Grounding Straps

[jbgroby]

I'm wanting to order the correct ground straps for the GMC,and the parts/assembly manual is of no use. NAPA sells grounding straps, but I wanted to ask the members what do you use?

And where did you make your attachments to the block/frame.

Thanks
Jake

[markeb01]

I believe you are trying to restore your truck as stock as possible, but wiring is one place I’d make improvements. The ground circuits in particular are notoriously undersized, and much of the system depends on sheet metal to return the circuit back to the negative side of the battery. With either new paint or rust and age blocking the return path, problems will eventually occur.

On my truck I ran 1 gauge battery cables to both battery terminals. Positive goes to the starter, and negative goes to the engine block. I run another 4 gauge battery cable from the engine block to a bolt on the passenger side of the radiator support, under the apron cover. All forward grounds (lighting, horns, etc.) connect to this post.

Another 12 gauge wire leads from the engine block to the pedal support inside the cab. All dash and cab grounds connect to this bolt.

And yet another 12 gauge wire leads from the same bolt on the engine block to the rear of the truck. All rear lighting grounds to this connection. All of my light sockets have ground wires attached to the housing, if they don't have dual terminal wiring to the bulbs.

If you overbuild the grounds, you’ll never have electrical gremlins with the turn signals, etc., in the future.

[cv65]

I cant agree more with marke01 you cant have too many grounds.What my stock chevy 283 3 speed had was, one ground on the rear valve cover bolt to the firewall about 9-10 inches long flat braid copper. on both sides .I had a friend give me a nice bunch of ground straps used on airplanes,and I put all of them to use,

[jbgroby]

Mark, can you provide a link of what and where you bought them? The ones listed at Napa are the following

[luvbowties]

Originally Posted by jbgroby

Mark, can you provide a link of what and where you bought them? The ones listed at Napa are the following

I nk Mark was referring to this type wire:

[Clyde65]

On my truck, I replaced the 50 year old harness with a cheap alternative.....without ground straps and it melted and fused a bunch of wires under the dash after a very short time.

Then I replaced with an AAW harness and strategically placed ground straps at the rear ( bed to frame) cab ( cab to frame), engine ( engine to frame) battery to frame and core support to frame. This may be over kill but you can not see them unless your looking for them, they are bonded to bare metal and painted over so not to rust and they friggin work.

[jbgroby]

I'm going to pick up new battery cables today (might as well everything else is new . I installed a full and new wiring harness from E-Z. I made a new and direct ground to the radiator support for the halogen upgrade harness.

I currently have the positive cable to the starter, the negative cable to a bolt on the exhaust manifold.

Do I connect another strap from the block directly to the frame on both sides? as well as another straop from the bed to the frame in the rear of the truck?

Do I connect a strap from the blocl to the cab?

Would be this enough?

Jake

[jbgroby]

I was posting when you were so I did not see your reply/ Do you have a source of for the straps? Are the one from NAPA OK? I don't mind spending more, just trying to find the right ones the first time. I have more time than money

[61 apache 10]

Originally Posted by jbgroby

I'm going to pick up new battery cables today (might as well everything else is new . I installed a full and new wiring harness from E-Z. I made a new and direct ground to the radiator support for the halogen upgrade harness.

I currently have the positive cable to the starter, the negative cable to a bolt on the exhaust manifold.

Do I connect another strap from the block directly to the frame on both sides? as well as another straop from the bed to the frame in the rear of the truck?

Do I connect a strap from the blocl to the cab?

Would be this enough?

Jake

The exhaust manifold may not be the best place to attach the Batt neg wire. The heat in this area will most likely cause an issue with expansion and contraction. Can you use the front of the head or alternator bracket instead???
Battery negative to the engine first. The starter is the biggest draw of power in the vehicle. Keep this cable as short and large as possible.
I run a big ground strap from the transmission tailstock to the transmission crossmember bypassing the tranny mount. This grounds the frame, allows for a short, heavy gauge wire and is well hidden. It is also a good place to run a ground strap up to the body. This body ground needs to be a large gauge also. If the core support is mounted on rubber, I use a short jumper across this body mount also. Under the dash I will also put a ground from the steering column to the firewall.
Use as large of a ground wire as you can.
Remember every circuit in your vehicle, depends on these ground wires to be able to return to battery and some of them have very high current draws.
Hope this helps

[Leverhead]

Everything said here + a dedicated ground from your alternator also (between alt & mount bolt).

I like batt cables with starlock washers on top of and below the cable ends. Keep grounds as short as possible & clean all contact points to bare metal (dremel works good for this) ....brush a little dielectric grease on everything before you tighten them down. Recommend avoiding self tapping screws and thru bolting also where possible.

