C2 SB A/C ; Length and gauge of positive battery cable?

[Bob S.]

Does anyone have a correct positive battery cable for a small block A/C car out of the car so an accurate measurement of its length can be taken? Mine has a 4ga replacement cable that's seen better days. I'm debating whether to replace with a reproduction or look for a 1 gauge or heavier replacement. 4 gauge seems too light; I suspect the original was #2 or better, but would like confirmation, if possible.

thanks for your help,
Bob

[Wayne M.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

Length of +ve battery cable for small block air and 396's is 70.0" from centre hole of spring ring connector to center hole that goes on solenoid terminal.

Don't know the wire gauge, but it might be heavier (ie. lower #) than the non-air car, due to its extra length and electric load capacity.

[Bob S.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

Length of +ve battery cable for small block air and 396's is 70.0" from centre hole of spring ring connector to center hole that goes on solenoid terminal.

Don't know the wire gauge, but it might be heavier (ie. lower #) than the non-air car, due to its extra length and electric load capacity.

Thanks for the length info! Still looking for the gauge of the original, as well as thoughts on heavier cable, e.g. #1 or 1/0 from others out there.

[William C.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

If you have your AIM handy, the part number of the part you are looking for might be a big help.

[Alan D.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

The electrical diagram in the AIM should give you a "4 B" Then check the AC section to determine if another cable was used to replace the standard build, "4 B"

[William C.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

If you check the AIM, the positive battery cable is indeed specified as "Same as regular production" Sheet 22.00 of the C60 section. I would be surprised it was other than 4 GA. #2 was just about defunct in auto use after the conversion to 12Volt systems.

[Bob S.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

The electrical diagram in the AIM should give you a "4 B" Then check the AC section to determine if another cable was used to replace the standard build, "4 B"

Just to bring this thread back to the original questions, as it seems to have drifted off in a different direction;

1) I don't have an original cable, so I can't tell what gauge the wire was. If it's #4 gauge, then I'm not interested in ordering a reproduction, as I think that's too light. If it's #2, I'd consider it, but prefer #1. Does the AIM have the wire specs? I didn't think so, but I guess I shouldn't assume, and will check the next time I'm near my AIM. Comments on optimal gauge for performance, not for judging, are appreciated.

2) I was asking about the length of the cable so I could compare availability and price of generic replacement cables that might be available in heavier gauge wire, and then have one on-hand when I pull the old cable if that's the option I decide on. I do have the length at 70 inches hole center to hole center, so that question has been answered.

thanks all!

-Bob

[Alan D.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

Typically GM used what was needed, but no more. So a 4 gauge wire drawing 50Amps will drop 0.15 Vdc over the 70"
Do not believe the starter even when hot draws that much (But have no idea!) Many voltage drop calculators on line, so once you know the actual Amps perhaps you may feel more comfortable.

(Since the old cable is the correct GM length - perhaps its original so don't throw) Know when I had my battery mounted in the back (C2) I ran welding cable with multi small strands, over kill.

[Bob S.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

Typically GM used what was needed, but no more. So a 4 gauge wire drawing 50Amps will drop 0.15 Vdc over the 70"
Do not believe the starter even when hot draws that much (But have no idea!) Many voltage drop calculators on line, so once you know the actual Amps perhaps you may feel more comfortable.

(Since the old cable is the correct GM length - perhaps its original so don't throw) Know when I had my battery mounted in the back (C2) I ran welding cable with multi small strands, over kill.

Great idea about looking at the voltage drop and the amp draw and see what difference heavier wire can make. The popular wisdom is that heavy gauge is good and as heavy as possible is best, but there's a point at which it's overkill. I'm not an expert and everything that follows comes from random sites; it sounds as though Chevy starters draw anywhere from 50 amps with no load to 500 amps with load, around 150 typical real world assuming no temperature extreme and a happy engine. #4 wire should work fine for all conditions except on the outer edge, i.e. 500 amps would have a voltage drop of more than 10% (1.44 v) with #4 ga, 0.96 v with #2 and 0.78 v with #1 ga. Probably not a big deal, but if I'm going to run new wire, I'll probably go for at least #2 wire. Remember that an A/C car has a positive cable about twice as long as a non-A/C car, and so has twice the voltage drop.

[David L.]

Re: C2 SB A/C ; Length and gauge of positive battery cable?

The 1967 Corvette AIM UPC C60, sheet E3, lists the following cable part numbers:
+ cable: 6286181
- cable: 2979821

My 1967 Chevrolet Parts Catalog (April 1967) lists GM # 6286181 in Gr. 2.342 for 66-67 Corvettes w/AC and described as "63 ctr. to ctr. holes".
GM # 2979821 is listed for 65-67 Corvettes in Gr. 2.341 and described as "CABLE (25 ctr. to ctr. holes)".

Dave