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I just bought a '71 F250 that I am just getting started on. I'm checking out the basic battery/charging wiring and I'm trying to find out where the original ground location would have been. The battery was grounded to the alternator bracket (the black line in the pic), but I see an old dark green cable that is bolted to the block and doesn't go anywhere anymore and has no connector on the end either. All the electrical diagrams I see only show "cable - battery to ground". Any help would be appreciated! Black line is the cable used when I bought it. Green line is the other cable that is bolted to the block and it's just resting there.
The primary ground should go to the block The starter ground is the block and you want the best ground for the highest load. You have several "degrees of separation" between the alternator bracket and the block so although convenient, its not the best ground spot. I would run a small ground from the battery to the inner fender and then make sure you have a ground strap from the back of the engine to the firewall. Another good ground would be from the block where the main ground is attached to the frame. The older and rustier the vehicle, the more grounds the better.
Thanks! I knew this wasn't right, but it's almost 50 years old so . I'll definitely move that off the alternator bracket and I'll be replacing that original cable from the block. It is pretty brittle.
So far, this inner fender is the worst rust I've found.
I would put the biggest ground you can find down to the block - a section of welding cable with nice ends works well. The factory cables were marginal at best. All the connections on your solenoid should probably be cleaned. Over time they can get dirty or oxidized which can give you weird symptoms. Just pull them off and use a little light sand paper or the equivalent to get them good and clean. A new battery to solenoid cable is probably a good idea while you are in there.
And whatever you do, if you think it'd be easier to just buy a new starter relay/solenoid than to clean the old one, don't!
Or at least if you ever do buy a new one and don't take the advice to pay the higher price for a quality one, or better yet a made in the USA one, just don't throw one away until you know for a fact it no longer works.
That long-winded warning was just by way of letting you know that way too many new starter relays are junk right out of the box. Way too many stories of them failing within a week, or not even working at all, to ignore.
In a pinch it's better to find an old beat up one out of the junkyard than it is to buy a new one. Less of a crap shoot.
Best thing is to do what GPatrick said and clean the connections on the old one up first.
The existing ground cable looks to be of fairly new construction, and of larger than stock gauge (both are good) and it also looks like it might be long enough to mount to the block?
Is that was you're getting the new ring terminal for? For that larger, newer black one? Or have you already looked at the black one that was being used, and found that it's too short to re-route?
Whatever you do, don't just put a new ring terminal on that old worn out and decrepit green wire. You would only choose to do that as a last-ditch emergency effort to get yourself home from being stranded. After which you would go right out and buy a new one of the proper length.
When in doubt, always choose new when it comes to battery cables. Even cheap ones are better than unknowns. And the good news is they're very inexpensive so you can splurge on the larger 2ga version with the secondary 10ga ground wire coming off of the lug that you can then attach to the body.
The existing ground cable looks to be of fairly new construction, and of larger than stock gauge (both are good) and it also looks like it might be long enough to mount to the block?
Is that was you're getting the new ring terminal for? For that larger, newer black one? Or have you already looked at the black one that was being used, and found that it's too short to re-route?
Whatever you do, don't just put a new ring terminal on that old worn out and decrepit green wire. You would only choose to do that as a last-ditch emergency effort to get yourself home from being stranded. After which you would go right out and buy a new one of the proper length.
When in doubt, always choose new when it comes to battery cables. Even cheap ones are better than unknowns. And the good news is they're very inexpensive so you can splurge on the larger 2ga version with the secondary 10ga ground wire coming off of the lug that you can then attach to the body.
Paul
Thanks Paul, I am changing the ring terminal on the good black cable. I checked the length on it and I'm good to reuse it. I'm throwing away the old green cable since it isn't any good. That cable was still bolted to the block at that grounding point, the previous owner just left it there disconnected from the battery or anything else which is why I wasn't sure it was supposed to connect to the battery.
. I'll definitely move that off the alternator bracket and I'll be replacing that original cable from the block. It is pretty brittle.
