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RE: [Cadillac_Performance_Association] Carb for 73 472

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  • Pollorey
    Sounds like your choke is not closing when cold. Is the carb clean? Start by a good cleaning with carb cleaner and then some WD40 around the choke plate and
    Message 1 of 6 , Mar 8, 2005
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      Sounds like your choke is not closing when cold.

      Is the carb clean? Start by a good cleaning with carb cleaner and then some
      WD40 around the choke plate and secondaries. Make sure the small links on
      the passenger side are clean and free to move. With the car cold both the
      secondaries and the primaries should be closed from view...completely
      closed.

      Good luck!

      -----Original Message-----
      From: Jeremy Stevens [mailto:jcopp24@...]
      Sent: Tuesday, March 08, 2005 8:27 AM
      To: Cadillac_Performance_Association@yahoogroups.com
      Subject: Re: [Cadillac_Performance_Association] Carb for 73 472


      Preston III
      Thanks for the awesome info on the carbs. My question is on the stock
      Quadrajet 400 that is on my 1968 Sedan De Ville. I think that my carburetor
      is fouled but not being a mechanic I would like a second opinion. My engine
      has about 38250 miles and it is original miles ( single owner before me )
      driving home last summer I went to accelerate and felt the engine choke up.
      The car obviously did not accelerate so I backed off the peddle and stayed
      at the speed the engine seemed to like for the rest of the ride.
      When I returned home I shut down the car and thought that maybe I had
      bought some bad gas because I had bought it in a small town. So I went and
      bought some drygas and filled the engine back up with regular unleaded. I
      have never used lead additive nor did the owner before... you might tell me
      that is my problem too... I have been advised either way on that question I
      just did what the previous owner had done.
      Either way now when I go outside to start the car I have to use a
      starter fluid/spray ( I think because it is cold ) But I have to give the
      car gas other wise it will stall out imediatly. Even after I let the car run
      for a half and hour by holding the gas down a little the car still can not
      stay running.
      There is my problem... I have been told my carb is probably clogged
      up??? That my timing belt has been advanced or retarded just enough so that
      this is happening??? Or that I have a clogged fuel pump even... I know you
      cant see the car but any advice on where to start would be great.
      Thank you,
      J Copp
      jcopp24@...


      >From: Preston III <prestoniii2002@...>
      >Reply-To: Cadillac_Performance_Association@yahoogroups.com
      >To: Cadillac_Performance_Association@yahoogroups.com
      >Subject: Re: [Cadillac_Performance_Association] Carb for 73 472
      >Date: Mon, 7 Mar 2005 12:24:26 -0800 (PST)
      >
      >Then grab a used original from the wrecking yard, and pay
      >a reputable mechanic to rebuild it.
      >
      >There's a place in California called "The Carburetor Shop"
      >that specializes in Quadrajets. Let them do a performance
      >rebuild. It'll cost you about $200-$250 for the rebuild.
      >They do fantastic work. PLUS, I think Edelbrock sells NEW
      >Quadrajets for around $350-$450.
      >
      >The small front venturi of the Quadrajet is where these
      >carbs get the fuel economy that they provide, and no
      >other aftermarket carburetor has the small primary
      >venturi. And the ultra LARGE secondaries make up for
      >the small primaries when you step on the "GO" pedal.
      >
      >Your factory Quadrajet probably measures something close to
      >900 CFM with all 4 venturi full open, but the Quadrajet
      >is a variable CFM carburetor, and calibrates itself
      >according to the air that's needed, and NOT what it's
      >capable of. Realistic calculations indicate that your
      >engine could live with a 650 CFM fixed flow. On a low
      >performance luxo-barge, 600 would probably be even better
      >for quicker throttle responce and better economy.
      >
      >A replacement carb like a holley, or carter just can't match
      >the fuel economy of your original, and the performance gain
      >will not be enough to offset the extreme loss in gas mileage.
      >These carb's are fixed CFM, and are jetted to provide the
      >appropriate amount of fuel at full flow, once you're into
      >the secondary circuit.
      >
      >If you put a holley on that engine, you wont be able to
      >pass a filling station. They're good carb's, but their
      >purpose is not for a daily driven boat. If you're building
      >a high performance car, there are other things that you need
      >to look into before you get to the carb; things like exhaust,
      >intake manifold, ignition systems, etc.
      >
      >Preston III
      >
      >--- "Tony D. Cato" <deacon_cato@...> wrote:
      >
      > > I need a new carb and rebuilding the original is not an option. What
      > > size carb and by who? THANKS!
      >
      >
      >
      >
      >
      >__________________________________
      >Celebrate Yahoo!'s 10th Birthday!
      >Yahoo! Netrospective: 100 Moments of the Web
      >http://birthday.yahoo.com/netrospective/






