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manncad

Help me fix my 1949 Cadillac

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The coil is designed for 12 v operation being used on 12 v battery. The mechanic said this morning he didn't have this ballast resistor and that there was no point to have it anyway. The car stayed in the shop and he'll have a look at it. God I wish I had one of you guys right here right now to fix this all thing. But I'm not desesparate and I'll find the problem.

I'll update soon

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If you have a 12V system and do not have a ballast resistor to cut the voltage down to 8.4 volts, you will ruin the ignition system. Perhaps French cars don't operate that way, but American cars most definately do. Your mechanic is completely wrong if he tells you a resistor isn't neccessary.

Here is a quote from a motor manual "the idea of the resistor is that you deliberately design

> the coil to operate at a voltage lower than 12 V and then use

> the resistor to get to that voltage under normal conditions.

> When you're cranking the engine with the starter the battery

> voltage drops and hence the sparks get weaker. To combat this

> you bypass the resistor as long as the starter is operating.

> This gives you pretty much similar sparks during cranking and

> normal operation.

Here is a page I googled..

http://aolsearch.aol.com/aol/search?encq...llover&ie=UTF-8

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To further explain how that system works, the solenoid mounted on the starter will have two small terminals. One of them received voltage from the ignition switch which activates the starter when the key is in crank position. The second terminal is called the "hot Shot" terminal. Under cranking conditions only, that terminal will be hot with 12V's. A wire runs from that terminal to the coil, so you have 12V's during cranking, to give your coil the extra voltage for cranking. When the engine fires and you release the key, that wire is now at 0 volts, and your ignition system is now running on the 8 V's supplied by the ballast resisted wire. The hot shot wire bypasses the ballast resistor during cranking only, to give you a little extra POP for starting..!

I'm betting if you look at your solenoid, you will only see the one wire. The hot shot isn't hooked up because you are running on 12V's all the time. Put the resistor in the system, hook up the hot shot wire and then you can spend more time with the berries.....

keep the faith, this issue will be resolved

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The car went to a first shop then a second one where I thought the machanic would be better. He adjusted the points, the advance and the 2 screws in front of the carburator. He told me the car was then running great, but without the air filter, which is plugged. So I went to pick up the car and realised it was not running well at all, even worse than before. Still black smoke, still missing and most of all, the coil burning hot. So I left without paying anything so far, a little pissed off. Anyway, I need to find a new and clean airfilter and a resistor ballast. So I have one question, can someone tell me what kind of resistor ballast I need for that car and where ? I will order it right away. I went online to look for it and there are a lot of different resistor.

Thanks

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I listed a site in a previous post, as to where to get the resistor. Perhaps French vehicles don't use them, but they were common for so many years in this country, that just about any parts store will carry them, They should only cost 5 or 6 bucks.

If you still have a friend in the states, have him pick one up and send it to you. Or any mail order catalog.

I am going to a parts store this afternoon, I will see if I can pick one up for you. I will check price and availability and if you like what you hear, I'll ship you one.

If only I were a wine drinker, I have struck the mother lode...!

I'll get back to you....

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If your old air filter has a number and brand name on it, let me know, I'll check on that too. I assume the stock '49 Cad had an oil bath, so if it has a paper filter, it isn't stock. with a number, I can cross it over....

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that would be so awsome if you get me this ballast resistor.

The old air filter has no number or name. They just call it Air Cleaner Filter Unit. Its quite big, with oil bath. I can't take it apart to clean the filter itself, and I dont think its papaer, it's most like a bunch of small wires. I don't know how to explain. if you give me an email, I can send you a picture.

if you ever find a resistor and a filter and ship it to me, don't worry for the payment back, my friend will send you a check from california.

As the mechanic worked on the car quite a long time, they want me to come back when I have the resistor and the filter to readjust the all thing, and then pay them, which is normal.

You know, I do believe the problem is the coil, it was so hot after 15 min drive, unreal.

