41 flatty, miserable, spark, stops running.

[Forty-wuns foever]

I'm new here so give a little time to get up to speed. I recently purchased a 41 Tudor Sedan, it has suprised me at every turn. Can of worms type things.

Any way, I have (had) the engine running. Had hot spark and good starting. Now I have a very weak spark at the plug and she just won't start. This is the second stock coil, the first one was the one that came on the car, it failed completly. Dist, has new points set at .014, new rotor, wires and plugs. I started it yesterday, it ran for a few minutes, I gave it some throttle and it started to run rough, then shut donw. Will not restart. I had some excess fuel showing around the carb but I don' see how that affects the fire. Any one have any ideas? Also, what was the standard power valve in the 41 Ford/Holly 94s?

Kinda long winded here but I do need help.

[uncle max]

A new NAPA Echlin IH-200 condensor might be in your future.

[Forty-wuns foever]

Is that the replacement for the original. I replaced the condenser when I changed the coil. Any idea where your suggestion may be purchased?

[ken ct]

Most original type repop condencers are made in you know where. Get the 200 . Did you set the points with the coil on the dist.If not they probebly measure .010 now. Most coils are n/g either even new ones. Napa for cond. Skip haney in fl. for coil rebuild. ken ct. I do dist rebuilds ,carbs as well as fuel pumps.

[Rich Overton]

Most of the guys are more knowledgeable here than me but just a thought. Are your points burned? I've had my "48 Merc. for about 8 years. Same senario as yours, you name it I've replaced it. It had a new Ford coil on it. ( no need to replace that, right? ) Well one set of points always burned within 50 to 100 miles. Finally decided to check the coil. Huh? no resistor! What the... put on an internal resisted coil. So far, So good. Check yours under the dash.

[Shadetree]

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I suspect the condenser too. The condenser IH-200 mentioned above is available at NAPA. I carry one in my glove box. Once the condenser goes bad and cools off, the engine will sometimes start but just for a minute or two.

Don't get discouraged. Most of us has gone through the same thing that is happening to you. Once you get it right there is nothing like a great starting and running flathead V-8.

Shadetree

[40Coupe]

[QUOTE=ken ct;250020] Did you set the points with the coil on the dist.If not they probebly measure .010 now. QUOTE]

How does that happen Ken?

You suggesting on the bench with coil mounted I hope?

thanks

[Tinker]

I agree with Ken on getting a coil rebuild from Skip. Also what do your plugs looking like?

[rotorwrench]

The ballast resistor is always part of the troubleshooting process as Rich Overton mentioned. They go through so many heat up & cool down cycles that eventually the wire will crack. A wire that is cracked can still make contact but will give you intermittent problems until it fails completely. When you get a head scratcher like this, you have to check the entire circuit from the power source to the spark plug.

Kerby

[Forty-wuns foever]

OK, how much voltage should the coil lead be getting. Mine shows full battery voltage but fluctuates as the engine is rotated. I understand the purpose of the points is to interuprt th power to the coil in time with the firing order of the engine. Is that close? Should I be getting this low voltage (2.5 v) when the points are closed?
You sage flatty owners should now it's hard for this old man to ask questions. I was directed to this site by one old ford guy who I greatly respect. I had one of these as a teenager just before Unca Sam put me to work in 1963. I never had to mess with this type of dist. My 46 had a late model Merc engine with the modern dist in the front. Oh well, guess I'm not to old to learn here.

Thanks to all.

I'll pull the dist and check the points with the coil installed. I did notice that the spring on the coil was quite strong. The only question here is why would I have a great spark on time and little to none the next if i have the same point setting even though it may be less. Wouldn't that just change the timing a little?

[Ken/Alabama]

I would start with a rebuilt coil from Skip.

[ken ct]

You should be getting 3 1/2 to 4 volts at the coil. No more no less. ken ct.

[Mike in AZ]

welcome, Forty-wuns...don't be shy about asking questions....the experts here will hopefully be able to point you in the correct direction to get your flathead running and keep it that way so you can enjoy your car....got pics??....Mike

[Milt K from Pa]

Ken CT,
Why does setting the points out of the distrib change when mounted in the distrib?? I use a KRWilson distrib fixture to finalize the timing and never find it off that much after normal .015 settings. Just need to know.
Milt K from Pa

[Ken/Alabama]

I think what your talking about is mounting the coil. The spring on the bottom of the coil puts pressure on the breaker plate and can cause things to change if there is the slightest amount of movement in there.

