O/D Relay

[jrlemke]

Does anyone know if I can use one of the common electronic relays (the little black cube with 4 or 5 connections) in place of the original on my '61 Hawk? If not, why not?-Jim

[greyben]

If it has 12 volt coil and at least 15 amp contacts, yes, but after 1957 overdrives no longer used a relay.

[PackardV8]

Does anyone know if I can use one of the common electronic relays (the little black cube with 4 or 5 connections) in place of the original on my '61 Hawk?

Yes, if you choose the correct relay and wire it correctly. I used several modern relays when building my '55 E12, rewiring the entire truck with a custom built harness.

If not, why not?-Jim

Because your next question is likely to be "Which part number relay and base should I choose and how should it be wired and does anyone have a wiring diagram?"

jack vines

[StudeRich]

With the proper Solenoid, Kickdown Switch and wire routing as greyben said, you don't need no stink'in Relay.

[jrlemke]

My '61 Hawk has a '56 trans. so it has a relay. It works fine for now, but I'm going to put the original one back in someday. What changes do I have to make when I change over? Also, does the Chev. o/d from '66 (Saginaw) use a relay or not? I have one on a Sag. 4 spd that will eventually go in the Hawk. Thanks- Jim

[Kurt]

With the proper Solenoid, Kickdown Switch and wire routing as greyben said, you don't need no stink'in Relay.

How owe does one know which relay does not need a relay? I have often wondered that.

[StudeRich]

How owe does one know which relay does not need a relay? I have often wondered that.

I don't know how owe knows, but the Relay or NO Relay is dependent on a 3 Wire Solenoid or a 2 Wire one.

[jrlemke]

Which is which and do I need to change the kick down switch? I have the switch for the earlier trans. Is one better than the other? -Jim

[Mrs K Corbin]

yeah, somebody got a wiring diagram for the no relay setup? Might try it myself.

[gordr]

Kickdown switch is the same, electrically, for the two types. There might be different style of kickdown switch to match up with different throttle linkages.

To digress a little: the kickdown switch is really two switches in one housing. There is a pair of normally-closed contacts that feed power to the solenoid, and a pair of normally-open contacts that ground out the ignition points via a grounding contact in the solenoid. So when you floorboard the throttle, power is interrupted to the solenoid coil at the same time that the ignition is momentarily interrupted, which slacks off torque on the driveline, allowing the solenoid to disengage by its own internal return spring. As it disengages, the grounding contact within it opens, restoring power to the ignition, even if the accelerator is still on the floor.

Anyway, what do you do if you have a custom engine installation, or aftermarket carb and throttle linkage, and also maybe electronic ignition with no points to short out? This is where you might have to get creative. You could replace the stock type kickdown switch with a single-contact microswitch, right next to the throttle shaft of your carb or throttle body. Let that microswitch control the coil of a suitable relay, one with normally-closed contacts to feed juice to the solenoid, and another set of contacts to interrupt either the ignition or perhaps the EFI if used, by either opening a circuit, or shorting one. For example, if you had a Pertronix in there, you could simple use the normally-closed contacts in the power feed from the ignition switch to the Pertronix. Your microswitch would apply 12 volts to one end of the relay coil, and ground to the other end of the relay coil would be supplied by the grounding contact in the solenoid, as before.

Just posting this as a reminder that the overdrive circuitry, as used by Studebaker (and others) may not be compatible with upgrades made to Studebaker engines, or with Brand X engine swaps. But there are ways to solve such dilemmas.

[TWChamp]

If you do use a relay from some other source, besides the correct voltage and amp rating, it must be rated for continuous duty.