1970 300 with Edelbrock 1411-light throttle knock

[challenger]

I am working on my wife's 300 convertible. She hardly ever drives it and several months go by between cruises. About every time I end up having one issue or another due to the car sitting.
This time I had to drain the fuel out of it because it would stumble & stall when trying to start from a stop. I read the manual on the 1411 that I put on it about 2 years ago. At that time it ran perfectly BTW. It stated that the stalling problem was in the idle circuit. I found that the there was some crap in the main well bleed tubes. I cleaned these and the car is 90% better with just a very slight hesitation from stop. I know the accelerator pump is working so I still suspect the idle circuit. The manual also states that pinging at light throttle while cruising is likely related to something in the idle circuit. Anyone with similar experiences?
I also have a Mopar Performance distributor and electronic ignition on the car. I put it in too many years ago to remember the details but I have the old distributor and the springs are out of it so I have a feeling I used these springs in the new distributor. I am trying to stay with non ethenol 93 octane fuel. Can I get some input on the proper timing & springs for such a heavy car so I can see what is in the distributor? Also am I best off with the vacuum advance connected? It has the 440 HP motor that is stock other than a phenolic spacer and Edelbrock carburetor. The car is original with 55k miles.
Thanks
Howard

 

[Pete Kaczmarski]

This sounds like my '79 New Yorker that was sitting for a period of time after the owner died. The carb needed to be rebuilt because of the use of ethanyl blended fuel. Now I only use non-ethanyl premium. The power has increased alot with the new accelerator pump in the rebuild. Fuel milege jumped 2 mpg to 18.

 

[Fratzog]

I've been fighting a pinging issue on the 440 on which I installed a 1411. It only occurs when the secondaries open. I've gone as rich as the chart in the manual allows with both sets of jets and rods. I fixed a vacuum leak but am suspicious of the booster. Not the same issue that you have but a common thread of the same carb.

 

[440Sled]

What is your timing set at?

 

[challenger]

What is your timing set at?

I'm not sure what the timing is. It's been a long time since I set it up. I doubt it would have anything to do with the total timing advance but more with either a lean condition at very light throttle or the timing advancing at too low an RPM for such a heavy car.
I'll call edelbrock today & ask them if there is another area inside the idle circuit that I should look at.
Thanks
Howard

 

[70bigblockdodge]

Its most likely in vacuum advance. Insert a 3/16 Allen wrench in the nipple where vacuum hose goes and turn ccw I would go maybe 1/2 turn then drive if its a mopar performance dist its probably pretty aggressive in rate turning ccw will make it have to pull harder so it will come off quicker when yo step into throttle or it will be less at light throttle. I maybe backwards on that and if it gets worse then just turn it back and start going the other way I.e. clockwise good luck. The best part is you get to turn adjuster drive turn adjuster ,drive etc.etc.

 

[moper]

There is a lot to tuning an aftermarket carb to a factory engine. First - great choice- I like the Performer line of carbs and the Carters they are based from. In tuning there's a rule - timing first, then carb. Because the timing affects the carb, and the carb does not affect timing.
So before you do too much I have to ask where the timing curve is on that engine. Did you verify the centrifugal and vacuum advances are working properly, how much of each advance there is, and when it occurs?
On the carb - did you take any vacuum readings while tuning it? One of the best tuning aids is a good vacuum gage, with a long hose, taped to the windshield while you're driving. My impression is the step up springs are not a good match for the stock cam and it's going lean. but firs tthings first - set up the timing curve, then look at the carb.

 

[1978 NYB]

Just a note bout Eddie carbs and vacuum advance. Make sure you have the vacuum advance hose hooked up to the vacuum port on the left side (driver's side) on the front of the carb so it has zero vacuum at an idle. If you hook it up to the right side vacuum port you'll have vacuum all the time and the timing will be advanced at an idle and it'll run like crap.

