My 61 f100 / 460/c6 is hard to start when hot. I've seen comments saying it may in part be the size of the battery cables. So what is the recommended gauge? I'm sure I've seen this info here, but several searches hasn't turned it up. The - cable on the truck now is 6 gauge. The + cable is hard to see any size but it is heavier, maybe 4 gauge.
also check the grounds to make sure good contact is made . 4 gauge is what I have listed for the old mousetrap style starters ( armature arm ) , they used in the 1970's and ground and positive should be the same gauge .
429-460's were always hard on starter and being hard to crank when hot. Make sure cables are heavy duty.... Number 0 welding cable is not overkill... And make sure the ground goes from battery to the block. One of the high torque mini starters might work better too. Sent from my Moto G Play using The H.A.M.B. mobile app
So it sounds like hevier cables are called for as a place to start. Right now the - cable goes to an intake manifold bolt.
If you search that auction site for "1/0 battery cables" a couple vendors will pop up that use real AWG stranded pure copper w/ marine grade insulation. Can spec 3/8" or 5/16" ring ends, and any length you want. Nice tin plate copper terminals. They don't cost all that much and are real quality.
How long are the cables? On a 12V system under high amps, voltage drop combined with distance will kill performance quickly. If the cables are under 3' long each, you can probably get away with #1 cable. For every additional 3' cable of added to total length, you should go up one wire size to keep voltage drop to acceptable levels.
if you have the starter I posted you need as much Amperage as possible , as I remember from high school ( 1980 ) those pulled close to 600+ amps initial to pull the arm on the unit to engage the starter , I always ground to the block ( near the starter the better , like the engine mountbolts or on a starter bolt as heads and intakes people tend to put sealants on them that can insulate the circuit path or they develop corrosion if its wet hole bolt ( cooling jacket ) and it acts like a resistor .
A high torque mini starter should relieve your starting issues along with good cables and a good ground and run an extra ground from the engine to the frame and a body to engine ground. Ford had them from the factory. How much timing do you have in the motor while cranking ? That will affect your hot start. You may need an MSD start retard. If you have a starter button get the motor spinning over and then turn on the ignition. That will help.
I bought a 1978 Lincoln once and it was embarrassing getting gas as the car wouldn't start after filling the tank. The car was 1 year old and the problem was the battery.
There are a lot of marine supply places on eBay that sell cables (eyelets on each end) for trim tabs on boats. These are heavy duty and fat, some are name brands like Merc Cruiser. The prices are good, I had mine made up by a local speed shop, ran me $38 but they made them up in 15 minutes. I use Quick Car stock car clamps that take the eyelets.
I had a 390FE in my OT 66 Fairlane and the cause of it not starting was the battery cable, once upgraded to a hearier one I never had a problem again.
I have an OT Ford that was hard to start when hot. Tried a new starter, battery, etc. Nothing seemed to help, until I put a heat shield on the starter and that problem went away.
Here is a table of the rated Ampacities of welding cable. I don't like to use anything less than 2/0 which is rated at 450 amps. 1/0 is good to 350 amps. No use having a battery that can output 700 amps and have a cable that can only handle 200 amps. The chart has a minimum length of 100 feet so they will handle a little more at shorter lengths. https://www.iewc.com/-/media/iewcglobal/files/resource-downloads/welding-cable-ampacities.pdf
Those charts aren't really applicable. The top chart assumes a 4 volt voltage drop; if you drop 4 volts in a 12V system, you're now down to only 8 volts. The lower chart is somewhat closer, but an acceptable voltage drop at 120-600 volts is still too high for a 12V system. The thing to remember is the amount of voltage drop for a given load in amps and specific wire size/length will be the same amount, regardless of system voltage. When you drop 4 volts and the system operates at 120 volts, that's only a 3% drop. At 12 volts, it's 33%. You really need to do a voltage drop calculation... http://www.calculator.net/voltage-d...nce=10&distanceunit=feet&eres=23&x=55&y=16
The chart is also for a 100 foot circuit at 140 degrees Fahrenheit. I suspect most automotive circuits are 10 feet or less. 4 volts in 100 feet would be 1 volt in 10 feet.
Actually, it would be .4 of a volt. Via a voltage drop calculation, it would be even lower (.25 volt) which is one reason I don't like this chart. Yes, you can always go big on wire size; electrically, it never hurts. But that big wire isn't always as easy to terminate, route, or hide. Plus it costs more. Battery CCA don't matter; it's how much current the starter draws. Yes, having the large battery is good as it gives plenty of reserve power, but the starter will only draw what it needs. Here's an example: Let's say the starter draws 350 amps (typical V8 starters draw about 250 amps). That's pretty much a worse-case (if it's drawing more than that, you have other issues). If the total cable length of both cables is 6 feet or less, #2 cable will deliver that 350 amps with a 2.4% voltage drop. Generally, any drop below 3% is very good; 5% would be acceptable, more than that you'll start having issues. If you increase the total cable length to 20 feet, you have to increase the cable size by five sizes (all the way to 4/0) and this will give a voltage drop of 2.5%, slightly higher. So only a few feet difference in cable length can have a major effect on wire size in a high-current circuit. 4/0 cable is almost as big as 5/8" heater hose... not something I want to install if I don't have to. If you're having issues with heat-soaking the starter (causing it to draw even more current), larger cables will help, but will probably just allow you to kill the starter faster.
Back in the good old days ? When R-12 was cheap I worked on an alcohol funny car towed with a 454 dually with headers. Every time we stopped for gas the starter would heat soak and we were stuck. So we started carrying a 30 lb. can of Freon with a hose. Just slide under the truck and spray the starter down and it would crank right up. Totally not environmental friendly , but it worked great.
I'm a luttle surprised by the HUGE variance in prive for these things. One that seemed to get good reviews was only $45.00 or so, others ran as high as mid 300.00s? Is there really that much difference in quality? (I don't want to be replacing starters as a hobby, but I don't want to spend more than I need to either. (Looking locally for heavy duty cables.)
What do welders operate at? 30 to 90 volts? There's a big difference in amperage between 6 or 12 volts and 90 volts. I'm not sure this wire chart is relevant to the lower voltage-higher amperage of cars. Maybe someone who knows more than me can chime in. Sent from my iPhone using The H.A.M.B. mobile app
Lot's of good advice on wire size, but have you considered heat? How is your exhaust or headers run? Are they close to the starter? Worth a look.
I didn't measure, but the header/exhaust-pipe is only about 2 or maybe 3 inches from the starter. The + cable is in that space and is held closer to the starter with some kind of clip with a plastic cable protector (?) in it. I was able to install a new 4 gauge cable hooked directly to a starter bolt closer to the firewall and several inched farther from the exhaust. The new 4 gauge - cabled helped a bit, but not enough. I'm thinking that when I get heavier cables I should get a + cable long enough to run it like i did the - cable.
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