What size starter cable gauge?

[David_Leech]

1928 Standard Six

 

Still on a six volt system. I think the starter cable is undersized or at least in poor condition and in need of replacing. Same with the chassis ground. It cranks too slow, barely sometimes. What size cables should be used on a six volt system?

[Bloo]

#00 would be a good choice. Some cars got by on less (maybe #1) but probably never as small as the #4 typically sold for 12v systems today.

 

<Smaller> - 8 - 4 - 2 - 1 - 0 - 00 - 000 - 0000 - <Larger>

 

Think of it as a big circle from the battery post to the starter post, through the windings, and then from the starter case all the way back to the other post of the battery.

 

For instance, if the ground cable goes to the frame instead of the engine/transmission, then there needs to be a third battery cable (or strap) running from the frame to the engine/transmission. It needs to be as good as the positive and the negative cable.

 

 

[David_Leech]

33 minutes ago, Bloo said:

#00 would be a good choice. Some cars got by on less (maybe #1) but probably never as small as the #4 typically sold for 12v systems today.

 

<Smaller> - 8 - 4 - 2 - 1 - 0 - 00 - 000 - 0000 - <Larger>

 

Think of it as a big circle from the battery post to the starter post, through the windings, and then from the starter case all the way back to the other post of the battery.

 

For instance, if the ground cable goes to the frame instead of the engine/transmission, then there needs to be a third battery cable (or strap) running from the frame to the engine/transmission. It needs to be as good as the positive and the negative cable.

 

 

00! There's my problem...

 

It's running what looks like #4 and just has a braided chassis ground. I knew I was going to need to make some cables, just surprised how undersized they really are!

[Bloo]

Braids are fine if they are big enough. The chassis ground only needs to be full size if the starter current is flowing through it. If you have #4, then larger cables and clean connections should make a big difference. Good luck! 🙂

 

 

Edited July 9, 2022 by Bloo (see edit history)

[Power Wagon Dude]

Good Information on Sizing of wire.

 

When I rebuilt my D-B, I took the 'flexible' Armored wire cover to my local Electrical (Wholesale) store and asked them to put the largest copper wire they could 'fit' in that flexible conduit. They suggested that I use a THN or THHN 'Heat Resisting' wire insulation.

 

I also had them install / 'Crimp" on copper lugs and shrink fit tubing (Red for Hot - Black for neutral) onto the lugs, so wire polarity was never in question. 

 

I have NEVER had a problem with melting or damaging any of these wires.

 

 Good Luck, from someone who Been there - Done that.

 

  

[David_Leech]

5 hours ago, Power Wagon Dude said:

Good Information on Sizing of wire.

 

When I rebuilt my D-B, I took the 'flexible' Armored wire cover to my local Electrical (Wholesale) store and asked them to put the largest copper wire they could 'fit' in that flexible conduit. They suggested that I use a THN or THHN 'Heat Resisting' wire insulation.

 

I also had them install / 'Crimp" on copper lugs and shrink fit tubing (Red for Hot - Black for neutral) onto the lugs, so wire polarity was never in question. 

 

I have NEVER had a problem with melting or damaging any of these wires.

 

 Good Luck, from someone who Been there - Done that.

 

  

I'm going to take the old cables to work this week and make new ones. I will solder on the new lugs. I think we have #4 to 0000 in stock. 

[cutdown]

Battery cables cant be too big, and I suggest you run the cables from the battery to the starter motor as well as the earth straight to the engine. That way you avoid voltage drop between engine and battery because you eliminate 2 extra connections in the earth circuit. Use your old earth cables to go from the engine to the body/chassis. On older vehicles, I also recommend running earths from all lights etc, direct to the battery for the same reasons. 

 

As a mechanic, I have seen too many stupid problems created by bad earths.

Edited July 13, 2022 by cutdown (see edit history)

[Pete K.]

All good info here. I use "00" on the old 6 volt vehicles. Not to go cuckoo here, but if you look into the Theory Of Electricity, electrons tend to travel on the outer strands of a conductor, under the insulator obviously. 00 gauge will work just fine. Soldering ends on works better than a crimp, but there is an art to solder correctly without burning or wicking.

[keithb7]

On my old Mopars that have battery under the front seat I find “00” is a little too big. The cables leave the top battery posts then quickly turn down under the battery box to the chassis. Single “0” is adequate and fits better. 

