Re: 3269 3461 AFB Carter Carburetor
Thank you Clem. I will do that and when I get it apart will let you know what I find. -John
Thank you Clem. I will do that and when I get it apart will let you know what I find. -John
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Re: 3269 3461 AFB Carter Carburetor
Tim and Clem, the holes are there just like in the picture that Tim provided. They are approx. 3/32 and they are not due to wear of the shaft against the body. I had to take a pencil torch to the threaded area just below the top of the body to get the stud to move. A weeks worth of solvent , rocking and tapping did not get it to budge. A few seconds with the torch and out it came. Everything came apart as you said it would. The carb is a D-3 from a mid May build 1963-340 HP. Hope that helps.- JohnComment
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Re: 3269 3461 AFB Carter Carburetor
Clem, I cleaned the carb and let it air dry outside today. I placed the flame of the butane pencil torch around the area that held the threads for a few seconds and that was all it took to expand the aluminum. I applied pressure to the stud, which I had double nutted, the whole time I was heating the area and it just started to turn. That baby was really in there. As I said before, the holes are there just as Tim described. Thanks for all your help. - JohnComment
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Re: 3269 3461 AFB Carter Carburetor
John,
Thanks for the information on the drilled holes in the secondary shaft bores on the 3461.
I am very curious why these holes are there because as stated before they are not on the 3720-21 carburetors. My opinion is to allow extra filtered air for the Duntov camshaft through the secondary throttle shaft bore.
I would like to know from others there opinions for the drilled holes in this area. Also, does anyone have a 3269 afb from a 62 corvette that can verify the holes we are talking about. I believe that carburetor is also used for the 340 and 300hp engines.Comment
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Re: 3269 3461 AFB Carter Carburetor
I'm still standing by on this one as well. Come on you AFB-ers. Wher are you?
Stu FoxComment
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Re: 3269 3461 AFB Carter Carburetor
i wonder if this was done to prevent dirt from being sucked into the area between the shaft and the carb body causing the shaft to bind in the bore.Comment
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Re: 3269 3461 AFB Carter Carburetor
Clem,
If you are saying the newer 3720-21's do not have holes in this area because of the possibility of dirt being sucked into the throttle shaft bores I agree with that. Also, the 300 hp car makes 17-19" vacuum draw and this much pull is bound to pull air from these holes around the shaft don't you think.
Still seems odd that it's eliminated for the 3720-21 and the question remains why are the holes there in the first place. They don't have anything to do with the secondary shaft bore or it's operation.
I still would like to know if they are on the 1962 model AFB's..
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Re: 3269 3461 AFB Carter Carburetor
Perhaps it was like you first surmised that it was that way for the L-76 (62 and 63). The 3720-21's was never intended to be used on the SHP engines and maybe with experience with the 62 and 63 L-75's they found it to be detrimental, specially after shaft wear over time, so they eliminated them.
Stu FoxComment
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Re: 3269 3461 AFB Carter Carburetor
it is just a wild ass guess on my part. i can't see why they would do it to get more air in to the engine because as the carb got worn the amount of air would change.Clem,
If you are saying the newer 3720-21's do not have holes in this area because of the possibility of dirt being sucked into the throttle shaft bores I agree with that. Also, the 300 hp car makes 17-19" vacuum draw and this much pull is bound to pull air from these holes around the shaft don't you think.
Still seems odd that it's eliminated for the 3720-21 and the question remains why are the holes there in the first place. They don't have anything to do with the secondary shaft bore or it's operation.
I still would like to know if they are on the 1962 model AFB's..Comment
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Re: 3269 3461 AFB Carter Carburetor
Clem and Stu,
I agree with your statements, keep in mind the AFB does not have a secondary throttle shaft stop screw like the Holleys. Maybe to keep the primary throttle blades and transfer slots in a proper adjustment this fix was done to allow more air, I can't think of another reason.
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Re: 3269 3461 AFB Carter Carburetor
holes in the pri butterflies would be a better answer for better control of more air. anyone here have a contact at edelbrock as they use a version of a AFBClem and Stu,
I agree with your statements, keep in mind the AFB does not have a secondary throttle shaft stop screw like the Holleys. Maybe to keep the primary throttle blades and transfer slots in a proper adjustment this fix was done to allow more air, I can't think of another reason.Comment
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Re: 3269 3461 AFB Carter Carburetor
Good grief! Aren't there any AFB Carter or Edelbrock experts or rebuilders that can answer this simple question? Your'e not exactly giving up any trade secrets with something as simple as a couple of holes!
Stu FoxComment
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Re: 3269 3461 AFB Carter Carburetor
Clem;
I believe I and Tim have most of them and between us over the past several weeks on this subject we have probably both re-read them cover to cover trying to find reference to these little holes of some sort. I haven't found any, even for different models. When anyone tells you that one model carb is the same as another except for some slight jetting change, don't believe them. I'm sure you know what I mean.
It sure would be helpful if someone with a 62 with a 3269 would post.
Stu FoxComment
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