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yes, this is an oil bath air filter, I did change the oil but there is also a filter itself and it was very durty. This filter can't be taken off the unit, it's inside. The only way to clean the filter is to let it sit several hours in gasoline and then dry it off with compressed air. I did all this, it looked pretty clean but the car runs better without the filter on.

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Send me your shipping address, I'll ship you a resistor. I just looked up one for a late 50's Cad. When they went to 12V, the resistor was used from that time until, I guess sometime in the 70's when they replaced the resistor with a special wire with the resistance build in.

BUNNELLYL@AOL.COM

This may not be the answer to all of your preformance problems, but it is a good place to start. Then you know at least that part is correct.

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here is an update,

I got a resistor from RocketDude and put it on this morning....but....the coil is still getting really hot. And also, after cleaning really good the oil bath air filter, I put it on, and the car was missing a lot. So, I took it off and the car was doing much better, still missing at high speed, but more like if I was pushing the brake pedal every 3 seconds or so. And then, as I said, when I came back home after 15 mins drive, the coil was hot.

I mounted it on the fire wall, with the wire of the ignition and the wire of the fuel pump on one side, the wire going to the + of the coil on the other side. So maybe I should try another coil, maybe it got too hot before, but I doubt it.

The car is still smelling gas and still black smoke.

I'm back at the beginning, not knowing what to do.

Maybe it's a ground that need to be wired somewhere.....I have no idea. What's sure is that the filter is not good.

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To check the coil take an ohm reading between the + & -- terminals when cold. For 6 and 8 cylinder engines you should be reading around 1.5 ohms or slightly greater. For 4 cylinder engines you should read around 3 ohms or slightly greater. Take another reading with the engine warmed up. A digital meter is much easier to reader then one with a pointer.

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I know nothing about Cadillacs and prefer magneto ignition (!) but an ignition coil is nothing but a large-ratio transformer. If the internal insulation has broken down, either on the low-voltage side or more likely on the high-voltage side, it might have a short-circuited turn. That would greatly reduce the spark, although perhaps you would still get enough for the engine to run, but it would almost certainly lead to excessive dissipation i.e. heat in the coil. It would be interesting to know what the average current consumption is (measured with a good old-fashioned analog meter because the digital ones give useless answers on currents that are varying rapidly). It should be no more than two or three amps. If it is significantly more, the coil is faulty.

Ken G, 1925 Rover 16/50 (San Francisco)

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Measuring the resistence (ohms) works just fine and a decent digital meter will also have a bar graph somewhere on the screen. I have done it many times checking coils and if there are breakdown issues, etc in the windings the meter will pick it up ohm wise. I always do a cold then warm / hot test as on occasion when things get hot they separate or resistence goes up throwing readings out of tolerance.

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I'm sorry, Ron, but that is not the whole truth. Yes, if the problem is an intermittent or permanent open-circuit, simple resistance tests will reveal it, and hot/cold tests might be more revealing. However:

a) The present problem might well lie, indeed is more likely to lie, in the secondary, that is, the high-voltage winding, and that would not alter the resistance of the primary (low-voltage) one which would be correct.

B) A short-circuited turn (as I say, more likely on the secondary) would have negligible affect on the resistance measured with a meter (of either the primary or the secondary).

I think the simplest solution (if it hasn't been tried already) is to try a different coil, perhaps even to borrow one, although as I recollect coils are not very expensive.

As a side comment, cars in Europe have operated on 12 volts since probably the 1930s (my 1925 Rover is and my father's 1934 Morris Cowley was 12 V), and so coils intended for 12 V operation without ballast resistors are commonplace (I had to change mine on a 1968 Mini). Using a lower voltage coil with a ballast resistor which is short-circuited while the starter is operating has the virtue of providing a fatter spark during starting without over-heating the coil in normal running, but my suspicion is that the practice arose first because in the US at least it allowed existing 6 V coils to be used in the new generation of 12 V cars.

Ken G, 1925 Rover 16/50 (San Francisco)

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Ken,

For the record I don't disagree with your statements. For me if the coil is reading defective after I check the ohm readings and it is not within tolerance ohms wise I replace the coil. Typically this always has fixed the problem.

