VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1937-1945 New to me 38 update

I tried to reply to the original post but discover it is locked maybe due to going offtrack. I haven't been mentioning my starting problems as the 38 had been firing up on the first spin until yesterday. She fired up but and i ran her for a while but i could start her later. I connected my small charger and it showed nearly fully charged but i did not check the voltage. the battery sat on the small charger for about three hours and it then showed fully charge, oh well. The 38 did fire up immediately which leads me to believe the battery might not be charging.

I am not sure that running an engine for even an hour would discharge a fully charged battery. The ignition only draws about 5 amps.

My thinking is that it is a heat driven issue. Sorry that I do not remember all the fixes you have tried.

Will the engine not crank over or will it crank and not start? If it will crank have you confirmed there is no spark?

Remember to be logical and organized as you troubleshoot this.

Engine fires up immediately when the starter spins. The no starting issue is when the starter doesn’t spin from what appears to be a weak battery. I haven’t taken any voltage readings as of now.

Yes, you should take some voltage readings.

One suspicion I have is that the problem is either in the starter motor or the contacts in the mechanical switch. When they get hot from the engine heat their resistance increases. Or the armature expands so much that it drags on the field coils.

Just some guesses. The next time that happens pour a bucket of water slowly over the starter to cool it. Then try to start it.

I assume we have gotten past the “too small a battery cable” issue.

I don't recall if your car is still 6 volt or not. If it is:
1: Clean battery cable to starter and ground connections.
2: 0 or 00 gauge battery cables.
Clean connections and properly sized cables are essential to a 6 volt system.

My first thoughts are the same as Tiny. I constantly have to insure clean cables and posts on the single 6 volt battery that I move between vehicles or engines. If clean cables and battery posts does not solve the problem I would suspect the battery. It may have a defect. Checking the voltage when fully charged and when it doesn't want to crank over the engine should help ID the problem. I keep a quality VOM on the shelf and use it often.

I would suggest making sure you follow Tiny's advice in the previous post, especially about the size of the battery cables (O, OO, or even OOO). In addition to the things mentioned by Tiny, you should have a good ground strap from engine to frame. Finally, rather than attaching your battery ground cable to the transmission housing or frame, try moving it as close as possible to the starter, even placing it on a starter mounting bolt; this will increase your cranking capabilities considerably.

This information comes from a little book that I recommended earlier, "Help: My Car Won't Start When It's Hot," by Randy Rundle. There is a wealth of info about electrical systems in this little book. I have followed the advice about attaching the ground cable to a starter mounting bolt and it has really eased starting in my 6-volt vehicles.

Jim

My 38 is 6 volt and I replaced all of the wits and cables for the ignition and charging and the strap is connected to the transmission housing. The positive cable is 1/0 from Napa with a lousy temporary connection. I didn’t drop almost $60.00 for a cable yet. I will order a new cable and connect the ground strap to the starter bolt if long enough. Thanks again gents

Am I mistaken or is the positive battery cable black while the ground is the strap and what length? I’m not at home so I don’t remember the length but not critical at the moment until I order cable

Go to a welding supply shop to have your cables made. Much less expensive than parts house cables. At least around here they are. Be prepared to tell them the sizes and types of ends you want on the cables (top or side terminal on battery end/size of hole in the terminal on the other).

Red is positive, black negative, but I don't remember seeing red on older cars.
Connecting to the starter bolt is a good idea. Brush the surfaces (starter and bolt) clean and don't use a lockwasher.
I recently measured the voltage drop across this connection and found 2/10 Volt, quite a bit when you start with six and actual cranking voltage is more like FOUR.
You can measure voltage drops with a digital meter. Just measure across each connection to see if any are dirty/corroded. Measure from end to end of each cable to see if their terminal connections are failing.
Wilson

I can say with all confidence that connections are good in terms of cleanliness/conductivity and I have suspected the battery early on as so many have suggested. With such a primitive system, I’m amazed at how sensitive this charging system is. A horse would be much more reliable.

^^This is how you find the trouble when the obvious things don't fix it.

I would only add that all Chevrolets of this era (and probably forever) are negative ground cars, unlike some other makes.

The cable going to the frame, transmission, or starter-to-bellhousing bolt (preferably a starter-to-bellhousing bolt) is ground. It may be a strap, and if so it will be bare and have no color. It goes to the negative post of the battery.

The positive cable will go to the starter power connection up on top of the starter. If old, it probably won't be red, maybe brown or black.

