Recommended Posts

I recently purchased a Carter AFB for my 64 Wildcat.  It is a core carb.  However after receiving it I found the secondary butterfly is frozen rock solid.  I have soaked it for 48 hrs and still will not  budge. (in carb cleaner and also pb blaster) I think also that shaft is bent.   anyone have a good solution  to free it up.  Also all the scres on all butterflys broke when trying to get it apart.

Share this post


Link to post
Share on other sites

Fill one sink with ice water and the other with hot water and dip them back and forth. 

  • Like 1

Share this post


Link to post
Share on other sites

This post is kind of like the old cliche of closing the barn door AFTER the horse escaped, however:

 

To loosen the secondary shaft, either an ultrasonic cleaner or heat (use an electric toaster oven).

 

Virtually ALL throttle valves are staked on the back side. If you must remove the shaft they MUST be ground off (Dremel) or filed off. If this step is not done, they will twist off.All of them.

 

After removing the remains of the screw on the back side, using a torch with a pencil flame, heat the screw. If steel, until red. If brass, until the flame turns yellowish-green. Be careful that you stay off of the valve with the flame of the torch. Allow to cool, and all screws will come out.

 

What you now have is restorable, however, unless this is a very rare carb (Super Duty Pontiac, NASCAR Chevrolet, etc.), the cost to fix it now exceeds its value.

 

Try the above on your next carburetor that is rough.

 

Jon.

  • Like 1
  • Thanks 2

Share this post


Link to post
Share on other sites

Should you be interested in how to remove the twisted screws:

 

If one has a milling machine with a tilt table:

 

Set the table to the angle of the throttle plates with twisted screws

 

If one has a GOOD drill press with a vise, one will need to fabricate a fixture to hold the throttle body at the angle of the throttle plates with the twisted screws.

 

The idea with both of the above is to locate the spinning center perpendicular to the screw, so that it may be drilled without damaging the threads.

 

Now, using a diamond tipped, pointed burr, center a "starter hole" in the center of one of the screws.

Drill a small hole through the screw. If you have the proper set-up, you will not touch the shaft.

Now, DULL a bit slightly larger than the one used to drill the through hole

Remove the casting from the vise, and heat the screw as in my post above this one

Reinstall the casting in the vise, and using the dull bit, gently jam the dull bit into the screw. Once it catches, it will spin the screw out the back of the shaft, saving the thread in the shaft, and the throttle plates.

Repeat for the rest of the screws.

 

Penetrating oil rarely is going to free a shaft that is frozen, you must use heat (see above post). PATIENCE IS ONE'S FRIEND!

If the shaft looks like it is true and undamaged other than frozen, after heating, reinstall the throttle plates before attempting to turn the shaft. The will help support the center of the shaft, and minimize the danger of the shaft twisting.

 

Opinion - unless a very rare and valuable carburetor, at the point where one has 4 twisted screws and a bent shaft, one might consider just starting with a different core.

 

Alternately, if common parts but one wishes to retain the casting because of a correct date code, cut out the shaft and plates, and then replace with parts which often may be acquired.

 

Jon.

 

  • Like 3

Share this post


Link to post
Share on other sites

Some of the old service manuals, in the carb rebuild section, showed how to remove those throttle plate screws during the rebuild process.  How to go to the backside, use a flat file, and file-off the bradded threads on the backside of each screw.  Which "staked" them into place.  Once that lip was removed, then the screw came out normally.  After the soak and clean-up, then the plates were repositioned on the throttle shaft and new screws were installed, suitably "staking" them on the bac side of the shaft.  After about the middle '60s, that section wasn't in the manuals any more.  As the positioning of the throttle plates with respect to the idle and transition slots in the primary (on a 4bbl) throttle bores became more important for emissions controls and such.

 

Once you get things all apart, IF the carb is the correct one for your car, you might consider getting those throttle shafts bushed so you don't go through this again.  The cost of which Carbking is referring to?

