two 6 volts batteries for more cranking speed

[Guest 1936 Ford Truck]

Having a problem with new optima 6 volt battery cranking fast enough for motor to start. (measuring 6.2 even when cranking so it is good.)

It turns fast enough just to start, but other times it turns slow, it happens either hot or cold doesnt matter and with no consistency.

new rebuild starter in place 6 volt. new cables sodered in connectors, positive ground system grounded to frame, and negative ran thru 300 amp discinnect switch.

if I isolate system and put striaght 12v to starter it cranks really fast every time and starts right up.

so i am thinking about putting 2- 6 volt optima batteries (in parallel) so i would have up to 1600 CCA. with just 800 ,which I know is a lot, it just doesnt turn fast enough to start.

anyone have any ideas or experience?

[ply33]

What gauge are those new cables with soldered ends? Starter cable gauge is critical with 6v systems.

I have heard that if the bearings/bushings are worn in a starter that you can also have a situation where it won't crank over well.

A assume you are dealing with a 36 Ford truck based on your ID. I don't know much pertaining to it exactly but I do know that a factory stock 6v electricals were a reliable and sufficient starting system for lots of cars for lots of years. So if the vehicle has starting problems now it is because of maintenance and repair issues and further modifying the vehicle to "fix" that is generally just putting a band aid on a problem that ought to be properly corrected.

[Guest billybird]

After making sure the cables are the correct guage, I would then look at the ground connections. Having been through this before, thats what it sounds like. Does this truck have a ground strap or cable? Most flatheads of that era have a ground strap from battery to firewall then firewall to engine block. The cars are this way I would assume the trucks are too. If everything is right on a 6 volt system, the optima should turn it over like a 12 volt. Mine does.

[Guest De Soto Frank]

How does it crank on 6-volt if you bypass that disconnect switch ?

Does the disconnect switch get hot after cranking the engine ?

[Dave Henderson]

Nothing has been said regarding how things were prior to installing the Optima, what the vehicle is, or why a rebuilt starter was installed. Is this a vehicle that stood idle for some time and is now being revived, or maybe one recently acquired along with the problem? Is the engine newly overhauled and tight? Some background info could assist in finding a solution.

Things not yet mentioned that you could try; bypass the solenoid (assuming it has one) with a heavy cable (one end attached, the other end applied by hand), or substitute a known good solenoid; Be leary of a newly rebuilt anything, the starter's brushes may not be seating properly, or the armature shaft may have a slight bend. (I personally experienced that with a '35 Ford coupe that would only start a few times before killing the battery); And, try another known good battery . To experience a speed-up with 12 volts is to be expected, but 12 volts shouldn't be necessary.

[Ron Green]

Assuming your cables are the correct size: I had major problems with soldered ends on my electric car as they had too high of a resistance and burned at the lug, and even melted the solder under a heavy load. The lugs / ends were designed to be crimped not soldered so you may want to check to see what type you have. Replaced the cables with factory crimped ends and all is well.

When waking the vehicles up from their winter I always parallel 2 batteries when starting them for the 1st time of the season.

[Ben Bruce aka First Born]

1936, you are getting a lot of good info. Want a little more? If the neg cable is not at least as large as your thumb, it is too small. This should be a 2/ 00[two ought] gauge. The ground cable should be as large, whether flat or round.

I have recently finished a 1050 Buick. Six volt. I had the starter rebuilt at a starter, alternator shop. They can also make the cables for you.

Good luck, keep us posted.

Ben

[Guest Timthemailman]

Again, not knowing the whole story, this is a shot in the dark but.... I had a VW w/ 6V system. The engine always started but turned over slow, even w/new battery. My Dad put a Mallory Magspark coil (I don't know what it was off of, my guess would be Ford) on it and it cured the problem. I'm not a gearhead but it sure worked for me. The coil gave it alot hotter spark. Good luck.

