rayjay1902

NEED HELP . NO SPARK. 1917 dodge

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I was out driving around , and she just died. no spark at plugs. bought a new 12v condenser from myers. it will not fit in my distributor ,its too big. then I noticed what looks like a 12v reducer on my firewall. wondering if someone in time replaced my distributor with a 6 volt. I tried the new condenser , but still no spark , im not sure if it matters that its a 12v and I need 6 v. I bought a new 6 v coil. im getting spark and she runs, but very rough. also my distrubor has 2 wires ciomming out of it , it makes a loop and connects to the old condenser. does anyone know how to connect a new condenser up? also what looks like a 12v to 6 v reducer is giving me a 12v reading on both ends, is it broke? or is it ok , I just need a 12 v coil? ugh ... trying to get her running for the aaca show in port st lucie in 20 days. I posted some pics so you can see what I have going on

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The white ceramic item looks to be a Chrysler product 12V ballast resistor. I am not sure what each end should read...

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Looks like a Delco distributor? 1917 is 12 volt, no need for a ballast resistor, it's built into the original coil. If you are replacing the coil you need a 12 volt with internal resistor, lose the white one. Condensers don't care about voltage, any one will do. Use a volt meter, follow voltage through the whole ignition system.

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I don't know where to put the condenser. the pic shows the original one. the clamp goest to a wire to the right side of the distrubator, the bottom of the condenser has a screw and its attached to a wire that goes to the left side of distributor. the car is 12 v , I just wasn't sure if someone put in a 6v distributor. but I guess not. I bought a 12 v coil, with no resistor , so I have to keep the one attached, but I didn't try to start her yet, got too dark out. will try in morning

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Hmm. This might explain why I melted a modern coil last year... Is there any way to test to know if they have the internal resistor built in? I eventually will get a reproduction of the original coil but in the meantime I'd like to keep the modern coil from melting again. Should I just wire in a ballast resistor like the one shown here? Sorry to hi jack the thread....

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The condenser doesn't care where you mount it. I've put external ones where the original one was inside. String the wire through an insulated hole and attach it to the hot side of the points just like the old one. An engine will run without a condenser to test if the old one is bad. But it will burn the points pretty fast. I have lots of VW condensers, they are proud to be used on DB's. There is a value of microfarids? that I'm sure someone will say matters. The amount that we drive these cars should not effect this, IMO. When you buy a new coil specify you need an internal resistor, doubt if anyone at Autozone or Pep Boys will know what you are talking about.

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The ballast resister should get hot with a load on it. I have never checked voltage at both ends but I have always thought that it will only offer resistance when there is a load on it. An old trick with a hard starting car is to jump across it to offer up more voltage when cranking. Some cars have this built into the starter or solenoid circuit.

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"doubt if anyone at Autozone or Pep Boys will know what you are talking about." That is for sure! I can see the blank stare when I ask for a coil with internal resistor to use with my '25 Dodge.....

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An automotive coil is a transformer in that it changes the low voltage primary input, 6V or 12V, into 20,000 volts on the secondary or output to fire a spark plug. The number of turns of wire on the primary side of the transformer compared to the number of turns on the secondary side determine how much the votage is stepped up. If you connect 12V to a 6V coil it will want to make a lot more secondary voltage than the system might be able to handle. The coil can run hot and burn itself out too.

You can add an external resistor to lower the voltage to 6V, but you will need to measure the resistance of the coil primary side to ground to know what resistor to use. If you measure the coil and find out its 30 ohms, then adding a 30 ohm ballast resistor, like the white one in your picture, in series with the coil will lower the input to the coil to 6V and it should work fine (its called a voltage divider network). Using a 12V coil would eliminate the need for a ballast resistor. The resistors that were used in 12V systems were put there to slightly lower the voltage to 9-10V when the auto is running to extend the life of the electrical components in the ignition system.

MoPars are famous for using external ballast resistors. Most drivers knew to carry a spare as they can fail over time from heating and cooling.

