How do yall ground your Alternator?

Bloodhound1981 said:

I think some people are getting confused with aluminum conducting electricity (yes, does so very well) with magnetism (nope not at all). Maybe because the whole positive/negative thing for both, I don't know.

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Well, that depends on if we are talking an aluminum alloy with nickel content.

Ricko1966 said:

Aluminum is an excellent conductor of electricity Aluminum used to be used to wire houses.

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till the corrosion between mating wires caused fires >

My battery ground wire, similarly to CalSgt 's rig, goes from the battery to a shut off switch (Thanks Jegs), near the bottom alternator bracket mounting bolt. (I.E. the engine block).

GM put a 3/8" threaded hole on the alternator bracket on the 87' so you can use a star washer and the self-tapping short bolt for your ground.
It is the same no matter what side your alternator is located.

This diagram is for the 82'.
Notice it shows the small bolt, star washer and it is pointing directly at the bracket under the alternator?

Or you can mount it on the top of the bracket, as in the lower picture.



Aluminum is great for A/C powerlines and feeder to the box. (Thanks Alcoa!)

Not to be used for DC, as the AuroraGirl has pointed out.
Aluminum wire is illegal inside a house, past the panel, according to the National Building Standards Electrical Code.

Everybody has to learn sometime. Use the search button next time and have fun!

*** Shrunk the picture so as not to waste bandwidth.

Cs130 alternators(only cs130, cs130d and ad230 alternators do not have this) hhave a convenient addition of a threaded bolt hole on the rear of the case of the alternator which is for grounding or a 3rd fonnection type bracket. same with ford 3g alternators from the same era. Nice feature to have. Has the same threads as one of the case ears (usually one case ear is threaded, sometimes both)

RanchWelder said:

My battery ground wire, similarly to CalSgt 's rig, goes from the battery to a shut off switch (Thanks Jegs), near the bottom alternator bracket mounting bolt. (I.E. the engine block).

GM put a 3/8" threaded hole on the alternator bracket on the 87' so you can use a star washer and the self-tapping short bolt for your ground.

This diagram is for the 82'.
Notice it shows the small bolt, star washer and it is pointing directly at the bracket under the alternator?

Or you can mount it on the top of the bracket, as in the lower picture.

You must be registered for see images attach

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what are the odds of that, we both talk abotu the cs130 having a ground connection on the back of the alternator at the same time (5am) lol!

mavtricks71 said:

Just need information on how to add a ground to my Alternator. Should I use a ground Strap or an insulated wire?

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is your truck using a cs130 or a 12si( both an option in 1986)
a cs130 has a a regular looking fan but the 12si looks more unique as far as alternators go

The cs130 has the threaded part on the back, the 12si I dont think does. The 12si can be upgraded in its ground by adding a lugged cable to the block where the bracket bolts to buit make sure if you do that you dont misalign anything. thats why gm used the alternator bracket on top originally was because of ease of access and wouldnt jack up the mounting points

The odds are looking like 1:1? lol

Rather poor odds, when things are almost even?

My CS130 is wired as a 1 wire alternator. It's a PowerMaster 200amp, with adjustable diode for Lead Acid, AGM or Lithium Ion batteries.
(They all use different charging rates and mis-matching the charge rate voltages can cause early failure).

CS130 has the 4 wire capability for the OBDII harnesses with voltage monitoring to the ECM.

12si works, it's just the major re-builder's are using crap bearings that crush to seal.
They wear out way too fast and cheap diodes.
Proper belt tension can ruin the bushings in a year.

AuroraGirl said:

is your truck using a cs130 or a 12si( both an option in 1986)
a cs130 has a a regular looking fan but the 12si looks more unique as far as alternators go

The cs130 has the threaded part on the back, the 12si I dont think does. The 12si can be upgraded in its ground by adding a lugged cable to the block where the bracket bolts to buit make sure if you do that you dont misalign anything. thats why gm used the alternator bracket on top originally was because of ease of access and wouldnt jack up the mounting points

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My Truck has the cs130 Alternator but i guess i wont add a ground wire seems everybody is saying I dont need one.

mavtricks71 said:

My Truck has the cs130 Alternator but i guess i wont add a ground wire seems everybody is saying I dont need one.

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It won’t hurt any to add one. Takes the variables of mounting bolt corrosion, etc out of the equation.

You most certainly should double the wire gauge of every wire in your engine bay, if you can afford to do so.
You can add extra grounds wherever you want.

