Originally Posted by Augusto
I'm planing in doing the popular ford solenoid conversion to cure hot starting problems on chevys, and I'm wondering if a different way would work better:
the usual way is splicing the solenoind in the bat cable, ok, but then this cable goes to the original connector on the starter motor solenoid and a jumper is connected from here to the "S" terminal on this solenoid, fine this will get full bat voltage to THE SOLENOID, not to the starter motor's windings, we still rely on the contacts inside this solenoid to get full juice to the motor, I'm thinking that the Bat cable should be connected directly to the other side of the solenoid, the one that holds the motor's wounds so the full voltage goes where it's needed, and not hampered by a poor contact inside the solenoid, which by the way still needs the jumper wire to the S terminal to activate it and engage the bendix.
what is the point installing a ford solenoid and still relying on the chevy solenoid to deliver full voltage to the motor's windings?
What do you guys think about this reasoning?
You actually have hit on the crux of the problem. The usual method of wiring the Ferd solenoid on a GM starter STILL requires the contacts inside the GM solenoid to work. The only advantage to this method is that you have significantly reduced the voltage drop in the wire that operates the GM solenoid, thus the improvement in hot starting.
Unfortunately, the method you are contemplating does not work without making changes to the internal wiring of the GM solenoid. The solenoid must still operate to move the Bendix drive into place on the flywheel. The internal wiring of the solenoid has two paths, one high current path to move the Bendix and a lower current path to hold it in. If you wire the Ferd solenoid the way you suggest, the internal wiring in the GM solenoid will cause the starter to stay engaged at all times.
Since you are stuck using the GM solenoid, there is an even easier way to fight the voltage drop. Disconnect the wire going to the "S" terminal on the GM solenoid. Wire a relay (or a Ferd solenoid) between the battery terminal on the GM solenoid and the "S" terminal. Keep these wires as short as possible and use heavy gauge wire. Use the wire that formerly went to the "S" terminal to operate the relay. You now have bypassed all the voltage drop in the wiring that goes to the ignition switch and neutral safety switch, which is about the best you can do with the GM starter. This should
solve any hot start problems anyway.