I have an automotive electrical manual printed in 1919. I'll see what it says about your Dodge system.

Terry

(Retired Sr. Electronics Tech RCA corp)

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The pictures of the 1917 Dodge distributor in my book and your set-up are different. I'm not sure how to tell what you have going on there. I will see if there is any thing else I have to help out. Can you see where/ show where the wire from the ballast resistor goes to on the dist? When the points are open, the voltage on both sides of that resistor will be about 12V. When the points are closed there shoud be a voltage difference from one side of the resistor to the other. When you used your new coil did your spark advance still work?

Terry

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Edited by TerryB (see edit history)

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Take a picture of the distributor looking straight down at it so the points can be clearly seen and with the rotor removed. Might be something similar in my book to use for a reference.

Terry

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I hooked up a 12 v coil and used the old condenser , running perfect. I would have put in the new condenser but don't know how to wire it up. ill still get the old coil repaired , but I heard it will take a few months and $250 ... ugh. but at least I can still get around. im going to take her on a long drive tomorrow and hope nothing burns out.

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what I thought was a converter is actually a ballast. so I am getting 12 v on both ends. the old one did have a break in it. when I used the new one with the old coil, it still had no spark. so I got a new coil with no internal resistor , they said its all they had. im hoping with the new ballast nothing will burn out.

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My 1919 books shows the use of some resistor / capacitor circuits in the ignition system and some relays. That type of setup can be used to change spark timing using the combined effect of a resistor and capacitor (condenser) so that's why I asked for wiring layout. My book shows several versions of this R & C idea.

My reference book will be on the for sale list in the not to distant future.

Glad to hear its running again.

Terry

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You can mount the condenser anywhere it will have a good ground. Connect the wire directly to the hot side of the points or tap into the wire going to the points.

The condenser stores voltage which is released when the points separate.

The released energy goes to the coil priimary where it gives the primary a significant shot of voltage which raises the output of the secondary.

A bad condenser or no condenser will result in lousy spark and reduce the points to scrap in no time flat.

Edited by cahartley (see edit history)

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TerryB, you will have to explain the theory of changing spark advance with a resistor and condenser, I've never heard that one. The picture from your manual shows the correct coil for a Delco distributor. The round thing on top is a resistor, shows in the other drawing as a coil of wire, nichrome I think. It gets hot, hence the cover. Rayjay do not put $250 in rebuilding the coil that is shown in the first pictures, as it's not the right one. $250 should be able to buy you a good Delco coil. They were used on several other cars. If you install the right coil, known as a mailbox, you will not need the white ballast resistor. The cheap way out is, like I said, go to a real parts store and ask for a new 12 volt coil with an internal resistor. Mid '50's Chevies and VW Beetle are two. Rayjay, in your third picture, what are the letters in the triangle on top of the coil?

Edited by nearchoclatetown (see edit history)

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Yea I'm having a hard time with the idea that changing the RC time constant (via different capacitor values) is going to change the ignition timing of the engine by any appreciable amount. The primary on these cars is controlled by a gear driven cam that opens and closes points (a switch). This cam is 'hard coded' (mechanically linked) to the position of the pistons within the engine. The point set can be moved relative to the cam to alter when the points open relative to piston position. I'm no electrical engineer but iirc, the RC time constant is a measure of how long it takes the circuit to discharge to some value of the full capacitor charge. I'm sure there is some optimum range for the constant for best ignition performance ( spark quality, etc.) but any change in the actual ignition timing would be very small I would think.

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Most coils today for older cars have an "R" suffix in part number, usually the factory sticker on the coil itself to signify it has an internal resistor. I have no ballast resistor on my '25, 12 volt system. It doesn't need one. A condenser is on a car only to protect the points from excessive arcing & burning the points. Body of condenser is ground, wire goes to hot side of points, (the movable arm). The original half-moon can type condensers on the old Dodges had two small terminals, one (+) other (-) that were wired inside the distributor body. A bad condenser can cause problems, if shorted it will bleed off your spark, backfiring, rough running...same if the condenser is "open" circuit.

