New Problem with Carburetor H2-2300 Holley 350CFM

Discussion in 'Ranchero Tech Help' started by Rancherestorer19, Jul 7, 2017.

  1. Sophie948

    Sophie948 In Overdrive

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    I would never have thought of a faulty PCV valve as the source of a vacuum leak.

    Hope that turns out to be what it was. Clearly it needed replacement anyway. Vacuum leaks are noted for being both maddening and easily fixed. Exception to the latter was having to replace my carburetor due to wear of the carb body from the throttle rod. I seem to generally have a flair for being the exception to "easily fixed".
     
  2. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    The PVC IS a vacuum leak, it is supposed to be.
     
  3. Sophie948

    Sophie948 In Overdrive

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    Yes, but isn't it supposed to also close? I mean, if one were to disconnect the hose from the valve, wouldn't that cause a massive dysfunctional vacuum leak?
     
  4. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    It doesn't close, it moves to a more restrictive position when vacuum is high. That way the air flow is somewhat constant during operation.
    If you disconnect it, or it fails, you have a significant vacuum leak at idle.
     
  5. Sophie948

    Sophie948 In Overdrive

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    Interesting stuff, Ribald1. I remember when everyone was whining and sniveling when PCV became required. Myself, I think they're an excellent idea, much much better for the engine than the draft tubes they replaced. Yes, I'm that old. [I put a catch can in the PVC line of my '65 to condense out crud so it doesn't get re-introduced into the engine. Works, but there's not as much condensate as I'd expected.]
     
  6. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    I run a filter and oil trap on my PVC systems.
    A condensate can will let about 90% of the oil mist and particulates go right on by.
     
  7. Rancherestorer19

    Rancherestorer19 In Fourth Gear

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    Yeah you were absolutely right. Even someone who has been working on cars for the better part of 20 years, that damned PCV valve threw me. Running good now though. I sprayed the hell out of it with some Carb cleaner. seems it got some gunk up inside it which was preventing it from closing properly causing this whole new world of mess. "Welcome to my Nightmare!"
     
  8. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    I am pushing 50 years of working on cars and it still happens to me on occasion.
    When you get a chance pull a valve cover and see if the rockers are covered in sludge. If so you need to do a serious engine flush.
    Crud in the PCV often means that oil is burning on the rockers due to overheating. The sludge will prevent the exhaust valves from cooling properly, causing the issue.
     
  9. handy_andy_cv64

    handy_andy_cv64 In Maximum Overdrive SILVER MEMBER

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    My first auto shop boss told me what his first boss told him about PCV valves: if you shake it and it rattles loudly or does not rattle at all, replace it. A loud rattle is a bad spring and no noise, it's crudded up.
     
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  10. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    A playing card held 1/8 inch above the vent on the opposite valve cover is the proper way to test it. Leave the shaking voodoo for light bulbs and eggs.
    The card should flutter during idle. As the throttle is opened it should stop moving then nail itself to the hole.
     
  11. Rancherestorer19

    Rancherestorer19 In Fourth Gear

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    Okay I finally figured this out. It is because there is a little black piece of plastic that sits on two pegs under the top vent of the Carburetor. it is a trick to get in there and keep in there as you put the bowl back onto the carburetor after you take it apart. I found it floating in the Carburetor bowl when I took it back apart. It is called a "Vent Body Baffle" according to Holley. Boggles the mind how a cheap little piece of plastic can make so much difference. Then again.. if it wasn't necessary, why would it be on there in the first place.. Thanks for the help guys. I appreciate it all. Now if I could get my fuel pressure regulator to stop intermittently giving it 10PSI and only stay at 5PSI I would have it made. Had to put one on because yeah without it. 15PSI and flooding. I get the point.. the regulator is no good! Time to buy a new one. we'll rig something up though. Electric fuel pump instead of the Mech one. I have horrible luck with Mechanical ones failing at the worst possible times and places.. which is anytime and anywhere.. so yeah pretty much..
    "It's just a monkey jumping up and down on a sponge"~Dad
     
  12. ribald1

    ribald1 In Maximum Overdrive PLATINUM MEMBER

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    If you go electric, mount it as low as practical, and as close to the tank as practical, and install a 10 micron (not a standard fine fuel filter, a screen type is OK), and change the filter every 30-50,000 miles.
    Do that, and get a good pump rather than one of the $30 ones and you have the secret to long and successful electric fuel pump use.
     

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