Technical EVERYBODY is Stumped with no suggestions

There were no 6 V systems that required a ballast resistor. The ballast resistor is for 12 V systems that run a standard coil that needs a reduced voltage in order to not overheat and burn up, which is the standard 6 V to 8 V as you will find..

Ford has an in-line resistor wire coming off of the ignition switch, feeding the coil positive with the key in the on position that wire reduces voltage to seven or 8 V at the coil positive, while cranking the brown wire over at the starter solenoid is wired into the same feed wire, going to the coil positive, and it provides cranking voltage for initial start up .

12 V dodge starting systems use a ballast resistor in the form of porcelain with a coiled wire inside, coming off of the firewall, feeding the coil positive.

The 6v system works without resistors inline. The pertronix is a simple magnetic switch, polarity of positive ground is simply switching red wire for black wire, BUT with THIS pertronix unit BOTH wires coming from unit are black. The unit is no longer in production I believe, there’s a newer version, but if it’s not broken it don’t need to be fixed.
If the pertronix was bad it wouldn’t fire, if the pertronix cause flat line at ANY rpm with the secondaries open, then they would cause flatline with any engine rpm. Added air and fuel does not increase the demand on the pertronix that will run 3500+ rpm’s on two barrels, but falls off with any portion of the other two barrels.

 

It certainly does. I forgot they used ported vacuum. Dam. too many years and to0 many Chevrolets I guess.

 

It H*** to be something extremely basic that I have fully overlooked. Thinking I knew what I was doing. I have refilled several of these for Cadillac and a couple for Corvettes but never one for a Chrysler, I’ve been doing this for lots and lots of friggin years and it just has me stumped. I am looking locally for a 400 CFM carburetor I can test on this engine to disprove the farm exhaust or field timing advance curve. Or to prove it correct but I definitely need a different carburetor to do this and I do not have any scoreboard carburetors in my shop.

 

What RPM is the motor turning at 65?

What is your at idle vacuum reading?

How many miles are on the motor.

If the distributor was in as poor of condition as you stated it was, I would have to wonder if the rest of the motor is in good enough condition to deliver to you what you expect. Maybe its flatlining because that is all it can do in its current condition.

 

OK very good points and I thought I mentioned that in my first post. Mileage is 101,114 miles. It is all original bought new by my clients grandfather. She is in her 50s. The car is all original, and has been maintained by the same man, since it was born..

somebody has gone through the carburetor before because I found newer gaskets on it but I don’t think they did anything but take it apart and put in a new accelerator pump and may be clean it out lightly. It’s never had ethanol, gas run through it. It has plenty of power on just the two primary Venturi, but who wants to use only half of your carburetor lol.

My old worn out Ford 360 with a four barrel would continue accelerating with both sections to the carburetor wide-open, and it had a measly 95 psi and all eight cylinders kind of worn down. This car is not worn down but it is old. I am positive. It’s carbureted related to the stumbling when the secondary is open.

I picked up a Timing light today that reads RPMs and timing, I am going to run the timing, light off of a separate battery outside of the car and use the probe around the plug wire while the car is running to check the RPMs and the degrees advance at any given RPM tomorrow after I re***emble the carburetor for the fourth time.

 

Well, I believe a lot of early 6 volt Fords did have resistors. Many other makes had some form of resistor to protect the contact points as well. Obviously added air and fuel does not increase the demand on the Pertronix but, it seems with enough resistance somewhere in the system you could produce enough of a voltage drop to cause a problem. That's all. It getting late now let us know what you find.

 

What is a farm exhaust or field timing advance curve?

 

The annoying little so-and-so that sits on my shoulder and continuously whispers in my ear keeps bringing me back to what you said above....

He and I will soon have to have a little talk about "quiet time"....

 

Oh lord voice text did me no favors there…. Oops.

mill gave more info tomorrow guys, Thank you for all the thoughts. I’ll check actual coil voltage with multimeter tomorrow. The coils specifically say do not use with resistor.

 

The distributor works smoothly now up to its maximum mechanical advance.

and I reckon it’s possible that this car never ran over that much because the carb could have been this way since birth, but I sincerely doubt it. I think it’s the basic Sunday driver no hot ridding or full throttle through the gears that caused the distributor malaise.