 

NTX5467

  • Like 2

Share this post


Link to post
Share on other sites

Hey I got the dual quad setup the other day and the carbs look way better from the top. The shafts are not in good shape... is it possible to replace them and the plates? Somebody was already trying to work on them and has done some damage. I have rebuilt a number of carbs over the years but these are rough. Any one know where to get parts in Canada for these carbs... or a good place to order online?

carbs.jpg

cleaner.jpg

Share this post


Link to post
Share on other sites

There were some comments on repairs from a company called CarbKing.  It requires ultrasonic cleaning (I guess). I was to the point of just putting on a new edlebrock.  

I have been in  contact with  Tom Mooney who is the tech rep for the Riviera Club.  He has spent a lot off time with me (way more than anyone else would have done) in working my carb issues.  It seems that this issue is common for the Carter AFB,s that sit around on a shelf or out in the weather.  I would try soaking the bases in PB blaster  or a product called Kroil.  I used Kroil a few years ago to remove stuck pistons in a Model A engine.  Works really well.  Good luck.

 

  • Like 1

Share this post


Link to post
Share on other sites

Without checking the prints, would guess that the shafts are unique to the dual quad carbs. Repeat, this is a guess.

 

The throttle plates often are not unique.

 

There is generally no reason to replace the shafts other than the efforts of Dr. Goodpliers (you know, the evil twin of Mr. Goodwrench). The methods described earlier in this thread work, and work well.

 

New throttle shafts can be machined by ANY competent machine shop that is interested in doing the work. A skilled enthusiast can do the work provided the enthusiast has a lathe and milling machine. One first needs to index the "double D" on the end of the shafts with the slot. Now one can first cut the slot using a milling machine and a "slitting saw". Once this has been done,  the holes for the screws may be cut and threaded, and the double D on one or both ends of the shaft cut. Now the original throttle arm may be installed on the correct side sliding over the machined double D, and peening to retain.

 

New throttle plates are more difficult, but may be done by a good machine shop. The first step is to take a piece of round metal bar, and turn it to the diameter of the throttle bore. Now the tricky part is to cut the shaft into two shafts at an angle the same as the closing angle of the throttle plates (Carter generally stamped this angle on the plates). Once the metal bar has been cut and both bars trued, two holes should be drilled into the two pieces of bar representing the position of the holes in the throttle plates. The holes in one of the shafts should be threaded, and studs installed. The holes in the other end should be just sufficiently large to slip over the studs. Now, measure the thickness of the existing throttle plates, and acquire flat metal of the same type (brass, aluminum, etc.) and thickness. Cut "blanks" which are larger than the largest diameter of the plates. Drill holes to represent the screw holes in each of the blanks. Slide the blanks over the studs in the end of the shaft with studs, slide on the other end, and secure with nuts on the studs. Place the shaft with studs into a four-jaw chuck on your lathe, and CENTER. Now, turn down the portion of the "blanks" to where the blanks are smooth with the shafts. Remove the nuts, the end cap shaft, and FINISHED throttle plates. Each will have the correct closing angle.

 

Jon.

  • Like 2

Share this post


Link to post
Share on other sites

I never thought about the closing angle... that is a slick way to get it perfect. I will take a picture tonight of the bottom... pretty ugly. Penetrating oil of any kind is not going to do anything by itself... its gonna take some heat and tons of patience. Thanks for the information.

Share this post


Link to post
Share on other sites

Looks like they were run without the stainless plates under them.  Very common.  Mine was the same way.   May the force be with you on this.

  • Like 1

Share this post


Link to post
Share on other sites

Is that a nut in place of the butterfly screw? 

Share this post


Link to post
Share on other sites

It is some sort of screw someone cross threaded into it. Somebody has tried in the past to work on them in the past... but was not patient. I got the main carb almost all the way torn down... the shafts (at least 1) are going to have to be replaced. The one jet of course has had an attempt in the past to be taken out and no longer has a slot in the head... gonna have to get out the "easy outs" (I have never understood why they call them easy... if you need them there is generally nothing easy about it). 

Share this post


Link to post
Share on other sites

I also suggest a set of left handed drill bits. Harbor freight has them. But not for the throttle plate screws, they need to continue through the shaft, like CarbKing says.

Share this post


Link to post
Share on other sites
Posted (edited)

"Notsoeasyouts"  often work well in steel; VIRTUALLY NEVER IN BRASS!