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Hey Rayjay1902, I had a rough running, hard starting problem with my 1939 Studebaker (that is not a swear word, you guys!). The problem was that all the connections in the low tension circuit consist of tinned brass fittings. The connections become little galvanic cells in the presence of moisture, oxygen and dissimilar metals (steel, zinc, lead, tin and copper) resulting in pitting corrosion of the steel bolt and oxidizing of the connector. Oxidized connectors on rusted steel have high resistance so you get a significant voltage drop across each connection. I was only getting 2V at the coil, so it was hard to start and ran poorly. Clean, retinned connectors with rust-free bolts fixed it.

Hope this helps.

Graham

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Are you using an original Northeast Coil Pete? I had always heard the function of the ballast resistor was to prolong point life.

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Yes, I found a good Northeast coil amongst my parts here. I even am running an original "tin can" condenser in the dist. body. Runs fine. There is no ballast resistor on my Dodge, whereas none shown in the original wiring diagram either. This car is designed to run on 12 volts. The condenser is the only part that protects the points from over-arcing and burning, also a condenser, when correct Microfarad spec's are in place, it will keep the metal of one point arm from "electrolytic action", or PITTING, transferring metal of one contact and building up on the other point arm contact. There IS a way to check your condenser if original is not known, for your specific engine. If you run the car for a while, usually one season, you'll notice a small "pit" in one point contact and a build-up of metal on the other point. Now, if your condenser is electronically under the Microfarad spec, the metal will be built up on your hot side point, (the movable arm) and a pit develops in the stationary arm point contact. If your condenser is way over the capacitance specification, metal will be noted building up on the other point, (stationary point arm) and a pit will be on the movable "hot" arm point contact. Most condensers are of the .20 to .25 Microfarad capacity, it's voltage should be well over the highest known point voltage of your car's ignition system, I would say 25% higher. Actually, ANY higher voltage capacitor will work, it will just be physically larger to the point of crazy big. I don't mean to hijack this thread, but this info may help someone.

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A word about new coils; The modern replacement coils don't like being mounted "upsidedown", with the outputs being on the bottom, facing down. The "oil" or cooling heatsink in the coil will heat up, normally, and flow away from the windings that create heat, ending the life of said coil in no time. The old firewall mounted coils didn't seem to have a proximity problem. One of the most common causes of burning out a coil is the low tension wires are fastened on backward. Try swapping terminals. (+)--- (-). The original coil in the early Dodge Brothers car (12v.) is just that- a coil of wire around an iron core, dropped into the iron body with the gasketed cover on top and connected up to the top cover terminal plate. If you read the Owner's manual, it states "That if moisture in the coil is causing no spark, remove coil from housing and place it in an oven on low for a short time, just enough to dry out any condensation". I'd love to see something like that written up in a new cars' manual!!! Just make sure your baked potatoes are on other side of oven rack.---Pete.

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The book I was referencing is Automobile Ignition, Starting, Lighting by Charles B Hayward c 1919. In the book there is a discussion about using the RC circuit and a relay to vibrate the coil. In this system, the relay is used to generate multiple sparks that override the normal spark timing. This was apparently used to get lots of spark to the plug during startup. Once running, the normal point contacts control timing. It was described as a carryover from the days of magnetos and was discontinued when storage batteries were used.

Terry

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A word about new coils; The modern replacement coils don't like being mounted "upsidedown", with the outputs being on the bottom, facing down. The "oil" or cooling heatsink in the coil will heat up, normally, and flow away from the windings that create heat, ending the life of said coil in no time. The old firewall mounted coils didn't seem to have a proximity problem. ---Pete.

I'm not sure where this kind of information comes from. Several cars mounted coils upside down, as you call it. Every air cooled VW Beetle, bus, and Ghia comes to mind. I'm sure there are others.

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