Hi, got a 69 ford 351w motor with a 1 wire alternator. I want to rewire it.
Question : because there is a) no ignition module
b) external starter relay.
c) 3 wire ignition switch
d) no accessory to be connected(lights etc)
e) 2 barrel carb with electric choke.
how do i wire a basic starting system?, key - relay - coil- starter- distibutor
all the wiring diagrams i have looked at show wiring for a 3 wire alternator.
do i need a resistance wire or ballast in the ignition wiring?
any help will be appreciated.
starter motor relay has 4 terminals, the coil has 2 ( i know the tach goes to -)
the ignition has 3 wires and battery ground goes to the engine. the starter has 1 terminal.
thanks

 

What are you doing? Making a engine stand? Do you have a points ignition?

 

I drew up some quick pics of basic wiring and put them in my gallery. They should be correct for starter and relay, ignition switch and coil/dist wiring if it has points. You probably won't need the diode with the four wire relay, but if your starter tries to stay engaged after starting then add it. As far as the alternator, it's gonna depend on the type. try to find some numbers and see if it's a GM or something else and I'll try to clarify that part. BTW, if it has points replace them and the condensor first and gap points to .019".

 

This diagram looks good for a GM stock alt. The diode would be placed in the small wire going from the ign switch term to the alt. But he said he has a one-wire alt so he shouldn't have to worry about a diode.

 

Actually, the diode between the start relay and the ignition coil has nothing to do with the alternator. I wasn't sure how the Ford relay was set up, having mostly dealt with GM products. The wire from the solenoid to the coil is there to supply full voltage during cranking (by bypassing the resistor/resistance wire). The voltage to the coil on the old points systems with a ballast resistor often drops too low during cranking due to the load of the starter, so bypassing during cranking gives a hot enough spark to help get it started. If one had a standard relay (or ran a wire from the solenoid coil wire) to supplement the voltage, then the "full-time, ignition-on" voltage to the coil's positive side could keep the solenoid engaged when dropping back to the "run" position. A diode would block this "back-feed". I figured if it's using the Ford 4-terminal relay, the "I" terminal is probably isolated, but wasn't sure. It's good insurance anyway, or could be added if the starter tried to stay engaged. I'm sure Marklut1 will clarify when he gets back online, but this was sort of a cross-post. The engine is in a boat and has rough idle, questionable wiring, and a Rochester 2bbl carb (which he's replacing. I'd keep it and rebuild it, myself, but that's just the old GM guy in me coming out! LOL). His other, slightly different post is in the Small block V8 forum if you want to check it out.

 

Okay Everyone who posted help, thanks a lot, its starting to make sense now,
the diagram is EXTREMELY helpful.
the wiring makes sense now and it fits into the basic layout on the system.
however the one wire alternator, i see it gets connected to the starter relay, not directly to the battery, is that correct?
another question, the resistance wire , what are the specs on it? ( i would like to restore this motor to stock)
thanks guys for all your help

 

200000+F150- You are correct of course about the aux contact for bypassing the resistor to the coil, and so long as you have this extra contact on the solenoid, you don't need a diode. Where you do need the diode is when using a conventional Gm alt on any vehicle. The wire I am talking about is on the #1 terminal of the alt that is hooked to the brown wire on a Gm vehicle. This brown wire is hooked to a hot in run at the ignition switch to bring the alt "online" to charge. If this wire is hooked to the same contact in the ignition switch that the coil positive is hooked to, the alt will feedback voltage on the brown wire, and not let the vehicle shut off. The diode or hooking the original dash "alt" in series with the brown wire will keep this from happening.

You are hooking the alt to the large terminal on the solenoid. This has a large wire going to the positive battery terminal. Electrically these two points are the same. If you want to hook it to the battery positive, it won't make any difference in operation.