Date: Tue, 8 Feb 2005 10:11:51 -0800
Reply-To: Jack <john.cook58@VERIZON.NET>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Jack <john.cook58@VERIZON.NET>
Subject: Re: Cleaning bad grounds
In-Reply-To: <000101c50d7e$89c3ad30$6501a8c0@jiggy>
Content-type: text/plain; charset=US-ASCII
I've stayed out of this but a couple of comments need some response.
1. Star washers. Do NOT use between terminal and ground surface
unless absolutely necessary to cut through paint or something. If
they heat up it's because a higher resistance has been introduced
into the electrical contact system via the washer. Bad!
2. Threads. Grease, anti-seize, peanut butter ... doesn't matter!
Any good contact system relies on the flat surfaces, NOT on the
threads. If using some substance on the threads creates a higher
resistance then something is wrong.
3. A typical stackup. Per "best practices" in industry.
Body metal. Bright & clean bare metal.
Ideally, surface is plated or tinned.
Terminal (ring or spade). Bright & clean. Proper connection
to wire assumed (different set of problems).
Flat metal washer. Sometimes omitted.
Lock washer.
Purpose is to maintain high contact pressure.
Nut or bolt/screw head.
4. If in bad environment, cover stack with grease or suitable
compound - I prefer silicon (e.g., DC4). Helps prevent corrosion and
eventual corruption of the gas tight metal/metal contact.
There are, of course, variations on the above. Key point. Well
designed ground systems do NOT normally rely on threads for
electrical contact unless there's no choice.
//Jack
'85 GL
On 7 Feb 2005 at 17:35, Antaki wrote:
> Do an Internet search on the following: anti-seize electrical conductivity
> Google returned:
> http://www.google.com/search?hl=en&q=anti-seize+electrical+conductivity&spel
> l=1
>
> The results indicate that many anti-sieze compounds have good electrical
> conductivity. Often these compounds have a lot of metal in them, so this
> makes sense to me.
>
> To make the best ground connection using a bolt, I count on the mating of
> flat conductive surfaces to each other. Clean the surface of the grounding
> metal (body, head, etc.), really well. Same for the piece being bolted to
> the grounding metal. I like to use anti-sieze on the threads sometimes, but
> grease or oil is ok, too, as long as it is on the threads and not the flat
> conducting surfaces. You can also use an internal lock washer (star washer)
> to bite into both surfaces of the connection, as long as it is not a
> high-current connection such as a starter. The high current will heat the
> washer, it will lose some springiness, and the connection is now loose! Or
> use the star washer between the bolt head and the connector, as long as it
> is not the only path for high current.
>
> The lubricant on the threads will make it easier to get a tight connection
> with less torque needed, especially if the threads are corroded. Remember,
> most lubricants will not prevent some metal-to metal contact between the
> male and the female threads.
>
> When I'm all done making the connection, I spray it with oil, rust
> preventative, or best yet, a zinc-rich spray if the application permits. Go
> to http://www.crcindustries.com/crcweb/ and search on the word zinc.
>
> Hope this helps!
>
> Ron A
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Tim Marciniak
> Sent: Monday, February 07, 2005 5:23 AM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Cleaning bad grounds
>
>
> Having had some starting and idle problems with my van I am going through
> and cleaning all the ground connections in the van. Does anyone have a sure
> fire method for cleaning the threaded bolt holes were the ground screws go
> in. I tried rolling up some emery cloth and just turing that in the hole
> but i cant see that that works very well. maybe running a threading tap
> might help but then there is the risk of crossing threads. Any got any
> other methods.
>
> Tim
> 1990 Multivan
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