[luvbowties]

Originally Posted by jbgroby

I was posting when you were so I did not see your reply/ Do you have a source of for the straps? Are the one from NAPA OK? I don't mind spending more, just trying to find the right ones the first time. I have more time than money

We've used, for years, conventional, round battery cable wire(use old, conventional, discarded, broken-ended-terminal cables if you have some lying around), cut pieces to the length needed, and soldered terminals[see below] to ends to allow for bolting securely to wherever bolts are used. Has worked just fine.

Remember, you do not have to use "flat" cables! One-gauge round up to 6-gauge round will provide all the ground--or 'ampacity'--you could need or use. *(Copied/altered from another forum 'somewhere' & dealing with newer vehicles with many electronic circuits: For the head to firewall ground on newer vehicles, the flat braid may be a bit better due to flexing: the thing to consider there, is the length, which is usually short. Also, they use large 'star' washers to help spread the wider parameter of the braided ground.)
Sam

[chevyrestoguy]

Great info here. I have fixed many vehicles where the builder never considered a proper ground network, and it caused a myriad of problems. Basic rule of thumb.... Battery: ground to the block, Ground strap between the engine and frame, ground strap between the frame and the cab, and ground strap between the frame and the bed.

Strip the area at the ground points down to bare metal. Make sure the ground lug makes full contact with the base metal. Use a star washer under the bolt head and attach nut to ensure that the attach bolt becomes part of the ground path. Check the path with an ohmmeter to ensure that it reads continuity. Either paint or silicone seal the attach bolt and ground lug to prevent future corrosion.

I tend to use the flat cables with heat shrink over the wire mesh because I like the way it looks. I agree with the comment about using a thru-bolt versus a self-tapping screw at the attach locations. Self-tappers can get loose over time if it's at a place that is disassembled from time to time.

Most mechanical gremlins can still get you home, but an electrical gremlin will strand you every time. Some of the wiring jobs I have seen are horrific.

[aerotruk63]

The accessories installation manual shows all the recommended ground points for a radio installation including the spinner disks in the grease cap on the front spindles.

[Mike Wessinger]

I used standard battery cables from Wal Mart on my truck. Last year, just after the engine rebuild, I would occasionally have starting issues. It was slow to turn over so I replaced the battery, thinking the old one was getting weak. New battery and the same issue. I replaced both battery cables with new, heavier cables and like mentioned above, negative to block and positive to starter. I also added another block to frame battery cable. Total investment was somewhere around $25, and almost a year later, and I have not had any more of that problem.

[CR72LB]

Thanks for all the recommendations for grounding!! I'm off to add all the grounding straps AND get a new battery cable.

I had the same 'hard to start' issue Mike W. had last night. After a few slow, hard cranks, smoke started rolling out from under the hood. The small wire from neg battery cable to fender wire was fried!

I just bought the truck in April so I had not gone through the finer points of the electrical system. The Neg battery cable is attached to the alternator mounting bracket, but the surface is painted. Sure glad I didn't have a complete car-B-Que in the parking lot!

[jbgroby]

OK, I know you fine folks like pictures - I made of the light duty ground straps for the body panels to frame and such. I'm telling you it was really rough to purposely grind the paint. I'll dab over the spots with di-electric and paint later

[jbgroby]

more pics

[jbgroby]

I also ordered the heavy duty ones from LMC for the Engine to the frame.

[jbgroby]

I soldered them as well and put 1 on the cab to the inner fender and 2 from the inner fenders to the rad support

[roll_the_dice]

Bump for a great 4 year old post! Just the information I was looking for! Thanks guys!!

[demian5]

Classic industries, sells a nice pre made kit for 70s camaros that I like.

[roll_the_dice]

I am going to do similar to what Mark did above and use 2 gauge battery cable with lugs on each end for engine block to battery then 4 gauge cable engine block to radiator support. I am going to use military style lugs for ease also.

I am thinking of using these straps I found on ebay for the cab grounds

[PGSigns]

I go to the junk yard and ask if I can go pull ground straps. They have always said go for it. Get a big handful for $20. The newer cars have them all over and are very well made. I ground the block to the frame, the engine to the cab, the tail light housings to the bed, the bed to the frame, the main ground from the battery to the head or intake, the secondary wire on the main cable to the core support, the headlights to the core support and the hood to the cab. Those are the main grounds I put on the truck.
Jimmy

[BobS]

If you're looking for a neat way to strip paint under the ground lug (or any electrical connection), look up something called a "Piloted Bonding Brush". They are available from aviation tool supply companies and are well worth the cost, in my opinion.

Bob

[Leverhead]

An easy way i do it is to use a dremel tool with a small sanding drum attachment and just easily sand away enough paint to get to clean metal under the washer and no more. The dielectric grease will keep it from rusting and the washer will hide it. I like to use a star washer under a flat washer for good contact.