Earthing Points

[james3004]

Is it worth my while welding some bolt to the chassis before painting it for earthing points?

Any suggestions of where to put them and what size bolts to use?

[adrianreeve]

You could do, m6 or m8 would be best. I just used rivnuts, so then icould decide the best place for earthing points as I went along when wiring the car up. As the rivnut pulls up on the back of the tube, it makes good contact with the bare metal inside the tube.

Hope that helps

Adrian

[Davey]

Sounds like a good idea to me. I'd suggest 8mm in the engine bay and 6mm elsewhere. 8mm near battery position and another 8mm near the engine. 6mm either side at the front for earthing the lights plus one either side at the rear for same. One or two 6mm under the scuttle perhaps for earthing instrument panel.

D.

[HandyAndy]

I,ve done the same as Adrian, fitted earthing points as I went along in places where they were needed, but Davey,s suggestion is also a good one , just be careful if you go this route that you don,t weld a bolt to the chassis that might "get in the way" later on in the build .

cheers
andy

[davidimurray]

Just a thought when I pondered this. Do the earth points need to be positively locked? I.e a bolt and a Nylock to show that it is secure. I remember Ash had a problem with his brake Tee being rivnutted on and he had to replace with a bolt and Nylock. Would the same be considered with the electrics. Just in case - I was going to do the front and rear lights with rivnuts, but the main battery to chassis to engine strap with a bolt.

[james3004]

like you say andy it is probably better for me to put them in after as they might get in the way of other stuff

Thnks for the replies

[HandyAndy]

Originally Posted by davidimurray

Just a thought when I pondered this. Do the earth points need to be positively locked? I.e a bolt and a Nylock to show that it is secure. I remember Ash had a problem with his brake Tee being rivnutted on and he had to replace with a bolt and Nylock. Would the same be considered with the electrics. Just in case - I was going to do the front and rear lights with rivnuts, but the main battery to chassis to engine strap with a bolt.

Good question David, not sure of the answer tho ,

The way I see it......

Ash,s IVA test was a "High profile" one, being in the magazine etc & maybe the tester went over his car with an EXTRA fine toothed comb etc etc, I,ve heard of cars passing the test with the brake T piece just rivnutted in place so its open to the tester,s opinion I believe

As the earthing points are merely just attaching a wire to the chassis I presume its classed as a non critical securing method , basically if the nut came off it wouldn,t allow a major safety component to "fall off".....

Thats the way I see it, rightly or wrongly I,m not sure
I remember one of Ash,s quotes...." use a Nyloc in a place that if it fell off would it kill me "...

cheers
andy

[davidimurray]

My logic comes from my my days playing with race cars and dealing with scruiteneers. The basic rule that we worked to was any fastener that could affect the operation of the car must have a positive and clearly visible locking method - i.e loctite was not acceptable as you couldn't prove it was there. So we used Nylocks, K-nuts, lockwiring etc.

I may also be paranoid as a mate who races dropped out of a race a few weeks ago when the plain nut on his earth stud come loose and the car died. Similarly I wouldn't want to be in the outside lane of the motorway when the engine cut out due to a loose earth!

[Davey]

My one concern over using rivnuts for earth points is electrolytic corrosion taking place and causing poor earth connections in the future. Basically if water and or road salt got into the joint between rivnut and chassis it could cause corrosion due to the zinc or nickel plating, classic dissimilar metals and moisture giving rise to the corrosion. If its on the joint between chassis and rivnut it could be very difficult to find and cure. Just a thought.

D.

[adrianreeve]

A smear of copper grease on the rivnut should protect it.

Cheers

Adrian