve on the side of the cover, also, you risk oil leaking out of the valve cover as well.
The PCV valve for that era should flow from the valve cover to the intake manifold (intake vacuum will be drawing the fumes from the crankcase into the intake for combustion), and block itself shut in the event of a backfire, preventing a flame from entering the crankcase. Small risk, but depending on gas contaminated oil fumes in the crankcase, and a reverse installed PCV valve, a backfire will have the same effect on your valve covers as a lit firecracker under a soup can.
Hope this helps
Frank

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The covers are heavy cast aluminum and have bosses on the top underside for baffle plate attachment. The supplied plates are for top-mounting breathers and weren't useful, but it was easy to shape a baffle for both the breather and the PCV valve and attach them to these bosses.
Thanks for the followup.
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