Earth lead

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75glnt
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Earth lead

Post by 75glnt »

Where does the earth lead from the battery go?! I forgot :P

Battery --> body

Body --> ???

Cheers :D
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Jordan1249
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Re: Earth lead

Post by Jordan1249 »

engine block
75glnt
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Re: Earth lead

Post by 75glnt »

Mint! Cheers brah :P

Nah, I pulled it all apart for the respray, now I've got back to putting it together, I forgot what I assumed I wouldn't :P typical!
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Jordan1249
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Re: Earth lead

Post by Jordan1249 »

hahah yer i know how that gets always take photos of everything hahah
Scorpma82
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Re: Earth lead

Post by Scorpma82 »

Couldn't u go straight from Battery to Block???

Or Battery to body only???
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Sigmaproject
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Re: Earth lead

Post by Sigmaproject »

The Earth lead bolts onto the block. On an Astron, it is midway between the alternator and the engine mount .
Jordan1249
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Re: Earth lead

Post by Jordan1249 »

On my one its negative to the block but has a section of insultation missing so its bare wire that is connected to the battery try well more just touching
75glnt
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Re: Earth lead

Post by 75glnt »

If I could go straight to my block (It's the same as the astron), I'm wondering why most cars are from the battery to the body, then to the block? Does it benefit me in any way at all? And can I actually go STRAIGHT to the block? I'm more it less asking for someone who has a working car, (preferably sg) to go check what theirs is like. :)

Thanks guys :)
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Jordan1249
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Re: Earth lead

Post by Jordan1249 »

like i said mine his basically straight to the block just has that little bit touching
75glnt
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Re: Earth lead

Post by 75glnt »

Yea I've seen the rest the same as that... I'm pretty sure mine was just straight to the block, and another wire from the terminal to the body
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Jordan1249
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Re: Earth lead

Post by Jordan1249 »

shouldnt make a difference only thing that make difference is the gauge of wire you use
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davetrees
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Re: Earth lead

Post by davetrees »

As long as the block & body are both connected by an earth strap, it doesn't matter electrically whether the -ve battery lead goes to the block or the body. Personally I prefer to run it to the body, to eliminate movement on the cable.
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LukeAussie
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Re: Earth lead

Post by LukeAussie »

That's right, it doesn't matter too much, since the whole thing is earthed. From memory, I run mine with nice fat gauge to the block, as the main think that pulls current is the starter. But really it doesn't matter, since that's the whole idea of "earth" :)
75glnt
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Re: Earth lead

Post by 75glnt »

Got it guys! :D fired her up last night

I used a really big gauge cable from the battery straight to the block (running it under the battery tray and into the loom so it stays tidy and minimalises movement). Then got some 25a wire from the terminal to the body (again, running into the loom for tidiness :P )
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davetrees
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Re: Earth lead

Post by davetrees »

BOTH wires (battery to block, and block to chassis) should be "battery cable" size ... 8-10mm diameter. (25A wire is nowhere near good enough ... remember that both your starter motor and alternator are earthing through it).

Note : The gearbox should be separately earthed to the body also .... just uses a 25A or so wire. It's also worth earthing the cylinder head to the body (certainly on the GB there is a spade connector on the firewall for this purpose, with a wire off the #4 inlet manifold stud. Stops things earthing through the throttle cable.)

90% of electrical problems in old cars are due to poor earthing.
75glnt
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Re: Earth lead

Post by 75glnt »

Thanks for that :)

So can I use the 25a wire from the head?
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davetrees
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Re: Earth lead

Post by davetrees »

Yeah, that will be fine .... mine is 15A or 20A wire I think. It's not "essential" to separately earth the head, but not a bad idea (the head gasket effectively makes it not earthed through the block, or at least poorly earthed).
75glnt
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Re: Earth lead

Post by 75glnt »

Fair enough :)
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cheaterparts
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Re: Earth lead

Post by cheaterparts »

davetrees wrote:Yeah, that will be fine .... mine is 15A or 20A wire I think. It's not "essential" to separately earth the head, but not a bad idea (the head gasket effectively makes it not earthed through the block, or at least poorly earthed).
head gasket would make little difference the head bolts are pretty heavy battery leads and are seated tight against both head and block
same goes for the engine to gear box unless you are using plastic bolts you should have a pretty good contact through the bolts

but as it has been said you need to cable the engine to the body no matter which way you fit the neg cable ( block or body ) as the rubber engine mounts insulate engine to body
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davetrees
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Re: Earth lead

Post by davetrees »

head gasket would make little difference the head bolts are pretty heavy battery leads and are seated tight against both head and block
same goes for the engine to gear box unless you are using plastic bolts you should have a pretty good contact through the bolts
True, but they still earthed both head and gearbox separately from factory - and manufacturers rarely do things for no reason ! I cured a couple of intermittent minor dash electrical issues by earthing the head to the body, and the reversing lights don't seem to work properly if the gearbox earth wire is disconnected.

The other critical earth points to check are the 2 spade-connector earth points inside the boot (one each side) that the tail-light clusters earth to. If these are loose or dirty, you get all all sorts of weird indicator/brake/tail-light issues (both front & rear) ! I have replaced the spades with ring connectors self-tappered to the metal.

(Probably worth noting though that my GB - being a rally car - is subject to much more vibration etc than your average road car ..... so it's pretty hard on loose electrical connections !)
Jordan1249
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Re: Earth lead

Post by Jordan1249 »

haha i just ran 2 8 gauge wires ground to the strut top hat bolts today cause the car was having trouble kicking over(too much audio equipment) seem to solve the problem
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