Edlebrock carb help. ANyfans of these things out there?

[47convert]

I have a 1406 Edlebrock carb on a stock 350 with a dual plane intake and dual exhaust with a 4 speed stick trans in my 60 ELCY.  It's a new carb, because the last one was using so much fuel it shot black soot out of both pipes every time I shifted gears or just touched the pedal a bit. This one's almost as bad. I have a fuel pressure regulator and a stock style 3/8" fuel filter in line. I've adjusted the idle screws to give me the maximum vacuum at idle and the thing runs very good - no flat spot, good acceleration etc. but it's too rich. I just bought a calibration kit from Edlebrock that comes with three sets of metering rods and jets as well as an assortment of metering rod springs, but no instructions as which ones do what. I'm thinking I need the smaller jets and rods but I don't know which springs to use and it seems ike Edlebrock should include so advice with this kit. I never had any trouble with Holleys that I couln't fix easily and I've had a bunch of them over the years so I'm trying to figure out why I bought these things. Any suggestions from Edlebrock fans? Do they have a website that offers assistance with hteir products? I sure can't find anything.

[purplepickup]

Here's the owner's manual that explains most everything you need to know. http://www.edelbrock.com/automotive/eps_intro.html  In section 2 (Tuning Procedure), you will see a link at the bottom of the page that takes you to a tuning chart for the 1406 http://www.edelbrock.com/automotive/eps_1406.html

They're really easy to tune once you understand them.  I get over 20 mpg with a 1406.

[Fat Cat]

are you sure it runs rich? Soot in the tail pipe is not enoug to prove it is running rich. The fuels that are for sale today will cause the tail pipes of a older car to be sooty, even a properly tuned one.

[47convert]

It's not really on the tailpipes - it shoots black smoke straight out. I'd like to put it on one of those exhaust analizers and compare before and after changing jets. Thanxf or the link George.

[Pope Downunder]

I have a 1406 Edlebrock carb on a stock 350 with a dual plane intake and dual exhaust with a 4 speed stick trans in my 60 ELCY.  It's a new carb, because the last one was using so much fuel it shot black soot out of both pipes every time I shifted gears or just touched the pedal a bit. This one's almost as bad.

Is it a manual choke model?  If so, it will probably be a couple of stages too rich.  Look at the calibration for the electric choke model for a good starting point.
You'll need a small magnifying glass to read the jet and needle sizes; and keep track on the Edelbrock calibration table so you don't get lost.

[47convert]

No[e it's got an electric choke and it pulls off good when it warms up.

[C9]

How big a cam are you running?

The springs that come with a new Edelbrock are most times geared toward a mild cam . . . plus the carb is jetted about 5% rich for the expected engine size it's going on.
(600 cfm for the small blocks and 750 cfm for the big blocks - generally speaking.)

Put a vacuum gauge on the engine and see what your vacuum is.
Stock cams pull about 18-19" vacuum at idle on a well sealed engine - well sealed meaning good rings, compression etc.
Big cams - advertised duration 280-290 degrees - will pull 10-13" of vacuum.  It differs due to lobe angle separation.
(Race cams will run 108-110 degrees and Street cams - still talking about the big cams - will run 112-118 degrees of separation.)

First thing I'd try would be to put in a spring that's rated about 4-5" below idle vacuum level.
More than likely, what's happening is at idle and at low throttle openings the metering rods are raising when they shouldn't and pouring extra gas into the intake.

Vacuum holds the rods down = closed.
Springs raise the rods up = open.

Since the rods are stepped, the further up they are the more open is the main jet.
You don't want the main jet to flow full or even extra fuel at idle and low throttle openings.

Try the pink springs if you're running a big cam.
The orange springs if the cam is mild.

Check too, to see if one of the rods is bent.
Bent rods can be found in carbs fresh from the factory.
Once the rod comes up, it stays up.

Pull the rod, remove the piston, with the short leg hanging over the edge, roll the rod on a known to be flat surface to see if it's bent.
You can straighten them, just use be careful and take your time.

A piece of thick glass is an excellent surface for testing.
Other good flat surfaces are the thicker pieces of Lexan (Polycarbonate - Lexan is a trade name) found at Home Despair and similar places.

Since the spring paint (used to ID the springs) will disapperar in a short bit of engine running, make sure to mark the container the removed springs are stored in because they are virtually impossible to ID once the paint is gone.

