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Positive and Ground cable size and location

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799Cj2a View Drop Down
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    Posted: 19 May 2013 at 9:13am
Hi everybody, this is my first post on the site so here goes:

I'm working on a '48 CJ2A serial number starts 153... It's been in a barn awhile and is in good shape but has sat for about 20 years untouched. From reading other posts on the site I think my biggest problem now is a bad ground and an overall aged, corroded electrical system. The starter was VERY slow to turn over and wouldn't get the job done. I sent out the starter and generator to a good shop to be cleaned/rebuilt. The battery is brand new and topped off. I was getting an initial spark at the plugs which quickly stopped. I tested the coil with a jumper lead and it gets plenty of spark at the plugs. I sanded/cleaned and dielectric-greased all the connections in the starter circuit but it hasn't helped. A bunch of guys have suggested in posts to look at the battery cable size. Sure enough, someone replaced the original cables with 12v ones when they switched over to a keyed start and solenoid. I'm putting a floor starter switch back in and removing the solenoid(I like the old fashioned stuff and I'm trying to keep it 6v).

I bought some 1/0 gauge welding cable, thinking the larger the cable, obviously the less resistance, but a welder friend of mine told me that if the cable gets too big, when it's energized from the battery(during starting), the cable can "absorb" too much and the battery won't have the juice to try another start without being recharged. If so, would I be better off using the original 1 gauge cable? Could I still use the 1/0 gauge cable for the negative lines(batt-to-block)? I'm going to solder and then crimp the ends in solid copper ring terminals-I want to do this right.

Also mentioned in another post was connecting the battery negative directly to the starter would help the starter; I also intend to make ground connections between the frame and block and the starter. What are your suggestions on actual routing of ground cables? Is it enough to make those two connections or would I be wrong in separate grounding between starter and block, block and frame, block and battery negative, starter and battery negative? What do you guys think? I'm not afraid of overkill as long as it doesn't affect performance.

Thanks in advance, sorry for being long-winded.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote F Bill Quote  Post ReplyReply Direct Link To This Post Posted: 19 May 2013 at 10:01am
Originally posted by 799Cj2a 799Cj2a wrote:

Hi everybody, this is my first post on the site so here goes:

I'm working on a '48 CJ2A serial number starts 153... It's been in a barn awhile and is in good shape but has sat for about 20 years untouched. From reading other posts on the site I think my biggest problem now is a bad ground and an overall aged, corroded electrical system. The starter was VERY slow to turn over and wouldn't get the job done. I sent out the starter and generator to a good shop to be cleaned/rebuilt. The battery is brand new and topped off. I was getting an initial spark at the plugs which quickly stopped. I tested the coil with a jumper lead and it gets plenty of spark at the plugs. I sanded/cleaned and dielectric-greased all the connections in the starter circuit but it hasn't helped. A bunch of guys have suggested in posts to look at the battery cable size. Sure enough, someone replaced the original cables with 12v ones when they switched over to a keyed start and solenoid. I'm putting a floor starter switch back in and removing the solenoid(I like the old fashioned stuff and I'm trying to keep it 6v).

I bought some 1/0 gauge welding cable, thinking the larger the cable, obviously the less resistance, but a welder friend of mine told me that if the cable gets too big, when it's energized from the battery(during starting), the cable can "absorb" too much and the battery won't have the juice to try another start without being recharged.UM...no. Unless your battery cable is made of nichrome heating element wire the larger diameter it is the better it will work. Good conductors do not absorb the current passed thru them.   If so, would I be better off using the original 1 gauge cable? Could I still use the 1/0 gauge cable for the negative lines(batt-to-block)? I'm going to solder and then crimp the ends in solid copper ring terminals-I want to do this right.

Also mentioned in another post was connecting the battery negative directly to the starter would help the starter; I also intend to make ground connections between the frame and block and the starter. What are your suggestions on actual routing of ground cables?The stock locations are just fine with good cleaned metal at the connections. You can use a star washer to bite into the metal and make a great electrical connection.   Is it enough to make those two connections or would I be wrong in separate grounding between starter and block, block and frame, block and battery negative, starter and battery negative? What do you guys think? I'm not afraid of overkill as long as it doesn't affect performance. I think with adequately sized cables and clean connections with a nicely rebuilt starter, overkill will not be needed. If you need additional grounds over the factory installation something is wrong with your jeep.
If you have problems after installing a new set of cables and the new starter try a voltage drop test in the starter circuit, testing from each connection to the next with a voltmeter.  Chances are too much new paint has insulated one of the connections. Don't overlook the starter to block mechanical connections including the starter brace at the front of the starter.

Thanks in advance, sorry for being long-winded.
If you haven't checked out the tech FAQ section, go to:
http://www.thecj2apage.com/forums/tech-faq_forum57.html
for a lot of great stuff you need to know!!

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Post Options Post Options   Thanks (0) Thanks(0)   Quote samcj2a Quote  Post ReplyReply Direct Link To This Post Posted: 19 May 2013 at 11:10am

Andrew, welcome to the group from a fellow Arlingtonian!   I have moved your posts out of the Parts Project to the forum where you should be asking questions about your Jeep.

I'm on the road now but I would enjoy meeting you when time permits.


Sam

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1947 CJ2A 122031 ACM 111989

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