Never believe colors, always follow the cables and look. In the 70s and 80s (and maybe still) the cheapie replacement cables sold in parts stores were often colored more according to length or number of extra wires hanging out than anything else. It is common to see old cars today with the colors reversed.

I would start with a very slow charge (Battery Tender). This is going to take a day or two. I take my battery out of my car in the winter and put on a wood work bench, do not put it on concrete.
Your local auto parts store will test the battery for you at no charge.
If you need to replace the battery you need to do your home work, deep cycle, cold cranking amps, etc. I am not a big fan of sealed battery where you can not check fluid level.
My battery is 101/8 x 6 3/4 x 8" high at the time it was largest battery that would fit in the car. The posts are on the top
The strap that bloo is talking about can been seen of The Filling Stations web site part # SA-102 and SA-103.
Everyone has said that the GROUND is very important.

The strap is installed but to the trans housing. The positive is new but not the best at the battery terminal, I need a good positive terminal connection

Hi Mike,

Keep focused on the basics. If the connection to the positive battery terminal is not solid you will have issues. Ignoring that will simply continue the problems. Remember that this connection is also how the battery gets recharged by the generator.

Here are a few other points.

The color of the covering on the cable is irrelevant. The idea of red for positive is a “nice to know” thing that some manufacturers promote. There are no standards even today that control this. Obviously there were none back in the 30’s either.

There are many similar looking but different size battery posts. On a typical automotive battery the positive post will be larger than the negative. To confuse it even more the posts sizes on batteries for European cars are slightly smaller than U.S. cars. In the situation with 6 volt batteries it can be even more confusing. I have what NAPA calls an “industrial” 6 volt battery in my car. Both posts are the same size.

So this also means that there are different battery cable terminal clamp sizes to properly fit these posts. The most common problem I see is someone trying to use a positive clamp on a negative post. No matter how tightly they tighten the clamp bolt it will not fit tightly on the post. You can buy “universal” clamps that are supposed to be able to fit both size posts. I have seen mixed results with those.

I have 2/0 cables that I bought off the shelf at our local farm and tractor supply store (Farm &Fleet). I just checked their pricing and they would cost me about $40 total to replace them today. They clamp nicely on the battery posts. The ground is connected to the lug on the transmission. Obviously the positive goes to the terminal on the manual starter switch. I do not have any starting problems, hot or cold.

Chipper is correct. A volt meter is critical to sorting this out.

If you go back and go over your original post, there were some really good steps in there including comparing your wiring piece by piece to the proper schematic. I believe you started and then gave up part way through. It only takes one incorrect wire or poor connection to cause many gremlins...

That old wives tale of storing batteries on concrete just will not die lol.

Go slow with the basics like Rusty suggests. Heck, maybe make a youtube video showing us details of your wiring as maybe there is something really glaring. You just never know with wiring once people mess with it, especially over many decades...

I replaced all of the wires in the ignition/charging system but did not work on lights yet

Maybe I am confused. I thought you were having starting problems.

I am not sure I understand how replacing the wiring for the ignition and charging relates to that problem.

If you look at the wiring diagram for a 1938 car you will see that the starting circuit is between the battery and the engine. The lighting and charging are downstream from the starting circuit. As I have stated before, the starting circuit is also the path for the generator to recharge the battery.

If the starting circuit is not working correctly nothing electrical on the car will work as it should.

Prior owner had the car wires as positive ground so it was recommended I replace regulator and the wire insulation was gone in many places so i replaced the wire also in case it was contributing to other potential issues

I have a digital multimeter

Had a scare yesterday, went for a spin and my 38 died at the intersection.gas showed 1/2 tank but no go. Removed air cleaner and saw no gas squirting in, she was out of gas so I have to fix gauge more specifically wiring and or sending unit(supposed new tank and hole in trunk might indicate something was done. I also received my repops vent shades and need to determine oil filter color-(new topic)

The 1938 vent shades were painted to match the car color.

I assume that you confirmed that the tank was just about empty. You can "run a car out of gas" if the tank is not vented properly.

Modern gas caps will fit the filler neck but they are not vented. The venting is provided through the evaporative emissions system.

Given all the interesting discoveries you have had with this car that would not surprise me.

I did not confirm tank was empty but I have not put gas in her since purchasing and have ran her as much as possible and took her for short trips never noticing the gauge going below 1/2 tank. I am using a reproduction 1930s GM Locking cap. I hope it is vented but never had a problem with my old 38 using the same type of cap. I can only guess the work done on her was incomplete or possibly flawed.