[Guest De Soto Frank]

I'm suspicious of that 300-amp disconnect switch; my 1952-'59 MoToR's Manual (the only thing I have handy right now) lists the '52-'55 Ford six-volt starters as drawing 725 Amps on "torque-test" ( formerly referred to as the "lock-test").

That's twice the capacity of the disconnect switch described in the original post.

A six volt vehicle should have battery cables no smaller than #2 gauge, preferably a bit larger, if possible.

If the battery cables aren't as big-around as your ring-finger, they're probably too small.

I've seen many "slow-cranking" six-volt vehicles with #4 or #6 gauge 12-volt battery cables.

[Guest 1936 Ford Truck]

great suggestions ...........lets see if this info helps

this is a 1 1/2 ton stake bed truck with flathead v 8 POSITIVE GROUND system.

when i got truck, 2 yrs ago, it had sat for about 40 plus years in a barn and I just had engine rebuilt, as I have been restoring the rest.

when i took apart the only "grounding strap" which remember is the "positve cable off" battery, was connected to frame just behind transmission, on cross memeber.

there was nothing going to motor from frame . the other cable "negative off battery" went to starter switch and then another from switch to starter. (which only has one lug and no solenoid).

this is how I have it wired now. except between starter switch and negative battery terminal I put a disconnect switch (300 amp) reminder the switch i am referring to is the floor switch you push down on.

the speed is the same with and with out the disconnect switch in use.

the positve ground cable I am using is just a battery cable like what would be used on a 12 volt system. maybe i should step up in size it is about as round as your pinky, but it is welding strand

do I need to go back to a strap as a positive to ground on frame or do i need to add a cable from frame to starter mounting bolt?

I am still using points and condensor and flat top coil system

thaks for all the suggestions

[Rusty_OToole]

Could be the starter was not rebuilt right. A local mechanic had a 55 Dodge Royal V8 that always started slow even after installing a rebuilt starter. Several years later, after trying everything including a new battery every year, he took apart the "rebuilt" starter and found it had 12 volt field coils. New 6 volt field coils and it started like a new car.

[MCHinson]

"positve ground cable I am using is just a battery cable like what would be used on a 12 volt system"

This may not be your only problem, but it is at least part of the problem. Install the correct sized cables for the 6 volt system and it will certainly be an improvement, if not the total fix.

[Guest 1936 Ford Truck]

ok more information i just went out and looked at everything again.

the cables which go from negative side of battery to starter switch (in floor) and then to starter says "Laribee 2 neoprene welding cable 610v" it is think stuff so what do you think.

then as I said incorrectly in prior posting, the positve cable goes from positive side of battery to disconnect switch 300 amp then to ground which is frame. that cable is "number 4 welding cable".

[Guest Bob Call]

Junk the disconnect switch. The cables for 6V should be 0 or 00 guage. Ground the battery to the frame or body and ground the engine to the same. I would also replace the bushings and brushes in the starter. Measure lengths of cables and go to NAPA and order correct lengths and guages. 12V cables are too small guage. I don't know for sure but your 2 and 4 guage welding cable may be too small. I would say that the 4 guage is definitly too small.

Edited July 15, 2010 by Bob Call (see edit history)

[Dave Henderson]

Sounds like you have a combination of things capable of contributing to the problem. First, that 12 volt cable isn't heavy enough for 6 volts and alone could be the problem. You could add another one like it in parallel to prove it out, or just get a proper 6 volt one which you will need anyway. And, aha, a newly rebuilt engine. And one that apparently has been sitting around for a while. It may be a bit on the tight side until broken in. What weight oil is in it? If you don't know, you could drain it and refill with a very light oil for start-up and a short break-in run. Timing can also cause hard cranking, if the plug fires too early on the upstroke.

[Guest De Soto Frank]

Couple more thoughts:

1 ) Rebuilt engine? It's going to be "tight" until it's been broken-in, due to increased friction between freshly-honed cylinders and new rings.

