Cleaning dark oxidation from a carb?

[58chev]

What do you use? For those of you who "been there done that"

I tried a method to clean and it turned the body of the carb dark, got all the crud and grease/oil off but left me with a dark tint to the aluminum.

I have read that I could soak it in Lacquer Thinner or Diesel?
I don't have access to an ultrasonic cleaner.

[Cliff Ruggles]

The method that you used has stripped off the protective finish which was applied when the carburetor was built.  The main body and airhorn got a bath in chromic acid, which reacts with the zinc in the base material and gives them there original appearance, and at the same time protects the metal from oxidation/corrosion, etc.

I would recommend having the castings restored, especially using this new fuel in them as it can be somewhat corrosive to the fuel bowl......Cliff

[58chev]

I would recommend having the castings restored, especially using this new fuel in them as it can be somewhat corrosive to the fuel bowl......Cliff

I was afraid of that. Is this something that can be done at home? Or will it have to go to a carb shop to get re coated?

[Ethan1]

I was afraid of that. Is this something that can be done at home? Or will it have to go to a carb shop to get re coated?

 Send it to, Cliff. He does amazing work recoloring the castings!

[Cliff Ruggles]

The cost of the materials would far exceed what it would cost to get them done.  There is a significant learning curve as well, even if you had everything required to do it at home.....Cliff

[Marx3]

If money is an object, I think the cheapest sollution for you is to buy another used carb and use it for parts.
Your carb looks like a very common Chevy side inlet 750 cfm M4M unit... Shouldn't be too hard to find for pennies.
This way you can "try again"  :-)



http://www.ebay.com/itm/QJET-ROCHESTER-CARB-CARBURETOR-/351006312652?pt=Vintage_Car_Truck_Parts_Accessories&hash=item51b99b48cc&vxp=mtr
Seller has not supplied any id number, but the throttle linkage looks very much like Chevy , not that you need to use the throttle plate...
50 bucks!

[Marx3]

even cheaper
http://www.ebay.com/itm/Rochester-Quadrajet-GM-4-Four-Barrel-Carburetor-17062757-/321632405867?pt=Motors_Car_Truck_Parts_Accessories&hash=item4ae2c9096b&vxp=mtr

[58chev]

I have resided the fact that I will have to get another carb for the bowls.

I will not purchase off evil bay as the sellers rake us Canadians with shipping charges. I will wait till spring and hit the swaps.
I have a 800CFM but think that is a little too much carb for my engine. and I have an older one from 68. Both of these are up on KIJIJI for sale. I'll use the proceeds towards another one or two.

I tore another spare down to find both primary and secondary plate rods ceased. All 4 little screws snapped, every cavity inside had remnants of wasps nests. Have it soaking in lacquer thinner to see if it's usable.

[Marx3]

oh, okay, that makes sense. :-)
I dont think you need to worry about the 800 unit being too big... remember all electronic Qjets where 800 units ( for all I know ) and they came on small engines, like 305, 307, 350.
Heck, the pontiac 301 came with an 800 unit.

I have had luck drilling seized pieces of throttle plates screw out and installing new screws no problem.

btw, are you sure you are not doing the damage over againg by soaking this carb in laquer thinner also?

[58chev]

btw, are you sure you are not doing the damage over againg by soaking this carb in laquer thinner also?

The first attempt, I used a concentrated ZEP Industrial Degreaser.
I have just recently taken the bowl out of the Thinner and it is starting to come clean and still has the original coating on it.

I might give in an purchase a Ultrasonic machine that has a large enough area to drop in the various parts of the carb.
I'll post up pic's of my progress. I kinda like the shape of the area where the fuel mixes on this 800.

[58chev]

Here are the results of using Lacquer Thinner to clean my carb.

I kept the top and bottom plates from the 750CFM carb as they came out looking reat.

I used the fuel bowl of this 800 CFM carb.


Every cavity inside the carb had old wasps nests inside.
after a good 12hr soak in Lacquer thinner.


Here is a pic of both the 750 and 800, only very slight difference in the air mixture chamber??









Getting there, soaking most of the mall parts now..

[Cliff Ruggles]

Those two castings are not the same type, requiring a different air horn.  The one on the left is single MAB, so takes the later style top.....Cliff

[58chev]

Those two castings are not the same type, requiring a different air horn.  The one on the left is single MAB, so takes the later style top.....Cliff

ThanX, I will compare the two air horns again. At first glance they looked to be identical.

[Cliff Ruggles]

I don't see pics of both airhorns, but those main castings do NOT use the same airhorn, and it's NEVER a good idea to swap parts around anyhow, for a variety of reasons.

It is a good idea to have all the oxidation and corrosion removed and the castings zinc/chromated, especially if the cleaning process has removed some or all of the original finish......Cliff

[58chev]

So looks like I'll be hitting the swaps looking for one that is as close to the first one I have.

Yep, the air horns are different.
ThanX Cliff for pointing that out to me.