Electrical Electrical ground question

[AnthonyA1234]

this may be a dumb question but I’m getting my car painted including the engine bay and unscrewed all the engine grounds so that the area can be painted. I’m wondering what I need to do to get the everything grounded properly when I put it back together. Right now from the factory the part of metal that the ground wire touches is painted so is it the threads that does the ground?

 

[AeroCoupe]

That is correct. Clean the threads with a tap and you will be good to go.

 

[AnthonyA1234]

That is correct. Clean the threads with a tap and you will be good to go.

Got another dumb question for you lol. I’m doing a wire tuck right now and need to make some new grounds. I’ll attach a pic below, it’s the starter solenoid screws and a ground cable. Can I just use self tapping screws to mount them and will that be a good enough ground? Or do I have to grind the chassis down to bare metal?

 

[AeroCoupe]

I think you already know the answer. The better your ground and 12V+ connections the better the electrical system will work. If you are contemplating using one of the self-tapping screws that will mount the solenoid I would not advise using it unless it is going into metal thicker than a single layer of sheet metal. The connection needs to be tight and secure so think some kind of locking washer so the connection does not back off. I will usually put the ground loop on the bolt or screw last with a flat washer before it and a lock washer between the screw or bolt head and the flat washer. You want the ground wire loop on bare metal so the connection to the body/chassis is as good as it can get. After you tighten the screw or bolt down I would suggest you use something like NO-OX gel to keep the connection from corroding.

 

[AnthonyA1234]

I think you already know the answer. The better your ground and 12V+ connections the better the electrical system will work. If you are contemplating using one of the self-tapping screws that will mount the solenoid I would not advise using it unless it is going into metal thicker than a single layer of sheet metal. The connection needs to be tight and secure so think some kind of locking washer so the connection does not back off. I will usually put the ground loop on the bolt or screw last with a flat washer before it and a lock washer between the screw or bolt head and the flat washer. You want the ground wire loop on bare metal so the connection to the body/chassis is as good as it can get. After you tighten the screw or bolt down I would suggest you use something like NO-OX gel to keep the connection from corroding.

Ok will do, so after I grind the metal down and hook everything up, I can just apply that gel over the starter solenoid screw areas and the other ground loop and that alone will keep it from rusting?

 

[AeroCoupe]

So I have never done anything but screw a starter solenoid down and they have worked for years so I would not worry about those connections. If you are going to use one of the solenoid screws to attach a ground wire then I would be more inclined to use the gel. Depending on how large the ground wire is I switch to a bolt vs a screw for added clamping force. Typically when I get past 12 ga wire is when I make the switch but its just a preference.

 

[limp]

You could opt for one of these grounding studs...... I bought one but have not made up my mind where to install it.... I do wish I would have done this when the dash and heater box were out.....

JL Audio Master Ground Lug – CE Auto Electric Supply

ceautoelectricsupply.com

 

[Mustang5L5]

The screw into the metal is good enough. Of course, more bare contact area will improve the connection, especially if any rust/corrosion present on the screw and/or threads into the metal.

Look at it this way, each time you make an electrical connection, take your time to make it tight and with the best contact you can make. Doing that work now will help prevent issues down the road

 

[AnthonyA1234]

Thanks guys! I’ll do a Home Depot run today and pick up some hardware and finish up the drivers side tuck today and I’ll hook my engine back up so I can test it out before I start the passenger side tuck. Appreciate the help.

 

[evintho]

A ground bar is the way to go. All ground wires to the ground bar then the bar grounded directly to the frame.

I welded a 1/4" plate to the frame with 2 studs. One for the ground bar and one for the Neg batt cable.

 

[qikgts]

That's a real nice job evintho. Super clean work in both pix!

​

 

[Noobz347]

I just wanted to add about the grounds:

A little dielectric grease on the threads and mating surfaces with a light coat of bare metal, wipe clean with alcohol or brake cleaner on a rag and then primer/paint over the top but... My engine bay is no where [near] as clean as the one above.

 

[AnthonyA1234]

Just finished the job and started the car and everything worked like normal.

On a side note, do any of you guys know how to remove the ignition coil plug wires from the plug? I see some tabs on the connecter side of the plug but I tried pushing them and pulling the wires and it didn’t work. I want to remove the plug so I can run the cable through a small hole in the fender apron and then just reconnect the plug after.

 

[evintho]

I had to lengthen the coil wires on my last swap. The easiest way is simply cut the wires a couple inches past the connector, remove the connector then splice them back together. You'll want to splice them together properly though. Those are two critical wires. I took a couple pics on how to correctly crimp and splice. Firstly, use uninsulated butt connectors. Absent that, you can use the cheap colored insulated connectors, just remove the colored insulators.......

Next, fold one side of the connector over the wire and crimp........

Then fold the other side over that and crimp........

Then as a safety precaution, add a dap of solder and wrap it with a single layer of electrical tape (I like Scotch #88)......

Then finalize it with a length of 3/16" shrink tubing.......

Now with just a little bit of effort, you have a professional, quality connection that'll last a lifetime. All the ground wires in my last post were done this way and I've been doing this for years on all my projects. Never had a connection fail!

 

[limp]

I had to lengthen the coil wires on my last swap. The easiest way is simply cut the wires a couple inches past the connector, remove the connector then splice them back together. You'll want to splice them together properly though. Those are two critical wires. I took a couple pics on how to correctly crimp and splice. Firstly, use uninsulated butt connectors. Absent that, you can use the cheap colored insulated connectors, just remove the colored insulators.......

Next, fold one side of the connector over the wire and crimp........

Then fold the other side over that and crimp........

Then as a safety precaution, add a dap of solder and wrap it with a single layer of electrical tape (I like Scotch #88)......

Then finalize it with a length of 3/16" shrink tubing.......

Now with just a little bit of effort, you have a professional, quality connection that'll last a lifetime. All the ground wires in my last post were done this way and I've been doing this for years on all my projects. Never had a connection fail!

Just remember to install the shrink wrap before you crimp the connector......