ExitWound

I've been having a lot of problem with corrosion of my terminals on the battery. Another no-start today led me to find this. This is the chassis-->NEG cable. Obviously, there's so much corrosion and rust that I'm not getting a clean recharge on the battery.



I've been using a non-original large gauge wire to go from the NEG battery terminal to the chassis ground on the firewall (shown above). I believe it's the source of my problem. I've routinely had to remove and sand down the corrosion off the terminal and its clamps and loops.

(The NEG cable I'm using to go to the engine block just happens to be red, so look past that.) It has a little wire connected to it apparently. Could this wire be used safely to connect to the firewall instead of the big fat black that keeps rusting? More succinctly, what size wire is SAFE to use as the chassis-->NEG ground cable, NOT the engine-->NEG cable?



(No cleaning has been done yet to the terminal clamps/wires)

pontifex4

I can't help you on the wire gauge question, but those grounds are crying out for dielectric grease.

ExitWound

I've acquired some protectant materials for the reassembly. I wanna be sure that the re-hookup is safe, that's all.

As far as I can see, there is NO connection from the engine block to the chassis itself...unless the connection is built through the engine mount bolts or something hidden like that. Is there a connection from the engine block to the chassis? Is the connection from the NEG terminal to the chassis redundant as a result?

Also, if anyone can take a peek to find their chassis-->NEG cable's size, that would be great.

Jay W

Corrosion on the battery terminals is due to the battery leaking ever so slightly around the terminal studs. Best to replace the battery when you change out your cable.

GTSilver944

Look at the back of the engine to find the ground. It goes from the upper bellhousing area to the upper/middle section of the firewall. It attaches to the firewall at a mount that holds the A/C lines. It's in plain sight, at least on N/A's.

choinga

I think you asked this over at Pelican as well? The ground cables are all about surface area - that's why they are so thick and if you break em open it's all twisted strand. Ground issues are quite common with these cars (ask me how I know)...just doesn't seem like this is a place where you want to cut corners - it ain't that hard to even make a cable that short using the right materials to fit into that spot.

ExitWound

Interesting. I don't think that I have that ground path. The corroded wire from the first picture is attached, in my car, from the NEG terminal to the firewall in the battery tray. Is this not where it supposed to be? Or am I just missing the wire you mentioned?

jpk

Here's an explaination of what I ended up doing on my early car. It can never hurt to have additional ground cables for the electrical system...

https://rennlist.com/forums/924-931-...ra-ground.html

ExitWound

jpk, yeah, that's exactly what I have near the battery tray in my car. It's a cable about a foot long that connects to the firewall area. I don't have the connection from the firewall to the engine block though inside the engine bay. I think I'll be doing that.

macho_mango

it looks alot like you're getting acid build up on the terminal. Do you have a proper vent on the battery?

peanut

I'd cut away that positive terminal clamp altogether. Its had it. (or is that a red negative terminal ?)
Buy a nice new heavy duty brass one . I would borrow a large soldering iron and solder an extension onto the small black wire. (Those bullet connectors are rubbish. )

Whilst you are there clean up the large neg cable ends and heat them with a blowlamp and solder or brass braze those too. it will prevent them rusting again.

If the rest of your earthing system is in a similar condition you've got some serious electrical issues.

ExitWound

I need to get things stabilized in the meantime. I can't continue working on the car in 12 degree weather.

I built a connection between the engine block and the chassis near the front ground connection (driver headlight area) and built a redundant connection on the firewall where the previous connection used to be. Made sure to scrape all the surfaces to bare metal. I cleaned the terminals and used some protective grease to hopefully prevent it from recorroding until the weather breaks.

What do you mean by "proper vent"?

pontifex4

We should point out that corrosion also happens on these joints due to the difference in electrical potential between the various types and compositions of metal involved, exposure to air, high temperatures, moisture, etc. It's basically inevitable to some degree.

macho_mango

my battery terminal looked like that on my old battery when I found out that the vent tube had gotten jammed (actually, melted and sealed off). I'd check to make sure that its open. If your battery doesn't have one, I'd suggest going with a bettery that is vented, or getting a dry cell.

ExitWound

I've never owned a battery that had a vent tube. I didn't even know what it was. I'll have to do some digging.

I do have to clarify that I get a LOT of corrosion, usually, after a long week of rain. Temperature not so much matters. But rain will tend to bring out the corrosion more.