[slocrow]

[You'll need a small magnifying glass to read the jet and needle sizes.

[Since the spring paint (used to ID the springs) will disapperar in a short bit of engine running, make sure to mark the container the removed springs are stored in because they are virtually impossible to ID once the paint is gone.

HERE, HERE............. :b-d:

[BFS57]

Hello!
Man, I must say that I have been battling the same sort of thing with mine! I finally got it pretty much right on. I had to use a jewler's eye loop to see the numbers on the jets and metering rods.
Having a manual is very helpful! Also, when I got my re jet kit (from local auto parts store) I had to go through a couple of them to get a complete and proper kit. All I can say is just keep at it until you get it right!
Now my wife wonders when I'm going to clean off those two black spots on our white garage door! You know, there kind of tough to clean off!
Bruce

[34ford]

Hey guys,

I've got a question to throw into the pile here. I have a GM ZZ-4 crate motor. I bought a lot of parts getting ready to build the car in the past few years. Sold the last car and thought I'd better get the parts with the money or it might disappear for other things. Now my question. I bought a 750 Edelbrock carb for the motor. The motor is running in the car but has yet to see the street. Is the 750 to big for the motor? I can't return it and don't want to sell it at a loss and buy a smaller one. I was wondering if it can be corrected with the right springs and rods. Seem to be a little gassy in the garage when it's running.

bob

[HOTRODSRJ]

It's not really on the tailpipes - it shoots black smoke straight out. I'd like to put it on one of those exhaust analizers and compare before and after changing jets. Thanxf or the link George.

Sounds like the accellerator pump is set too high if it's puffing black smoke or soot on slight throttle movement.  I would move the arm away from the carb to the lower holes one at a time. This leans the pump.

The transition circuit that manages the rods/jets with springs.... actually comes a tad lean working with some anticipated performance cams. The spring is usually the "orange" spring which usually has to be change to a more stiff or silver spring with the less cam and more vacuum you have.

[HOTRODSRJ]

Hey guys,

I've got a question to throw into the pile here. I have a GM ZZ-4 crate motor. I bought a lot of parts getting ready to build the car in the past few years. Sold the last car and thought I'd better get the parts with the money or it might disappear for other things. Now my question. I bought a 750 Edelbrock carb for the motor. The motor is running in the car but has yet to see the street. Is the 750 to big for the motor? I can't return it and don't want to sell it at a loss and buy a smaller one. I was wondering if it can be corrected with the right springs and rods. Seem to be a little gassy in the garage when it's running.

bob

I have found that 600s are more adaptable to these ZZ4s with better throttle response.  It's not like they are turning high rpms and need 750s but you can easily tune the 750 to your engine with a calibration kit and patience. Lot's of folks running them.

The "gassy" garage smell means your idle circuit is not tuned correctly and has absolutely nothing to do with size of carb. Turn the mixture screws in a quarter turn and see if it goes away, but keeps a stable idle.  You can actually tune with vacuum gauges or a tach.  I prefer the vacuum gauge.

[34ford]

Thanks Steve. Will try that next time I fire it up.

bob

[C9]

A couple of tips for identifying the metering rods:

Use a dial caliper or micrometer to measure rod diameter at both steps.
I use the dial caliper and it's fast and accurate.

I have a fairly good magnifying glass in the shop, but it helps to use it in good light - sunlight if possible - and an added aid is a second magnifying glass added to the sight path.

- or wear your bifocals like you're supposed to -

[Gilles]

I use an Edelbrock 600 CFM with manual choke on my 350 Chevy powered 32 roadster. The engine is stock (1973 Camaro) except a  dual plane manifold, headers and dual exhaust.

I followed the Edelbrock instructions for rejetting the carb. I found that 2 steps leaner than stock in cruise mode and power mode works great. For this the jets are 98, I don't remember the number of the rods. I had to one step harder springs thought.

The engine runs great and goes a little  over 5000 RPM.

With 29" rear tires, a 3.42 rear-end ration and a TH700 R4 the gas mileage is 23 MPG  (american gallons)at 70 MPH on motorways, 20.5 MPG at 55 MPH on two lanes roads, and 15 MPG or less on very shorts trips in town.

I'm sure that put the carb directly on the engine without to rejet it ( is that most of the people do)  is a waste of gas on a stock or mild engine. At the price the gas is now ( around 5.5 US$ per gallon in France, more than 6 in England) it's a thing to take care carefully.

Gilles