 

A carburetor is a perfect example of a Galvanic cell (two dissimilar metals in the presence of a liquid). In this case one has aluminum, brass, and gasoline. Ion flow takes place and beads of corrosion build up in the threads, making the jets difficult to remove.

 

There is a method that always works, once perfected; BUT IT SHOULD BE PERFECTED ON A SERIES OF JUNK CARBURETORS!

 

Bill of materials:

 

(1) Set of left-handed drill bits THAT YOU HAVE DELIBERATELY DULLED

(2) Reversible drill

(3) Empty 5-gallon bucket

(4) Piece of 1-inch foam rubber (for the bottom of the bucket)

(5) Acetylene torch with jewelers tip

 

Procedure:

 

(1) Fill the bucket approximately 3/4 full with water

(2) Light the torch, and adjust to a pencil flame

(3) Rotate the point of the flame on the periphery of the jet, always moving in a circle, always on the brass.

(4) When the color of the flame changes from blue to yellow-green, drop the casting in the bucket of water.

(5) Repeat steps 3 and 4

(6) Spray liberally with your favorite brand of penetrating oil.

(7) Using the left-handed drill bit of the appropriate size and the reversible drill, gouge the jet, and it will spin out.

 

It should be noted here that using this procedure with a stubborn jet to begin with, will never allow the jet to lose its slot. Not that I am advocating reusing jets, but a screwdriver is easier than the drill.

 

AGAIN, PERFECT THIS PROCEDURE ON CARBS THAT YOU CAN THROW AWAY!

 

Why it works:

 

The heat will burn the oxygen from the corrosion molecules thereby reducing the physical space they occupy in the threads. This allows a good penetrating oil to lubricate the threads, and the left-handed turning action will spin out the jet.

 

And yes, I HAVE removed literally hundreds of jets using this method.

 

CAVIAT TO THOSE THAT APPLY ANYTHING TO ANYTHING: This is not meant as a generic fix, rather a fix in working with the Carter AFB castings. The melting temperature of aluminum (the base metal of the Carter AFB casting) is maybe twice the melting temperature of zinc alloy. Thus, if one tries this method on a zinc-alloy body, one must be extremely careful. The method will still work, but there is zero margin for error (i.e. the flame slipping from the jet onto the casting).

 

EDIT: For those that think maybe the notsoeasyout would work instead of the drill, consider: the force to "grab" the jet applied by the notsoeasyout is virtually sideways, thus pushing the soft brass against the side of the casting, and creating additional friction, whereas the force exerted by the drill is virtually in the same plane as the drill, not creating additional friction. But try it if you will. I was never successful, but it might work for others.

 

Jon.

Edited by carbking (see edit history)
  • Thanks 3

Share this post


Link to post
Share on other sites

Ya I have a set of left hand drill bits (although very sharp currently). When you say of appropriate size you mean like a 3/16 to a 1/4'' bit? I have a bunch of old quadra bogs under the bench i can practice with. I am going to give it a try.

Share this post


Link to post
Share on other sites

The 1/4 inch should work well.

 

Check the numbers on the Q-Jets before practice. Some of them are worth more than the dual quad carbs!

 

Jon.

Share this post


Link to post
Share on other sites

Well got 1 out of 4 out. I actually almost had it out in one piece. I am gonna need new shafts. I have been looking around online and I found a Corvette parts website that lists the shafts... but doesn't specify what model number carter afb carb they are for. I wonder if they may work with some slight modification? I know I could get shafts made it would just be easier to find something new.

carb shaft close up.jpg

carb shaft.jpg

Share this post


Link to post
Share on other sites

Send me an email with the carb numbers, and which shafts you need for each. I might have decent used ones. Will look.

 

Jon.

  • Like 1

Share this post


Link to post
Share on other sites

So I got the primary shaft out from the primary carb. I also got the rounded off jet out as well. Thanks again Jon for the advice on how to get that out... I actually couldn't believe how well that worked... it was the first time in a long time I have that surprised and happy moment working on a car. Only thing I did a little different was I drilled the jet top slightly to get to fresh brass (found it helped during "practice"), and I didn't use a drill I did it by hand. That carb is now completely disassembled and ready to go in my mini hot tank. 

jet.jpg

primary shaft.jpg

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now