 

Been through it...VALVE SPRINGS !!!!

Mike

 

That could be a very good call, Mike. The following is from another site. If the wrong springs have been in from new, it would explain why it seems that the problem has always existed, and the engine has always topped out around the low 3000's rpm mark.....

How do I know if my valve springs are weak?
When the springs are too weak to follow the cam profile, one of several things usually happens: Engine rpm will flatten out (not increase after a certain point), the engine will pop through the intake or exhaust, a spring will hit the valve seat and bounce into the piston, or the spring will simply break.

 

If memory serves me right... the front and secondary floats are different... one has a different bend to the arm to clear something in the secondary bowl = no fuel in secondary bowl.

 

You mentioned earlier that the car is still running a positive ground system. Any chance that the ignition coil polarity has gotten reversed at some time?

 

You can rule out/confirm a restriction in the exhaust with a vacuum gauge.
I’d guess a stock 331 should have around 18 in/hg at idle. Increase the RPMs (out of gear) to 2500 or so. The lower the vacuum becomes the more restriction there is. Been years since I did this and can’t recall the proper spec for servicing it. Something like should stay within 2-3 in/hg.
Beats drilling a hole and putting a bung in the exhaust to measure back pressure.

 

Fuel hose internally collapsing ? Sock in gas tank plugged ? You could tape a fuel pressure gauge to the windsheild

 

I would look at fuel volume, as mentioned above there could be a issue in the tank , a metal line corroded partially shut. I have seen that a couple times where the car would run to a point and then flat line.

 

Had an OT injected build that would crank and idle but would stumble and fall on its nose
Found a rag ****ed up into the pick up tube.

 

Life would have been easier had the OP posted the carburetor identification; however:

The OP suggests the engine is all original, thus the carburetor should be a 2041s.

Comparing the calibrations listed by the OP to original:

Secondary jets: now .055~.056, original .0595
Metering rod power step: now .059~.060, original .058
Primary jets: now .080, ORIGINAL .0935

So 4 1/2 sizes lean on primary jets, 1 size lean on metering rod power step, and 2 sizes lean on the secondary jets!
How does it even run 65 MPH?????

Jon

 

@Gary Kitchens , are you able to confirm the carb model number as mentioned in prior post?

Did someone modify carb to improve it's lacking performance?

 

Dang you guys are smart

 

Check primary voltage at the coil. Low voltage can cause similar symptoms. Engine runs fine until under a load.

 

Not ported vacuum, venturi vacuum. It see a vacuum signal as more air rushes through the venturi (high engine rpm). It much like the venturi port on a Holley carburetor that supplies vacuum to the diaphragm to operate secondary's.

 

Please disregard, I got confused and thought I was replying to a post about a Ford Load-O-Matic distributor.

 

Quote OP " the car is one owner, unmolested, all original" end quote.

Quote Will Rogers "It isn't what we don't know that gives us trouble, it's what we know that ain't so." End quote

Jon

 

Mike, have you read through my first post? If it is valves like you experienced, I need schooling in why the valves prevent the secondaries from allowing the car to increase rpm’s from ANY rpm above idle, yes I can drive the car up to 65 mph on the front half of the carb?

 

Okay 28 explained it. But it doesn’t explain why I can hit 65 in the two gears of this auto trans, and it doesn’t explain why it will not increase in any rpm when tipped any amount into the secondary venturis.

thus morning I’m re***embling the carb, I’ll be using a tach on timing light to verify the timing range. I’ll even attempt to video the secondaries opening again in a better lighting situation that show the fuel flowing.

ALL of your thoughts are helping me narrow this down! THANK YOU ALL VERY MUCH! KEEP IT COMING

 

Yes this is very true!

carb number is 2041S

 

Is the linkage to the secondaries freely operating ON THE CAR, not just on the bench? If you are stepping on the gas, is someone watching the carb to verify proper operation?

 

Carb King is the best fuel system resource out there and we are very lucky to have his knowledge available for all of us to learn from.....listen to what he has to say!