Okay, im my 50 Fordor, i want to hook up my OD system but I cant seem to find a voltage drop unit that actually puts out 6v; Damn, I already smoked the clock in the dash. I voltage drop unit that I have is a white ceramic disk w/ a termination point on each side...the posts are marked...I put the voltage drop in the circuit and put a Fluke meter on it and it still reads 11.98 volts (fluxuating up and down, but no less than 11 volts.) straight off the battery. I bought (2) of these and they both work the same...like ****. Does anyone have any suggestions to a reliable voltage drop unit or maybe have one laying around they could sell. Im at a loss.
The one from Ron Francis is kinda expensive, but it works. For your O.D. you could get a 12V solenoid pretty easily and skip the voltage drop there altogether.
Been running a 6V solenoid on my OD on a '49 Merc for 8 years. Been 12V all this time also. No problems with the solenoid. Seems the voltage regulator(?) you bought a pair of may just be ballast resistors. Not enough current flow thru the resistor to ground thru the Fluke to drop the voltage. Ford used a unit under the dash for years I think beginning in 1957 clear up thru 1970 that would work well for dropping the voltage to your gauges.
blown49 nailed it - you've got dropping resistors that require a bit of current through them to actually drop the voltage where you could notice it...not having them hooked up to anything means you won't see any significant drop. Solenoids don't care about voltage, but running your 6V solenoid on 12V means it will run hotter, but should be fine as blown49's experience attests. If it makes you feel better, run one of those dropping resistors inline...
Okay, If im reading this right, wire 12v directly to the relay on the firewall and it should operate okay? If so...thats all i needed to know. I may put a drop inline just for sense of ease.. My only concern is frying relays and solenoids on this OD setup on the car. I dont want to know what it would cost to replace or repair them.
Well, the relay doesn't care either, but it will run hot too. Might as well run a 12V relay designed for continuous duty at roughly double the current rating of the 6V one...
I think Ill try the 6v drop first, Who would carry the relay made for 12v? even the solenoid (on the shelf item(s)?)....Dennis Carpenter? Im talking about the one mounted center on the firewall. There is an old Ford place here in San Dimas, i can check there too.
12V O/D Solenoids seem to be tough to come by & bring fair money when they do show up. Having said that, they should be plentiful, because they were used from mid-50s to early/mid-60s & most 3-spd O/D were B&W units, so should interchange. As far as the relay, see if the original has any current ratings or other markings on it. It might say something like 6V 3A (6 volts 3 Amps) & in a perfect world, you'd like to find a 12V 6A relay that's designed for continuous use. I'm afraid there isn't an "off the shelf" part that fits necessarily - you'll have to look at the IPG (illustrated parts guide) for some electrical suppliers to your favorite parts store to see if you can find what you need. Of course, this ***umes you don't use one of those modern, computer-only, catalogs-scare-the-16year-old parts stores & have a real parts store to go to. You may have some luck at Radio Shack, but again, you'll likely have to look through their catalogs as they don't carry nearly as many actual parts anymore. In a perfect world, you could look up the part number of your original/replacement relay, then find a case style in the IPG & see if there's a 12V equivalent (there usually is) & then compare the current ratings of the two.
Er...When you go from 6 volts to 12 shouldn't the amp load drop in half?? I think you've got him shopping for the wrong thing. A 12 volt chrysler (and probably other brands) starter relay will work for the O.D. relay. I hear Idaho Transmission Warehouse 800-225-6568 is pretty good about having obscure OD parts.
