Re: 1947 convertible
 

A bit more work on the problem today. Checked the hot terminal on the ignition switch body and found 2 of the 3 were very hot with the switch in the on position. Tested the condenser and found it to be good.
Used a test light to learn the points were opening and closing and then took off the distributor and confirmed that. They did look a bit over heated.
Finally we tried to find the ballast resistor thinking that could be the issue of the ignition switch over heating. But we could not find it. I found a tiny aluminum box on the upper inside of the firewall. It was 1/2" by 1 1/5" long. It did not look like a resister but that's the only thing I could find.
Can someone tell me where to look for it?
That's where we are at this point. Not much closer to a solution.
I ordered a new ignition switch body on the off chance there could be an internal short.

Re: 1947 convertible
 

Have you checked the voltage regulator?

Re: 1947 convertible
 

I thought I had sent another update Tues. night but it doesn't seem to appear, so I will try again.
A good friend and super mechanic came over to look at the '47. He found 2 terminals on the back of the ignition switch body became very hot when the switch was on. Voltage dropped from 6V at switch to 4.5V at the coil. He thought the distributor point might be stuck but a test light proved they were operating fine. We took off the distributor and checked the condenser which tested fine. Points opened and closed but seemed discolored as if they were hot.
Looked for the ballast resistor thinking it had failed and could be the cause for the heated terminals. However we could not find it under the dash against the firewall which is where we guessed it should be mounted. I did find a small metal rectangular box (1/2" x 1 1/2') high up on the firewall. It had 5 wires coming out of it. It did not look like a modern ballast resistor.
Is this it or or can anyone tell me where it is mounted?

Re: 1947 convertible
 

I did not check the voltage regulator. My mechanic friend made no suggestion.

Re: 1947 convertible
 

Update: A mechanic friend joined me yesterday to look at the '47. He found 2 heated terminals on back of ignition switch body when ignition was in the ON position. He thought the points might be closed but a test light confirmed they were opening and closing.
We removed the distributor and found the points opening and closing but they seemed discolored. The condenser checked out as well.
Next we looked for the ballast resistor under the dash but not sure we found it. What we did see was a small metal box (1/2" x 1 1/2") with 5 wires coming out of it. It did not look like a ballast resistor.
Can anyone tell me where to find the resistor?
Thanks.

Re: 1947 convertible
 

Did the firewall part look like this? There should be both an ignition resistor (smaller piece to the left) and the breakers in the box cover to the right.

Re: 1947 convertible
 

Have you tested the voltage regulator?

Re: 1947 convertible
 

I did not see a box like that but will look tomorrow. I assume this is up high on the inside of the firewall.
Thanks,

Re: 1947 convertible
 

A hot wire is caused by a high resistance in that circuit. A bad connection somewhere is the usual culprit. It can be a loose terminal at a component, such as a switch or connector. A common cause is the ignition switch, itself. As they age, a groove is worn into the Bakelite that holds the contacts for the moveable part of the switch. For your '47, order part number 01A-3704, $17.50 at C&G (800) 266-0470.

Re: 1947 convertible
 

I did order and just received today a new ignition switch body and will replace that. That was our first thought as well for being the culprit. I hope it is as simple as replacing it.
Re voltage regulator, I understand that can be tested when the engine is running, which of course it isn't yet but will do so when it is.

Re: 1947 convertible
 

Have you pulled the distributor cap and checked the rotor/cap interface, making sure you have a good circuit to the plugs?

Al Hook

Re: 1947 convertible
 

I did not pull the cap apart, but did take the distributor body out. It would be hard to believe I would have no spark at any plug wire due to anything but a broken rotor, which was in tact. But I will separate at the cap, it should be a two piece unit.
I still cannot find the ballast resistor. I've looked on the inside and the outside of the firewall. Where should it be?
I have purchased a new (modern) unit and may put that in line before the ignition switch.

Re: 1947 convertible
 

'47 Convertible update.
I pulled the distributor off and the point gap was very close to spec, I changed the points and condenser and, lubed the cam and re installed the distributor. Removed and replaced the ignition switch body which I found to be black at the large brass contact spot making me think there was not good contact. I added an inline ballast resistor as I could not find one anywhere in the car. Is is possible that the Skip rebuilt coil could have the ballast resistor inside? In any case the voltage between the ignition switch and the coil is now 6.13 instead of the 4.5 that I had prior to this replacement.
The car turned over but would not fire though we know we had spark. Now what?
We checked for the gas pumping into the carb by pulling the throttle linkage.....nothing. Put a vacuum pump on the fuel line ahead of the carb and pulled on it. We noticed particles swirling in the sediment bowl. Curious because I had replaced the fuel tank and blew out the fuel line. We reattached the fuel line to the carb it started up and ran fine.
Now I am thinking of replacing the fuel line and draining and inspecting my "new" fuel tank for contamination. The particles were black and silver. None of the rust I had seen in the old tank.
So I find it odd that I had a fuel and an spark problem the same time. Glad this is only a hobby.....

Re: 1947 convertible
 

So is there an in-line fuel filter? If there is crud in the bowl, there is now crud in the carb.

Re: 1947 convertible
 

As I said, crud in the bowl and probably fuel pump and carb. I will go through the carb (again) and make sure it is clean, and replace the power valve. The replacement which I have already installed,according to Charlie's, is not manufactured correctly and tends to leak. That was on my to do list after learning about it after I went through the carb.
A see through in line filter is going in the fuel line just ahead of the gas tank. I should be able to keep tract of what crud is still in the system and replace the filter when "full".

Re: 1947 convertible
 

No ballast resistor in the coil.

That 4.5 v should be enough to start the car as that is what the ballast resistor does-reduces the voltage. It should be fairly easy to find under the dash, although I have no personal knowledge of where it is on those cars. On my 39 and 45 truck, both are above the steering column on the firewall. If you find it, you can jump it to see what happens and if the car starts. Maybe bad connections there, too, so you can clean them once you find it. Fortyniner's photo is probably correct for your car. I am by no means an expert on this, but I do have some experience with difficult start problems on my cars. Others here know much more than I do.

Re: 1947 convertible
 

3 people have looked for this ballast resistor with no luck. It is NOT on the firewall. We followed the ignition wire on its way to the coil and not found anything. There have been some coils that have the ballast resistor built in, so I have read, and I was wondering if Skip Haney, the coil rebuilder guru does that when he rebuilds the OEM coils. I have one of his in my car. In any case we added an inline ballast resistor. When we had the ignition switch turned on I could see the resistor giving off some smoke for a few seconds before it stopped. I think that was because it was new and any sort of coating that was on it burned off.
Thanks everyone for your comments in trying to solve the problem. I think I am not 'good to go'. I just have to go through the fuel system as previously mentioned.

Re: 1947 convertible
 

I can't speak for Skip, but I have several of his coils and I don't think he would include a resistor, knowing that the external one was/is standard in that metal box under the dash. You did the right thing to add on in the circuit and yes, the "smoke" was the initial heating process.

Sounds like your ignition problems are solved.:rolleyes:

Re: 1947 convertible
 

Why not just give Skip a call? 941-637-6698 mailto:[email protected]

Re: 1947 convertible
 

I wonder if the car had a modern coil at some point? That is the only reason i can think of for not having one, but maybe the PO took it out? That wouldn't explain to me why the voltage is 4.5 at the coil, but, as I wrote earlier, I am by no means an expert.