edelbrock carb tuning?

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SirDan

SirDan

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I have a stock bottom end 318 with a 340 cam, ld4b intake, 2" dual exhaust from the manifolds back with an H pipe and a 600cfm edelbrock performer carburetor. Its got the stock jets and metering rods and stuff. I have a jet/metering rod kit for it but, Its my first time tuning a 4 barrel so I don't know where to start even.

She runs pretty good all around but there is 2 issues. The first issue i have is when i go from idle to light throttle it lags then kicks in. The second thing is sometimes the car does tire melting burnouts that would make chevy guys cower in fear. Other times it can barely break the tires loose. also if it helps any my mpg is about 11mpg. I know its a v8 but I'm thinking i can do better (3.23 gears and 275/60/15s).

I'm thinking go down a size in the main jet? but thats just my guess.:dontknow:
 
I don't mean to be rude but I don't know why you guys even bother with these carbs.

From what you describe the first thing I would do is drill the accelerator pump squirter about .010" larger, tighten up the secondary air door about 1 turn and go from there.
 
Gezzz, freeakin Holley guys! OMG!

G Jones, I know you mean well, but the Edel. Performers secondary air door is counter weighted.

Before we get there, on the accelrator pump arm, is the rod on the arms hole closest to the carb?
 
Dan, move the rod to the hole closest to the carb. Let me know.
 
Would that be going up or down a hole? And this would be a smaller accel pump shot? Either way ill give it a shot tomorrow it looked damn easy to do.
 
Guitar Jones said:
I don't mean to be rude but I don't know why you guys even bother with these carbs.

From what you describe the first thing I would do is drill the accelerator pump squirter about .010" larger, tighten up the secondary air door about 1 turn and go from there.
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WTH ? Do you think you can just throw a Holley on a car without any tuning ?
Its a carburetor dude,you need to tune each and everyone to the car.
Give the guy a break.
 
SirDan said:
I have a stock bottom end 318 with a 340 cam, ld4b intake, 2" dual exhaust from the manifolds back with an H pipe and a 600cfm edelbrock performer carburetor. Its got the stock jets and metering rods and stuff. I have a jet/metering rod kit for it but, Its my first time tuning a 4 barrel so I don't know where to start even.

She runs pretty good all around but there is 2 issues. The first issue i have is when i go from idle to light throttle it lags then kicks in. The second thing is sometimes the car does tire melting burnouts that would make chevy guys cower in fear. Other times it can barely break the tires loose. also if it helps any my mpg is about 11mpg. I know its a v8 but I'm thinking i can do better (3.23 gears and 275/60/15s).

I'm thinking go down a size in the main jet? but thats just my guess.:dontknow:
Click to expand...


First off Rumble gave you the right advice. Give the carb a bigger pump shot by moving the pump shot to the hole closest to the carb base (move it up). Take it for a drive. Better yet ?

Do you have a 1405 or 1406 ?
The reason I ask is because we need to know what color springs you have in the carb. There either orange or yellow.

Leave your jets the way they are for now. If anything we will be fattening the primaries up a bit with just a rod change.
 
I don't mean to hijack SirDan's thread but I have basicly the same problem with a 273 I built. Lowcompression pistons, .030 over, mild solid lifter cam. I have a new 1406 and it dies at about 2500 rpm until about 3000 rpm. Tried changing springs and it didn't help. 18" of vacuum @ idle.
 
it would also be good to make sure you have your adjustment screws tuned properly!

yes they mainly only effect the air/fuel ratio at idle but they do slightly effect the idle to throttle transition aswell.

this is also assuming your timing is good,spark plugs and wires are good,fuel system has been taken care of and all that aswell.

start the car,let it idle...... (some people do this slightly different than others but they all pretty much land you the same result) starting with the right adjustment screw.....turn it to the right until you can hear and audible difference in the idle of your engine....then turn it back to the left a quarter of a turn.

do the same thing with the left side.

( I believe this adjustment put the engine on the rich side of a tune.......to put it on the lean side you would do the opposite) meaning......instead of turning to the right you would turn to the left until you hear and audible difference in the idle ...at which point you would turn back to the right a quarter of a turn.

again....this mainly effects idle but can play a roll in the idle to initial throttle transition.

you will also want to make sure your choke is working properly .

you say sometimes it will melt the tires and other times not so much which sounds like an intermittent problem (wich would not be associated with internal tuning like jets and what not is what I would think) more so something as simple as your choke linkage is sticking every once and awhile and either bogging it down because the choke is closed somewhat when hot or because its open to much when cold.

lots of different factors can come into play.

as for the carb debate.....you will have your holley guys and your eddy guys and so on just as you would a chevy guy or a mopar guy.......does not mean one is better than the other....just means certain people have certain preference.

sure a holley can be pretty extensively tuned.....compared to an eddy but even and eddy has a pretty wide range of tuning capability.

holleys have more spots that can develop fuel leaks compared to an eddy.

they each have high and low points....I PERSONALLY like edelbrock.
 
I'm just askin......have you read the destructions? Have you been to the Edelbrock website?
 
SirDan said:
Would that be going up or down a hole? And this would be a smaller accel pump shot? Either way ill give it a shot tomorrow it looked damn easy to do.
Click to expand...