[rotorwrench]

Measuring voltage in a circuit with a resistor is a task that can make more questions for the average repairman. The voltage is only dropped for the component that the voltage is applied to. When you check the voltage at the wire connecting to the coil it will be read as system voltage. To read the actual drop in voltage from a resistor you have to check the voltage across the resistor itself by contacting the ends of the resistor in parallel with it. Polarity has to be observed to get the correct meter reading. Red lead to the positive side and black to negative side. Just remember that the power in a positive ground system flows opposite that a modern system with negative ground.

It might be easier to just check the resistance of the ballast resistor my first isolating the circuit to it then check its resistance with an Ohms meter.

Kerby

[Forty-wuns foever]

OK, if I remember any thing from my learnin in the Navy, a resistor only works when it is loaded (attached to the coil). But the coil only loads when the points are closed. therefore completing the circuit. Is this correct ?

If so, with the ignition on, and the points open, the lead on top of the coil would read system voltage, it would drop to its design when the points close.

Ken ct indicates the coil voltage should be between 3.5 and 4 volts. I get a little less than that at the top post when the points close.

This may be a no, no but when I bought the car, it had a brand new 8 volt battery in it. Is this a problem. From what I've read, the only casualty may be the life of the various bulbs in the car.

I have not messed with th car for a couple of days. Got the carb on the bench in pieces. Needs at least a new power valve. It leaks, the rubber diaphram is shot.

The accel pump is new, and I have a gasket set so this will also be a learning curve. What is the difference, other than the operating connection for the choke and throttle, between the 8BA, eab, mod 59, and mod 91-99. I have a couple of each. The car came with the mod 59 on it.

Thanks guys.

[BIG MIKE]

I don't know I just go thru walls and over old cars mate! Did your Coil get Hot???

[rotorwrench]

Originally Posted by Forty-wuns foever

OK, if I remember any thing from my learnin in the Navy, a resistor only works when it is loaded (attached to the coil). But the coil only loads when the points are closed. therefore completing the circuit. Is this correct ?

If so, with the ignition on, and the points open, the lead on top of the coil would read system voltage, it would drop to its design when the points close.

Ken ct indicates the coil voltage should be between 3.5 and 4 volts. I get a little less than that at the top post when the points close.

This may be a no, no but when I bought the car, it had a brand new 8 volt battery in it. Is this a problem. From what I've read, the only casualty may be the life of the various bulbs in the car.

I have not messed with th car for a couple of days. Got the carb on the bench in pieces. Needs at least a new power valve. It leaks, the rubber diaphram is shot.

The accel pump is new, and I have a gasket set so this will also be a learning curve. What is the difference, other than the operating connection for the choke and throttle, between the 8BA, eab, mod 59, and mod 91-99. I have a couple of each. The car came with the mod 59 on it.

Thanks guys.

Correct on the resistor operation.
The coil BAT wire will read system voltage when disconnected from the coil and switch on. When the connections are restored and the points are closed, it charges up the capacitor/condenser. Opening the points causes the condenser to kick the charge out and induct a high voltage from the primary winding to the secondary winding that jumps whatever spark gap the distributor rotor is aimed at at the time. No condenser, VERY weak or no spark. Leaky condenser, weak spark and breaker point wear. Too high a micro farad condenser capacity, also weak spark and point wear. Bad ballast resistor = weak or no spark. The ballast resistor controls the amperage in the circiuit from getting too high. The old plastic case coils were made differently than the later can coils used on the 8BA family of engines. They had an antiquated iron core and the primary & secondary wire windings were made to work with the odd iron core. This was why they needed the ballast resistor in the first place. The later can type coils had the proper primary resistance to cope with the amperage draw so they didn't need a ballast resistor until they upgraded cars to 12-volt.

I'd ditch the 8-volt battery. They will turn the starter better but nothing a good cleaning of connections wouldn't usually cover. The generator can only put out around 7 to 7.5-volts so the 8-volt battery will never charge properly. It would need 9 to 9.5-volts for proper charge. Also remember your ignition system is designed for 6-volts too.

All of the Chandler Groves or Holley 94 type carbs work about the same way but they were upgraded for better service as time went by. A bad power valve is somewhat common due to the design. Replace that and make sure all the places that can leak are plugged and all the places that are supposed to pass air or fuel are open then the carb will function normally. The float valves and accelerator pumps that a lot of kits come with now days have a hard time with modern mogas. There are several folks on this board that can help you out with the carb if things don't go right with it or the parts. If the accelerator pump is squirting fuel out the right place then it's probably OK.

Kerby

[Newc]

Hi all; Remember an earlier post about 94 bowl vents being different for top fan engines and crankshaft fan engines. 39-41 low fan eng use an external bowl vent? right? later Newc