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Posted by: Tom Mar 9 2014, 12:22 PM

Thought I would do a little experiment to show what arc damage does to copper surfaces.
The first picture is two new alligator clips. The contacts.
Second is after 100 close/open events using a small relay - 0. 150 amps.
Third, forth, and fifth are after 100 open/close events using the starter solenoid- about 35 amps.
The current thru the starter solenoid is about 233 times as strong. I was actually getting a small shock due to the inductive spike and had to insulate my hands.
As you can see even with my poor camera skills, no damage can be seen after the 100 close/open events with the small relay. The arc damage does look significant after only 100 close/open events of the starter solenoid.
Would love to disassemble a failed key switch to see what the contacts look like.
Tom

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Posted by: Tom Mar 10 2014, 05:39 AM

I guess there is no interest in what happens to our key switches due to arc damage. Lots of looks, but no replies or questions? With the supply of NOS switches dwindling ( according to others who have replaced their switches more than once due to crappy materials in the switches from ??), I thought there would be a lot of interest in protecting the switches in our cars. Every time I think of this issue, I am reminded of the oil filter commercial where the mechanic is saying " you can pay me now, or pay me later".
I know there are those who insist that our cars work just fine electrically, but the evidence says different. Adding a relay to a starting system that should have had one from the factory is not in my opinion "hacking" a car's electrical system. It is simply updating it to standards almost all car manufacturers use today.
Tom

Posted by: FourBlades Mar 10 2014, 07:00 AM

I agree about the relay being necessary.

I had one of the new ignition switches fail after only 2 years.

John

Posted by: budk Mar 10 2014, 07:06 AM

QUOTE(Tom @ Mar 10 2014, 07:39 AM)

I guess there is no interest in what happens to our key switches due to arc damage. Lots of looks, but no replies or questions? With the supply of NOS switches dwindling ( according to others who have replaced their switches more than once due to crappy materials in the switches from ??), I thought there would be a lot of interest in protecting the switches in our cars. Every time I think of this issue, I am reminded of the oil filter commercial where the mechanic is saying " you can pay me now, or pay me later".
I know there are those who insist that our cars work just fine electrically, but the evidence says different. Adding a relay to a starting system that should have had one from the factory is not in my opinion "hacking" a car's electrical system. It is simply updating it to standards almost all car manufacturers use today.
Tom

I was one of the ones that viewed your post but did not respond, simply because I was not sure what point you were trying to make.

Now that you have added some information I fully understand and agree with your contention that having a relay in the circuit would be a good idea.

Posted by: jim_hoyland Mar 10 2014, 07:11 AM

Great illustration of the effect from voltage spike. I'm thinking that same test on a working (new ? ) switch will reveal more to us 914 owners whose cars seem to start now.
Thanks for shedding more light on this

FYI- I have added the relay

Posted by: cary Mar 10 2014, 07:28 AM

I have a relay in both my cars. You only need to get stranded once with a failing ignition switch ............

But I think I tossed the switch after I changed it many years ago. So I'm no help.

Posted by: Spoke Mar 10 2014, 08:09 AM

Nice experiment.

From this one can also understand the rapid wear of ignition points during their lifetime.

Posted by: 76-914 Mar 10 2014, 08:17 AM

You don't need to convince me. In another arena; this and electrolysis is precisely why building codes will no longer let you ground to the copper pipes in your home. I've seen copper pipes that were in close proximity of one another (as in damned near touching) arc until one begins to leak, beneath the slab. $$$$$. Besides, I have a relay and I just began to re-connect your fuse box last nite.

Posted by: rick 918-S Mar 10 2014, 08:18 AM

I have never had a switch fail. (944 did )

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