Fuel System: AFB replacement question

[53k]

I haven't touched the carburetor on my '64 Avanti R-1 since I bought it in 2010 and there is no way it was touched when the previous owner or owners had it. I had an identical 3506s rebuilt by a local man who loves to work on AFBs and it is beautiful. Anyhow, the gasket that was under the old carb is different from the two types that came with the rebuilt carb. Which type replacement should I use (or should it be neither)? The one on the left of the picture is obviously the old one. There are two of the one on the left which I assume means they can be used together to make one gasket thicker.

[dynolou2]

The one on the far left is closest to what several venders sell for the R 1, the gasket is .200 to .240 thick depending on which one you choose. They are made up of a stack of gaskets stapled together. The gasket in the middle is from a gm product late 50's or early 60's, far right is an aftermarket, perhaps Mr. Gasket - hot rod item. The thick gasket is/was to try to isolate carb from heat in the intake. Lou Cote

[bezhawk]

If you only have the one gasket (on the left) you can get individual gaskets to stack from your local parts store. They are a #57 gasket.
The stack of three will equal the stock thicker gasket the car came with.
However.....there is alway a however, they will be slightly more compressible so extra car must be taken when you tighten the carb down so you don't break off a mounting ear, or warp the base.

[spokejr]

If you only have the one gasket (on the left) you can get individual gaskets to stack from your local parts store. They are a #57 gasket.
The stack of three will equal the stock thicker gasket the car came with.
However.....there is alway a however, they will be slightly more compressible so extra car must be taken when you tighten the carb down so you don't break off a mounting ear, or warp the base.

Would there be any value in making a phenolic spacer and two thin gaskets?

[bezhawk]

Would there be any value in making a phenolic spacer and two thin gaskets?

Yes, by all means, if you have the hood clearance, do it. anything to defeat heat soak is a good thing.

[53k]

Thanks very much Lou and Brad. Your answers were exactly what I needed.
Strangely enough I never had a carburetor heat problem with that old gasket and it was just under 1/16 inch in thickness. Putting the two new gaskets together, one from the left side of the picture and another just like it, gave me just over 1/8 inch thickness squeezed together by hand. Tightening the carb down probably compressed the two to something around .2 inches. The carb was virtually perfectly set up- idle, air screws, choke, etc. He has connected the accelerator pump rod in the middle hole of the accelerator pump lever and I got a pretty significant lag from that. The old carb had the rod in the top hole so I changed the rebuilt one to the top hole and it helped a lot.

[doofus]

There is probably a lot of slack in the linkage to that pump. most AFB carbs start with middle hole. you can straighten the link from carb base to accel. rocker to remove some of that slack. dont try to tweak "S" link at top of pump, dont ask ,it will break. Luck Doofus

[53k]

There is probably a lot of slack in the linkage to that pump. most AFB carbs start with middle hole. you can straighten the link from carb base to accel. rocker to remove some of that slack. dont try to tweak "S" link at top of pump, dont ask ,it will break. Luck Doofus

Thanks. I remember doing that on AFBs in the distant past. I know the hesitation is due to not getting enough "squirt" so I'll give that a try.

[Xcalibur]

I've replaced any number of the ol', often worn-out, missing parts, etc. AFBs with new Edelbrocks and never looked back... never had to; they always start and run!!!

[53k]

I've replaced any number of the ol', often worn-out, missing parts, etc. AFBs with new Edelbrocks and never looked back... never had to; they always start and run!!!

I probably should have done/should do that too. Having a couple AFBs laying around I didn't want to get in to the modifications for using an Edelbrock. I couldn't beat the hesitation problem by putting the accelerator pump link in the top hole of the lever so per Doofus' suggestion I straightened the link a bit and the problem improved, but not to 100%. So, checking for slop in the linkage to the pump I found that the primary throttle shaft wobbled when the accelerator pedal was pressed. I had told the builder that the throttle shaft would need to be bushed, but that didn't get done so, for tomorrow I'll drive the Avanti to our IDYSD outing and just feather the throttle when needed.
I'm wondering if that wear in the carburetor casting will cause a significant vacuum leak.

[GrumpyOne]

I probably should have done/should do that too. Having a couple AFBs laying around I didn't want to get in to the modifications for using an Edelbrock. I couldn't beat the hesitation problem by putting the accelerator pump link in the top hole of the lever so per Doofus' suggestion I straightened the link a bit and the problem improved, but not to 100%. So, checking for slop in the linkage to the pump I found that the primary throttle shaft wobbled when the accelerator pedal was pressed. I had told the builder that the throttle shaft would need to be bushed, but that didn't get done so, for tomorrow I'll drive the Avanti to our IDYSD outing and just feather the throttle when needed.
I'm wondering if that wear in the carburetor casting will cause a significant vacuum leak.

Have you considered having the carb rebuilt by Dave Thibeault? I've dealt with Dave in the past and it appears that he has an excellent reputation for rebuilding carbs and other specific parts. In addition he has, (or had), an Avanti R-1 though Janet may chime in as to actually owns it.

I'd give him a call...

[53k]

Have you considered having the carb rebuilt by Dave Thibeault? I've dealt with Dave in the past and it appears that he has an excellent reputation for rebuilding carbs and other specific parts. In addition he has, (or had), an Avanti R-1 though Janet may chime in as to actually owns it.

I'd give him a call...

I might do that. It's been quite a while since I bought anything from him. It's sort of ironic and not the first time I have done it then wished I had something back. Some years ago I figured I'd never have another R-1 so I gave Dave a half dozen or so NOS Studebaker R-1 carburetor klts.