MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGA - battery cable length / eyelet size

Was calling Napa to get new cable for battery to switch size ie .. eyelet and length ? switch to starter / eyelet size and cable length ? engine ground lenngth ?
60 coupe
karl

The long cable from the battery is 93 inches and the eyelet hole for the starter switch terminal is 5/16". Three metres cable will be enough for the car if you have an original battery layout. Mike
m.j. moore

The Battery cable from the battery to the starter switch is 95" overall and has a 5/16 eyelet at the switch end. I just measured 2 cables. Don't go shorter, 95" would be a minimum. I would recommend a welding ground cable (2AGW or 4AGW) with 5/16 eyes on both ends instead of a length of battery cable. The welding cable is more flexible carries more amperage and has less voltage drop. (makes the starter spinn faster)
The cable from the starter switch to the starter is 13" long and has a 1/4" eyelet at the starter end and a 5/16 eyelet at the switch end.
The engine ground strap that goes around the left front motor mount is braided, uninsulated and 6.5" long.
The long cable may need to be longer if your battery terminal isn't in the right front corner of the battery tray as original.
R J Brown

I think this is going to make a new web page. Does anyone know the length of the cable origianlly between the two 6 volt batteries, and the length of the original battery ground cable?
Barney Gaylord

Okay, I got impatient amd jumped the gun a bit. I would still like the numbers for cable length for public record, but I had a more important issue to work on (all night).

I had a knee jerk reaction to the mention of 4 AWG for battery cables, but wanted to check it out before possibly putting foot in mouth. For some cars with shorter cable runs, 4 AWG battery cables would work fine. For the MGA, the OEM cable running from battery to starter switch is much larger. I bought my main battery cable as an OEM replacement part from an MG dealer in 1976. Hint: I wouldn't recommend shrinking it to 2 AWG.

On the other hand, I haven't found much reason to increase battery cable sizes larger than original issue, unless you really think that 1/16 of a volt is worth all the bother. For all the "boring" details, see here: http://mgaguru.com/mgtech/electric/ss_103.htm

All comments welcome.
Barney Gaylord

Barney
Gauge for cable is backwards. 2 is one size bigger than 4. I just measured both old original cables I have and they are 2 gauge (.250) not 1 (.290) as your site indicates. The original cable has course strands (about 40) and less copper than welding cable of the same gauge. You are right about not using 4 gauge. The writing on the welding cable I looked at said 2AWG and looked thicker than it was.
R J Brown

I went over to my boat repair friend and he had a nice cable ready to go . Actually it is 2 cables sandwiched together . Neg and poss , they cable is very flexable .I am going to split the cable . I called my welding supply co and all he had was 1/2 inch ends . Napa had the old school battery cables and cut to length capabilities but I think for free I will roll with the boat cable run first , until saturdays build and I hear from the car club rebuild group . I have Napa on standby .
karl

R J, - I don't have the numbers backward. I know 4 AWG is smaller than 2. And I meant what I said, I wouldn't recommend shrinking the MGA battery cable to 2 AWG. The original main cable from battery to starter switch is 1 AWG. I don't know where anyone got the idea the 4 or 2 would be making it larger, unless maybe they though all cables were 4 AWG. Like I said, it's in the "boring" details on the web page.
Barney Gaylord

Barney's math seems to be correct. Not sure about the chassis resistance estimate though. I haven't worked it out and don't intend to.

As he has stated, there is no electrical reason to replace the wires. However there are other reasons: 1) After years of abuse under a car, the insulation may have been worn or overheated compromising the insulation. Since this is not a fused line, the insulation jacket must be kept in tip-top condition. If yours is deteriorated, I would recommend replacing it. 2) Your wires may have been trimmed back due to several re-termination attempts and no longer has a comfortable reach to it's intended location. replcing the entire length is "better" than adding a short extension. 3) If your car was like mine when I got it, there was no battery wire to begin with. So a new one was in order.

As long as you are replacing it, why not increase it to "0" AWG wire since #1 is not generally locally available.

Hint- If you are re-using your existing wire, and it need new terminations, the copper has probably become oxidized. This increases the resistance of the crimped connection. I have found that a common bathroom cleaner called "The Works" instantly cleans the copper wire. Just rinse and rinse and rinse after it is cleaned as the chemical is VERY Acetic. Any remnants will cause long term corrosion.

Chuck
Chuck Schaefer

This thread was discussed between 17/10/2006 and 19/10/2006

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.