The Stovebolt Site Forums The Shop Area The Electrical Bay 1946 Chevy Pickup 6 volt starter and possible ground/short problem

Never mind...Jerry is 100% correct.

Almost all 6 volt cranking difficulties can be traced to two problems. The first is too-small conductors and the second is poor connections. I got my education on 6V cranking in the early 1960's, keeping a flathead Ford V8 with 11:1 compression running. The same things I did back then work today. Buy or make battery cables from cable at least #1 size wire, and 0 or 00 is better. I use #0 welding cable and crimp, then solder the connectors onto both ends. Run the ground cable all the way to one of the bellhousing bolts, not to the frame or body like it was done originally.

Next- - - - -disconnect and clean EVERY connection in the circuit- - - - -both battery terminals, the ring terminals at the ends of the cables, and be sure the starter housing to bellhousing contact is clean, oil-free, and tight. Get everything clean and shiny with a wire brush or a wire wheel in a drill motor, then tighten the connection securely.

A 500 CCA 6 volt battery is pretty weak. You're sending a boy to do a man's job. Measure the voltage at the battery posts during cranking. If it goes below 4.5 volts after you've done all of the above chores, get a bigger battery. The shock you're getting with the battery charger running is a design flaw or a short to 115 volt house current inside the charger. That's a potentially deadly situation, as it only takes 1/10 amp of current across a major organ such as your heart to kill you graveyard dead! A 15 amp wall plug has 150 times the current capacity needed to provide a fatal shock. If you're going to continue to use that charger (I wouldn't!) drive a steel rod a couple of feet into the ground and attach a jumper cable from the vehicle to the grounding rod.
Jerry

The Optima battery is excellent.
It fits into the battery box on an angle.
If you do not drive often, get a cheap 6v battery tender.

As posted many times, the size of the battery cable is critical, and clean battery cable connections are critical.

Ditto on the disconnector- - - - -the only one I'd consider would be the one we used on round track race cars with a 1000 amp surge rating. The ones with a plastic "flag" handle aren't usually rated for 6 volt current draw.

For instance:

https://www.jegs.com/i/JEGS/555/10307/10002/-1

Jerry

Terminal voltage while cranking will tell the tale, but only if the connections are clean and tight and the cables are big enough. 6 volts leaves absolutely no room for error where voltage drop across connections are concerned. Dropping more than 1/10 volt per connection is too much.
Jerry

6 volts you shouldn't feel a shock soaking wet. A static charge you will feel, but gone instantly.

Nope. 6 volts can only push 1/2 the amps thru the same resistance (your body in this case).
I used to check 9 volt batteries (the little rectangular ones) by putting my tongue on the terminals. Tingle = good battery, no tingle = bad battery.

Actually it is the amperage, not the volts. A static shock is thousands of volts, but not enough current duration to be fatal. As little as 50 milliamps can do it though, but would probably need at least 30+ volts to push it through your body. A GFCI outlet trips at 5 milliamps, which is checking for equal current flow on both wires, not the voltage.

A HEI coil produces a minimum of 25,000 volts on open circuit, and I've seem scope patterns with a spark line over 50K. One of my classroom demonstrations used to be holding a spark plug in my hand with a HEI distributor running on a Sun tester, and let the students watch it fire a spark. Of course I made it a point not to touch the tester and get myself well grounded. Then I'd challenge the big, tough gangbangers to do the same thing! Very few of them took the bait, and the ones who did ended up doing some amusing dance moves!
Jerry

Any copper or brass alloy connector can be soldered. I use 60/40 lead/tin rosin core solder (definitely NOT acid core) and a Propane torch. I buy cable in bulk on Ebay, and there's also a hammer-style terminal crimper available there. For the cost of a few custom-made cables, you can be set up to make bunches of them, any length you want. IMHO, anything bigger than about 1/0 gauge is overkill, especially if you use fine-strand welding cable instead of the wire with thicker individual wires. Electric current is carried mostly on the surface of a wire, so a conductor with a thousand fine strands has less resistance than the same gauge of wire with a hundred thicker ones. The fine-strand wire is also more flexible.
Jerry

It looks like you're well on the way to having some excellent quality cables. That hydraulic crimper sounds interesting- - - - -mine does the same thing with a 3-lb. hammer with the crimper sitting on my anvil. Soldering a well-crimped connector is sort of like using a belt and suspenders to hold your pants up- - - - -overkill, but effective! The disconnect can be located in either cable, as long as it interrupts the current flow. I always attach the ground cable to the block or bellhousing, since the starter is by far the heaviest current draw item. Then I run smaller-gauge ground cables to the frame, body, and bed to assure the lights and other accessories are well-grounded. There's no such thing as having too many grounds. If you're running a DC generator, be very sure the base of the voltage regulator is well-grounded to the generator housing. Lots of charging system woes can be traced to poor grounding between the generator and regulator.