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    • RGermain
      from what you have described, it sounds to me that the problem is your carb. My first thought is that it s a stuck, or sticking, float. if you go to a major
      Message 2 of 6 , Mar 8, 2005
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        from what you have described, it sounds to me that the problem is your carb.
        My first thought is that it's a stuck, or sticking, float.
        if you go to a major auto parts store ie; autozone, you should be able to buy a reman. for under $200. The 472 family of engines were pretty common. You should have no problem finding a carb. WOrst case, you'll need to cross reference the number on your carb to find a new one. But I doubt you'll need to.
         
        I wouldnt suspect the timing chain, but it's an easy thing to check.
         
        There have been many arguments for and against lead additive.
        From what I've gathered and from my own experience, you dont need the stuff.
         
        Older cars needed lead in the gas to act as a "cushion" between the valves and the valve seats. Since there is no longer lead in gasoline, you can put in the additive. New cars use hardened valve seats. If you ever re-do your heads, make sure they put in hardened valve seats.
         
        As long as you dont race, tow, advance the timing, or drive the car hard, you should have no problem.
         
        I have a 1968 DeVille convertible and a 1968 Dodge Coronet 440 that for years I used as daily drivers in Chicago and never used the additive. I have yet to have a problem with either car resulting from the lack of lead or additive.
        But, if you want to use it, go for it.
         

        Jeremy Stevens <jcopp24@...> wrote:
        Preston III
             Thanks for the awesome info on the carbs. My question is on the stock
        Quadrajet 400 that is on my 1968 Sedan De Ville. I think that my carburetor
        is fouled but not being a mechanic I would like a second opinion. My engine
        has about 38250 miles and it is original miles ( single owner before me )
        driving home last summer I went to accelerate and felt the engine choke up.
        The car obviously did not accelerate so I backed off the peddle and stayed
        at the speed the engine seemed to like for the rest of the ride.
             When I returned home I shut down the car and thought that maybe I had
        bought some bad gas because I had bought it in a small town. So I went and
        bought some drygas and filled the engine back up with regular unleaded. I
        have never used lead additive nor did the owner before... you might tell me
        that is my problem too... I have been advised either way on that question I
        just did what the previous owner had done.
             Either way now when I go outside to start the car I have to use a
        starter fluid/spray ( I think because it is cold ) But I have to give the
        car gas other wise it will stall out imediatly. Even after I let the car run
        for a half and hour by holding the gas down a little the car still can not
        stay running.
             There is my problem... I have been told my carb is probably clogged
        up??? That my timing belt has been advanced or retarded just enough so that
        this is happening??? Or that I have a clogged fuel pump even... I know you
        cant see the car but any advice on where to start would be great.
        Thank you,
        J Copp
        jcopp24@...


