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Results 1 to 20 of 20
  1. #1

    Default "My hose to flame arrestor is

    "My hose to flame arrestor is always popping out of the valve cover and I want to either put a solid plug in the valve cover, or a breather plug, in it. Will this hurt me in any way. My auto guy says it will be fine. I still have a vacuum line to PCV valve in the other valve cover. Doesn't this cause oil to get sucked into the carb?"

  2. #2
    Join Date
    Feb 2006
    Location
    Arlington, VA, USA
    Posts
    952

    Default "On a car, I would say it woul

    "On a car, I would say it would be fine to just vent both sides to the atmosphere, but there isn't the same kind of air flow around the engine on a boat that you have in a car.

    1) You need to have both sides vented and not just one. When running at high RPM/load conditions, you can have some serious blow by venting. If you have only one valve cover vented, you'll have higher velocity which might push oil out of the vent.

    2) It should be ducted to the flame arrestor on a boat, as the engine is in a confined space. Lots of hydrocarbon vapors in that stream and you don't want that building up in your engine compartment."

  3. #3
    Join Date
    Feb 2006
    Location
    Arlington, VA, USA
    Posts
    952

    Default "I'm assuming you have a V

    "I'm assuming you have a V8, btw."

  4. #4
    Join Date
    Aug 2008
    Location
    Fairport, NY
    Posts
    1,471

    Default "Exactly; you really want to h

    "Exactly; you really want to have all the blowby sucked up into the outside of the flame arrestor and then into the boat engine. You might want to solve why the hose is popping off. Is it 5/8" diameter or so? Is there a tremendous amount of blowby at cruise?
    I'm not certain why there are PCV valves on boats; mine uses a 5/8" hose on each side to the arrestor. Internally, the engines are clean after decades of use."

  5. #5

    Default "Thanks for the info guys, I&#

    "Thanks for the info guys, I'm glad I asked and didn't make that mistake.
    Steve"

  6. #6
    Join Date
    Sep 2007
    Location
    Egg Harbor, New Jersey, USA
    Posts
    1,572

    Default "Dave, Do you have PCV valv

    "Dave,

    Do you have PCV valves? I have been elbow deep in my 1992 454's with no sign of them? Having read this type of topic a few times, I am wondering IF I should have them or not. No mention in the parts books..."

  7. #7
    Join Date
    Feb 2006
    Location
    Arlington, VA, USA
    Posts
    952

    Default Guys... Dump the PCV valves

    Guys...

    Dump the PCV valves unless specifically stated in a manual! They are purely for emission control. Focus on safety and performance.

  8. #8
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    12,606

    Default ".."Dump the PCV valves un

    ".."Dump the PCV valves unless specifically stated in a manual! They are purely for emission control. "


    No, no, no! The PVC system is essential for engine life, especially in a marine environment. Moisture collects in the engine oil, turning it into acid that eats the bearings and sludge that plugs up return holes. Since marine engines run cooler than auto engines, it's harder to get rid of the moisture and--being in a marine environment--more moisture is always present. A bad combination!

    So make sure that system is working and keep it in top shape.

    Jeff"

  9. #9
    Join Date
    Feb 2006
    Location
    Arlington, VA, USA
    Posts
    952

    Default AHHHHH Forgot about the moistu

    AHHHHH Forgot about the moisture removal element! So true. Thanks!

  10. #10
    Join Date
    Oct 2007
    Location
    , ny, us
    Posts
    835

    Default "In the United States,The pcv

    "In the United States,The pcv has been on all automotive engines since 1963. It reduces pollution and does a great job of keeping the oil clean. Before PCV valves, the recommended oil change interval was 1000 miles and engine life was comparitively short...especially if the car was only driven on short trips. It is a simple but very effective device. Many owners of pre 1963 autos have added a pcv to keep the oil cleaner. Another device which helped oil to stay clean was the 195 degree thermostat which replaced the 180 degree thermostat. The engine ran hotter, helping the moisture in the oil to evaporate quicker and allowing the carburetor to be jetted leaner.
    Heres a link which explains the PCV system and it's development:
    http://www.secondchancegarage.com/public/239.cfm"

  11. #11
    Join Date
    Dec 2008
    Location
    Bourne, MA, USA
    Posts
    261

    Default "I have 1989 Crusader 454s in

    "I have 1989 Crusader 454s in my 1990 Silverton 34C and no PCV valves. There are hoses from each valve cover going to the carb flame arrestor but they never pop off. Perhaps Steve only needs are slightly longer or less stiff hose.

    When in use, why would there be a PCV on only one valve cover? And why don't all marine inboard engines have them? Do any Crusader engines use them?