2) The stock ground strap between the transmission and frame should be adequate, as the tranny / bell housing / engine are all bolted together, and should act as "one piece of iron". Unless perhaps these components were painted separately, and the mating flanges have a layer of paint on them; in the factory these components were usually painted as one unit, after they had been assembled together. If you want to run a second ground cable (#2 or #0) from one of the starter mounting bolts to the frame (( clean bare metal at both ends ! )), that won't hurt.)

3) Cable gauge/capacity: the #_ is the size of the conductor; "welding cable" refers to flexibility ( fine-stranded, flexible jacket), not current capacity.

That hunk of #4 Welding Cable bewteen the disconnect switch and the frame is probably one of the culprits. You need #2 gauge or larger.

If you want to do-up one set of cables and never have to worry about them again, go to a big truck shop, and have them make your cables up in #0 cable.

4) Leave that d___ disconnect switch out of the circuit for now !!!!

When you're done working with the truck for the day, disconnect the battery. Once you've got it cranking and starting reliably, you can see about getting a properly sized disconnect switch in the circuit.

5) MoToR's Manual 1935-1942 lists current draw for ALL Ford starters at 500 Amps on "lock-test". Your disconnect switch is 200 amps undersized.

Edited July 15, 2010 by De Soto Frank (see edit history)

[Guest 1936 Ford Truck]

Thank all. Your suggestions are good so I am going to:

1) up grade cables to "O" strain welding cable for flexibility

2)by pass disconnect switch

3)add a grounding cable from starter mounting bolt to frame

I'll let you know what happenes

[Guest Robin Coleman]

Just a quick thought before you go replacing everything....Find where the problem is first. The voltage at the battery is not nearly as important as the voltage at the starter. It must be checked under load. Anything over a 10% drop WHILE cranking is too much. If you have a voltage drop of any significance then backtrack to each component looking for less voltage drop...When you find it then that part is probably at fault. As important as voltage is current draw. As available voltage goes down, current draw goes up. It takes very little resistance in a starter circuit to ruin your day.

[Guest 1936 Ford Truck]

ok up date

replaced the wires to "0", cleaned all grounding contact points and added a cable from motor to frame.

wow problem solved, spins perfect. I even added back in my disconnect switch, after i tested everything and no problems.

thanks for all the advise

[ply33]

ok up date

replaced the wires to "0", cleaned all grounding contact points and added a cable from motor to frame.

wow problem solved, spins perfect. I even added back in my disconnect switch, after i tested everything and no problems.

thanks for all the advise

And thank you for getting back and letting us know how it turned out.

[trimacar]

This is a great read, to see the entire story, problem stated, discussed, solved.

As many of you, I've been enjoying old cars for decades. How many times have you heard this problem? All the time. People say the old 6 volt system doesn't work, converted to 12 volt is seen as a good selling point, and so forth, all because the cable issue is not understood nor corrected.

They worked when new. Just like steering, brakes, and all the other systems, if they didn't work right, people would never have bought the car new in the first place.

A good story with a happy ending!

[Guest]

This is a great read, to see the entire story, problem stated, discussed, solved.

As many of you, I've been enjoying old cars for decades. How many times have you heard this problem? All the time. People say the old 6 volt system doesn't work, converted to 12 volt is seen as a good selling point, and so forth, all because the cable issue is not understood nor corrected.

They worked when new. Just like steering, brakes, and all the other systems, if they didn't work right, people would never have bought the car new in the first place.

A good story with a happy ending!

X2 could have not said it better although for me going from six to twelve is not a selling point. To the contrary it is a notation I make when looking at the car as a problem that no one took the the time to fix properly. Also, I think it really looks out of place to look into a engine compartment and see something that shouldn't be there. After seeing a alternator on a V-12 Lincoln at a show I wouldn't even look at the rest of the car.

BTW in the 70's a guy two doors down from me was trying to get this 37 Ford woody ( he has since become a lifelong frend ) started. At the end of his frustration he installed a 6-12 battery. 6volts to run the car switching to 12 volts for the starter motor. The car still had problems starting hot. After finally solving his problem for him the car is a joy to drive, mechanical brakes and all. The hot start problem turned out to be Piston/ring to cylinder wall clearance and too tight main and con rod clearance at .00075. That was the first time I rebuilt a flat head V-8.

