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1947 convertible Question:
New to the V8 world and have been enjoying my '47 convertible this summer. On a trip Sunday the car suddenly started running poorly, like someone turned a switch. I stopped and found a plug wire had popped off. Started driving again and it did the same thing but this time the plus wires were fine. I pulled all wires off and crimped them to tighten the fit on the plugs. The car ran well for another 20 mins and then it ran poorly and this time quit. Upon inspection I could find nothing wrong. It would turn over but and fired once but would not run. I live in Maine and the temps were in the 50s so do not expect vapor lock. Sediment bowl was full. I had it towed home. Haven't done anything else to determine cause but suspect it's electrical. Any suggestions on where to start looking? |
Re: 1947 convertible coil, condenser, wires, fuel pump, fuel filter, pluged fuel cap, restricted fuel line, just a few possibilities.
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Re: 1947 convertible Coil & condenser would be my starting point.
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Re: 1947 convertible Is it the original coil? Or has someone converted a it to a remote coil. Skip Haney rebuilds coils, search this forum for his info. Also Tubman on this forum sells condensors that should last you a long time.
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Re: 1947 convertible As the other guys have said it's likely ignition. If it were mine, not knowing the past maintenance of the ignition system, I'd have the distributor tuned up and timed, change condenser and check the coil.
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Re: 1947 convertible Will it start now that it has set a while? Coils will start to act up when they are hot and then work again when cooled down (as will condensers). Replacing the condenser would be a fairly easy first check. If that is not the issue I would suspect the coil next. Having the distributor rebuilt and checked out is a good idea as well. Several members here on the Barn provide that service. Not sure, but think Skip might do distributors as well as coils.
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Re: 1947 convertible Thanks for all the educated thoughts. To answer some of the questions I replaced gas tank (sheets of rust inside and sediment bowl looked like I was running Jack Daniels), blew out fuel line, replace fuel pump and rebuilt the carb though I did not use the reworked Power Valve that Charlie suggests. Bought and installed a rebuilt coil (remote) done by Skip.
Correct distributor. This car had undergone a full restoration but have no specific details. It did not start after it sat for several hours, turn over yes, but won't fire. I did loosen gas cap and tried it but did not fire. I think I have a new condenser which I will try tomorrow. I'll keep you all informed as to how I do. |
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I have experienced this problem. Phil NZ |
Re: 1947 convertible Have you checked for spark to the plugs? If not, just remove a plug wire from the spark plug, attach to a used plug you have laying around (or remove one from the car). While cranking the engine, with ignition on, you should see a spark from the plug when touched to a metal service.
Spark should be bluish. If spark is yellow, you may need a new coil and/or condenser. If spark is bluish, your problem is probably fuel related. If no spark at all, you may need to look at the dizzy. Good luck, |
Re: 1947 convertible Yes, sediment bowl is full. Need to check plug for spark. Removed the condenser, OEM style, and have new one ready to go it.
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Re: 1947 convertible If you can organize your trouble shooting in an "elimination" style, then you will know if a certain part is ok and not the cause of your problem. Going in and replacing several parts at once, may solve the problem, but then you will not know if those replaced parts were any good. I would suggest going one step at a time. Enjoy the journey and the satisfaction that comes with solving the mystery.
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Re: 1947 convertible Send your coil to Skip for rebuild
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Re: 1947 convertible OK, the coil in my car is a Skip rebuild.
I did blow out the fuel line from engine compartment to the end of the line at the tank. Seemed quite open but still worth checking again. And yes I make only one change at a time and then try to start after each time. |
Re: 1947 convertible Do you have a fuel filter in the line?
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Re: 1947 convertible No inline fuel filter, brand new original style fuel pump
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Re: 1947 convertible Update: Checked for spark at the plug wire and nothing. Replaced coil, no change. Found I had 6V at the ignition switch with switch on, but it dropped to 4.5V at the coil.
Since I had installed a Columbia 2 speed rear this past summer I decided to take the wire connection off the back of the ignition switch just to make sure I had not compromised the wiring. In the process found that red wire terminal on the back of the ignition switch was very hot, hot enough to burn me. It was only hot with the ignition switch in the on position. I have not got into the distributor yet, that is next. But I am not sure what could be going on in the distributor that could cause this issue. |
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. |
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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.
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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 1 Attachment(s)
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.
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Have you tested the voltage regulator? |
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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.
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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.
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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: |
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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.
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