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Battery Ground to block location

Eoth

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Mar 10, 2004
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I have decided to replace my crusty battery cables. Looking things over, I see that my battery negative is grounded to the block via a bolt on my exhaust manifold. It seems to be effective enough (never any noticeable ground issues) but is there a better bolt I should be using?
 

DirtDonk

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It was either there, or very near the front of the head like yours is.

An even better place is closer to the starter. Some just use a starter bolt, but if your engine block has the threaded hole just in front of the starter motor (just above the pan rail), you can clean up that surface and use that for a good solid ground that's also pretty out of the way of other things.
I even keep a supply of dual-threaded studs in my electrical tool box just for this. It's like a 3/8" coarse thread into the block, and a fine thread on the outside to run a nut up. But a bolt would work just fine.

The reason I like to keep the main battery ground closer to the starter motor is that is what uses the most juice on the engine. And since I always make sure to add additional grounding points from the engine to the body, and the engine to the frame anyway, I don't think that losing the big cable ground from next to the alternator is that big of a deal.

I'm thinking that not all Ford engines have that threaded hole, but it's worth a look. If you have one, it only takes a few more inches of cable, which is not a big expense as things go. A few more pennies spent up front can do good things.

The only thing to keep it out of the way of, would be the exhaust manifold. But that's easy to do if you just run it up the frame rail and straight over to the hole. Easy peasy.

Paul
 

ntsqd

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Concur, as close to the starter as is reasonable. Depending on access, bell housing bolts work too.
 

NicksTrix

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on the right side of the block below the #1 plug, just behind the timing cover there is a 7/16 x 14 threaded spot just for a cable.
 

DirtDonk

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And once you change out from your stock cable (if it's even still original?), make sure to include a new body ground from the battery as well. The original had one, so any new ones should too.

This is what an original negative ground cable would have looked like (minus the hack job of course) on a '72:
iPhone Pics 29 02022016 Bronco sighting and Gil's 66 024 (Large).jpg

Paul
 

broncodriver99

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And once you change out from your stock cable (if it's even still original?), make sure to include a new body ground from the battery as well. The original had one, so any new ones should too.

This is what an original negative ground cable would have looked like (minus the hack job of course) on a '72:
View attachment 386968

Paul

Not sure about earlier years, but my '73 and a few other later models that I have seen(or paid attention to) had the chassis(body) ground going from the rear of the drivers head or a bolt on the intake manifold to a stud on the firewall near the throttle bellcrank.
 

Steve83

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This shows the 2 factory locations for a V8 block ground:



The cable from the battery (-) post should be directly against the BARE block (no paint or rust - just electrical grease; not dielectric or thermal or chassis). Then, another heavy cable can be run from the SAME bolt (this one against the bolt head so the main stays against the block) to the frame via a soldered tab on the uncut cable, and then to the body. All points of contact should be clean & greased, like the block.
 

croft75

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Not sure about earlier years, but my '73 and a few other later models that I have seen(or paid attention to) had the chassis(body) ground going from the rear of the drivers head or a bolt on the intake manifold to a stud on the firewall near the throttle bellcrank.
,

That's where mine was
 

DirtDonk

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That's interesting guys. Even though I've seen all those grounds on other vehicles, in all my years I've never seen a factory ground strap/cable from the engine to the body.
I would love to see pics of the locations, studs and type of cabling used, if you happen to either have old photos, or still have the original ground straps in place?

Our stock '76 at WH does not have anything like that (that I've noticed). Nor do two of my friend's '77's. One is an original and relatively unmolested Ranger that's still a daily driver.
Going to have to see if I can peek under the hood again on that one. Hopefully the kids haven't messed with it since I saw it last!

