What connectors should I use for engine and body grounds?

thuddles

TJ Enthusiast
Joined
Apr 24, 2020
Messages
162
Location
CA
Whats up guys, had a question about the motor and body grounds, and the connector/lugs you should use. I was planning on using a 3/8 lug. I want to make sure i'll get a good connection. I don't wanna fry my amp I just installed.

The rear motor ground seems like its tapered. I drilled out the 3/8 to fit around the bolt, is that gonna be ok?
The body ground also had a lug with some kind of teeth on it. Will I be ok using a standard 3/8 aluminum coated copper lug?

Thanks in advance for any help.

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Use copper for battery and ground cables. I like to use #2 cables but I see a lot of #4 used. And I think #4 is OEM.
The bolts are best with either a built in flange head or a star washer, but I've had some vehicles using a regular split washer for decades without an issue. Aluminum is not a very good conductor and also reacts with steel causing corrosion where copper doesn't.
 
Use copper for battery and ground cables. I like to use #2 cables but I see a lot of #4 used. And I think #4 is OEM.
The bolts are best with either a built in flange head or a star washer, but I've had some vehicles using a regular split washer for decades without an issue. Aluminum is not a very good conductor and also reacts with steel causing corrosion where copper doesn't.

Should i go as far to replace my ground terminals? I used purple copper plugs on all (+) but i only had so many so i finished my (-) with the aluminum. Its already installed but i want it to be right.
 
Assuming by aluminum you mean tin plated copper lugs, correct? If so, the tinning is used to prevent corrosion and typically required for marine grade connections.

You will be fine with tin plated copper lugs.

sorry yes i believe so, n00b electrical guy over here my bad!

is there a better lug i can use for the rear motor to body ground? The bolt seemed tapered with ridges to the bottom i just wanted to make sure it was going to be good with a traditional lug.

You will not fry your amp with poor grounds, it just won't work as well. Your pictures look great, really nice work. I wouldn't change a thing.

haha cant be too safe! I've read some crazy stuff on these forums
 
@thuddles. As long as the crimp is good, the connection is clean and secure, you should be fine opening the lug a bit. Definitely don't want to remove too much material and make the ring too thin, as long as it is secure under the bolt, I don't see any reason you would need to change what you already did. Looks good.

That being said, not sure what the thinner (12 or smaller gauge?) Wire is you have grounded with the larger cables. As long as it is only expected to carry a small current, it is fine as well
 
As said, drilling the lug bolt hole open a bit is fine as long as it doesn't weaken it to the point of failure, but that would be an obvious problem. I've seen some true aluminum lugs used before. I mean, they will work, but they are a very poor choice. Aluminum against steel will corrode. Copper won't. The steel can still rust behind the copper but isn't caused by the copper. I always try to oversize all battery and ground cables. Just cheap insurance. Also any aux. power feed lines. Be sure to have a fuse in there too.