PCV question |
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GMacLaren
Senior Member Joined: August-22-2013 Location: St. Louis, MO Status: Offline Points: 495 |
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Posted: May-29-2015 at 5:06pm |
(Ford 302 V-8, circa 1974.) Here’s a photo of the “spacer” between the carburetor and intake manifold. It’s “upside down” showing the path it imposes on the crankcase fumes picked up via a PCV valve in valve cover. The “spacer” piece is 1-1/8 inches in height. I’d like to eliminate that 1-1/8 inch by routing fumes directly into the intake manifold. There is already a threaded hole in the manifold, now plugged with a pipe plug, making it a simple thing to unplug that hole, and route the fumes there, instead of into this “spacer." Your thoughts? |
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GottaSki
Grand Poobah Joined: April-21-2005 Location: NE CT Status: Offline Points: 3327 |
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I prefer to distribute the vapors amongst all runners vs one, so to not create a lean condition in one jug and risk burning a piston.
That said, some route that way without incident. Newer carbs have the pvc port right on them. If your carb is on the way out, its a simple solution. |
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"There is nothing, absolutely nothing, half so much worthwhile as messing around with boats...simply messing."
River Rat to Mole |
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5762 |
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you can certainly do that George although there is concern about leaning out the cylinder/s on that intake runner. Not sure that it's been proven to be a problem or not though and several, myself included, have a PCV plumbed that way.
Can I ask why you are removing the spacer? |
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Hollywood
Moderator Group Joined: February-04-2004 Location: Twin Lakes, WI Status: Offline Points: 13510 |
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Because of the engine tilt, aren't the rear most cylinders fairly rich already? Given the choice you should plumb to back.
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GMacLaren
Senior Member Joined: August-22-2013 Location: St. Louis, MO Status: Offline Points: 495 |
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I'm trying to make the engine box smaller -- narrower and lower. It's always seemed (to me) to be "too big" for the boat. The "spacer" is 1-1/8 inches high, and employs two thick (@ 1/8" each) gaskets instead of one. -=Grant=- |
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GMacLaren
Senior Member Joined: August-22-2013 Location: St. Louis, MO Status: Offline Points: 495 |
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If the "spacer" was phenolic, I thought it might be an insulator to help prevent carburetor boiling or heat soak. But being aluminum, I doubt if it helps much -- if at all. Could it be needed to improve vaporization? I'm not sure where the existing plugged hole enters the manifold circuit -- and would rather not remove manifold to see. If I do the plumbing, I'm quite sure it would be very tight fitting -- no risk of leak.
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cboland
Senior Member Joined: July-15-2004 Location: Atlanta, GA Status: Offline Points: 185 |
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I don't mean to threadjack here, but speaking of PCV valves, I've never paid much attention to mine. Is this a part that should be replaced periodically? I'm at 1100 hours on my engine and I know I haven't done anything and I doubt previous owners did.
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Bud
1999 Sport Nautique |
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GMacLaren
Senior Member Joined: August-22-2013 Location: St. Louis, MO Status: Offline Points: 495 |
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There are some good descriptions of its care and function on the web. -=Grant=- http://www.agcoauto.com/content/images/engine/pcv_system_extracting_moisture.jpg |
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GMacLaren
Senior Member Joined: August-22-2013 Location: St. Louis, MO Status: Offline Points: 495 |
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On my boat, the "clean air" intake is via the filler cap.
And the blowby/oil vapor fumes are introduced via the spacer shown above. |
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