Have fun! Cranking a hotrod flathead V8 with 11:1 compression in a 47 Mercury convertible in the early 1960's was my introduction to diagnosing 6V starting problems, but I was lucky that my father was one of the best auto electrical specialists in Nashville Tennessee!
Jerry

The disconnect needs to interrupt ALL the current flow, as it's the only way to positively prevent parasitic drains on the battery from infrequent driving and/or short circuits. Run the ground cable TO THE BLOCK first. The more connections you add between the battery and the starter, the more possibility there is to have a high resistance connection or a loose one. Making two extra ground connections for the starter current to go through serves no useful purpose. "This ain't rocket surgery!" The simplest circuit is usually the best, and millions of stovebolts managed to have a long useful life without fancy stuff like a battery disconnect. Since it's already there, go ahead and use it, but it's really an unneeded extra.

10 gauge? Maybe you mean 1-0? 10 gauge primary wiring is used in places like the charging leads from the generator to the regulator, the ammeter, and finally to the battery cable terminal at the starter for battery charging. It's definitely not meant to carry starter current.
Jerry

That should work nicely. I use the negative post disconnect to kill all power to truck. My ground goes like this . Ground of battery to cab,cab to frame,frame to engine, then to Alternator. Never had a problem ,all ground connections clean and shinny, after done spray connections with battery cable protection.

I understand what you're trying to do, and for the most part, you're going about it the right way. It would just be better if we get on to a one-on-one conversation. PM or phone works a lot better.
Jerry

Take that wire back off. It's not a ground. If you crank the engine with it attached you'll burn the wire. It will be a dead short while cranking.

That might be a 12 volt starter. They're the only ones that had the small terminal on the side to bypass a resistor used only with 12 volt ignition systems during cranking. Take the starter off and measure the shaft diameter like I suggested.

Ground the frame/body using one of the starter mounting bolts if you need to. The starter is already grounded when mounted to the engine.

"Electric current is carried mostly on the surface of a wire, so a conductor with a thousand fine strands has less resistance than the same gauge of wire with a hundred thicker ones."

Good morning Keroppi,

I checked the above quote with one of my sons who is a electrical engineer and he explained that how electricity travels is actually dependent on its frequency. He explained that it's the electrons that actually move in a conductor and electrons repel each other and stay as far apart as they can. How electricity flows is explained in this article:

https://physics.stackexchange.com/q...the-surface-of-a-wire-or-in-the-interior

See what I was talking about in our PM?

The side terminal will only be shorted during cranking if you ground it. That huge mass of cast iron of the starter nose cone IS the ground, since it's bolted to the engine block!
Jerry

A starter operates at the virtual equivalent of a dead short. You're reading a resistance through the windings of the field coils and armature that is so low your ohmmeter is seeing zero resistance.

Let's do a little math. A 6 volt starter that's drawing 200 amps will drop the terminal voltage of the battery down to about 4.75 volts or so due to the high current load. 4.75 divided by 200 (E= R X I ) gives a resistance of 0.02375 Ohms. Your ohmmeter simply can't read that low, even a digital one. The small stud is connected to the UPSTREAM side of the starter motor, not to ground. It is there to switch full battery voltage to the (+) terminal of the coil when a 12 volt ignition system is being cranked. As soon as the starter pedal is disengaged, the ignition primary voltage goes back to approximately 9 volts, from the downstream side of a ballast resistor that is there to protect the points from burning.

None of these items- - - neither -the bypass terminal nor the ballast resistor is used with 6 volts. A 6V starter switch does not have the small side terminal, since it is not needed. The switch with the bypass terminal will fit either starter, however.

NOW- - - - -please find out if you've got a 12V starter before doing ANYTHING else with the wiring system!
Jerry

I'm getting a little frustrated with your stubborn refusal to do a little simple testing. Try removing the switch from the top of the starter (one cable connection and two screws) and check it for continuity while it's removed from the starter housing. I have a feeling that the small stud is shorted to the switch housing, (It's supposed to be insulated.) and the conductor that normally makes contact with the main terminal during cranking has probably been burned away due to the short. It's pretty obvious that you do not understand the function of that small terminal which was not even included on starter switches for 6 volt systems. You've either got the wrong switch or the wrong starter. We need to find out which is the case before doing anything else. If you're trying to crank a 12 volt starter with 6 volts, you're on an impossible mission- - - - -it will NEVER crank the engine at the correct speed.

It’s time for everyone to take a deep breath and let this thread rest for a few days. Jerry has tried his best to explain. Alan has tried his best to understand. Nothing is getting accomplished and feelings are getting hurt. At this point no one is going to learn anything.
We can come back in a few days and revisit this when cooler heads prevail.

Justhorsenround. Thanks for the assist.
Rusty Rod

First. I locked this thread instead of just deleting it because it does have a lot of value.
Second. I deleted several posts and edited a bunch more that contained unrelated information.
Thank you for your understanding. Please keep your posts civil and on topic.

Keroppi, how is this project coming along?