Voltage drop question

[36tudordeluxe]

Got a '36 with 12V system with negative ground. Show 12.8V at battery, starter solenoid and hot side of ignition with ignition switch off. When I turn ignition switch on shows 12.28V on the hot side and 12.15V on the cold side. Is this too much of a voltage drop from the 12.8V; is the differential between the two ignition posts too great. What I want to know is this acceptable? Have meticulously cleaned the ignition switch but sometimes I have to wiggle the on/off lever to make contact.

[cmbrucew]

36
You may need some new parts for your switch.
It is a good heavy duty switch that should not have any drop.
Bruce

[JSeery]

Might check the resistance through the switch. To check it you need to disconnect it from power.

[36tudordeluxe]

It is the original '36 ignition switch, will check with multi meter. Thanks

[19Fordy]

Could you install a relay to lessen the load on your original switch?

[JSeery]

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Originally Posted by 19Fordy

Could you install a relay to lessen the load on your original switch?

That's not a bad idea at all, in fact it's always better to bypass any ignition or main power switch with a relay. Just be sure it is a 6v relay and remember that some modern relays contain a diode that can cause issues with the polarity. I would suggest either a VW type relay or a starter type. The Cole Hersee 24059BP would be a good one.

NOTE: Just checked, the Cole Hersee 24059BP is a continuous duty relay, but is the 12V version, I could look up the 6v one if you are interested.

[George/Maine]

Seeing you have a 12 volts system and hope you have the correct resister and coil for 12 volts. Best get a 12 volt 4 post selinode, and take that old switch and have it for looks and put a key start switch in the push button hole.
If you still have starting problem use the I terminal on selinode and wire direct to coil.

[JSeery]

Originally Posted by George/Maine

Seeing you have a 12 volts system and hope you have the correct resister and coil for 12 volts. Best get a 12 volt 4 post selinode, and take that old switch and have it for looks and put a key start switch in the push button hole.
If you still have starting problem use the I terminal on selinode and wire direct to coil.

You know it always irritates me when people don't read the post before they reply. Well, guess I am guilty this time!!!!!

On a 12v system, any auto parts store relay will work fine. I like the metal heavy duty type, but that is just for looks, any relay is ok in your system.
Edit: and thanks George for setting me straight!

[36tudordeluxe]

Bubba's set me up with coil & resistor. I don't have a starting problem, car fires immediately. The only problem I have is the voltage drop itself; maybe I should leave well enough alone. Am going to investigate my ignition switch and see if I can find a cause for voltage drop; will do the relay if I can't find the problem. Thanks everyone for the advice.

[36tudordeluxe]

Put the meter on my '36 ignition switch and believe I have a problem. With key turned counter clockwise in the on position and thumb lever in the on position I show no resistance between the two posts on back of ignition switch; however, when I push the thumb lever to the off position the meter indicates the ignition is still on as I'm not showing any resistance on the meter; it's not until I turn the key to the off position that the meter indicates off. Is this the normal operation for a '36 ignition switch? Sometimes with key on and thumb lever in the on position the ignition isn't actually on. Will disassemble & see if I can do a better job of putting switch back together?

After disassembly of ignition switch box I noticed the Bakelite piece is warped and doesn't fit completely in the case, maybe this explains problem. Ordering a new one.

[George/Maine]

If you can get on both side of switch you should read Zero volts or very small.
If you have and old switch you could read some voltage. dirty contacts.
Best use the switch for looks and get a key start switch.

[russcc]

Those ignition switch parts are available NOS from Tracy in Arlington TX and Ray Helgers in RI. I would use NOS, versus something from who knows where.

[36tudordeluxe]

Originally Posted by russcc

Those ignition switch parts are available NOS from Tracy in Arlington TX and Ray Helgers in RI. I would use NOS, versus something from who knows where.

Glad you reminded me I have Tracy's # at ANTIQUE AUTO SUPPLY.

[G.M.]

I posted several times on how to clean and increase the amperage capacity of the ignition switch. Look in past posts. G.M.

[36tudordeluxe]

G.M., waiting for NOS switch from ANTIQUE AUTO SUPPLY, don't know how to search for past posts, but would like to know how to bring new switch up to your standard. Thanks for the help.

[G.M.]

Originally Posted by 36tudordeluxe

G.M., waiting for NOS switch from ANTIQUE AUTO SUPPLY, don't know how to search for past posts, but would like to know how to bring new switch up to your standard. Thanks for the help.

When the flat black plastic part with w/ brass contact pads was machined it is left with small ridges. Lay 600 paper on a hard FLAT surface like a piece of glass and in a figure 8 motion get rid of the ridges then finish with 1,000 or 1,500. Take the contact wipers and spring them out about .030 being careful not to let the little springs pop out. This is to give a little more pressure after the next step. With the 1,500 or 1,000 on the glass sand the ball contact ends with all ball ends on the glass so you get little flat ends about .080 on the ends. Now with the ridges removed and more contact surface area on the flats this switch will carry much more amps without arcing. The accessory side can handle more of a load. G.M.

[36tudordeluxe]

Originally Posted by G.M.

When the flat black plastic part with w/ brass contact pads was machined it is left with small ridges. Lay 600 paper on a hard FLAT surface like a piece of glass and in a figure 8 motion get rid of the ridges then finish with 1,000 or 1,500. Take the contact wipers and spring them out about .030 being careful not to let the little springs pop out. This is to give a little more pressure after the next step. With the 1,500 or 1,000 on the glass sand the ball contact ends with all ball ends on the glass so you get little flat ends about .080 on the ends. Now with the ridges removed and more contact surface area on the flats this switch will carry much more amps without arcing. The accessory side can handle more of a load. G.M.

G.M., really appreciate the help. Thank you