Re: surgung issue persists 340 4bbl
[Re: Mopar73340]
#325596
05/23/09 09:27 AM
05/23/09 09:27 AM
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Joined: Feb 2003
Posts: 12,675 Columbia, CT
moper
I Live Here
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Sounds to me like it might be lean, or it might be the vacuum pod adjustment. There is no reason to unplug the vacuum advance on this car except ignorance... So lets fix that. The vacuum advance only works at light throttle and cruise conditions. It add advance to the engine at these times because it gets much better milage and more power with less throttle. But, it's "tuned" for a certain level of vacuum. The cam change affected that. So now you need to adjust it. I believe what is happening is the timing is getting advanced too much at cruise. There should be a small allen wrend that will just fit inside the vacuum hose nipple on the vacuum advance dashpot on the distributor. Something like 11/32. In any event, unplug the hose, take that allen wrench and stick it into the nipple... It will go in and engage a screw in there. Turning clockwise will lower the vacuum required to advance. Counterclockwise will raise it. I go two full turns as one adjustment. Drive the car with the hose connected, disconnect and go two turns counterclockwise, reconnect and drive agin. When the surge is gone it's done. No reason to lose it entirely. Also, you may find that tuning the rest of the ignition curves will help it run better too.
Well, art is art, isn't it? Still, on the other hand, water is water! And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now, uh... Now you tell me what you know.
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Re: surgung issue persists 340 4bbl
[Re: RapidRobert]
#325601
05/23/09 02:01 PM
05/23/09 02:01 PM
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Joined: Feb 2003
Posts: 455 Ashburn, Virginia
ashburnmike
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mopar
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Quote:
Quote:
Any other suggestions to try before I pull the carb off the car? Mike
yes , dont need to take the carb off just change these rods on top
Thanks Robert, Paul Fancsali, in an earlier post, recommends going to a .120 needle and jet the primary to 101. I'm not sure where all this stuff is inside my carb but we will soon find out.
Now the hunt is on to find someone locally who may have the parts. Mike
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Re: surgung issue persists 340 4bbl
[Re: B5 GTX]
#325603
05/23/09 10:50 PM
05/23/09 10:50 PM
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Joined: Feb 2003
Posts: 455 Ashburn, Virginia
ashburnmike
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Quote:
What is the total timing and at what rpm does it come in at? I would bet it is to much or it is to much coming in to fast. Put a light on it and see how much it has at 2000 rpm them 3000 rpm. I never bother with initial timing on a performance motor, you are much better off setting the total timing.
good luck scott
I moved the timing to about 12 btdc @ 2500rpm. This didn't have much effect by itself...however...since there were many suggestions that I was too lean...I backed the A/F screws out as far as they would go without coming out of the carb. This has reduced the surging alot but it still does it. we are getting closer.
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Re: surgung issue persists 340 4bbl
[Re: ashburnmike]
#325604
05/23/09 11:09 PM
05/23/09 11:09 PM
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Joined: Jul 2003
Posts: 6,167 Maryland
GO_Fish
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Obviously you shouldn't have to have the A/F screws out that far to make a difference. But at least you have found an improvement! Carter AVS strip kits (metering rods, jets and springs) are scare and costly if you can find them at all. It may be time to consider modifying your Carter AVS to Edelbrock AVS specs. The Edelbrock AVS uses Carter AFB style metering rods and jets, which are still available as an Edelbrock AVS strip kit. Edelbrock has their carb manuals all online in PDF format, complete with tuning graphs. To change to the Eddy AVS style, you'll need to get (or fabricate) flat Carter AF B style metering rod covers instead of the "humped" Carter AVS metering rod covers you have now. Then buy a Edelbrock AVS strip kit, and swap your Carter AVS metering rods and jets for the Edelbrock AVS equivalents. This is not nearly as hard as it sounds. The AVS is a very user friendly carb, well suited for beginners. You can do it! BTW, while you have the carb off, you would be wise to install a 1/2" phenolic 4 hole spacer between the carb and the intake. The AVS carbs are well known for boiling all the fuel out of the bowl on hot days when you shut the motor down... the 1/2" spacer will cure the dreaded hot start problems...
Last edited by GO_Fish; 05/23/09 11:17 PM.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph
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Re: surgung issue persists 340 4bbl
[Re: RapidRobert]
#325606
05/24/09 09:17 AM
05/24/09 09:17 AM
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Joined: Feb 2003
Posts: 455 Ashburn, Virginia
ashburnmike
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I'm trying really hard to avoid getting into the guts of my carb with my limited experience. I did take one of the humpback plates off carefully (you'd think I was defusing an landmine) and familiarized myself with the step-up piston, step-up spring and the metering rod. Now I see what you are referring to. I will search the internet for a vendor for the rods you recommend,Robert and also the phenolic spacer Scott recommended. In my frustration last evening, I was looking at the Edelbrock site and considered taking this carb off and replacing it. Then study the one I have. I still have no idea where the jets are (lol)
If I can find the rods and it solves the issue...that was certainly be more cost effective
The '70 Z-28 guy up the street said to toss the Carter and get a Holley. "A real man's carburator". I told him once this issue is squared away, my Moparts partners and I are going to take this little Dart to track and blow the doors off his little Holley fed, white striped, orange car.
