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Discussion Starter #1
I was dredging through old posts on the forum and it looks like a few folks have used a 48-51 Ford starter button.


I really like the looks of this starter button and the price as well. But in another post http://www.ffcars.com/cgi-bin/ultimatebb.cgi/ubb/get_topic/f/40/t/004931.html? Someone says:

“the switch is a one wire that works as a switched ground which isn’t a problem with a wood dash but I would assume it would cause problems with a FFR metal dash”

Is saying that the switch just connects between the case and one lead out the back? I’m planning on using the normal FFR dash so I'm wondering how I could wire this. Has anyone used this with an Aluminum dash? How did you wire it up?

Thanks!
-Bret
 

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I'm not familiar with that button, but if it is a one wire deal, switched to chassis ground when pressed, you could use it pretty easily by using a relay. Of course, this all assumes your dash (and the case of this switch) is grounded.

Run a switched 12V wire to one side of the coil on a standard N.O. relay and to one of the load terminals. Run a wire from the other side of the coil to the start button. Finally, run a wire from the other load terminal to your starter solenoid.
 

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See later posting. I have CRS disease and gave out bad info on this post. posting below is accurate.

[ November 04, 2005, 08:32 PM: Message edited by: DeraldRice ]
 

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Discussion Starter #4
Thanks Wade and Derald. My car wiring ignorance is about to show (I design computers and have an electrical engineering degree, but I know very little about car wiring).

Let me start with a couple of very basic concepts that I think I understand, but common mis-use of words has made it confusing. The "Starter Relay" is a switched relay that just delivers power to the starter. The "Starter solinoid" is the blob on the side of the starter that shoves the starter gear into the ring gear. Right?

So the basic starter circuit is starter switch (or key) to energize the relay which powers the starter motor and solinoid. Does that sound right? The relay needs to be pretty beefy then.

I understand wiring it through a relay, and looking at my427sc's wiring diagram, it looks like the standard mustang starter relay is actually assuming switched ground (through the clutch switch too). Is that true? That would work very nicely (but I'll have to pick up a relay).

Derald, are you saying I don't need a starter relay at all and that this little button can be the ground for the full current drawn by the starter motor and solinoid? That just doesn't sound safe, especially if I wire up the clutch and/or tranny neutral switch.

Thanks for the help! --Bret
 

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I don't know the answer to your last question for sure, but earlier vehicles often didn't use relays. They engineered the part to handle the amps and used heavier wire. Since the bodys, frames and engines were very heavy and because there were limited electrical accessories, the additional weight of the part and of the wire was unimportant. Scott
 

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A 51 Ford has a key start.

The start button on all 50 Fords and 51 Woodies is as described. It is snaps into the steel dash and the one slide connector wire makes a ground when pushed. This will work with a relay as long as your dash is grounded. I have it ground a relay to start the 289/AOD in Park or Neutral when the key is on.

The original button in my 51 Woodie doesn't say start on it but it did start the old flathead with the key on and the Ford-O-Matic in Park only.
 

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I APPOLOGIZE............... I gave out some bad information and have spent the last hour at the shop going over how it is installed into my track car. I will attempt to clarify it now. The original design of the start button is a grounding devise. As I have used it, the start button is NOT used as a grounding devise. It does feed 12 volts to the solenoid. One wire comes from a switched 12 source to the case of the start button, and another wire goes from the back of the start button to the "S" termninal of the solenoid. I do have a 10 amp fuse in this circuit. The start button NEEDS to be insluated from grounding. Operation is to turn the key to run position, press the start button, and release when engine starts. It is a one wire setup. I did not use a seperate relay since the solenoid is a relay. Sorry for the confusion, I will explain further if needed.

Derald.
 

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Discussion Starter #8
Thanks Derald. I think that makes sense now. I do want to run both a nuetral and clutch safety switch in there (in parallel so it's an OR thing) so I think I'll go ahead and make sure there's a relay in the system.

Are you saying that the starter solinoid has a relay built in? Then why do the Mustangs use a separate starter relay? Well, I'm not quite that far in the wiring, but I think I have enough info now to get it sorted out.

Thanks for all the help! --Bret
 
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