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Technical A nasty surprise!

Discussion in 'The Hokey Ass Message Board' started by rustydusty, Jul 30, 2017.

  1. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,729


    Opened up a Rochester 2bbl for rebuilding and found all this corrosion. Do you think that it is rebuildable? I would rather not invest in a new carb, too many other things I need to spend money on! 0730171456.jpg 0730171456.jpg 0730171458.jpg
    chryslerfan55 likes this.
  2. partsdawg
    Joined: Feb 12, 2006
    Posts: 2,771

    from Minnesota

    I've rebuilt worse looking ones.
    Engine man likes this.
  3. 64 DODGE 440
    Joined: Sep 2, 2006
    Posts: 4,174

    64 DODGE 440
    from so cal

    Just for piece of mind I think that a non-corroded one would be worth the investment. How sure are you that you can get all the crud out of the inner passages?

    Sent from my SGH-T999 using The H.A.M.B. mobile app
  4. s55mercury66
    Joined: Jul 6, 2009
    Posts: 3,980

    from SW Wyoming

    Make sure all the passages are clean and clear. This is a great time to learn all about that carb, including how it works.
    slim38, ClayMart and kiwijeff like this.

  5. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,729


    The bronze jets etc. don't seem to be corroded. Carb cleaner and air pressure "should" be able to clear the passages. I will probably have to hone the accelerator pump cylinder. I already have a rebuild kit, so I can try it then if it doesn't work, scrounge up the cash for another carb.

    Problem is, the 2bbl carbs are as expensive or more than a 4bbl!
  6. Speedwrench
    Joined: Nov 21, 2009
    Posts: 1,027


    I would be concerned about the corrosion in the accelerator pump well among other things. By the time you get the crud cleaned out of it, it may be enlarged to the point that the pump won't seal properly or will not move properly due to the marks left by whatever abrasive used to remove the oxidation.
    Hudson31 and scrap metal 48 like this.
  7. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,729


    Accelerator pump has a flexible rubber cup that should fit. I'm going to try a brake cylinder hone after fitting a scrap of wood in the fuel slot.
  8. greybeard360
    Joined: Feb 28, 2008
    Posts: 1,539


    Run it thru the dishwasher.... You may be surprised how that will clean it. And yes, use the soap you would normally use in there for your dishes.

    Sent from my Moto G Play using The H.A.M.B. mobile app
    slim38, Mark Roby and Los_Control like this.
  9. Speedwrench
    Joined: Nov 21, 2009
    Posts: 1,027


    If you are a shooter or have a friend who is, you might see if you can find a shotgun bore cleaning brush that is close in diameter. As I remember it, that's what the commercial rebuilders used to do and it will be easier on the bore than a brake cylinder hone.
  10. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,729


    Good idea. Looks to about about the size of a 20 gauge!
    chevy57dude likes this.
  11. Engine man
    Joined: Jan 30, 2011
    Posts: 3,476

    Engine man
    from Wisconsin

    The old carburetor cleaners would clean that up. Maybe try various diluted muriatic acid solutions. You can always use the rest to clean oil off concrete.
    SLCK64 likes this.
  12. chevy57dude
    Joined: Dec 10, 2007
    Posts: 5,880


    Take a strip of fine Scotchbrite in a large cotter key. like a little flag, only on both sides. Use it in a drill at low speed. Very gentle.
    lothiandon1940 likes this.
  13. RmK57
    Joined: Dec 31, 2008
    Posts: 1,608


    Kleen-flo makes a carburetor and metal cleaning solution that you dip and leave in over night. It's nasty stuff but works fantastic.
  14. manyolcars
    Joined: Mar 30, 2001
    Posts: 8,377


    Thats rebuildable
  15. oldolds
    Joined: Oct 18, 2010
    Posts: 3,050


    I never tried it. But there have been posts on here to soak in Pine-sol.
  16. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,729


    Some great advice guys. I am going ahead with the carb rebuild.
    Joined: May 5, 2015
    Posts: 757


    Do it while your wife is out of the house.
  18. oj
    Joined: Jul 27, 2008
    Posts: 6,247


    Don't do it. All that white stuff is from cathodic reaction of the gas and raw zinc casting. The carbs' protective coating is gone, you'll scrub yourself silly to clean it and within a few months it will be right back. Its a chemical reaction, thats why the coatings are on carbs to prevent that 'white death'.
    If it is a valuable carb you can replace the coatings, those rochesters are plentiful, find one without the white death and rebuiild that one.
    64 DODGE 440 and carbking like this.
  19. carbking
    Joined: Dec 20, 2008
    Posts: 2,909


    Looks like the carb has been sitting for some time in the presence of ethanol-laced fuel.

