Solenoid Internal Mystery

[bc.gold 3,406]

I'm old enough to remember when the copper contact was solid copper you could disassemble the solenoid turn the copper contact over for a fresh surface then turn the power terminal lugs 180 degrees. Done this hundreds of times on those old 50's and 1960's Delco starters.

 

The solid copper contact washer was fitted loosely which allowed it to rotate onto fresh surface then they started using a steel contact that was copper plated.

 

This new style of contact is on a fixed position destined for early failure, just because you hear the solenoid click when power is applied does not mean that power is making it's way through the contacts which maybe badly burnt.

 

In images 3 and 4 you can clearly see that the tops of the copper power terminals are badly oxidized. It's actually quite brilliant what the engineers have done with the contact in image 5.

 

Contact in image 5 is springy when it slams against the power lugs it spreads out, a scrubbing action to clean off the accumulated oxides.

 

A battery with a low charge is hard on the solenoid contacts and the starter also hard on the battery sometimes causing the internal plates to buckle.

 

This solenoid below is from the mid 1990's, the copper contact appears to be silver plated and you can see that the solenoid coil is independent and grounded internally to the metal mounting bracket.

 

 

 

 

 

 

 

Edited August 5, 2019 by bcgold

[bc.gold 3,406]

The internals from Delco starter, you can see the circular wear on the copper contact from being allowed to rotate, also you can still turn the power lugs 180 degrees for a fresh surface.

 

Notice on the round contact the etching that has occurred with many starts.

 

I stand corrected on closer examination it appears that the copper was applied using powdered metallurgy, compressed powder applied under high hydraulic pressure.

 

 

 

 

Edited August 5, 2019 by bcgold