 

[70bigblockdodge]

I agree with both moper and 1978nyb the vacuum gauge is definitely needed I was kinda going off of what he said about it happening recently which I'm guessing means it was good before

 

[challenger]

I played a bit with metering rods & step-up springs with little improvement. I went into the carb and it was a mess from sitting with ethanol fuel. It also ate the fuel pump.
I took the carb as far apart as I could and cleaned it in my super duper, non Harbor Freight, USA made ultrasonic cleaner. It came out clean as can be. I blew out all the openings and chased the tiny ones with guitar strings. It runs nearly perfectly with a huge improvement in power. I still have a slight ping at cruising speed so I think I'll try the next jet richer in the primary.
The fuel pump in this thing is a female dog to replace considering it is fairly easy to get to. The brackets for the alternator gave me fits until I used the 1/4" socket/extension. Plenty of grime on this original engine which I really hate dealing with. The push rod for the fuel pump was a learning experience as well. There was zero in the FSM about a push rod if you can believe that.
The timing is 12* initial but I need to get a higher range tachometer to check the curve. The vacuum is hooked up to the ported vacuum on the carburetor-not the manifold vacuum.
I really don't think the detonation I am getting is from timing though as it is happening at super light throttle at highway speed. This points to a lean mix more than timing I believe.
This car has the "TNT" motor FWIW.
I'll get back with the curve on the distributor asap. My immediate mission is figuring out how to adjust the top. It was brand new 3 years ago and was super tight when we got it back. It stayed up/latched for a while in the garage as the fuel was rotting the carburetor. The we lowered it for another spell while the fuel was rotting some more. Now I can't get it to latch. We should have taken it back to the dude that did it. He said it would be tight but to leave it in the sun and it will stretch. I'll post here on the top issue & hopefully get some clue about adjustments. Again the FSM isn't great in the area of the convertible top.
I have to say I've read a lot about the Edelbrock 1411 & similar. Most threads really beat the hell out of them. I've found it to be an extremely easy carburetor to work on. It was abused in this car yet I was able to clean it completely with no kit plus the $60.00 calibration kit is a very handy thing. I don't work on many carbs but his one has got to have about the easiest primary tweakability going. I give it a thumbs up for sure but I DON'T want to start a flaming carb war PLEASE.
Thanks for the help here & I'll update the rest when I get into it.

 

[70bigblockdodge]

I like edelbrock carbs once I played and figured it out and I still have some more tweaking, I want to get a wideband air/fuel meter and tweak away. In may we got 13 mpg to and from Columbus in a 440 challenger with a mopar performance 292- 509 cam running about 65-70 with 2.94 rearend I can barely get that in my challenger with a 383 and a holley. I would like to see a carb debate that no one will win because they all have their strong points. BTW I still think your knock is in vacuum advance. Glad you seem to have gotten it to run better good luck with top I have never messed with one

 

[challenger]

I like edelbrock carbs once I played and figured it out and I still have some more tweaking, I want to get a wideband air/fuel meter and tweak away. In may we got 13 mpg to and from Columbus in a 440 challenger with a mopar performance 292- 509 cam running about 65-70 with 2.94 rearend I can barely get that in my challenger with a 383 and a holley. I would like to see a carb debate that no one will win because they all have their strong points. BTW I still think your knock is in vacuum advance. Glad you seem to have gotten it to run better good luck with top I have never messed with one

I also need to get a tach & vacuum gauge in the vehicle & drive it to see where the vacuum is at cruise speed.
Do all Mopar Performance distributors have the vacuum advance that is adjustable?
Right now the vacuum at idle is 17". The TNT 440 has a slightly larger can than the stock version but I feel 17" is still right. The documentation states this would call for the strongest spring. As mentioned the vacuum advance is the first thing I can check as soon as I get hold of a tachometer.
I have timing tape on the damper so I should be able to just run it up while in park and record the advance curve yes? If I see vacuum advance still in at cruise speed I would agree this is something that could cause the pinging.
One positive about the carb cleaning was a lot more power. I suspect the power metering was really out of whack because of the dirty carb because I did a WOT test from a stop-no brakes applied & the tires smoked up for about 20' & it didn't sound like it was going to stop any time soon so I let off. I think it is awesome that a boat like this will light up the tires (no peg leg burnout either) for such a distance. Prior to cleaning I'd get a slight screech.
This should translate to better mileage as well. Or maybe not.