I know some people say you need a alternator and 12 volts to run all this extra bits of gear these days. For these people I say you belong in the modified crowd. For me, I want to experience the car for what it is- in it's own place in time.

Don

[30 Hupp]

For me, I want to experience the car for what it is- in it's own place in time.

Don

Couldn't agree more!

Dale

[trimacar]

I agree, as it was is the best- and I was being sarcastic when I said that the 12 volts was a "good" selling point, to me also it's a sign that someone hasn't researched and fixed the real problem.......

[KRK Sr.]

36 Ford truck, now that your voltage drop problems are solved here is my two cents on answering your first question, I own a 1929 Pierce with two Optima 6 volts in parallel keeping them 6 volts, the car is connected to a battery tender when not in use. It is the no easier to start than the 30 Pierce with only one 6 volt battery. However when flooded or vapor locked it gives me a longer shot of getting it started during these troubles. Starting with a fully charged 6 volt battery is more important to getting hot spark and easy starts with maximum cranking speed. Karl

[Guest 1936 Ford Truck]

Thanks again guys and I agree I have had many people say just change out motor to something modern, convert system to 12 volt. up grade away from mechanical brakes.

But I have kept this as it was in 36 all is original, all I have done is paint and rebuild.

believe it or not, this truck runs like a sewing machine and drives nice. I just plan my stops a long way in advance.

[Guest hectorb1]

does anyone know if a  ford model A starter fits a essex super six. the housing looks identical on pictures but before I go ahead and buy one I'd like to know??

[Guest]

Glad you fixed it. Regarding your original question, I have a dual Optima 6 volt battery pack in my 1937 Cord. You can see the one I am using at www.henmach.com. I also used their custom length 2/0 welding cables and am very pleased with the package. Although pricey, the pack is very nicely put together including the holder and the cables/terminals that tie the 2 batteries together. Icing on the cake, after you get everything else in the system as it should be.

[Hudsy Wudsy]

I've had experiences with proper sized cables that still had too much resistance in them. One thing that I will suggest for anyone experiencing these kinds of difficulties is to simply crank the engine over with the ignition switch off for a little while (not too long) and then go and feel the various cables cable junctions and ground straps for heat. If the problem doesn't show itself, then crank it a little bit longer. I've always found that sooner or later the problem will show itself. It really works to help locate the high resistance spot.

[Guest]

I just realized how old this thread is, LOL. If the OP is like me, he's had about 10 cars since then, and the subject truck is probably long gone. Oh well, informative anyway.

[Friartuck]

Agree with trimacar and 31 Caddy, this is a useful thread (problem and solution) and is now a few years old. I'd like to take it one step further and if 36 Ford Truck (Original Poster) is monitoring his own thread I'll suggest doing one thing to help determine which solution did the most good:

 

Disconnect the cable from the engine to the frame and how does the starter perform? In other words was increasing the cable size or adding the cable from the engine to the frame or a combo the real solution.

 

My experience with the Optima brand has not been stellar. The initial output is good, but lacks in longevity.  While two in parallel may improve the cranking time, I have a confined space. Given the price of the Optima, I'll stick with my wet cell and replace every 5 years. 

[60FlatTop]

Anyone remember Gus and the Model Garage? There was a story there a long time ago about a customer who wondered why his dashboard glowed red when he started it.

 

http://www.gus-stories.org/

 

Turned out the mounts isolated the engine, including the starter, from the ground. All the starting current was returning through the temperature gauge copper tube that was attached with a clamp to the back side of the dash board.

 

I never did get through the High School assignment to read Homer or Dickens, but Gus; well, that was useful stuff. I still get chastised by my wife, the librarian. "You never read any novels." she says while I read a shop manual I picked up at a yard sale... for a car I don't even own. This evening I'll be reading about real world applications of quadratic equations.

Bernie