Not Hudson but may help a Hudson

[Deleted User]
[Deleted User]
edited November -1 in HUDSON
I am restoring a 29 Dodge Bros pickup and yesterday I pulled the carb. The truck has been sitting for about 5 years. I pulled the top off the carb, an updraft Tillotson and the bowl was lined with a white crystal like substance. Almost like something had leached from the pot metal. The loose stuff all washed away but there is still a white coating to some parts of the bowl that won't gunk off or wash off. It was also in the jets and most every where else gas had flowed. Does anyone know what this stuff is? I'm guessing some kind of precipitate from the new gas but it could be something leached from the metal. I expected varnish but got something that looks like it was cooked up in a meth lab.



Harry

Comments

  • Unknown
    Unknown
    Harry,



    That sounds like oxidation caused by exposure to moisture.
  • [Deleted User]
    [Deleted User]
    Dave, that is a possiblity but I think oxidation would affect other parts of the truck equally and how would all that moisture get into the carb? Also while I've seen residue like this in water systems with hard water, rain water doesn't have the same high mineral content so usually not the same amount of residue. The other thing is I've never seen water residue form a flaky powder. Still, you could be right and thats all I'm seeing.



    Harry
  • Unknown
    Unknown
    The corrosion you are seeing is caused by electrolysis. The White or Pot Metal of most carburetors leaches out the aluminum oxide and creates crystals on the surface of the casting. The real cause is the low grade electrical current that continues to flow due to the dissimilar metals ... Pot metal and steel etc. A very small amount of condensation occurs every day as the sun rises and sets. The light coating of moisture is sufficient to allow for the electrolysis to occur.

    Same principle used to reverse the rusting process when using baking soda and a battery charger... just takes longer to occur and the current is micro amps versus amps.

    Hope this helps
  • rambos_ride
    rambos_ride Senior Contributor
    Good discussion topic...

    Anyone know what an acceptable cleanup method is for this type of oxidation?

    What would predicate the part being declared unuseable due to pitting - only the mating surfaces?
  • [Deleted User]
    [Deleted User]
    Dan, no pitting, this stuff looks like it formed on the metal but not from the metal, except that it's clinging to the metal better than most paints. The loose stuff brushed right off, the stuff on the metal resisted carb cleaner and solvent so far. I would like to remove it but I won't wreck the carb body to do it. If push comes to shove I'll just leave what I can't get off. I'm mostly wondering if anyone else has seen this or may know what I'm looking at.



    Harry
  • [Deleted User]
    [Deleted User]
    Ken, I missed your post before I responded to Dans. Electrolysis makes sense. We used sacrificial anodes in reservoirs to fight it, same thing on boats but the sacrificial metal always deteriorates, this is not the case in my carb, there is no pitting and the carb body looks great.



    Harry
  • rambos_ride
    rambos_ride Senior Contributor
    I've got 2 WA1's with external oxidation

    Is Glass Beading a no-no on carb bodies?
  • [Deleted User]
    [Deleted User]
    I do all of my carbs and small parts in one of these. I am too old to work hard cleaning stuff anymore. This and my tumbler run around the clock cleaning parts.



    http://cgi.ebay.com/6-5-liter-ultrasonic-cleaner-timer-heater-NEW-FREE-SHIP_W0QQitemZ220322649708QQihZ012QQcategoryZ48723QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
  • SuperDave
    SuperDave Senior Contributor
    I agree, it's oxidation and probably agrivated by the alcohol content of the gasoline that seems to absorb or attract water. I've seen the same thing on WA-1's that I have taken apart. I doubt it hurts anything until it becomes a "free agent' and clogs the jets! I have blasted carb parts, but then after that was done, I used a Dupont product that is intended to treat aluminum prior to painting. Some kind of "conversion" coating that I dip the parts in. Gives the part a clean smooth coating that looks a lot like the original factory coating. It does help maintain the original look and resists the corrosion process. It fooled the tech inspectors at the local stock car track..Covered up "ahem" unauthorized air horn modifications.. I think Dupont paint stores still sell it. I bought mine years ago in a quart container. Can't recall the part number..maybe I can find it somewhere. Dan may know, since he has a great deal of experience in painting.
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