 

[70bigblockdodge]

It's definately in timing because pinging is detonation which is only cauased by compression lighting off fuel early or spark plug lighting off early if you have no knocking at full throttle, full cylinder filling/no vacuum and knocking at part throttle, partial cylinder filling high vacuum then it has to be vacuum advance all mopar dist have adjustable vacuum advance takes a 3/32 Allen in where hose goes on ccw will pull it off quicker and not pull as much at part throttle or stepping back into throttle. Hope this makes sense and helps

 

[moper]

All factory distributors have an adjustable vacuum advance. But - it adjusts the level of vacuum it moves with - not the number of degees it advances. A couple clarifications - regardless of the literature - all factory 440s used the same cam except the 6bbl. The differences in power ratings were a result of manifolding/packaging. If you have repalced the camshaft you more than likely need to tune the vacuum advance and this should be done prior to the carb tuning. Take an 11/32 allen wrench and take the car for a ride. When it's at operating temp (and this is where the vacuum gage helps) take the allen wrench, remove the vacuum line at the vacuum advance, insert the wrench into the nipple and feel around until it falls into the socket and get's rigid. Then turn the wrench clockwise until you feel it "click" once per revolution. That is the "zero preload". Plug the line back on and take it for a ride. At cruise and light throttle you may experience popping, surging, or pinging. If you do, note the vacuum level on the gage and throttle load. Then stop, take the wrench and turn it counterclockwise two turns, and drive it again. You should have 8-10 turns before you're at "full preload" and that is where it will take the highest suction to move the advance arm. If it still has problems, look to the step up springs and metering rods because chances are it's lean. Then repeat the vacuum advance adjustment drive.

 

[saylor]

im no expert, but I went thru carb hell a couple of months ago so I just wanted to share some stuff - your idle circuit is just at idle, once the throttle plate opens enough past the idle transfer slots you go to the main circuit.

and I say pinging is from 1) lean mix or 2) bad timing. pinging under acceleration load almost has to be timing ya?

 

[challenger]

Thanks for the great information.
Moper- are you saying the factory was feeding the public a bunch of B.S.? The "TNT" 440 FSM says the cam is larger in the TNT but I can't prove it. There are several specs in the FSM that are different between the 440 4-bbl and the, "high performance 440". This is a 55k mile original car so the engine has never been apart. Personally I wouldn't care if the engines are the same regardless of the literature. It is surprising to hear the engines are the same though for sure.
I'm no expert either but the Edelbrock manual and the factory dude I spoke with mention that the idle circuit for the 1411 does come into play at just off idle transitioning to the primary circuit. Maybe a coincidence but prior to adjusting the idle mixture as per the carburetor manual I got rid of a lot of the stumble I had while going from a dead stop to an easy acceleration. I also couldn't give WOT from a stop without completely stalling and that is completely gone.
I thought that the cruising speed detonation was the last hurdle but I am feeling a super slight hesitation from a stop so I suppose there is a tiny bit to do to get rid of that annoyance.
Thanks for the help.
Howard

 

[moper]

There are 3 realities in domestically produced cars of this era: (1) Design/Engineering reality, (2) Marketing reality, (3) Production reality. The only one that is ironclad is production. For example - the engineers designed a piston and chamber for the '68 440. The FSM will give you specs for chamberr size, piston volume, etc, and going by those the static compression ratio will come out about 10.5:1. The marketing guys will publish the "10.5:1 compression HP 440-4bbl V8". But when you take a '68 440 apart and measure - the production realities are glaring. The chambers are 5-8% larger than designed & the blocks are .040 taller than designed because of production machining inaccuracies so the truth of the matter is they were really about 9.3:1. I sold jobber parts (think Napa, Car Quest) in the 80s and the reality was there was only one camshaft for the 440 4bbl. Didn;t matter if it was a TNT or std 440. But the std 440 had poorer flowing exh manifolds, single exhaust, no windage tray, and a more restrictive air cleaner. The main engine was the same. The bolt ons changed what that engine was capable of churning out in that particular car.

In regard t othe Edelbrock... The Carter designs are more sensitive to airflow and less adjustable in the accelerator pump circuit than the Holleys. So the idle mixture is more critical especially in the transition area and the metering rod choice and rod chioce is just ascritical in the part throttle transitions.