Ross.

I still have positive ground so hooking up a negative ground solenoid moves the contactor the wrong way. I really need to change the polarity but was trying to do things one step at a time. In your diagram having the wrong polarity moves the contactor down instead of up.

 

New plugs, cleaned and re-gapped the points and re set the timing. Fired right up.

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Sounds good Mike! Glad you got it running.

 

I'm with Ross on this one. I had to change to neg. ground due to installing a neg. ground radio. This was nearly 40 years ago, and I still have the original starter solenoid operating on 6V neg. ground. - Bob

 

If your solenoid is grounded by the mounting bracket like mine it matters. If you change the polarity on an electro magnet it will reverse the direction of force (movement). Google Ampere's right hand rule. If you reverse the polarity the contactor will move in the opposite direction.

 

Congrats on the first run, Mike!

Do you still have your old solenoid? Could you cut it open to see how it works? I think the typical diagram with a moving core is a simplification of how they actually are constructed.

PS -- all 51-on Ford solenoids are grounded thru the bracket

 

F1 Mike, The '51 and earlier solenoid that ground thru the bracket will work fine with the polarity switched to negative ground. I used one for years on my '47 COE.

 

I'm still using the old solenoid, I cleaned it up good enough that it's working OK. I have one on my other truck that I can take to pieces. I'm still not convinced. I tried 2 other solenoids, one brand new and neither would switch. I can think of at least one way that it would work either way. I'll update tomorrow.