1947 Ford Supe Coupe all original, been fighting myself to change that but the Gods of the pristine original won't work with me. However, I bought a 6V Batt with around 650 CCA and somewhere around 750 CA but the flatty just barely turns over and lags. It's not enough to even get fuel to the glass bowl on the mech pump. My question is, starter? Battery? something internal robbing the starter of the torque needed to spin the crank. I also noticed a bit of a spark from the lead off the starter. Not much but was looking like it was getting hot. I must say that it was running fine until a "friend" wanted to clean and dress the motor for me. I hate myself for that but lesson learned. I've changed oil and plugs, plus battery. Please help. I miss diving her. She also has a Strom 97 rebuilt. Thank you in advance.
Gotta love 6 volt systems. How are the battery cables? New or Original? I know over time the cables get corroded internally and can develop high resistance. Also if your friend dressed the engine he might have gotten the starter too wet and might have gotten water in the starter. Just a couple ideas to start with. Sent from my SM-G900V using The H.A.M.B. mobile app
Battery cables are new, grounds, etc but all other wiring is completely original. I'm going to replace them now that you mentioned that. I can't believe I didn't think to do this but it's a little disheartening. I'll start with the starter but these other wire leads to ignition and other components are some sort of cloth insulation and I have no idea what guage they are. Can I use modern wiring with a best guess at the guauge or does this even effect the starting, being that I have a push button solenoid and am still getting lag cranks?
You really need some thick ass battery cables for 6v. Over the counter won't do. A lot of people use 00 welding cable. Napa batteries tend to be crap. Optima 6v is better.
2/00 or "double ought" cables. The drugstore battery cables will not work. Will not work. Will not work. Any corrosion or paint (high resistance) in the charging and start system will cripple a generator or alternator, and soak up the current needed to fire the plugs. This is still true today but will be obvious in a 6 volt system. CCA in a battery is important, but buy the biggest, heaviest battery that will fit. Generator equipped cars and trucks are different compared with those with alternators in that there is little to no charging at idle. Consequently unlike alternators at certain running conditions the entire electrical system is running on the battery alone. Therefore reserve capacity is also important. A marine or deep cycle battery would be ideal if the CCA rating could be met in a size that will fit. High CCAs always comes at the expense of reserve capacity and a small battery can get smoked quickly. Any car or truck that is kept in a high state of tune will light off right away, constant or extended cranking on the starter is very hard on solenoids, batteries and starters. A good rule of thumb to follow is ten minutes rest for every ten seconds of cranking. Nobody does this, but it keeps the rebuilders in business.
Must have heavy cables 00 and clean all grounds including where starter contacts engine block! Very important Sent from my iPhone using The H.A.M.B. mobile app
Look first where You are seeing the sparks, could be a high resistance connection. ( corroded, paint or bad cable) If it was cranking good before cleanup look for something simple.
Cables and grounds, clean and file all grounds. Sent from my SAMSUNG-SM-G890A using The H.A.M.B. mobile app
Works for me on old 6v Ford Ferguson tractors... Temporarily jump the battery with a 12v battery while you are are cranking it over. So, 2 people, one at the starter button and the other with the jumpers, at the battery with one cable connected. While you are cranking, the other person momentarily touches the unconnected cable and she may fire right up. But, as others have said, all connections clean and tight.
The spark from the battery terminal is a telltale sign that your terminals need to be cleaned and tightened.
You say you have new battery cables but you don't say what gauge they are. 12 volt battery cables will not do the job.
Before you get to far with the cables have the Battery tested under load. Battery might be showing 6 volt but will die quickly under load.
I was just having a similar issue. Pulled the starter apart, cleaned the brushes and rust from the inside surfaces. Lubed the bushings and put it all back together. Turns over really well now. Sent from my iPhone using The H.A.M.B. mobile app
How is the battery hooked up. Ford 6v systems are positive ground and not neg. ground. I would pull apart the starter and clean grease and put it back in. Make sure the motor is grounded good.
I had a '47 Super Deluxe coupe with the same issue. (photos in my albums) It was the 12-volt battery cables that were on it when I bought the car. Get the proper heavy (00) 6 volt cables, as several have already mentioned.
Try putting jumper cables in parallel with the cars cable and ground strap and see if things improve. Charlie Stephens
Not rocket science but you must have good battery, I recommend Optima. Really really heavy duty battery cables OO for sure. Starter must be up to snuff. There is a gent who makes custom cables for old cars (not cheap and I don't remember who). I have run 6 volt on both of my projects see attached. Also look back in thread for 53 Merc with blown McCullough...its a 6 volt to!
I'd expect a voltage drop test while cranking would point exactly at whichever connection needed cleaning, or cable needed replacing.
The larger diameter the wire or cable, the less resistance it has. The heavy 00 cables will have far less resistance that the 4 gauge cables commonly used on 12V systems, Every circuit on a 6V car uses a heavier gauge wire than the same circuit would need on a 12V car. Resistance produces heat. If your cables get hot to the touch, they are too small to do the job. Also the longer the wire or cable, the more resistance you have, so if you have an extremely long battery cable, go up a cable size. You will never have a problem caused by a battery cable being too heavy a gauge. If your cables are heavier than you really need, it will just cause the starter to spin a little faster. Bigger cable means less resistance which means more amps getting to the starter. Corroded terminals will get hot under load. I have seen lead battery terminals melt from somebody grinding on the starter. If you do convert to 12V, you can keep your 6V starter. If your engine has good compression and is tuned up well, it doesn't take much to start it. You can burn up any starter grinding on it, whether it is 6 or 12 volts. With a well-tuned engine that has good compression, a 6V starter can live a long time on 12 volts.
I agree w/ Gene re; using an Optima 6v battery. My '38 had me nervous 'cause when it was up to temp, it would turn over so slowly, I was afraid it wouldn't catch. (though it always did) After installing new OO cables, I found a character on e-bay with a 6v appearing battery case that an Optima fits into. I set it up and unless you know what you're looking for, you can't tell it's not authentic. Now it spins over and starts fast! Good starter + good battery + good tune up = good fuel = good times...
As others have said, 00 gauge wires and good connections. If you already have that or once you do, it still cranks slow, then pull the starter and go through it or have it rebuilt. Mine had a bent shaft and caused poor cranking. New battery cables and a 650CCA battery spins my flatty over just fine.
Did your friend do any painting when he detailed the engine? That's where I would start. When I converted my engine test stand to run 6 volts as well as 12, I decided I needed better cables. To my surprise, my local NAPA store was able to make up everything I needed on the spot for $40. Don't give up; I have a 255 Merc with 160 lbs compression in my '51, which should be harder to turn over than your stocker. With an 800 CCA Optima, it turns over just fine. Keep looking, you'll find it.
As Paintslinger said check to make sure you hooked up the battery with positive ground. Then cable size, then starter, voltage reg, coil, etc.
The Jalopy Journal