Up a hole. More pump shot. It is the accelrator pump.

63VALIANT*KISS said:
if u went to the bottom one would that give u a better mpg?rumblefish i have a eld 1407
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No, the mileage aspect is in the jetting/tunning. The pump shot is to cover the opening of the throttle blades letting in more air and causing a lean condition which results in waek acceleration or engine sputtering out/dieing.

the pumpshot introduces more fuel to take up room to keep balance of the air fuel mix from going to lean. Once the throttle blades open up, alot more air is introduced into the intake/engine. Without the extra gas, the engine runs lean and dies or becomes week.

To much fuel results in black smoke out the tail pipe at worst, slow acceleration if just a bit much. The amount of fuel introduced by the pumpshot should be just enuff to produce a strong get up and go. The amount of fuel savings and resulting mileage is very minor.
 
Guitar Jones said:
I don't mean to be rude but I don't know why you guys even bother with these carbs.

From what you describe the first thing I would do is drill the accelerator pump squirter about .010" larger, tighten up the secondary air door about 1 turn and go from there.
Click to expand...

Those of us that are smarter than you use them........... * Judging from the carb savvy advise in your comment*

Where was I? Oh, yeah.....

The first issue i have is when i go from idle to light throttle it lags then kicks in.
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Your metering rod springs are too weak, go stronger step at a time, pump shot will not affect "just off idle" stumbling. What is happening is there is a stumble you can't feel that drops the vacuum, if the spring is weak, the metering rods will not lift, a stronger spring and it will lift the metering rods. I bet if you put it in 1st gear and run around like 1800RPM on flat ground you have a lean miss too.

Other times it can barely break the tires loose.
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Does it stumble or just have no power? Sometimes on the teens and 73's you have to actually put more weight in the secondary door. If it runs smooth with no power (seeming) and other times burns out, it could be your rear rbakes are out of adjustment and if you hit the brakes twice before you try the burnout, it pumps them up and they outgrab he teens monster torque output. :toothy10::toothy10:

Work on the stumble first. If you got the kit for your carb, the spring you have stock in the carb will not be in the kit. :-D

And excuse Guitar Jones, the metal shavings from all his extensive oiling mods have worked their way into his brain giving him heavy metal poisoning and making him grouchy. (And blind)
 
no one memtion...check your timing...and get your distributor recurved...
 
600 cfm electric choke 1406 carbs are set up for "economy" out of the box......which means they run pretty lean (DANGEROUSLY LEAN) other can explain what that does in detail but essentially it detonates pistons ( UN-GOOD)

Move the stock front jets (95-98's I think) to the rear and put the 100's in the front with the stock meter rods...... replace the stock metering springs with the Orange ones from the kit....

remove the vacuum advance tube and plug the port at the carb........ then start dialing in your timing

OH ya moving the accelerator pump UP to the TOP most hole will give you a lil extra squirt

The counter weights on the secondary s are cast/stamped....you can shave them if you want/need to for quicker open but do it a very little bit at a time...once you go to far you are screwed.....shave a taste then try it......shave a taste then try it when you get close STOP.....typically the next shave will take you over the edge and it will open too fast and bog....

ALSO check your ignition....sounds a lil like you may be getting random spark levels..... are you running points or HEI........if points they may need replacing....if HEI have it checked....it may be failing or going "random"....

my 2 cents
good luck
 
Dude, you can't tell someone what springs, jets, and suck to run on their crab from a computer............

AND I have had 1406's that ran pretty fat in stock form, a lot depends on the cam, manifold, head, timing, altitude, gears in the car.............................
 
I got one!

Go to Edelbrocks website and study the tuning procedure, or read the book that came with the carb. Randomly changing springs to here, jets to there, can buggar a carb WAY off. In other words, for example, there are some spring and rod combos that flat WILL NOT WORK without running rich/lean somwhere.... READ the book.
 
dodgetkboy78 said:
I got one!

Go to Edelbrocks website and study the tuning procedure, or read the book that came with the carb. Randomly changing springs to here, jets to there, can buggar a carb WAY off. In other words, for example, there are some spring and rod combos that flat WILL NOT WORK without running rich/lean somwhere.... READ the book.
Click to expand...

Sorry, you're a little late. I already mentioned that
 
Damn so many different answers. at this rate maybe i should just do my own thing. :-?

Also i was going to mention my timing but my balancer slipped. If i had to guess id say around 10-12 btdc. My distributer advance was sticking the past week, the car was real hard to start and stuff. found a distributer out of another engine in the garage with all shiny parts in it. I'm thinking it was rebuilt recently. anyway that should help a bit but, it still seemed like i had some light throttle off idle hesitation. No chance to try a burnout, it was right around the time when kids were getting off school. I'm not looking to piss anyone off or hurt anyone.:angel9:
 
haha,
I'd agree that it sounds like a pump issue (at least the off idle issue), i vote for listening to rumble first. then maybe try something else. my one unique, hopefully unnecessary piece of advice is to try one thing at a time. (unless thats properly doing all the carb adjustments as indicated from a spec sheet) (and i'd shy away from anything that involves a drilling of holes in the carb ;p)
thats my nickles worth, keep the change (exchange rate is bad with me anyhow)
 
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