        >From: Preston III <prestoniii2002@...>
        >Reply-To: Cadillac_Performance_Association@yahoogroups.com
        >To: Cadillac_Performance_Association@yahoogroups.com
        >Subject: Re: [Cadillac_Performance_Association] Carb for 73 472
        >Date: Mon, 7 Mar 2005 12:24:26 -0800 (PST)
        >
        >Then grab a used original from the wrecking yard, and pay
        >a reputable mechanic to rebuild it.
        >
        >There's a place in California called "The Carburetor Shop"
        >that specializes in Quadrajets.  Let them do a performance
        >rebuild.  It'll cost you about $200-$250 for the rebuild.
        >They do fantastic work.  PLUS, I think Edelbrock sells NEW
        >Quadrajets for around $350-$450.
        >
        >The small front venturi of the Quadrajet is where these
        >carbs get the fuel economy that they provide, and no
        >other aftermarket carburetor has the small primary
        >venturi.  And the ultra LARGE secondaries make up for
        >the small primaries when you step on the "GO" pedal.
        >
        >Your factory Quadrajet probably measures something close to
        >900 CFM with all 4 venturi full open, but the Quadrajet
        >is a variable CFM carburetor, and calibrates itself
        >according to the air that's needed, and NOT what it's
        >capable of.  Realistic calculations indicate that your
        >engine could live with a 650 CFM fixed flow.  On a low
        >performance luxo-barge, 600 would probably be even better
        >for quicker throttle responce and better economy.
        >
        >A replacement carb like a holley, or carter just can't match
        >the fuel economy of your original, and the performance gain
        >will not be enough to offset the extreme loss in gas mileage.
        >These carb's are fixed CFM, and are jetted to provide the
        >appropriate amount of fuel at full flow, once you're into
        >the secondary circuit.
        >
        >If you put a holley on that engine, you wont be able to
        >pass a filling station.  They're good carb's, but their
        >purpose is not for a daily driven boat.  If you're building
        >a high performance car, there are other things that you need
        >to look into before you get to the carb; things like exhaust,
        >intake manifold, ignition systems, etc.
        >
        >Preston III
        >
        >--- "Tony D. Cato" <deacon_cato@...> wrote:
        >
        > > I need a new carb and rebuilding the original is not an option. What
        > > size carb and by who? THANKS!
        >
        >
        >
        >
        >
        >__________________________________
        >Celebrate Yahoo!'s 10th Birthday!
        >Yahoo! Netrospective: 100 Moments of the Web
        >http://birthday.yahoo.com/netrospective/





      • Preston III
        If your car is truly original, it wouldn t be a bad idea to rebuild the carburetor. It sounds like something within your choke is broken, and that can cause
        Message 3 of 6 , Mar 8, 2005
        • 0 Attachment
          If your car is truly original, it wouldn't be a bad
          idea to rebuild the carburetor. It sounds like something
          within your choke is broken, and that can cause all
          kinds of problems.

          Check for hard and brittle vaccuum lines too, for leaks.

          It's doubtful that you have timing chain problems at 38K
          miles.

          One problem at a time, and the carburetor would be the place
          to start.

          Preston III

          --- Jeremy Stevens <jcopp24@...> wrote:
          > Preston III
          > Thanks for the awesome info on the carbs. My question is on the stock
          > Quadrajet 400 that is on my 1968 Sedan De Ville. I think that my carburetor
          > is fouled but not being a mechanic I would like a second opinion. My engine
          > has about 38250 miles and it is original miles ( single owner before me )
          > driving home last summer I went to accelerate and felt the engine choke up.
          > The car obviously did not accelerate so I backed off the peddle and stayed
          > at the speed the engine seemed to like for the rest of the ride.
          > When I returned home I shut down the car and thought that maybe I had
          > bought some bad gas because I had bought it in a small town. So I went and
          > bought some drygas and filled the engine back up with regular unleaded. I
          > have never used lead additive nor did the owner before... you might tell me
          > that is my problem too... I have been advised either way on that question I
          > just did what the previous owner had done.
          > Either way now when I go outside to start the car I have to use a
          > starter fluid/spray ( I think because it is cold ) But I have to give the
          > car gas other wise it will stall out imediatly. Even after I let the car run
          > for a half and hour by holding the gas down a little the car still can not
          > stay running.
          > There is my problem... I have been told my carb is probably clogged
          > up??? That my timing belt has been advanced or retarded just enough so that
          > this is happening??? Or that I have a clogged fuel pump even... I know you
          > cant see the car but any advice on where to start would be great.
          > Thank you,
          > J Copp
          > jcopp24@...





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