[David_Leech]

Thanks for the advice. I just located my real hard start issue, the rear housing on the starter fractured. Not sure how. New topic to follow...

[Bill kelly]

00 cable I used a forklift battery for positive ground and 975 cranking amp’s. On your starter center plate and bushings are good 

[Bill kelly]

8 minutes ago, Bill kelly said:

00 cable I used a forklift battery for positive ground and 975 cranking amp’s. On your starter center plate and bushings are good 

I would love to see what inside of fuel vacuum should look like 

[Farmallregular]

On 7/14/2022 at 9:35 AM, Pete K. said:

All good info here. I use "00" on the old 6 volt vehicles. Not to go cuckoo here, but if you look into the Theory Of Electricity, electrons tend to travel on the outer strands of a conductor, under the insulator obviously.

NOT TRUE...the skin effect only applies to alternating current, not to DC.  At DC, current distributes more or less uniformly through the conductor.

 

Any place that works on over the road trucks will have, or can make/get, 2/0 cables. 

 

Keith

[Pete K.]

By Jove Farmallregular, you are correct. DC current DOES flow mostly uniformly through a conductor. Good eye farmall!

[David_Leech]

22 hours ago, Farmallregular said:

NOT TRUE...the skin effect only applies to alternating current, not to DC.  At DC, current distributes more or less uniformly through the conductor.

 

Any place that works on over the road trucks will have, or can make/get, 2/0 cables. 

 

Keith

I'm at a Mack Truck dealer, made my cables here with 2/0 and soldered on copper lugs. Ran dual starter relays bridged with a copper bus. Not taking any chances with this installation!

[Mattml430]

2 hours ago, David_Leech said:

I'm at a Mack Truck dealer, made my cables here with 2/0 and soldered on copper lugs. Ran dual starter relays bridged with a copper bus. Not taking any chances with this installation!

I spent 12 months next to a marine electrician completely re wiring a 72 foot cruiser and on all the cables, especially high current cable he always told me to crimp them before soldering them. 
He told me if ever there was a loose terminal the solder can melt and then it would come loose. 
It made good sense after he explained that, so did your man crimp your terminals before soldering them, he most probably did. 

[Farmallregular]

19 hours ago, Pete K. said:

By Jove Farmallregular, you are correct. DC current DOES flow mostly uniformly through a conductor. Good eye farmall!

Thanks.  Spent 45 years as a practicing engineer on an assortment of spacecraft, aircraft and communications systems, skin effect is something you worry about at RF.

 

Keith

 

[trimacar]

If you really want best ground, run a ground cable directly from battery to starter mounting bolt, cleaning surface of paint and primer.  Makes a huge difference.  I have one car with ground going both to starter and to frame, no issues and engine turns over quite well.

 

They started well when new, with nice clean frame connections.  100 years of rust and corrosion, not so much…

[David_Leech]

7 hours ago, Mattml430 said:

I spent 12 months next to a marine electrician completely re wiring a 72 foot cruiser and on all the cables, especially high current cable he always told me to crimp them before soldering them. 
He told me if ever there was a loose terminal the solder can melt and then it would come loose. 
It made good sense after he explained that, so did your man crimp your terminals before soldering them, he most probably did. 

When I solder them I fill the lug with solder and once it's melted, plunge the cable in. Couldn't crimp it if I wanted to. 

[David_Leech]

4 hours ago, trimacar said:

If you really want best ground, run a ground cable directly from battery to starter mounting bolt, cleaning surface of paint and primer.  Makes a huge difference.  I have one car with ground going both to starter and to frame, no issues and engine turns over quite well.

 

They started well when new, with nice clean frame connections.  100 years of rust and corrosion, not so much…

I'm going to run a ground to the new starter end plate. That's where mine is getting it's ground. For now, running it from the end plate to the frame or another good location. If I'm not happy, then I'll run one to the battery

[Bill kelly]

I need a 1927 dodge coupe door striker plate  my number is 937-469-4429

[David_Leech]

The starter is rebuilt and cranks over fantastic now. No ground to the starter, just the frane

[Mark Gregush]

On 8/4/2022 at 12:32 PM, Bill kelly said:

I need a 1927 dodge coupe door striker plate  my number is 937-469-4429

Best to start your own wanted ad, not at the end of someones post about battery cables. Don't post your number in a public forum, anyone can read it logged in or not.