    The corrosion is certainly removable. The best way is to use a glass-beading machine, but use crushed walnut shells rather than glass beads. I agree with OJ (above), but you won't be satisfied unless you try it.

    Once the corrosion has been removed, one can then inspect the casting for pitting, and make a determination if the casting is still useable.

    oj likes this.
  20. Use a non-abrasive media blaster....baking soda, will preserve most of the finish and get rid of the crud.
    But first run it through the dishwasher...blast...then run it through the dishwasher again with no soap.
  21. Yeah, the plating is shot. I would get another one. It is possible that a rebuilder may be able to re-finish it or yours would be a core towards an exchange. Just give it in with the top back on.
  22. 3banjos
    Joined: May 24, 2008
    Posts: 471

    from NZ

    A replacement should be an easy find. That carb is the less desirable for the multi carb guys. Front inlet.
  23. Looks like traditional patina > runs like stink.

    Just kidding. I'm with the hunt up another crowd. :)
  24. carbking
    Joined: Dec 20, 2008
    Posts: 2,909


    A wee bit more information on this:

    (1) The corrosion is NOT the issue!!!!!
    (2) The corrosion is zinc oxide (ZnO)
    (3) The corrosion can be removed; as I mentioned before, my choice would be blasting with crushed walnut shells. Rick also mentioned blasting with baking soda.
    (4) Others have mentioned chemicals. Zinc Oxide is fairly easy to dissolve and then wash IF YOU LIKE TO USE CHEMICAL (I personally like to avoid them). Zinc oxide may be dissolved by muriatic acid ZnO + 2 HCl -> ZnCl2 + H20 (Zinc oxide with muriatic acid will yield Zinc Cloride and water). Zinc oxide may also be dissolved by using a base (sodium hydroxide) - ZnO + 2NaOH -> Na2[Zn(OH)4]. I dislike using chemicals because sometimes one gets a nasty airborne surprise!
    (5) The zinc oxide is a result of the factory coating (it IS not plated, the zinc alloy casting was ETCHED using a combination of nitric, sulfuric, and chromic acids) being removed. Once the coating is removed, a carburetor is a perfect example of a Galvanic cell (a.k.a. battery). There is ion flow when the zinc combines with oxygen (often from water, especially with ethanol) forming the corrosion. Once the corrosion is removed, THERE WILL BE PITTING! THE PITTING IS THE ISSUE! One really needs to inspect the floor of the bowl to determine the extent of the pitting. Anyone really enjoy gasoline leaks on a hot engine?
    (6) As mentioned by several, the factory coating is gone. Unless it is reapplied, as stated by OJ above, in a few months the corrosion WILL BE BACK! I really dislike doing something that I know will need redoing in a few months!
    (7) Finding someone to reapply the factory chromate finish (not the cheap dye some are using just for appearance) is difficult. Re-read paragraph 5. The factory chromate is done using chromic acid. Chromic acid is a carcinogen and also causes mental issues. The EPA doesn't want it done, and requires an approved waste water treatment facility (those in their 60's or above may remember when so many of the chrome plating shops went out of business).

    Personally, I believe this one is too far gone, but if you want to do it, get rid of the corrosion and inspect the castings

  25. BamaMav
    Joined: Jun 19, 2011
    Posts: 4,577

    from Berry, AL

    Mine looked almost that bad. Soaked it in a gallon of carb cleaner overnight, washed it off and let it dry, it was fine. Put a kit in it and ran it until I pulled the engine last spring, probably put 2500 miles on it or more with no problems. I'd clean it first, then make sure it's not pitted too bad. If it is, you can find another pretty easily.
  26. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,729


    Bit the bullet and ordered a new carb. No use spending the time rebuilding the one I have, only to have it crap out in a month or two.
    64 DODGE 440 likes this.
  27. millelacsrick
    Joined: Oct 29, 2013
    Posts: 20


    Good choice.
  28. jeffd1988
    Joined: Apr 12, 2016
    Posts: 537


    [​IMG]. This works
    pat59 likes this.

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