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Technical Water Cooled ( or warmed ) carbs

Discussion in 'The Hokey Ass Message Board' started by Stephen Lovelady, Mar 8, 2018.

  1. My 52 DeSoto Firedome with the low deck 276 Hemi uses a Carter WCD 884S water cooled ( or warmed ) carburetor. The coolant flows through two tubes - one from the back of the water pump bypass, through a passage in the base of the carburetor, and back into the cooling jacket at about the Number 2 intake runner.

    I ended up twisting one up pretty bad to the point it is now completely unusable. Corrosion had cause the 1/2" inverted flare nut to seize onto the tube which I believe is made of a copper alloy. The other came out ok. I was able to loosen them enough to remove and did a good cleaning.

    I plan to re-create the broken tube using some 1/2" soft copper and flaring both ends. The inverted flare nuts are available through a local Fastenal distributor so that's not a huge issue other than I have to get a 1/2" tubing bender and make an almost 180 degree bend.

    I do have a technical question though... If I plugged the water outlet holes and ran the car without the water through the carb base I'm sure the car will run fine. I'm concerned about fuel boiling off and vapor lock.

    Does anyone in the forum have any experience with this? I've seen other folks use a more modern carb without water cooling with no negative reports. Any thoughts from the forum?
     
    chryslerfan55 likes this.
  2. Hnstray
    Joined: Aug 23, 2009
    Posts: 9,712

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    Is there ANY connection or mechanical relationship to the automatic choke setup? If not, then I doubt the elimination of the water heater would have any significant adverse effect on the carb in normal operation. Warmup is assisted by the water circulation, but after that the benefits are minimal or non-existent imo. That said, I also do not see any negatives from restoring the water circuit.

    Ray
     
  3. belair
    Joined: Jul 10, 2006
    Posts: 7,596

    belair
    Member
    1. H.A.M.B. Chapel

    Had a 4bbl on my 250, with headers. Never needed the water heat. The headers provided whatever heat was (or was not) needed. But I don't live where it gets real cold or terribly humid, drove it all year round. Never had a problem with vapor lock, fuel boiling away, or hard starting. Never had the carb ice up.
     
    Last edited: Mar 8, 2018
  4. The Shift Wizard
    Joined: Jan 10, 2017
    Posts: 1,032

    The Shift Wizard
    ALLIANCE MEMBER

    I tend to think of it only as "warming" and I've never thought of it as doing any "cooling". Mostly for extreme cold weather starting and running. I don't think a couple of ounces of coolant in the passageway could be a benefit regarding heat soak in the fuel bowl. But if you know you have that issue, and not just guess that you may have it later, it's easy enough to test it both ways and compare. It's not like anything is all buttoned up and you can't get at it.
     
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  5. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 8,487

    Rusty O'Toole
    Member

    I don't know why they chose to build them that way. All I know is if I restore a Chrysler built engine to exactly the way it came from the factory it will start and run like a modern car with fuel injection. If I monkey around I can get it to run decent but never as well as the factory setup.
     
  6. Clay Belt
    Joined: Jun 9, 2017
    Posts: 313

    Clay Belt
    Member

    I actually have never heard of this sort of setup. May just be my youth, but any chance someone could post some photos/explain it?
     
  7. Hnstray
    Joined: Aug 23, 2009
    Posts: 9,712

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    If memory serves, somewhere in the late '60s/'70s era, Ford had an aluminum spacer plate under the carb with water ports for warming the carb as described by the OP on his DeSoto. Buick used a water heated choke coil on a Rochester 2GC carb on '66 era 300 cu in V8s Special/Skylark....I have one on hand.

    Ray
     
  8. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 4,387

    Ebbsspeed
    ALLIANCE MEMBER

    Here's an image of a similar carb. Water inlet is at lower right. WCD844.jpeg


     
  9. Relic Stew
    Joined: Apr 17, 2005
    Posts: 1,079

    Relic Stew
    Member
    from Wisconsin

    I have one from a '64 FE. Water barbs on the left side, passage runs around the perimeter.

    For the OP, the water flow is from the intake manifold (hot spot of the engine), through the carb, then to the pump. It supplies heat to the carb to improve fuel vaporization and prevent icing. Most useful in cold weather driving.

    carb plate 001.jpg
     
    Last edited: Mar 8, 2018
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  10. carbking
    Joined: Dec 20, 2008
    Posts: 2,283

    carbking
    Member

    Chrysler used this feature on several of the Carter carburetor in the very early 1950's. The biggest issue was from the fact that anti-freeze did not yet have sophisticated corrosion inhibitors as they do today. If the anti-freeze was not changed annually, then the corrosion bugs ate the aluminum throttle bodies. These carbs, with a useable throttle body, are quite scarce today.

    For the OP - in addition to fabricating the fitting as you mentioned, I would suggest a good inspection of the coolant passages in the throttle body to make certain there was no leakage of coolant into the throttle area.