Volts divided by resistance = current (amps). Since the resistance of the solenoid does not change the current is doubled. Law invented by a hot rodder that souped up chariots in Rome I think by the name of Ohm.
okay, im getting confused. I x R = V Current times resistance equals volts (right?) If the system is 12 volts - the fuse/current cant exceed 3 amps then the resistance is 4 ohms. In a 6 volt system, at 6 volts, and a 3 amp (current) fuse is used, the resistance cant exceed 2 ohms. I did a bit of research...check this out....how to make your own voltage drop unit...needs a little math...and simple enough to build. Voltage Drop I found this on ebay...this is what I am using. Voltage drop
I was going through the same thing till I found a 12v solenoid. The 7806 voltage regulator on that page is no where near capable to handle the load the solenoid will use. I was going to re-wind the coil windings on my 6v solenoid. Theoretically it is posiible to convert it to 12v. I can't remember the specifics right now, but basically you use magnet wire with half the guage, same number of turns (I think). The problem I found is that finding wire long enough requires you to buy alot of it and at that point you could afford a NOS 12v solenoid. There are actually two coils in the O/D solenoid. One to engage it and a smaller, less current, holding coil. Make sure you hook up all the wires back correctly. I found out that system is actually alot more complicated than it looks. For instance, when disengaging the O/D for an upshift, it actually grounds the ignition for a split second, so that the pressure on the solenoid plunger is release and it can retract. Here's a complete online manual for that trans. http://www.tocmp.com/manuals/trans/Borg-Warner Overdrive/index.htm
Yes I X R = V is correct Therefore V / I = R and V / R = I If the resistance of the solenoid is 4 ohms then on 6 volts it would be 6 / 4 = 1.5 amps If the resistance of the solenoid is still 4 ohms then on 12 volts it would be 12 / 4 + 3 or double the current. The resistance of the solenoid does not change. If I remember right the solenoid is fused for 30 amps in the Ford/Merc Borg Warner OD units for 6 volt operation.
Starter relays are not intended for continuous duty. Continuous duty relays are typically wound with two coils to include a holding coil...just like the solenoids. A relay is nothing more than a solenoid that actuates a switch. The principle is the same. And as has been pointed out, the current doubles when you double the voltage ***uming resistance remains the same. (As an aside, technically speaking, coils (as found in solenoids, relays, etc) aren't measured in ohms, per se, it's impedance & has to do with coil saturation. However, for automotive applications, our simplification works just fine - we're not building high-end electronics here, just relays & solenoids! It's just semantics, really.)
There is alot of good information, and its making me do a bit of research of how this works. Speaking of which...i need to 'school' myself of how this whole system works electrically, and I think the answer will be there, whether we run 12 or 6v on the system. If its working for Blown49, at 12v, then the solenoids and relays must be seeing intermitten voltage, thus the reason for it not burning up...totally. I downloaded that overdrive book posted here and will be reading it for more info. Ill keep you posted. But to go back, the white voltage drop above then wont work. 6v drop at 4amps. (need to find out the running current of this system ) If the amperage is higher, say 30 amps; you would need (8) of these in series for 6v at 32 amps total?
Get a genuine transformer. then you'll know for sure. You can't really test a resistor unless its under load.
blown49's solenoids & relays are seeing full system voltage, not intermittent voltage. Just because something is rated for 6V does not mean it will burn up on 12V, just that more current will flow through it - all else being equal. Recall that 6V wiring is heavier than that required for 12V, so you're not going to burn up your wiring - the coils inside the solenoids & relays are not different. More current is going through his solenoids & relays which means they will get hotter than normal, but does not mean they will necessarily burn out. You shouldn't have any (original) circuit pulling 30A. Your voltage drop will likely be just fine. Again, we're not building high-end electronics where voltages are crucial - most components, especially coil-wound ones like relays, solenoids, & motors, will run on a wide range of voltages. That white resistor rated at 4amps is generic resistor drop typically used for things like heater fan motors. 4amps is probably a nominal maximum (how's that for a contradiction in terms?) current rating & it will likely prove sufficient for anything within +/- 1.5A. For liability reasons, they're going to tend to stay on the low side to prevent overheating. 'Close enough' really is sufficient for this stuff...
I found the answer on the FordBarn...it confirmed alot of what you guys where saying.... Here is the link: http://www.fordbarn.com/earlyv8/forum03/messages/104634.htm Thanks for the help!!! 12v is okay...just slams harder...
...and runs slightly hotter. I could go into Watts law here, but math really isn't necessary...and I'm too lazy.
I'll trade you a 12 volt one for a 6 volt one. PM me or email me at artbornerror81 (AT) AOL (DOT) com
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