Many times I will also do a high voltage test before I even do the ohm test. There are various ways and test methods and equipment for this such as: http://www.handsontools.com/store/show_product/?product_id=1938 though I use a cheaper version. I didn't mention this to Emmanuel as many don't have this or any type of high voltage tester, but do have a ohm meter.

In any case for me this is what I have found to work the best. Everyone does things differently and I have too many vehicles to keep an extra coil for each.

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I have seen some distributors where the wire lead that goes from the points, exits the dist. body and goes to the coil will develop a short to ground that can't be seen easily with the naked eye. Don't overlook that--with the points visably open and the wire disconnected from the coil check (ohm out) that wire to ground.

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Good point. I have seen this wire rubbed to bare on occasion due to it being crammed into the distributor especially if converting to Pertronic's.

Also on some engines (Triumph comes to mind) there is a short ground wire from the distributor point plate that runs to outside the distributor to a ground. Sometimes this corrodes at the screws or will have an break in it that drives you crazy as it is intermittent . It works one minute and nothing the next.

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Then, maybe I should check the wires from the points to the coil.

The ballast resistor I got did not take care of the problem. Coil still burning hot after 10 mins ride.

Also, anyone who knows where I can get an oil bath air filter for that type of car is welcome to let me know.

Is there any way to put photos on this forum. I could post some here and maybe you'll find the issue.

About the ohms or voltage check, I dont have the meters to do it, and I dont want to drive the car to another mechanic right now. But I will check as soon as I get one from someone.

thanks again

Emmanuel

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Maybe your coil is ok even though it seems to be running hot to the touch?

I am unsure about 49 Cadillac coils however the coil in my Amphicar you can't even touch and I have tried several both old and new. At our national convention (64 cars) this was a major discussion so we felt a fair amount of coils after run in and they were all extremely hot to the touch. Seems this is just how it is with these cars.

Have a good weekend.

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very interesting Ron. I called the guy who owned that car for 30 years ( my best friend now ) and he told me last night that the coil always been hot on the touch....so maybe there's nothing to do then.

And about the oil bath air filter, he said soaking it in gasoline would do nothing, better soaking it in lacquer finner and then burn it...which I'll try to do this morning, whithout burning myself hopefully....

Emmanuel

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I wouldn't burn the air cleaner mesh. Some of those old oil bath air cleaners have a mass of jute to soak up oil to assist in the cleaning effort. It is usually packed into the top of the unit and is not easily seen. I was a mechanic for 45 years and always cleaned those air filters with cleaning solvent and a nylon bristle brush, blew out with compressed air and then air dried.

Be sure to check your ignition timing and also see if the exhaust system has a "heat riser" baffle. If so, and it is stuck partially closed, it could cause all your problems. It appears to me that you have carburetor issues.

If you could come across with an old (blue color) "MOTORS MANUAL" covering 1949 models there is a "troubleshooting" section in it which will help you narrow down your problem. There will be a series of diagnosis(es) for your exact problem. Good luck!

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Thanks Gaugeguy,

you are right, I won't burn it as it is not made of steel mesh but more like a plastic mesh. The laquer thinner did take some of the durt off as it came out brown and durty liquid. I'm not sure what is a heat raiser baffle, but the exhaust system has been talked about in the this forum, and I don't know how to deal with it. The mechanic either.

I do have the 1949 Cadillac shop manual and read many times section 10, Engine fuel and Exhaust section, but it didn't help.

Anyway, my friend keeps telling the problem come from the metering rods inside the carburator, so he'll try to find me a new or rebuilt Carter Carburator as he comes visit in one month. Actually, if anybody here knows where I can find one....for cheap of course...I'll take it.

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Last night we were talking cars and someone brought up a 1963 Chevy pickup that had much the same symptoms as manncad's car. Turns out the pickup had been changed over to V8 from six cylinder, by a Ford mechanic.

After several years of trying to diagnose the problem and toting a spare coil everywhere the truck went, someone finally realised the coil wasn't properly grounded, as the Ford mechanic wired the coil Ford style instead of GM.

This might be something to look at.

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