Carter AFB Guidance Needed

Havasu Dave · Aug 29, 2016

Hello,

I'm running the stock 4329S on my non-modified 440 Mag. It is very similar to the other AFB's from what I can tell.

I just rebuilt it, used solvent, then carb cleaner. (Floats were not even close)

However I now have two issues:
1. Accelerator Pump-side idle jet does absolutely nothing. I can feel a slight vacuum when I remove it, engine still idles. Turn it all the way in, engine still idles. Air bleed clog, or any other ideas?

2. Slight surging on deceleration. I did find and plugged up some vacuum leaks, and now have a stead 12 inches. I know it's not a lot, but I did not have this issue before rebuilding. Could the misadjusted (too full) floats have hidden this?

Acceleration is great, starting both cold and hot great. Just the idle jet and deceleration/holding speed surge issue. Thanks in advance for any guidance.

lewtot184 · Aug 29, 2016

the idle jet is the small brass tube attached to the primary cluster. the adjusting screws just regulate the volume. look at the bottom of the idle jet tube to make sure no debris is in it. also check the idle air bleed hole on top of the cluster to make sure no dirt/debris have it blocked.

mopar 3 B · Aug 29, 2016

Did you get the main metering rods back in the main meters with sprngs underneath and the caps back on right? Seal rings back under main meters?
Surge on deceleration! That is a new one.

Havasu Dave · Aug 30, 2016

mopar 3 B said:
Did you get the main metering rods back in the main meters with sprngs underneath and the caps back on right? Seal rings back under main meters?
Surge on deceleration! That is a new one.

Thanks Mopar 3 B. Surge is in any range from cruise to decel. Rods and springs are assembled correctly, but there are no seal rings. Could you please explain these and where they would go? I assume you are referring to the pistons.

I was also wondering if the Edelbrock components are interchangeable?

To Lewtot, I will remove the air horn and double check the bleed holes. Good place to start, and thanks for the detailed reply.

lewtot184 · Aug 30, 2016

AFB's are fairly simple and easy to work on. there are some Afb websites that can give full details and diagrams of all parts.

lewtot184 · Aug 30, 2016

try www.mymopar.com and look up AFB's.

Havasu Dave · Aug 30, 2016

lewtot184 said:
AFB's are fairly simple and easy to work on. there are some Afb websites that can give full details and diagrams of all parts.

Thanks, I found some of the manuals there and have joined so I can search.

The reason I asked about Edelbrock interchangeability was that I see some scaring on both the metering rods and pistons. 50 year old carburetor and all that.

So far I found no indication either way. Your idle recommendation sounds like a winner, and I will definitely report back on that.

lewtot184 · Aug 30, 2016

the original metering rods are 3 step and are no longer made. edelbrock 2 step rods and pistons can be used as replacements. edelbrock stuff will interchange.

the deceleration surge may come from the vacuum advance. it's adjustable.

PRND21 · Aug 30, 2016

In my experience, any surge condition is caused by an overly lean condition: vacuum leak? Or as lewtot says, too much timing as in vacuum advance adjustment. Good luck

TetanusShot · Aug 30, 2016

!!New Edelbrock pistons DO NOT interchange with old style AFB lids!! The "wells" or whatever they are called are different diameter and depth. There is a washer under the rod retention spring on the old style pistons that takes up the clearance.

This bit me in the butt when I was trying to tune my carbs. They were a mix of vintage carter and new edelbrock parts. You can use new rods and springs just fine but keep the original pistons and covers with the lid.

Darthomas · Aug 30, 2016

TetanusShot said:
!!New Edelbrock pistons DO NOT interchange with old style AFB lids!! The "wells" or whatever they are called are different diameter and depth. There is a washer under the rod retention spring on the old style pistons that takes up the clearance.

This bit me in the butt when I was trying to tune my carbs. They were a mix of vintage carter and new edelbrock parts. You can use new rods and springs just fine but keep the original pistons and covers with the lid.

Rubber or leather accelerator pump pistons?

Havasu Dave · Aug 30, 2016

All, I took Lewtot's advice and went after the air bleed on the affected side and sure enough the top tube sticking out was plugged. Not sure what it was plugged with, but it was much harder than carbon build up, and seemed to be a casting issue.

The advance is at 12.5 per the book, as are all carb adjustments, and even the fluttering or surging stopped after tending to that idle problem.

I appreciate the heads up on the metering pistons Tetanus, and everyone else who chimed in. Pretty good feeling getting something working right.

Now to attend to those vacuum leaks. All of them are hose related, so easy fix. This is an AC car, so the darn vacuum is all over the place. Maybe after that, I can play around with metering rods and springs, but it's running pretty darn good right now in 100F weather. Thanks again!

lewtot184 · Aug 30, 2016

i just measured an assortment of old carter and newer eldebrock step-up pistons. there was .002"-.003" difference in some of them. whether that is wear, old '60's carbs, or manufacturing tolerance i don't know, but it's not enough to prevent me from using any of them.

69L48Z27 · Aug 30, 2016

Is this air bleed you guys are talking about part of the Venturi cluster? I have a similar problem on a rebuilt carb and it sounds like in need to check this too.

TetanusShot · Aug 31, 2016

lewtot184 said:
i just measured an assortment of old carter and newer eldebrock step-up pistons. there was .002"-.003" difference in some of them. whether that is wear, old '60's carbs, or manufacturing tolerance i don't know, but it's not enough to prevent me from using any of them.

I measured mine again last night and got .023"-.025". Then I tried putting old pistons in a new lid, they won't fit. Maybe there are two different types pistons? The old pistons I measured came out of two '66 383-440 afb's and two 273hipo afb's. The new pistons were from a pair of Edelbrock 1407's.

HALIFAXHOPS · Aug 31, 2016

lewtot184 said:
AFB's are fairly simple and easy to work on. there are some Afb websites that can give full details and diagrams of all parts.

Here is the one I use, great guy also and very reasonable on parts.

http://jgronoj.weebly.com/

lewtot184 · Aug 31, 2016

TetanusShot said:
I measured mine again last night and got .023"-.025". Then I tried putting old pistons in a new lid, they won't fit. Maybe there are two different types pistons? The old pistons I measured came out of two '66 383-440 afb's and two 273hipo afb's. The new pistons were from a pair of Edelbrock 1407's.

i measured an assortment of old and new pistons. i also took out the original pistons from the 4618s avs on my 69 r/t (original carb and parts) and compared it to the newer edelbrock pistons on my ch28 dual quad; they were identical in shape and size. there may be some differences thru the years but from what i have all seem to be able to interchange.

TetanusShot · Aug 31, 2016

Well that explains it! The old Carter AVS pistons must match the new Edelbrock AVS and AFB's, but the old Carter AFB's pistons are different.

69L48Z27 · Aug 31, 2016

69L48Z27 said:
Is this air bleed you guys are talking about part of the Venturi cluster? I have a similar problem on a rebuilt carb and it sounds like in need to check this too.

Any help with the air bleed locations?

lewtot184 · Aug 31, 2016

69L48Z27 said:
Any help with the air bleed locations?

the small tube that sticks up vertically from the primary cluster is the high speed bleed. the small hole on top of the primary cluster is an idle air bleed along with another idle air bleed on the side of the cluster. the large brass tube coming out the bottom of clusters (primary and secondary) are the emulsion tubes. the small thin brass tube sticking out of the bottom of the primary cluster is the idle jet.

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