1939 LaSalle Radio, 6-8 volt resistor?

[FRED ZWICKER #23106]

I recently installed an 8-volt battery in my 1939 LaSalle. It was the exact same physical size as the 6-volt battery and really helps get the car started, especially when hot. The lights are all rated 6-8 volts and work perfectly.  I had the voltage regulator adjusted for the higher voltage and everything seems to work perfectly, without any wiring changes. About 30 years ago, I had another 1939 LaSalle and installed an 8 volt battery with similar results and no problems of any kind. This seems to be a simple solution for faster and easier starting.

Before installing the 8-volt battery, I disconnected the radio until I could check things out. Before installing the radio (it is still disconnected), I checked the Internet and saw where someone (David Steele) said that he would not work on a 6-volt radio if the car had an 8-volt battery. I checked with the battery manufacturer, who furnished a resistor to reduce the voltage from 8 volts to 6 volts for a nominal cost of $14.  This resistor is to be installed just ahead of the radio.  Accordingly I sent an email to Daniel Steele (who repairs antique car radios) and told him of the exact circumstances. He got back to me right away (thank you) and replied that as stated on his web site, he would not work on a 6-volt radio if connected to an 8-volt battery.  If this is the case, what function is served by installing the resistor?  If the correct resistor is used, isnt the power into the radio now 6 volts?  If so, what could be the problem?  I was going to hook up the clock to the same resistor.

If I had to make a choice, I prefer to drive a car that will start immediately, even if no radio, than to have a working radio and a car that might not start (especially when hot).

Fred Zwicker

[Jack]

Adding a resistor inline to reduce the source voltage is probably not a terribly accurate method to do this.

Are you "electrical"? If so measure the impedance (resistance) of the radios power "in" and determine how much current the radio draws. Lets say the resistance is 2 ohms, using Ohms Law the radio will draw 3 amps at 6 volts.

The you could build a simple voltage reducer using a 6 volt zener diode tied to the base of a "pass transistor" that will handle 3 amps. You could even mount this little circuit inside the radios box.

If this is "overwhelming" then you can buy devices that will do this

Jack

[Doug Houston]

If you use an 8 volt battery, the generator regultor will have to be adjusted up to NINE.FIVE volts; not just 8 volts. Otherwise, it cant charge the battery.

The dropping resistor you need will depend on the current that the radio draws. On that car, its about 8 amperes. You cant just grab some resistor and expect it to work.

I have told stubborn restorers that I wont touch a radio if they were going to use it on an 8 Volt battery. They  come to their senses occasionally, but not easily.  

If you have a competent mechanic with some genuine electrical savvy working on the car, it will start very energetically on 6 Volts.  You may have done it on a dozen cars n the past, but its the wrong thing to do. An 8 volt battery is a lousy cop-out for not doing a job right!

[FRED ZWICKER #23106]

Thanks Doug,
You have convinced me.  Luckily that I disconnected the radio prior to installing the 8-volt battery and that I have not yet connected the radio as yet. I will see how a new extra-heavy 6-volt battery will handle things. Some are recommending an Optima battery, or something like that. One thing that I did do prior to starting the car (after installing the 8-volt battery) was to have the regulator set at around 9-volts.

Please see my post of last night relating to a problem that I am now having with my electric fuel pump, which could be causing the ammeter to show a discharge.  It might be possible that this could be related, although everything has been running fine since installing the 8-volt battery 3 weeks ago. Thanks,

Fred Zwicker

[Rhino 21150]

A proper six volt REGULATOR to handle a ten amp draw can be easily constructed by any geek. It wont be cheap. You wont be able to run the clock off it since it would be tied to the battery all the time and would drain it much faster than the clock alone. Ditch the eight volt battery and use Dougs trick of having a ground stud attached to the brush plate of the starter.
If you insist on using the resistor with a RADIO you will have all sorts of weird problems with the radio every time you adjust the volume. And you run the risk of burning out the filaments of RARE AND EXPENSIVE tubes.
Actually, many radios with cassette players that are before digital tuning will work fine on a six volt car with reduced volume. They were designed to keep playing until they completely killed the twelve volt battery of the modern(ish) car. The less expensive speakers will make as much sound without as much quality on the lowered output of these radios.

[Bryson Talamini 21505]

Fred, I agree with Doug 6V will work fine. Lots of older posts on this but generally use extra thick cables to your starter and connecting the engine to the chassis. I have a big cable for my main earth running from the battery direct to a bell housing bolt next to the starter mounting bolt on my 37 LaSalle. Keep the cables as short as possible. I have just replaced the 6V Optima battery on my 289 cu in 1927 Chandler after 8 1/2 years and I recommend them. By the way the extra force of 8V on the solenoid will eventually break your engagement mechanism [I have seen this happen]
Bryson in Oz!

[Fred Zwicker #23106]

Taking everyones advice, I removed the new 8-volt battery and replaced it with a commercial heavy-duty 6-volt battery with 575 cold cranking amps (the 8-volt had only 525 cold cranking maps, so I am in hopes that the 6-volt battery holds up and starts the car quickly). So far, so good and I was able to connect the radio, which is working fine without any worries and the clock should be OK on 6-volts as well.  I also was told by several electrical gurus that the ammeter and gas gauge both work on resistance, so that using an 8-volt battery would not give the right reading. This may have accounted for me running out of gas at just under 1/4 tank on the gauge (when using the 8-volt battery).  My cables are heavy and grounding straps good.