Thanks

Paul
 

brianstrange

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I like to run the ground from the battery to the block, with an intermediate connector on the frame. This way it's one clean wire. This can be done by sliding an over-sized lug from the depot, over the insulated wire. Create a stud point on your frame (5/16" nutsert, stud and counter-nut, then another nut that tightens the lug.) Sharpen the lug screw a bit to penetrate and secure the wire, and you're done. It's also good to add a ground strap from the motor to body as mentioned. As far as never too many grounds....... It's best to have as few properly sized ones as needed. It will save you when it's time to chase an issue. Also, NEVER ground electronics etc... to the battery.
 

brianstrange

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Another tip - If you do a junkyard run, grab some battery terminals and as much power wire as you can from a newer F-150 or larger Ford Truck. The quality of those battery terminals, and the 4 awg wire they use from the factory is second to none. Even though it's used, it will last years longer than other products sold today. The Battery terminals will never lose function because they are stainless as well. I usually grab a bunch, throw it in the tool bag, and they charge me $5 for it.
 

Broncobowsher

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So a longer ground cable, or a shorter cable at the front of the head?
The iron of the engine and the added fasteners has more resistance than copper wire, but there is so much iron that I don't see how it is better to run a longer cable. Yes, copper flows better, but it is much smaller. I still just run the shortest pratical cable. For rear battery mount I ground to the tailhousing of the transmission.

As for grounding the frame, why? What electrical items are on the frame? Remember the engine sits on rubber mounts. Body sits on rubber mounts. Oh, the gas gauge sending unit needs grounding. What really needs grounds? The engine and the body. Yea, you can ground the frame. But don't waste good money on it.
 

DirtDonk

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An extra buck or two for the longer ground cable? And maybe another 5-10 bucks to ground the frame? For the peace of mind knowing that this large ladder looking chunk of steel will never become an RFI magnet to mess with a computer, or anything else grounded to it in the future? I say it's just cheap insurance.
My '79 came with four ground straps between the cab and frame from the factory. So it's not exactly without precedence. Just keeps all the metal bits in one big happily bonded family.;D

The shorter cable to the front of the block is a perfectly legitimate location, as Ford has proven. It's just that some of us like different locations that take a slightly different route and maybe a longer cable or two.

Paul
 

Steve83

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I like to run the ground from the battery to the block, with an intermediate connector on the frame.
That's how most later F-series & Broncos are done, and Ford calls that G102.
...an over-sized lug from the depot, over the insulated wire. ... Sharpen the lug screw a bit to penetrate and secure the wire, and you're done.
That's not a very secure or reliable connection. It's better to solder a simple Copper tab to a short stripped section, just like the later trucks have.

.

...or just snag the negative cable assembly from a junker. That's what I put on Frank's '75, using a block ground stud in a new hole in the frame forward of the Right spring tower.
Also, NEVER ground electronics etc... to the battery.
Why not? That's where everything goes eventually, anyway.
The Battery terminals will never lose function because they are stainless as well.
I don't think they're stainless, but regardless - battery acid will eat stainless, and DOES attack those newer clamps.
I usually grab a bunch, throw it in the tool bag, and they charge me $5 for it.
That's how I collect a LOT of good used parts for nearly nothing.
As for grounding the frame, why?
Winch, trailer, aux. battery... Whatever. Why not? One more chunk of cable isn't gonna break the bank or overload the tires.
 

twisted 66

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I may have went overboard and I have aluminum heads and intake. I have 2 gauge going from battery to block, battery to body, block to frame, head to head, head to frame. More than needed probably but at least I will not need to worry about good grounds. I made my own cables so making my own lengths was a benefit.
 

ntsqd

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I have mobile electronics (ham radios) that specifically say in their manuals to pull both of it's power & it's ground directly from the battery.

Some electronics will be hampered by a ground loop. A ground loop acts as an antenna of sorts and picks up any EMI or RFI nearby. I define a ground loop as if you can trace more than one path thru the grounding system back to the battery from any place in the ground side of the electrical system, then you have a ground loop. Some disagree with this, but their definitions make no sense to me and while theirs may be more technically correct, mine results in less likely to have a problem from this.
A visual for this that may work for some is this: visualize the battery as the root ball of a tree. Pick any part of any branch in the tree and there is only one path down to the root ball, the other options at every intersection is an eventual dead-end except for the direction towards the root ball.
 
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