Mike
EDELBROCK PERFORMER SERIES 600 CFM, ELECTRIC CHOKE CARBURETORS CALIBRATED FOR FUEL ECONOMY Designed for small-block and small displacement big-block engines, these carbs are recommended only for stock to Performer level applications. They are not recommended for use on RPM or Torker II intake manifolds. Match with an Edelbrock Performer or Performer EPS manifold and other brands of similar design. Calibrated 2% leaner than #1405. Includes both timed and full vacuum ports for ignition advance. Comes with: Metering Jets - Primary .098, Secondary .095; Metering Rods - .075 x .047; Step-Up Spring - yellow (4" Hg). Use our Carb Stud Kits #8008 or #8024 if needed, see Installation Items. For auto trans throttle lever adapters and more, see Tuning Accessories.
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Re: surgung issue persists 340 4bbl
[Re: RapidRobert]
#325610
05/24/09 10:26 AM
05/24/09 10:26 AM
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Joined: Feb 2003
Posts: 455 Ashburn, Virginia
ashburnmike
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....yes....and those series of questions will be forthcoming....I assues you. I'll report back with a different post when the strip kit arrives and I put them in. Thanks to everyone who has taken me this far solving this issue with your comments and suggestions. Have a great Memorial Day weekend. Let us all take a minute to remember our fallen comrades who allow us the freedom to mess with these old cars in the first place. Mike
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Re: surgung issue persists 340 4bbl
[Re: RapidRobert]
#325611
05/24/09 12:20 PM
05/24/09 12:20 PM
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Joined: Jul 2003
Posts: 6,167 Maryland
GO_Fish
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Quote:
Here's a pic of a strip kit $42.79 at O'reillys(they ordered it-2 days) though w your carb the kit # will be different. Only caveat is when you drop the rod assembly on top of the spring that you then wiggle it slightly till it finds its hole rather than forcing it.
That I know of, nobody sells strip kits for the Carter AVS (occassionally you see a 30 year old used kit on Ebag). The kit above is designed for the Edelbrock AVS which uses Carter AFB style metering rods and jets. You cannot just install Eddy AVS metering rods in a Carter AVS without going inside the carb and changing the jets and metering rod covers also (so that everything is AFB style). The Carter AVS uses a longer 3 step metering rod, where the Eddy AVS uses shorter AFB 2 step rods.
Last edited by GO_Fish; 05/24/09 12:25 PM.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph
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Re: surgung issue persists 340 4bbl
[Re: GO_Fish]
#325612
05/24/09 04:12 PM
05/24/09 04:12 PM
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Joined: Feb 2003
Posts: 455 Ashburn, Virginia
ashburnmike
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Posts: 455
Ashburn, Virginia
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Quote:
Quote:
Here's a pic of a strip kit $42.79 at O'reillys(they ordered it-2 days) though w your carb the kit # will be different. Only caveat is when you drop the rod assembly on top of the spring that you then wiggle it slightly till it finds its hole rather than forcing it.
That I know of, nobody sells strip kits for the Carter AVS (occassionally you see a 30 year old used kit on Ebag). The kit above is designed for the Edelbrock AVS which uses Carter AFB style metering rods and jets. You cannot just install Eddy AVS metering rods in a Carter AVS without going inside the carb and changing the jets and metering rod covers also (so that everything is AFB style). The Carter AVS uses a longer 3 step metering rod, where the Eddy AVS uses shorter AFB 2 step rods.
That is a bummer but good to know now.
I think my best option at this point is to invest in a new replacement carb, enjoy driving the car, and get the proper conversion parts for my old AVS.
I will look for a similar carb @ the Carlisle show and see if I can find one to practice on.
I will call Edelbrock Tuesday and get the recommendation, but what are your thoughts on which unit to go with.
Thanks
Mike
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Re: surgung issue persists 340 4bbl
[Re: RapidRobert]
#325614
05/24/09 08:47 PM
05/24/09 08:47 PM
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Joined: Jul 2003
Posts: 6,167 Maryland
GO_Fish
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Now you are on the right track! As long as you change everything to AFB jets and metering rods (and flat cover), then you are good to buy the Edelbrock strip kit (actually, everything you need to swap ((except the flat metering rod covers))is in the Eddy kit). Just swap the new jets and rods in and put your Carter parts you remove on the shelf. Pretty simple conversion, then you have essentially an Eddy AVS. Edelbrock won't want to speak to you about converting your Carter, they are in business to sell you a new Eddy $$$$$. But the main difference between the Eddy AVS and the Carter AVS you have is AFB metering rods, jets and flat metering rod cover. It's not a hard swap, you can do it in an hour (even if you've not done it before). Check the Eddy AVS PDF's on their website, it will be a big help in dialing the carb in.
Scott B.
"I'm a self-made man... I started with nothing, and I still have most of it!"
68 360 rusty B'cuda 'vert (GO Fish)13.59@ 98.72 mph
69 340 GTS stock 14.18@ 95.60 mph
01 5.9L Ram 1500 Quad Cab 4x4
01 3.5L 300M 16.23@ 86.97 mph
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