V8 fuel pump plate

Discussion in 'Gas Engines' started by sean-nós, Sep 13, 2012.

  1. PAR
    Joined: Nov 2003
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    Location: Eustis, FL

    PAR Yacht Designer/Builder

    Nope, it's a vacuum line Frosty, typically used on the PCV, which is probably something you don't think is necessary either, but this single device has made boat bilges a 100 times cleaner, at the very least (not to mention the environment). On a car it might be used as a power brake booster vacuum supply, but on this particular carb, the automotive version has a similar vacuum port on the back side of the base as well, just for this purpose.

    It's not opinion, I have the data, which I gather each year. Okay it's mailed to me, so not much work in it. There's this thing they have now called "G----o----o-----g----l----e", maybe a few strokes on your keyboard can free you from ignorance on the subject.

    You wouldn't have the qualifications to get hired, nor would likely last long if you managed.
     
  2. Frosty

    Frosty Previous Member

    Its a PCV not a PVC that what plastic pipes are made of.


    The vacuum line keeps bilges clean? Rubbish --The PCV valve scavenges the crankase not the bilge.

    What on earth are you on about, You think you leave a vacuum line open to scavenge bilges.

    That line goes to the fuel pump breather-- as pictured.

    You are giving very dangerous and incorrect advice.

    I see now why USA needs so many regs to keep people like you safe.
     
  3. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    The PCV or other ventilation systems keep the bilges and enginerooms free of oil. They scavenge the fumes from the crankcase.
    Frosty: you have been on a anti-USA campaign for a while. If you have data, please post it. Otherwise, apply the same standards to yourself as you ask from others. Each time we post about safety, you counter with demands of published data. Can you offer any data to back your claims?
     
  4. Frosty

    Frosty Previous Member

    The crank case is closed, it is open only to the PCV valve on the rocker cover . This is connected to the (what you call ) a flame resistor on what we would call a air filter. The fumes from the crank case is then consumed by the engine.

    Dont make it personal Gonzo that is beneath you. Anti USA campaign --oh please.

    The enclosed engine compartment is then scavanged by the engine intake itself ( as is any) keeping bilges clear --not a direct result of a PCV valve. It is sometimes the case that there is not enough vacuum from a boat running mostly full RPM and the vacuum fitting is there fore not used . It is then connected to the air cleaner so any bypass from the rings in to the crank case ends up being sucked down the carb and burned .

    Talking of links your links of hundreds of fires boil down to just one in 2007. I did notice that you did not reply when i asked for more info.

    Sean heres a nice Boat fix Link with USA coast guard regulation to connecting your PCV.

    http://www.boatfix.com/merc/Servmanl/18/18E5R2.PDF
     
  5. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    PCVs create a negative pressure on the crankcase that is more efficient than a hose close to the air intake.
     
  6. Frosty

    Frosty Previous Member

  7. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Frosty, it would be nice if you actually knew what your where talking about, before you started ranting. Previous to the PCV (previous typo corrected) was the road tube, which was quite literally a tube coming directly from the block, dumping crankcase fumes, smoke and oil into the bilge or if in a car, onto the road (hence the name). The PCV is a one way valve that allows these combustion and crankcase gases to pass through, to be re-consumed by the engine. I didn't need Wiki whatever to find this, I've known about it since their implementation became mandatory in 1967. From a technical stand point it's a system of evacuating the gases and can be preformed a few different ways, all of which are probably too complex for you to fully grasp, particularly the implications and employment of these systems, at least more so then the physical realities of their operation. You're the type that probably yanks all the pollution controls off your car, thinking it'll run better and have more power. Of course you'd be wrong, but what's new.

    Back to PCV's; boat bilges used to be covered in soot and oil before the wide spread use of PCV's, which were voluntary in the USA up until '67. Interestingly enough most manufactures used them, in spite of not being forced, prior to '67, especially higher end models.

    Lastly, that base plate vacuum port would never go to a fuel pump. First it's way too big and second why would you even think it was necessary to have a vacuum need on a mechanical pump? On a marine version you have only a supply and a return line attached to the pump, no vacuum. I'll ask again, which you failed to answer last time. How many of these have you R&R'd over the years? I've done dozens, I've even rebuilt them, when that was still possible.
     
  8. Frosty

    Frosty Previous Member

    Here is a picture of a marine fuel pump . There is instructions at the bottom telling you how to connect the pump to the base plate of the carb,--that would be a vacuum fitting.


    http://www.summitracing.com/parts/MRG-7732/


    This is what makes it marine by USA coast guard regulations, it is to save fuel from a broken diaphragm ending up in the bilges.

