Technical My Crazy Dual Quad Carter AFB Restoration

Killer job!!
So awesome to see threads like this!! Thank you so much for taking the time!!

 

Tom - in the for what its worth category:

The step-up pistons should ALWAYS be replaced when rebuilding a Carter AFB!

Early production pistons were brass (brass was used successfully on earlier zinc alloy bodies, which are harder than the aluminum of the AFB). Carter quickly found that these would wear the AFB castings, and replaced them with aluminum. But movement of aluminum on aluminum creates wear. So Carter deliberately produced the aluminum pistons from an aluminum alloy MUCH SOFTER than the body alloy. The pistons are sacrificial. They wear and are replaceable; thus saving the main casting.

A few thousandths of wear allows vacuum to slip past the piston and out through the vacuum chamber vent, allowing the springs to keep the piston higher longer, thus changing the timing of the rod movement, and causing the engine to run rich. Of course, one can tune by purchasing weaker springs; but just a hassle not required when the parts are replaced as Carter intended.

But your work does look great!

Jon.

 

As far as the design goes.........I would guess its a 360*/open plenum design intake.
More for top-end performance than around-town puttering.
That don't mean it can't work on the street..just have to "adapt & modify" a little.
Prolly lottsa initial timing....& limit the total timing. Maybe even lock-out the timing.
May require more rear gear.....more stall (if you drive a sissy A/T).
Really good high-energy ignition system ....really good spark.
Like said above..... 1:1 linkage....maybe play with the secondaries to keep them closed until higher RPM to lessen the chance of the "big ''B-word'!
What about playing with different spacers under the carbs............think tunnel-ram on a shorter scale??

 

Thank you Crkrjac! That's a great complement. If I can provide a little inspiration to the next guy then it's all worth while.

 

Thanks Jon, I was not aware of the evolution of the step-up pistons. Do you happen to know what alloy? 1000 series? These were in pretty good shape as were the bores. I probably did not even remove .0001". I will keep this in mind going forward as they are easy to change that is if I can find some good ones.

Tom

I did notice a fair bit of wear on the rods themselves where they ride in the piston.

 

The ridges on the pistons are 0.430 +- 0.001.

The holes in the pistons are 0.082.

Most of the step-up rods are fabricated using 0.081 brass stock ( I have fabricated a lot of them).

These are calibrated parts, and for best results, these specs are important.

I don't remember the alloy, and am too lazy to search the microfilm, sorry

Jon

 

Rocky - WHEN are you going to do that 2 x 4 Pontiac?

You have been thinking about it since Noah landed the ark!

Jon

 

Hell, I dunno, Jon. Maybe I'll put it all together this winter. I appreciate the tip on which carbs to buy. I must have 6 or 7 of them...running outta excuses. Thanks for the nudge.

 

Tomcat11, I don’t mean to be a critic. But those carbs look phenomenal!!! They look bitchen and I hope they work as good as they look for you.
Maybe you could list the chemicals and power supplies and where you got all the stuff. I got a feeling there are a bunch of us looking for this information.

 

I need a set of WCFB's for the Caddy. Those things are stupid money.

 

Wow @tomcat11!...that's beyond next level. Thanks for posting. To think I consider it a success when I solvent tank and brush clean, install a kit, check adjustments, install and it runs...I bow to your work.

 

They look great, you planning on running gas in these?
Can you show us what they look like in a year or two.

 

Thank you SS327. Critics are always welcome. They should function well right from the get go but in any case are easy to tune.

The Zink/Copy Cad plating kit and optional Chromates are from Caswell.
Power Supply, Thermometer, and fish tank heaters are from ePay.
Everything else is available at your local hardware store.
A Donor carb allows you to pick parts that are in the best condition.

Everything is fairly cheep but, it does start to add up. The good new is once you have everything you are set for the future.

 

Thanks anothercarguy. I have rebuilt many carbs just like you say and in most cases that's just fine but in this case they will be visible so I had to go the extra 9 miles on these.

 

What things of beauty .

 

Thank you sir. Yep.

 

You've done an amazing job!

 

Really nice.
I love detailed carburetors.
Thanks for taking the time and effort and sharing so many of the important details.
I have a slew of 94s, a gaggle of 97's, and a handful of Holly and Carter 4bbls I'll be getting very intimate with. This thread is one of my very valuable references.

 

Really , very , very nice!

 

No matter what engine or how long it takes for you to get the desired look…any and every V8 looks better with dual quads.
Don’t be stuck on air filters from the past or present. I once used cooking lids from kitchen supplier and these are Harley Davidsons replacements.

 

Thanks Rickybop. I'm with you on detailed carbs. Sounds like you have enough to keep you busy for awhile.

Thanks man.