    Thanks,
    Erich"

  12. #12
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    5,595

    Default "Every PCV valve I've seen

    "Every PCV valve I've seen installed connects to the carb/intake; ie it ensures crankcase blow-by removal by ensuring it makes its was back into the combustion chamber thru the induction system. The carburetor is usually calibrated to accomodate this fact.

    Typically, the PCV valve occupies one rocker cover and the other has the 'breather vent'. the ventilation air enters thru the breather, usually equipped with a poorly maintained filter, 'scavanges' out the crankcase, and finds its way to the PCV valve and into the intake.

    The bulk of the marine engines I've seen do not use the PCV valve but do provide for ventilation of the crankcase via the hose(s) that started this thread. Usually one per rocker box and they connect to the barbs at the flame arrestor. Though they don't ventilate continuously like a pCV system, they do help. If nothing else, they provide for a lower pressure in the crankcase and that will help the engine much more than positive pressure in the crankcase."

  13. #13
    Join Date
    Nov 2008
    Location
    Trenton, Ontario, Canada
    Posts
    325

    Default "Do any Crusader engines use t

    "Do any Crusader engines use them?

    I have twin 350s, (Crusaders)} and they have them...engines are 1993."
    Don Keye
    From 600 kts to 6 kts
    Dun-Fly'N

  14. #14
    Join Date
    Sep 2008
    Location
    Maryland - USA
    Posts
    5,595

    Default "Don: if your has them then Cr

    "Don: if your has them then Crusader (or GM) must have felt a need for them. As far as how widespread their use is, for Crusader, maybe we'll have to wait for Rick's input here; the bulk of my experience is with that old stuff (mostly black when it left the factory), carbs and no ECUs, though I'm not opposed to them."

  15. #15
    Join Date
    Oct 2007
    Location
    , ny, us
    Posts
    835

    Default "I am not sure why marine engi

    "I am not sure why marine engines do not use PCV's but I think it has to do with the fact that marine engines spend less time idling at lower RPM's than automobiles. At low RPM's the flame arrestor mounted hoses are probably less effective than a pcv system but at higher RPM's I think the system with the hoses running to the flame arrestor is probably capable of removing a greater amount of Blow by and keeping the oil cleaner. Because Marine engines typically cruise at 3000 RPM or more, the volume of crankcase gases being sucked in and burned is probably greater with the two hoses running directly from the valve covers to the flame arrestor. If for some reason,a marine engine were to spend most of it's life at idle, I believe the PCV system would be better."

  16. #16
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    12,606

    Default "Good points, Bob. Damn littl

    "Good points, Bob. Damn little vacumm in a marine engine while on plane.

    Jeff"

  17. #17
    Join Date
    Nov 2008
    Location
    Trenton, Ontario, Canada
    Posts
    325

    Default "<[img]"http://www.marineengin

    "&#34;On Plane&#34; ????

    The last time I was &#34;on plane&#34; would be traveling from Toronto to Denver on Air Canada !!

    My normal cruise speed is about 5.6 kts. Max power will give me 10 kts and I would then use my gas gauges as speedometers.... while I push half the river/lake ashore!!!"
    Don Keye
    From 600 kts to 6 kts
    Dun-Fly'N

  18. #18
    Join Date
    Feb 2006
    Location
    Arlington, VA, USA
    Posts
    952

    Default ""but at higher RPM's

    "&#34;but at higher RPM&#39;s I think the system with the hoses running to the flame arrestor is probably capable of removing a greater amount of Blow by and keeping the oil cleaner.&#34;

    I think Bob&#39;s point here is right on. I think a PCV valve is idea for an engine operating in transient speed/load conditions... but with the constant speed and throttle settings on a boat, I suspect you get adequate crank case scavenging from the open hoses to the flame arrestor.

    Is that a Douglas DC6 over there, Don or a P3?"

  19. #19
    Join Date
    Nov 2008
    Location
    Trenton, Ontario, Canada
    Posts
    325

    Default "Civil designation is a Convai

    "Civil designation is a Convair 580...
    Canadian Military designation was a CC-109 &#40;Cosmopolitan&#41;

    That one had the call sign as &#34;Smoky 02&#34; as it was the personal aircraft of the Deputy Commander NORAD based in Colorado Springs...what a great 3 year tour....but I missed the water."
    Don Keye
    From 600 kts to 6 kts
    Dun-Fly'N

  20. #20
    Join Date
    Sep 2003
    Location
    New Tripoli, PA, USA!
    Posts
    12,606

    Default "You can't have everything

    "You can&#39;t have everything, Don. I absolutely LOVE the moutains--especially western Montana--but the kids are on the &#34;right&#34; coast, so...

    Jeff"

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