I have a crap earth

landy-lee · Jan 12, 2019

Evening guys

So i have been chasing earth problems all week now and i am convinced it its the earth that goes from the battery to the chassis to the bell housing.

It looks in good condition but behind all the paint i think its ****ed.

Question is can i go from the battery straight to the bell housing?

If not can i drill and tap the chassis or is that not good enough fixing?

Also is that the only earth strap?

does the body earth though the chassis?

Cheers Landy-lee

Al2O3 · Jan 12, 2019

You want a good earth to the chassis and the engine/box. Just take the existing ones off and get them nice and shiny with some emery cloth or similar.

terr · Jan 12, 2019

and multi earths from battery to different points

Litch · Jan 12, 2019

"and multi earths from battery to different points"

Agreed, I would never rely on continuity through fixings (especially on an older vehicle) and always provide straps to main earth points to which connections are made.

tottot · Jan 12, 2019

I have my main earth from the batt to the gearbox.Its the way it should be.

Litch · Jan 12, 2019

…..and to the chassis.

mick 1986 · Jan 13, 2019

landy-lee said:
Evening guys

So i have been chasing earth problems all week now and i am convinced it its the earth that goes from the battery to the chassis to the bell housing.

It looks in good condition but behind all the paint i think its ****ed.

Question is can i go from the battery straight to the bell housing?

If not can i drill and tap the chassis or is that not good enough fixing?

Also is that the only earth strap?

does the body earth though the chassis?

Cheers Landy-lee

Have you removed the earth strap and tested for continuity? Just because it “looks good” doesn’t mean it is good. Mine looked ok, but when I removed it, it looks as though it’s been soldered by a 5year old. It’s getting replaced when I start the rebuild.

Oldseadog · Jan 13, 2019

Al2O3 said:
You want a good earth to the chassis and the engine/box. Just take the existing ones off and get them nice and shiny with some emery cloth or similar.

^^ Wot he said, and then clag them with Vaseline before you reattach them.
Vaseline is the Landy Lover's bestest friend!

Litch · Jan 13, 2019

"Question is can i go from the battery straight to the bell housing?"

If you do that then the only chassis / body earth is via mechanical connections (handbrake cable etc) as the engine / drivetrain sit on rubber mounts. It is a well documented problem of handbrake cables overheating due to failure of the correct earth straps.

"If not can i drill and tap the chassis or is that not good enough fixing?"

That will be a start but at the end of the day you need to clean the connection point down to bare metal to ensure a good connection and then protect to prevent corrosion. Probably better to drill a hole, clean down to bare metal on both sides, attach strap using nut & bolt (corrosion protection goes without saying).

Apart from a pair of straps that run from battery-chassis and battery-chassis-gearbox I also have some smaller cables that run direct to main earth points on the bulkhead, rear body etc and all ancillary earth connections are cabled directly to these points. None of my body electrical circuits rely on a body or chassis earth, it exists but I don't rely on it.

mick 1986 · Jan 14, 2019

Litch said:
"Question is can i go from the battery straight to the bell housing?"

If you do that then the only chassis / body earth is via mechanical connections (handbrake cable etc) as the engine / drivetrain sit on rubber mounts. It is a well documented problem of handbrake cables overheating due to failure of the correct earth straps.

"If not can i drill and tap the chassis or is that not good enough fixing?"

That will be a start but at the end of the day you need to clean the connection point down to bare metal to ensure a good connection and then protect to prevent corrosion. Probably better to drill a hole, clean down to bare metal on both sides, attach strap using nut & bolt (corrosion protection goes without saying).

Apart from a pair of straps that run from battery-chassis and battery-chassis-gearbox I also have some smaller cables that run direct to main earth points on the bulkhead, rear body etc and all ancillary earth connections are cabled directly to these points. None of my body electrical circuits rely on a body or chassis earth, it exists but I don't rely on it.

