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Technical Holley 94 power valve craziness!

Discussion in 'The Hokey Ass Message Board' started by captaintaytay, Apr 16, 2015.

  1. I,m rebuilding my Holley 94 (model stamped on housing --(8BA with Ford logo on opposite side).

    I have a kit that I purchased about 4 years ago Part # 15302B from Mac's.
    I believe that it is a "Walker Products" kit. (Chinese parts maybe, IDK
    The new power valve is a 85 or 8.5
    From all the reading I've done, it seems like it's to big.
    I see posts on multiple blogs that say to use anywhere from 5.0 to 7.5.
    The jets that are in it are .047 and from what I read those are wrong also.
    This is a stock 8BA motor no frills, running just the single carb.
    The power valve that is in it now has no markings and looks to be longer then replacement one. The old one has a shoulder on it and new one is flat. Can anyone give a starting direction to go? Bruce Lancaster has given some other tests to do, but I need to get this carb fixed and back on to proceed. appreciate any help.
     
  2. deadbeat
    Joined: May 3, 2006
    Posts: 655

    deadbeat
    Member

  3. Charley NY on the ford barn is the go to guy for 94s.I believe he talks about chamfering the area for the P V to seat.
    He also has all the correct parts.
     
  4. dan c
    Joined: Jan 30, 2012
    Posts: 2,520

    dan c
    ALLIANCE MEMBER

    vintage speed has the right ones. 7.5 is what you use with a single carb.
     

  5. 57Custom300
    Joined: Aug 21, 2009
    Posts: 1,424

    57Custom300
    Member
    from Arizona

    I know a lot of people here trash Vintage Speed but that's where I've been getting my 94 parts for years. Carries the correct power valves in any number you might need.
     
  6. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    First...be aware the PV (UNLESS it is broken or leaking..see below) has no effect on idle or steady driving at normal speeds. It cannot "dump" extra gas as many seem to believe, and it is not rated by size like a jet. It feeds via venturi drop only when vac is low enough to actuate it. It is an on-off valve that does not regulate the amount of fuel added into the main circuit, the restriction that does the metering is in the passages in the carb body leading up to the fuel bars.
    No telling what PV you have...but look at these things: First, the upper part within the fuel bowl...some 4150 ones that are being dumped into 94 kits are too big at top and you can see where they jam against the casting. Clearance as needed so the thing can move.
    Second, one for a Ford carb has a flat ring corresponding to the rim of the hole in float bowl the thing screws into. This holds the gasket that prevents fuel leaking past the valve, turning it into an extra drizzle of unmetered fuel at all speeds. 4150 PV's have their gasket ring too far out to seal.
    Best test is to remove throttle body, fill fuel bowl, set it down on the throttle body and await developments. If there is a leak, your fuel system is out of control at allspeeds. Getting one with correct vac can wait, but 7,5 is reasonable, the 9 one is not too far off to run while you sort other stuff. Jets are a touch small, maybe 049 better. I'm guessing Sii Valley can't possibly be high altitude...
     
  7. Yes Bruce, Simi Valley Altitude about 800 ft. above sea level.
    I will try the fuel bowl/throttle body test.
    Also just curious does the length of the PV matter?, old one is longer then new one.
    I have to replace it as old one's diaphram is cracked all over.
    New PV does not hit casting inside bowl either.
    Thank you Bruce.
     
  8. Hey Bruce, did you get my PM?
     
  9. clem
    Joined: Dec 20, 2006
    Posts: 4,188

    clem
    Member

    7.5 power valve is stock. I have 57 jets in my 8 ba. Runs really well. Same carb on my 283 sbc as a single runs almost as well as 2 x carbs with 51 jets. And 2 x 4.5 PVs. All Carbs are larger 1&1/16
     
  10. 6.5 PV's are usually in the kits I have opened. The PV is a switch only. It opens the port to allow more fuel during engine load conditions. The ports drilled in the housing control the AMOUNT of fuel. If you are using the stock cam a 51 jet and a 6.5 power valve (single carb) will work. If you experience a bog or hesitation under a light load the power valve will need to be changed. (bog is too much fuel- use a lower number PV ) Use a power valve that has a flat surface and use a nylon gasket. The red ones are two halves glued together and the alcohol in the fuel will cause them to separate and leak. Make sure the check ball in the accelerator pump well is free moving under the clip and the valve in the nozzle well is free moving.
     
  11. Dreddybear
    Joined: Mar 31, 2007
    Posts: 6,084

    Dreddybear
    Member

    Start with 51 jets and 7.5 PV. Either from dickster27 or vintage speed as others have noted. The correct PV the brass button is tiny, on the modern ones they're big and flat and don't fit..
     
    clem likes this.
  12. Dreddybear
    Joined: Mar 31, 2007
    Posts: 6,084

    Dreddybear
    Member

    I didn't even read this when I posted my somewhat hurried response yesterday. This is all good advise here ^
     
  13. Right now guys I'm running 7.5 PV and .049 on the jets, I have other things involving distributor, timing and a repair on the block to do. Once I get these issues taken care of then, back to carb. The set up I have right now works for what I need to do.
     
  14. 90% of drivability problems are distributor (timing, mechanical - vacuum advance) related.....
     
    INXS likes this.
  15. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    ESPECIALY on '49-up cars.
     

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