    The heat from the water tends to make the carburetor more efficient, thus improving fuel economy and lessening carbon buildup.

    Carburetion 101 - fuel atomization.

    There are three major methods of increasing fuel atomization:
    (1) Increase air velocity.
    (2) Add heat (remember the "heat of vaporization" principal). Fuel vaporization is an endothermic process.
    (3) Add additional fuel

    Too little heat, combined with too much fuel can cause "icing". While icing is generally less common with a Vee type engine than an inline, it can still occur under certain atmospheric conditions.

    Jon.
     
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  11. Beanscoot
    Joined: May 14, 2008
    Posts: 634

    Beanscoot
    Member

    I don't see how the water jacket could help cold starts - by definition the water is cold. It will take a fair while for the coolant to get warm enough to warm the carb. So it will help warm up the carb after the engine is warmed up.
    I think the main effect will be to prevent icing.

    Ford used this coolant warmed carb system in the first small blocks in 1962, but abandoned it by the next year.
     
  12. carbking
    Joined: Dec 20, 2008
    Posts: 2,283

    carbking
    Member

  13. carbking
    Joined: Dec 20, 2008
    Posts: 2,283

    carbking
    Member

    And the 1963 Ford 289 CID did ice up! We had one.

    Jon.
     
  14. Hnstray
    Joined: Aug 23, 2009
    Posts: 9,712

    Hnstray
    ALLIANCE MEMBER
    from Quincy, IL

    It doesn’t help with cold ‘start’.....only helps warmup process. The water in the heads begins warming rapidly upon engine start up and most systems use recirculation in the block/heads before the thermostat opens. So, the warming water gets to the carb base pretty quickly.

    Ray
     
  15. Engine man
    Joined: Jan 30, 2011
    Posts: 3,455

    Engine man
    Member
    from Wisconsin

    Ford and most manufacturers changed to drawing heated air from around the exhaust manifold into the air cleaner using a diverter that closes when the air is warm. Remember the flexible round tubes connected between the air cleaner and exhaust shroud? People got rid of the original and put the chrome air filters on instead. Then they had trouble with carburetor icing in the winter.
     
  16. Beanscoot
    Joined: May 14, 2008
    Posts: 634

    Beanscoot
    Member

    Yes, those hot air hoses worked better than the hot water heating, because they warmed up a lot quicker. Early emissions systems relied on a constant air temperature intake (100 Fahr. as I recall) so mixed heated and fresh air accordingly.

    The wife's small pickup would ice up occasionally when the hot air duct fell off. I did manage to get the air cleaner off in time once to actually see the frost, kind of cool since the weather was above freezing at the time.
     
  17. Tri-Power
    Joined: Jun 23, 2008
    Posts: 143

    Tri-Power
    Member
    from Memphis

    Not the same as yours, but my 292 Chevy 6 has a water heated (manifold) pad under the carb. I bypassed the carb heater, and the car ran horribly. I'm pretty sure this was in the summer, too.
     
  18. carbking
    Joined: Dec 20, 2008
    Posts: 2,283

    carbking
    Member

    The cause of carburetor icing is often misunderstood.

    The change in state of gasoline from a liquid to a gas (atomization) is an endothermic process (external heat is required). The richer the calibration of the carburetor, the more heat is required.

    The cooler the air, the less volume of water which the air will hold. Thus, when the air temperature drops to a level where there is more water than the air can hold, condensation occurs. If the surrounding metal surface (the carburetor) is sufficiently cold, then icing occurs.

    One may think of icing as a winter phenomena; and icing can occur in the winter. However, since the cold air has already removed much of the water from the air, winter icing generally occurs during freezing rain, sleet or snow (higher humidity).

    I have actually observed severe icing on an inline 4 at 50 degrees F. The carburetor was way too rich, and the weather was rainy.

    The shrouds mentioned by engineman were used by most of the US manufacturers. Generally, they worked well for awhile, but were mostly ignored during service. The idea was to provide heat at lower RPM, and then remove the heat at higher RPM. The Ford ones we had were controlled by a spring, which would fatigue over time. I replaced the spring in mine more than once.

    Chrysler used an electronic sensor to sense air temperature, and then sent a signal to a relay-controlled vacuum motor. The sensing valves were like classic voting in Chicago (vote early, vote often). Replace the word "vote" with the word "fail". The Carter thermoquad got a horrible reputation simply because of the lack of understanding of the function of the sensing valves, and their failure (its gotta be that *&^%$# plastic carburetor!!!).

    Returning to icing. Should it occur, generally pulling to the side of the road, and running the engine at a fast idle for 30 seconds or so will clear the carburetor. If the engine dies, do not panic; let the engine sit for 30 seconds to a minute, and the engine heat will clear the carburetor. The engine may now be restarted.

    Jon.
     
    6inarow likes this.
  19. xlr8
    Joined: Jun 26, 2006
    Posts: 651

    xlr8
    Member
    from Idaho

    The heat will sometimes boil the gas with modern fuel, especially winter blends.
     

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