I am relieved that I do not have to worry about faster burnout of lights, possible problem with starter motor and also possible problem with the electric fuel pump and maybe even the generator. It turns out that the fuel pump is a booster pump and not really needed, except for a cold start, after car sits for a long time, or for vapor lock, so this is also good news.

In the process, the voltage regulator went out and I am wondering if this was due to the 8-volt battery and regulator setting to 8.9 volts?  I was able to locate a NOS regulator and it is on its way, so should have everything solved by the latter part of next week.  The original voltage regulator on a 1939 LaSalle is Part No. 1118204 and has a 2-bolt mount.  It is different from the No. 1118202 regulator used on the 1940 LaSalle (3-bolt mount) and later year Cadillacs.  I guess it is possible to use another regulator, but it might not be easy and the original is always best.

Thanks for everyones good advice.  I really appreciat the feedback.

Fred Zwicker
1939 LaSalle Convertible Coupe

[JIM CLC # 15000]

08-26-06
Fred, Buy yourself a 6Vdc battery "Charger" I got a small charger from SEARS. Hook it up a day or two before I plan to start-up the old girl, Has been working like a champ.
The one I have will also has a switch for 6 or 12 volts and believe me, IVE had to use it.
Good Luck,JIM

[FRED ZWICKER #23106]

Thanks for the advice - everyone is right. I previously installed an 8-volt battery, but did not connect the radio (luckily). The car started quickly every time, but the 8-volt issue was a problem, as it presented other issues, as well as the big issue of damaging the radio.

Last week, I purchased a very-heavy duty 6-volt Interstate Battery that has a cold cranking amperage of 575 amps, which is more than the 8-volt 525 cca (see my previous post on this same thread from last night). Prior to purchasing the heavy-duty 6-volt battery, I called Auto Zone and they had a 6-volt battery in stock, but it had a cold cranking amperage of only 450 (a long way from 575 cca that I purchased). After installing the 6-volt battery, connected the radio and it worked perfectly.  Problem solved (I hope).  I have a Battery Tender which is easy to use, so will keep the new 6-volt battery fully charged at all times.

Fred Zwicker

P.S. One member mentioned that when using an 8-volt battery, the extra force of the 8 volts on the solenoid will eventually break the engagement mechanism. (He had a 1927 Chandler with a 289 cu. inch motor, so this might not apply to the LaSalle). However, if it does apply, would not a 12-volt switch to give the starter extra power result in the same risk?

[Jack]

Ah Shucks . . . I was hoping yopu would go the "techie route" withe zener !

Your solution was elegant and effective.

Jack

[Bryson Talamini 21505]

Fred. Pleased to hear things are now going fine. Yes a 12V start switch would result in the same problem. The time I saw the engagement mechanism fail was on a late 30s Buick, but not many people in Oz try the 8V route, 12V volt conversions are fairly popular [although I find a properly done 6V system to be more than adequate] Your new 3 bolt regulator should work ok but you will need to find the regulator settings for the model generator currently on your car and set the regulator to those values otherwise you might burn out the generator.
Bryson in Oz

[FRED ZWICKER #23106]

Hello Bryson and thanks for the reply.

A NOS (#1118204)regulator is coming in today via Fedex from Florida. The generator on the car is the correct Delco 3-brush generator # 1101056 and my technician plans to take the generator and new regulator to his friends shop where they are going to run everything on the bench to get the right settings, before installing on the car.  Hopefully they can get it right without any further problems, as I realize the complexity of all of this.

I read an automotive book that I had at work on voltage regulators and there were about 30-40 illustrated pages, going into too much detail for me, but let me know that there is a lot more to all of this than to just turn one screw to do the settings.  The guy in Florida (Dave from Yesteryear) mentioned that after finalzing the settings, do NOT overtighten the bolt that holds the cover on the 1118204 regulator, as overtightening can slightly bend the back plate, throwing it out of adjustment.  He also mentioned letting things warm up for about 15 minutes before doing the adjustments and that it might take a few tries to get it exact.

I originally (about 3 weeks ago) installed an 8-volt battery (big mistake, as all on this forum noted).  I had the voltage regulator set for 8.9 volts and the car started instantly and everything was working great, except that I was unable to safely connect the radio, for fear of burning it out.  I then bought a resistor to bring down the voltage, but did not install it, due to more feedback on this forum about more problems with such a setup. Then (still with the 8-volt battery and settings), the ammeter showed a discharge (no longer charging).

To make a long story short, I went back to a new 6-volt heavy duty commercial battery with 575 cold cranking amps (the 8-volt had only 525 cold cranking amps), and had the regulator set back for the 6-volt battery.  I then connected the radio, which works great. I then thought everything was taken care of.  My man got the generator to charge OK, but the ammeter fluctuates back and forth and the trouble was diagnosed as being in the regulator (but could be the generator, as anything is possible). I am wondering if previously setting the original regulator for the 8-volt battery had something to do with this?

So when the NOS regulator is installed, I am in hopes that I can get this problem finalized this week, as would like to drive the car for the remaining weeks of summer.

Fred Zwicker
1939 LaSalle Convertible Coupe - Maroon