Strange tune-up find

[my427cobra]

Hi all. While performing my new years/spring tune -up on my Cobra,new plugs, oil change, carb adjustment, timing check, filters etc, I came across something strange that I have never seen before.

When I removed the coil wire (351C with stock distributor and pertronix ignition module), the end of the coil wire in the top of the coil was quite stuck and when removed with a little more than normal effort/pulling, the brass connector end that sticks into the top of the coil was covered in a greenish corrosion.

The other end of the coil wire that goes into the top of the distributor cap was nice and shiney.

A test with a voltmeter initially showed no conductivity between the two ends of the coil wire.

When I scraped through the "green corrosion", with the tip of the voltmeter probe, the conductivity was fine.

The car ran fine before, so higher voltage was penetrating the "green corrosion", but it was getting harder to start.

So what gives?????? What caused the corrosion?

I just cleaned the corrosion off the brass tip, got it shiny again, and it will probably work just fine.

Right?

Cheers
Greg

[spdbrake]

Its just dissimilar metals and galvanic corrosion. The further each metal is away from each other on the periodic table the worse it gets.
Here is a simplified table.
http://irongrain.lowercaseproduction...-Corrosion.pdf
You can help prevent it by putting some Dielectric grease on the contact areas. Also on the plug wires contacts, the dizzy cap and each spark plug.
https://images-na.ssl-images-amazon...._AC_SX466_.jpg

[my427cobra]

Thanks spdbrake. Pretty much what I thought but it was strange to me as it was only on the coil ens of the wire. All other connectors including the plug wires looked good.

I'll get some dielectric grease tomorrow.

Cheers
Greg

[Anthony]

I started using ox-gard instead of permatex dialectric.

[Gaz64]

A few reasons for this to happen.

The coil lead has many times more sparks than each cylinder lead.
The coil end of the lead is hotter than the other end due to the heat of the coil.
The coil end boot could have had a compromised boot allowing moisture in.
The male to female connection might not have been as tight as could be.
An finally, the dissimilar metals involved, combined with any or all of the above, will give various levels of this phenomenon.

I have had cases where the lead has corroded so badly, that the bakelite tower has cracked from the growth buildup.

Gary

[snakeeyes]

Originally Posted by Gaz64

The male to female connection might not have been as tight as could be.

Gary

Story of my life, Gaz.

[Gaz64]

Originally Posted by snakeeyes

Story of my life, Gaz.

Didn't realise I made a funny there,