What Size Starter or Battery Cable Should I Use 1962 Cadillac

[JackGriffin]

But a starter will only be run for short bursts - those figures are for continuous use, aren't they? Welding earth cables are favourite as they have a high continuous rating and are very flexible due to using multiple small wires.

[Plumpcars]

I think you are way under with the 25. I use modern flexi cable. On a slightly modified 348 Chevy which is probably comparable to yours I use 603 in the link. On my 55 which is a radical build I use 605. Length plays a huge part in your calculations but I would not go less than these. I have no hot start issues at all which is often a problem with a GM starter.

Battery Cable - Flexible

ps. remember that your earths need to be just as good.

[Darren West]

i agree with your cable choice 100%

[V8 Sarah]

Thank you everyone for all your inputs and I will try to respond in one hit here

The car is a 62 Caddy with the original battery at the front and the length to the starter solenoid is about 4 feet, but badly routed so will end up about 6 feet when better routed and secured. The engine 390ci running on 10/40 classic oil with higher zinc content

I saw a sight today in America selling 'original spec' Caddy starter wire and the spec said 4 gage (American spelling), which if I am right converts to around 25mm2 ...that thought does seem a little small and so is the wire currently fitted ...I'll post piccies tomorrow in between work if i can to show you. The spare wire I have here is 25mm2 multistrand, which as you all say may be well under rated. I just need to get this right.

Thank you brading, but there is no need to apologise, we are all here to help, learn and support each other and non of us ever stop learning

Thank you Plumpcars ..I'll Google 605 wire tomorrow and have a gander .... The earths have already been changed to overkill 40mm2and run one directly to the block too ... I did this too on my CF1 van lately and what a huge difference on starting

Thanks Darren too

All this help is very much needed and appreciated ...It's now time for sleepies as I have an early start ...I'll check back during the day

Sweet dreams all

Sarah

[Plumpcars]

My number 605 relates to a part number on the link I attached rather than a Google item. Check that website, they also sell stiffer older style cable. My choices are what work for me and I'm not saying that they relate completely to factory. The 605 is overkill but used along with a heavy earth circuit to eliminate any possible issues. I also incorporate Ford style solenoids in all my GM re-wires but that is another story. For the Caddy I would use the 603 probably and yes I've run a few early Cads myself.

[boblester40]

Looking at FLC ratings for cable for starters is pretty much useless apart from as a guide , the peak current drawn by starter motors will always exceed the FLC of the chosen cable and that is why they get warm with repeated cranking , for anything big old and american i would use 35mm minimum , long runs over a meter or so i would go bigger again , dont forget the CCA of batterys can be over 800 amps and you will approach that on a cold day.

Most the maximum current carrying capacities quoted in BS7671 are in relation to domestic or industrial installations , the buggeration factors of motor vehicles is much greater , it would be unacceptable to have more than 1 volt drop whilst cranking over you starter cable according to the regs but as you know you get much more .