What size earths are you using? I’m thinking along the lines of 70 or 95mm from battery to chassis and gearbox. 16mm to bulkhead and rear quarter lights. 4mm to all “black” body earths (headlights, rear light clusters, etc.).

landy-lee · Jan 19, 2019

Todays job is making and fitting a new earth.

flat · Jan 19, 2019

Neat job, having the right tools does make stuff like this easier

nobber · Jan 19, 2019

Im just doing mine at the moment, local motorfactors doesnt have any that I can use, cant buy through work cos I need them today so I'm resorting to making some. @landy-lee thats a nice crimping tool, I take it you solder them in after crimping?

landy-lee · Jan 19, 2019

nobber said:
Im just doing mine at the moment, local motorfactors doesnt have any that I can use, cant buy through work cos I need them today so I'm resorting to making some. @landy-lee thats a nice crimping tool, I take it you solder them in after crimping?

I work along side electricians witch is handy for borrowing there tools!

I did not solder after as the crimp holds it very tight. I think the key is to use heat shrink to prevent water working its way in to wire around the crimp.

nobber · Jan 19, 2019

landy-lee said:
I work along side electricians witch is handy for borrowing there tools!

I did not solder after as the crimp holds it very tight. I think the key is to use heat shrink to prevent water working its way in to wire around the crimp.

I tend to solder mine, the reason being copper oxidises, if you use brass fixings this will also oxidise, crimping with a decent tool like yours creates whats called a cold weld and is a decent fixing anyway but I do tend to solder when I can.

mick 1986 · Jan 19, 2019

landy-lee said:
I work along side electricians witch is handy for borrowing there tools!

I did not solder after as the crimp holds it very tight. I think the key is to use heat shrink to prevent water working its way in to wire around the crimp.

I would always solder these connections, even if the crimp is firm and well attached.

The trick is to get the contact area as large as possible, to reduce resistance, and reduce the bolt drop. The only contact area on a crimped joint, is round the wire/cable. A soldered joint should have around 80-90% contact area, but hoping more towards 100%.

It’s not an incorrect method of just crimping them, it’s just a belt and braces approach by soldering.

nobber · Jan 19, 2019

I picked up a new earth today from a local shop, I didn't want to because they were crimped, a little short and fairly thin cable so not ideal, but its a temp solution until I get to the workshop and make a new one properly, my old one was totally knackered and causing a lazy starting scenario.

CBS sell the bits,

https://www.carbuildersolutions.com/uk/brass-solder-on-battery-terminals

Its silly easy to do,

Or you could just buy premade cables , the problem being you just dont know what your getting, but they are really cheap anyway.

MrWorf · Jan 20, 2019

Apart from a pair of straps that run from battery-chassis and battery-chassis-gearbox I also have some smaller cables that run direct to main earth points on the bulkhead, rear body etc and all ancillary earth connections are cabled directly to these points. None of my body electrical circuits rely on a body or chassis earth, it exists but I don't rely on it.[/QUOTE]
I like the sound of this ...... What cable do you recommend ? I know how domestic cable is rated (like 2.5mm vs 1.5mm twin'N earth for example), but how do you specify what cable you want for cars ?

nobber · Jan 20, 2019

MrWorf said:
Apart from a pair of straps that run from battery-chassis and battery-chassis-gearbox I also have some smaller cables that run direct to main earth points on the bulkhead, rear body etc and all ancillary earth connections are cabled directly to these points. None of my body electrical circuits rely on a body or chassis earth, it exists but I don't rely on it.

I like the sound of this ...... What cable do you recommend ? I know how domestic cable is rated (like 2.5mm vs 1.5mm twin'N earth for example), but how do you specify what cable you want for cars ?[/QUOTE]

Live cables is worked out by the amps it will carry, earths are less of a problem but I like to keep them at least the same size as the corresponding live.

mick 1986 · Jan 21, 2019

MrWorf said:
I like the sound of this ...... What cable do you recommend ? I know how domestic cable is rated (like 2.5mm vs 1.5mm twin'N earth for example), but how do you specify what cable you want for cars ?

All cables that we would use are speced by the CCC (Current Carrying Capacity) and given in its CSA (Cross Sectional Area) in mm2 (millimetres squared). You need to know what the cable is doing before you could be advised what to buy.

nobber said:
Live cables is worked out by the amps it will carry, earths are less of a problem but I like to keep them at least the same size as the corresponding live.

In 12V DC systems, earth cables are arguably more important to overspec to than live cables. Don’t fit an earth cable that is smaller than the live cable, in a 12V DV system.

I have a crap earth

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