    There not just 2 fitting as you say, you are wrong , It has 3,-- one being attached to the carb port,--this is what makes it marine.

    I am at a loss as to why you are quoting regs of 1967,--thats nearly 50 years ago!!!

    I could explain to you why sometimes the PCV valve is removed for boats --not the piping just the valve, but I fear that would be too much for you to grasp.

    Again your a giving dangerous and incorrect advice --you dont even know USA regulations.

    Heres some help for you on USA regulations and boat building in general. It gives all the basics you need. Page 34 paragraph 2.

    http://files.dnr.state.mn.us/education_safety/safety/boatwater/backyardboatbuilders.pdf
     
  9. sean-nós
    Joined: May 2010
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    sean-nós Senior Member

    I'm getting a bit mixed up now so can someone tell if the angled pipe at the top of the carb goes the fuel pump or is it to be vented by the crankcase or dose it go to the flame arrester.:confused:


    [​IMG]
     
  10. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    The top is the correct place
    The bottom is a vacuum port and hence below the throttle butterfly so it could be pressurised in a backfire so not there
     
  11. mreoe4sure
    Joined: Jul 2009
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    Location: trustafarian land

    mreoe4sure who me

    Sorry it has become difficult. The thread has become a little heated about regulations and not about what you need. Frosty gave you a link to a marine fuel pump and you will read that there is three connection on it. Like I told you was on the fuel pump you showed in your picture. Standard automotive fuel pumps usually have two ( inlet and outlet) and a small pin sized hole above the diaphragm to let the air move in and out when the diaphragm moves. When the diaphragm goes bad gas would leak out this hole( no big thing in a car it would go on the ground) Bad in a boat, ends up in the bilge. So they put a nipple on the fuel pump and you hook it to the carb. The one on the top of the carb is above the choke plate and will not have vacuum on it till air starts to move due to venturi action . It will be very low vacuum. Thats the one you hook it to. At the rear of the carb is a brass pipe plug it is below the throttle plate and has manifold vacuum, there is also a fitting with two orange caps in the manifold. That is where you hook the PCV to ( positive crankcase ventilation valve). It goes in a grommet in the valve cover. The hose is special ( vacuum hose will collapse due to oil etc) It is similar to brake booster hose. It has a woven cord built into it for strength and rigidity. The size of the valve and hose will determine which of the manifold vacuum you hook to. It might hook to the tee, or you may have to get a fitting to replace the brass pipe plug. If you look a your picture, look above your throttle arm linkage you will see a chrome breather pushed in to your valve cover. It has about a 5/8 inch nipple sticking out of it. That is the one that hooks to the spark arrestor . The idea is that The PCV Puts the crankcase under vacuum ( works against blowbuy ) Motors used to leak oil out of seals due to positive pressure and would vent oil smoke to the atmosphere . More leaks as they got older. When They work it will pull air thru that breather so that the engine is at a slight vacuum. Under full throttle you lose vacuum and any blowbuy will go into the carb to be burned via that breather tube . It also will work this way when the motor gets older and the PCV cannot keep up with the blowbuy. This system was not designed for boats but for cars to meet pollution standard, but work well in boats because they help keep the engine area clean( no oily film on everything or small oil leaks everywhere)
     
  12. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    the line from the pump to the carb does not need to have vacuum on it
     
  13. Frosty

    Frosty Previous Member

    That is correct but if it was all you had it would not hurt.


    The third attachment from the pump ie--the 1/4 nipple is just an overflow.

    Coast guard regulation stipulate that any fuel hose attachment nipple should have a barb or rings so the pipe will be secure when clamped.

    So the straight pipe in the picture would be a vent to the throat and be an acceptable place for the PCV.
     
  14. powerabout
    Joined: Nov 2007
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    powerabout Senior Member

    strangely enough I have never seen a clamp on the particular hose we are talking about nor a barbed fitting..hard to believe but true.
     

  15. Frosty

    Frosty Previous Member

    PCV valve is not considered a fuel fitting therefore it is not necessary to be barbed.

    He has PCV valve system on his engine as I can see the PCV breather on one of the rocker covers. Unfortunately there is no pics of the other side.

    He has doubled back some piping from the TCV I dont know why as it is unoperational without a vacuum supply.

    The TCV would have operated the EGR which as you can see is plated over --correctly.
     
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