If you plan on running a HAM Radio, you'll need grounds to every door panel, every fender, your bumpers and the chassis in quadruplicate.

Nobody here should dissuade you out of adding extra grounds, especially to your alternator.

Here is an excellent article on Ground Bonding for Short Wave antennae:
http://www.k0bg.com/bonding.html

A vehicle is not a ground plane, but rather acts like a capacitor between the antenna and the surface under the vehicle which acts as the ground plane. Since the surface in question is a poor conductor of RF, ground losses occur. If we wish to maximize the system efficiency (the mobile station as a whole), we need to maximize the RF continuity of the vehicle, hence proper bonding. Obviously, proper antenna mounting, and placement are important too. Remember, it is the metal mass directly under the antenna, not what's along side, that counts. And a ground strap is not a replacement for proper mounting!


Bonding also minimizes the leakage of RFI into (ingress) and out of (egress) the various bolted on parts of the vehicle. The exhaust and tail pipes are good examples of RFI egress. Bonding horizontal surfaces (trunk lid, hood, etc.) will have a greater effect than bonding vertical ones like doors, and hatches. It is not uncommon to see a 20 to 30 dB drop in received noise levels once they're properly grounded. Bonding is especially important for body-on-frame vehicles, like pickup trucks. In these cases, the bed and cabin should be bonded to the main frame as well as between the bed and the cabin to prevent ground loops.

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There is no such thing as overkill with grounding your chassis.
People who keep adding amplifiers and radio equipment without researching how the fields of electricity effect the entire system, spend a fortune on bad alternators and have frequency hum in their audio. This also effects the fields in the coil and the engine sensors on modern OBD2 ECM's.

A GM HUMVE has well over $25,000.00 in radio communications grounding installed into the chassis.
I have spent a great deal of my life dealing with high voltages. The learning with regard to counterpoise, never ends really.

When I was installing house alarms and telecommunications systems, half the installers would ground and half would not.
There was evidence the lightning came back up through the ground rod and shorted the telcom systems, when grounded!

This is why I posted on another thread, using an isolated timing light can be more accurate.

Read some of these posts:
https://forums.radioreference.com/threads/mobile-antenna-grounding.352065/

-Rred Nov 21, 2014 "Ground" can mean an earth ground, a chassis ground, a counterpoise, etc., many different things. Actually what you are doing on a car or boat is "bonding" different pieces, not necessarily grounding them at all, unless your car tows a substantial plow blade to cut into the earth. Or as gasoline tankers used to do, drag a chain to ensure static was is charged to the pavement.

One layer of paint will not greatly interfere with the radio frequency energy from the antenna flowing into the car body and finding an efficient counterpoise. RF jumps that gap, treating it as a small capacitance, even though DC electricity might not be able to jump it at all, or be greatly reduced by it.

"Ground" is like "food", a very vague term really that covers many things, which are not at all alike.

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You can spend years learning about ground.
It is worth your time to learn about it.

mavtricks71 said:

My Truck has the cs130 Alternator but i guess i wont add a ground wire seems everybody is saying I dont need one.

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You don’t need one but in my Opinion there are very many things you can over do. Grounds on a system are not one of them.

the case is going to be metric thread, its probably a 10mm-13mm. I cant visualize that the best but I would more inclined to think its13 but that battery terminal stud dosnt look too much different in size and its probably a 10mm

Actually, the threads will probably be M8x1.25.

MikeB said:

Actually, the threads will probably be M8x1.25.

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for the rear lug? Well now that you mention it... if the stud is 8mm,,, then youre right. But i cant remember if the positive studs are 10 or 8mm

CalSgt said:

Stock trim they usually ground to the engine block through the housing.

To upgrade add a heavy gauge wire to the frame or negative battery terminal

Stereo guys running big amps do the “Big 3”
- heavy gauge charge wire
- heavy gauge Alt ground to battery
- heavy gauge body ground

Or the big 5 which adds
- heavy gauge engine ground
- heavy gauge ground from battery to frame

Here’s mine partially done, one of the blue 4ga cables to the batt lug of the alternator and the alternator ground is 4ga to the frame. 0ga cables from the frame and fuse block to the battery.

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I usually do this on every vehicle I buy or anything I'm working on that has aftermarket accessories. I am mainly an audio, accessory and interior guy so that is usually every car I work on including my 70 C10 with a mild audio system. You can never have too good of a ground so...