edelbrock carb issues

Posted By: dusterbd13

edelbrock carb issues - 08/06/14 03:12 AM

so ive ben fighting carb issues in my duster for a while. its bad enough to where ive all but stopped driving it.

idle mixture is set properly with a vacuum gauge, with the ac compressor on, fully warmed up.

electric fuel pump, regulated to 5.5 psi.

floats set to 1/2 from the carb gasket to the top of the float with the cover inverted.

stock jets, rods, and springs.

3/8 thick insulating carb gasket.

air gap intake

so my issues are a few fold.
1. will not restart hot. seems to be vapor locking.
2. doesn't pull nearly as hard as with the 850 double pumper I had.
3. erratic idle with ac compressor on.
4. diesels on cutoff.

while adjusting float level tonight in a vain attempt to solve the hot start issue, I forgot to put the metering rods and springs back in. no covers either. the car ran significantly better when I got on it. almost like the old double pumper. I was excited. when I put the rods back in, it was back to its same old tricks. I don't know if it was all in my head, but with no rods or covers the hot start issue seemed all but gone, but I didn't really validate that well. also didn't seem to even think about dieseling.

so what am I missing? im thinking that the rod and jet combo is way too lean, causing most my troubles, and the springs too stiff. does this sound right?

please, help me out here. I just want to finish out until my leg surgery driving this car.

Michael

Posted By: Pynzo

Re: edelbrock carb issues - 08/06/14 03:36 AM

Any out of the box AFB or AVS Eddy is totally jetted wrong for small block or b/rb mopars. Give up a baseline of cid and and a stock jetting for that motor will be advised.

Posted By: dusterbd13

Re: edelbrock carb issues - 08/06/14 03:38 AM

360 with indy heads, solid roller. made 390 rwhp on the dyno with the 850 holly and a single plane. now running the dual plane and the eddy.
5 speed, 3.55 gears, 3400 lbs

Posted By: Pynzo

Re: edelbrock carb issues - 08/06/14 04:20 AM

Good info but what Eddy are you using? Stock AVS jetting for a '69 340 and 383 is an .089 primary for a 630 cfm carb. What are you trying to run? Set your baseline jetting to stock figures and build from there.

Posted By: RapidRobert

Re: edelbrock carb issues - 08/06/14 05:11 AM

reset floats to 7/16" and go 3 thou richer on the jets. Which eddy? what springs/what cam/what idle speed. EDIT richen the idle mixture screws

Posted By: scratchnfotraction

Re: edelbrock carb issues - 08/06/14 12:48 PM

Quote:

reset floats to 7/16" and go 3 thou richer on the jets. Which eddy? what springs/what cam/what idle speed. EDIT richen the idle mixture screws

if it ran well with no needles/step up pistons/covers in the pimary jets it is way lean and that made it more than fat with a huge vac leak.

I just went from a 600 eddy to a holley 6210 650cfm spredbore dbl pumper and cant believe how much better mine runs.

ditch the eddybroke

Posted By: Mr.Yuck

Re: edelbrock carb issues - 08/06/14 01:09 PM

2. doesn't pull nearly as hard as with the 850 double pumper I had.

Then put that back on.

Posted By: Dcuda69

Re: edelbrock carb issues - 08/06/14 04:46 PM

Quote:

2. doesn't pull nearly as hard as with the 850 double pumper I had.

Then put that back on.

Yep!

or any Holley. There's more threads around complaining about the eddy carbs. I know the Eddy lovers will chime in but......oh well,here's some info for ya

https://board.moparts.org/ubbthreads/show...e=3#Post8218208

Posted By: DaveRS23

Re: edelbrock carb issues - 08/06/14 05:17 PM

Eddybroke

Posted By: feets

Re: edelbrock carb issues - 08/06/14 07:43 PM

I have always been able to get an engine to run little harder with a Holley but have much better manners and mpg with the CarterBrocks.
Since I don't race it was an easy decision. AFB wins.

The AFB is no harder to tune than a Holley. The same basic problems happen with each style of carb. Some issues show themselves in different ways.

It really helps to have eyes and hands on the carb to be able to determine the problem. It could be something as simple as a poor vacuum signal to the carb due to the lumpy cam. If the primaries are opened too far at idle it can uncover the transfer slots. When that happens you'll never get it running right.

1/2" is too deep for the floats. Back that down a bit as suggested.

Get the front end dialed in for good cruise and idle. Leave the back half for making power.

Quote:

1. will not restart hot. seems to be vapor locking.
2. doesn't pull nearly as hard as with the 850 double pumper I had.
3. erratic idle with ac compressor on.
4. diesels on cutoff.

1. Could be an ethanol fuel issue. The AFB fuel bowls sit directly above the manifold and aren't as isolated as the Holley carbs.

2. It should give close performance but the much larger Holley will likely make more power. In fact, I bet the 850 would pull harder than a Holley sized to match the AFB.

3. A/C compressor is going to pull either carb down. Basic physics there. If it didn't impact the 850 as much it was a sign that you likely had the idle tuned less than perfect.

4. Dieseling on cutoff is likely due to hot fuel and/or excessive timing.

The Carter AFB has a better reputation than the Edelbrock. The Eddy 750 has been a poor performer since inception due to poor reverse engineering. I understand the larger AFB has a better reputation.
Eddy carbs have different jetting out of the box based on manual or electric choke.

Posted By: TJP

Re: edelbrock carb issues - 08/06/14 09:53 PM

Quote:

so ive ben fighting carb issues in my duster for a while. its bad enough to where ive all but stopped driving it.

idle mixture is set properly with a vacuum gauge, with the ac compressor on, fully warmed up.

electric fuel pump, regulated to 5.5 psi.

floats set to 1/2 from the carb gasket to the top of the float with the cover inverted.

stock jets, rods, and springs.

3/8 thick insulating carb gasket.

air gap intake

so my issues are a few fold.
1. will not restart hot. seems to be vapor locking.
2. doesn't pull nearly as hard as with the 850 double pumper I had.
3. erratic idle with ac compressor on.
4. diesels on cutoff.

while adjusting float level tonight in a vain attempt to solve the hot start issue, I forgot to put the metering rods and springs back in. no covers either. the car ran significantly better when I got on it. almost like the old double pumper. I was excited. when I put the rods back in, it was back to its same old tricks. I don't know if it was all in my head, but with no rods or covers the hot start issue seemed all but gone, but I didn't really validate that well. also didn't seem to even think about dieseling.

so what am I missing? im thinking that the rod and jet combo is way too lean, causing most my troubles, and the springs too stiff. does this sound right?

please, help me out here. I just want to finish out until my leg surgery driving this car.

Michael

#1 is a known edelbrock issue, GOOGLE
Edelbrock heat soak,
Edelbrock, hot start,
Edelbrock percolating

#2 There is a large difference between a 600 and 850 CFM so I am not surprised. My thought is the 600 may be a sit small while the 850 is too large.

#3 Tuning issue or may need an idle step up solenoid

#4. Tuning, idle is too high, see #1

Posted By: MY340

Re: edelbrock carb issues - 08/08/14 08:27 AM

My 1970 Duster 360/904/3.91 combo with a Comp 280H cam, Weiand high rise manifold, Hooker headers ran great with a 750 cfm Eddy #1407. Great throttle response and no problem with hot starts. I always held the pedal halfway or so to the floor on hot starts. On cold starts after the car sat for a few days I cranked it over several times before pumping the gas pedal then it fired right up. Today's gas makes things tricky besides a good carb tuning and don't forget the importance of correct ignition timing for your combo.