1962 AFB Carb Recalibrating

[Jeff C.]

1962 340HP with correct intake manifold and 3269S AFB appears to running lean at normal curise on 91 octane California gas. Does anyone know the answers to the follow questions.
1. What size are the stock main jets and metering rods supposed to be?
2. Will Edelbrock performer jets and metering rods fit this carb?
Two different classic car shops in my area have quoted approx $400 to $500 to do a all incompassing tune up to recurve the timing and recalibrate the carb. I would like to take a shot at it myself before spending that kind of money on a tune up.
Thanks!

[Terry D.]

Re: 1962 AFB Carb Recalibrating

Jeff
Check the archives for the info you are looking for. I know the instructions on how to do an advance curve are there and I'm pretty sure so are the carb stats you want.
You can call the Edelbrock info line and probably get the info on the carb also.

Terry

[Duke W.]

Re: 1962 AFB Carb Recalibrating

You can buy distributor curve kits from the big hot rod parts houses. One is made by Moroso, the other by Mr. Gasket. All you need is the three sets of springs. Don't use the weights in the kit. Use the OE weights.

The following method assumes the OE weights and springs are installed in the OE dual point distributor, which has no VAC. You can get a good idea if you take the timing map with a dial back light. Full advance should be in at a lofty 4600.

Set your initial timing at 12 degrees with the OE springs (assuming it doesn't ping with 12 initial and the OE springs) and install the lowest tension set of springs. Measure the maximum advance, degs@RPM, with a dial back timing light, and let us know what it is.

With the lowest tension set and 12 initial you should see the full 36 - 12 initial plus 24 centrifual - by about 3000.

If the engine detonates install ONE of the mid-tension springs on one side and retest. If it still detonates install the second mid-tension spring on the other side. Continue the method until it doesn't detonate.

Keep in mind that detonation is highly sensitive to inlet air temperature, so if you set it up on a cool day, it might detonate on a hot day - especially after slogging through slow traffic.

You actually have four spring sets includilng OE so determine where they fit as as they may not be the stiffest.

Now I have a question for you: What makes you think the carburetor is lean?

Duke

[Christopher R.]

Re: 1962 AFB Carb Recalibrating

The information on the 3269S should be in the ST12. I have, from another source, the following:

Metering Rod: .069" x .060"
Primary Jet: .104"
Secondary Jet: .068"
Idle Jet: #65 - .035"
Float Adj. 5/16" level, 3/4" drop
Primary Venturi: 1-1/4"
Secondary Venturi: 1-9/16"

But re-check this info in the ST12.

[Christopher R.]

Re: 1962 AFB Carb Recalibrating - One More Thing

One More Thing.

Yes, the Edelbrock Performer ones will fit. I believe either Jegs or Summit or both sell the jets and the rods individualy.

[Jeff C.]

Re: 1962 AFB Carb Recalibrating

Thank you all for responding. Chirstopher, the information is in the ST12 which kind surprised me. Duke, the engine basicly runs fine except for a irratating slight surging at steadly state curising approx 2500 to 3000 rpm. I've been told by several people that given the gas that is available in Calfifornia the carb might be runnig lean. The engine was rebuilt last November and is stock except for flat top pistons and a generic tachdrive vacuum adv distrbutor. The distrbutor is set up using advance springs that start at 800 rpm and max out a 2600 rpm and your recommended VC 1810. I have checked the resulting advance using an adjustable timing light and a mighty vac. I am purchasing a stock dual point distributor but that is more for originality.
Jeff

[Duke W.]

Re: 1962 AFB Carb Recalibrating

Surging at idle can be a sign of leaness, but I don't think it's the fuel. It's probably due to the greater exhaust gas dilution from the low compression pistons. It may not even need premium.

The solution would be to increase the main jet one size. Mixtures diluted with exhaust gas need to be richer for good ignitibility. Both Edelbrock and Federal Mogul offer AFB main jets.

Duke