1939 LaSalle Electrical Questions

[39LaSalleDriver]

Since I didn't trust the wiring which came with my car, I am now installing all new wiring which I got from Narragansett. Their instructions if you want to call them that, aren't particularly detailed, but fortunately with some diligence, can be more or less figured out. I'll be having a few questions over the next week or two about electrical things and figured I'd just lump them all into one topic/thread.

My first issue is that the starter and solenoid that came on my car from what I can tell is not stock. I have three wires in the harness which are to connect to it and the solenoid.

The “Y – R” wire with ring which connects to post number 1 goes to the horn relay “Bat” terminal, then on to the ammeter, and then on to the starter button. I base this on the continuity through the harness and the diagram Narragansett provided.

The “Y – R” wire with the spade connector I THINK connects to post number 2, and again, based on continuity, goes to the same starter button wire as above.

Am I correct so far? If so, the problem I now have is that the third wire, a “Y x G”, needs a place to go. The other end based on continuity connects to the voltage regulator “Arm” post, and then on to the generator.

So what post should I connect the “Y x G” wire to?

I have continuity between posts 2, 3, and 4 on the solenoid. The original factory schematic is rather confusing to me on this point as it shows (in theory) the starter relay being separate from the solenoid even though I believe them to be housed in the same unit.

Could any of you guys with electrical expertise clear this up for me? I've spent days trying to noodle this through with no success, and don't want to fry something when I get it all back together. Thanks,

[Tom Beaver]

Jon,

Your starter and starter solenoid are not what came with your car originally, so the wires in your wiring harness will not match up exactly, as I think you know.  I can pass on a functional description of the OEM starter wiring that I got from Doug Houston some time ago, when I was asking about where the wires went.  Here are his comments:

Starter wiring:

On the 1937 to 1939 cars the wire from the starter solenoid to the voltage regulator is for the "It's already running" relay. The relay pulls in when the generator starts putting out electricity, meaning the engine is running, and the solenoid/starter is disabled. Can't engage the starter when the engine is running. Clever, eh?
The regulators changed in 1940 and the starter safety relay was eliminated. From that time on, the low side of the starter relay (On the back of the solenoid) was connected to the generator armature, and that circuit did the same thing, only without needing a relay. The idea is that when the engine is not running, the generator is a low resistance path to ground, but when the engine is running, the generator armature is at the same potential as the ignition(battery) circuit. This puts both sides of the starter relay at 6 Volts (hot side), and the starter can't operate. Yes, it is very clever.

This may help give you some idea of how to connect your wiring harness and you will also need to verify which type regulator you have.  The regulator on my car was a later 1940 unit and didn't have the safety relay so I wired it up as Doug explained above, you essentially run the ground wire from the starter relay to the generator armature via the armature post on the regulator, and it works, it is very clever.

Hope this helps.

Tom Beaver

[Bob Schuman]

Ther is another consideration you need to be aware of. The solenoid in your photo is the type first used by Cadillac in 1950. Prior to that, the solenoid incorporated a small relay. In the 1940-1949 design the ignition switch and starter button fed the relay, requiring only a small electrical current, and when the relay closed it fed a much larger current to the solenoid to pull the gear into the flywheel and energize the starter motor. In the 1950 and later design, there was no relay, and the wiring, ignition switch, ammeter, and starter button were designed to handle the much larger current draw of the solenoid directly.
I believe that if you use the solenoid without relay, as you  now have, it will overload your ignition switch, starter button, and wiring, and will likely cause very short life of some or all of those parts.
It may be a direct replacement of your solenoid with a 1940-1949 solenoid onto your starter, I'm not sure about that. Then your new harness will match up with the terminals on the solenoid. The downside is that new or good used solenoids are not easy to find. An alternate is a separate relay addition, which maybe someone who has done that can comment on.
Bob Schuman

[jackworstell]

No# 4 doesn't look like a terminal to me.    If it isn't then I think ground for the solenoid is provided thru the case and not thru the third (unused) wire.

If stock then the third wire would provide ground for the solenoid thru the "safety relay" mounted on the regulator
( alternately thru the generator armature )   as Tom points out.  But you don't have stock

HOWEVER   as Bob points out.....your starter button and ignition switch and associated wiring
will be at risk if you hook up as shown in your first post..  If I  ere doing this I would feed  #2 button from a small relay and in turn the small relay would be activated by the starter button.

Looking at your first post the wire to #1 looks to be a heavy wire as it should be #12 or #10...
it carries all the current to operate everything in your car.    The wire on #2 looks to be smaller as it should be...it carries only enough current to operate the solenoid.

We have a 1937 series 60  and a 1937 Buick Special.   We are lucky in that both still have the original style solenoid...with a  small relay attached to the solenoid  (not to be confused with the "safety solenoid" at the regulator which has a different purpose).   If one of these days either of these fail then we will probably not be able to find another ....they are getting rare.
And if this comes about we will then use a solenoid similar to the one you are using but take pains to power it thru ( via the starter button ) a small add-on relay

Jack Worstell      jlwmaster@aol.com

[jackworstell]

Suggestion...take the wire off of #2 terminal.   Then use an ohmmeter    to check between
#2 and ground.... if low resistance ( I would guess below 100 ohms )   then the ground for the solenoid is thru the case and the third wire is not needed.

If very high resistance ( near infinity ) then the third wire is needed to provide ground.   You said
the other end of the third wire does to the generator armature wire
 ( at the regulator i guess ).....good..... this is one of the set-ups Tom described
In this scenario I'm not sure where the third ( ground ) wire attaches to the solenoid in that #4 doesn't look like a terminal to me 

Jack Worstell               jlwmaster@aol.com

[39LaSalleDriver]

Thanks for the suggestions...please keep them coming. I have to confess that right now I'm so confused and frustrated I'm ready to put a gun in my mouth  I also apologize for coming across as being so dense, as I can normally be a pretty quick study, but this electrical stuff drives me up a wall. It doesn't help that I'm trying to use factory spec replacement wire on aftermarket parts which were designed for who knows what...

If I am reading correctly, Tom is suggesting an arrangement something like this attached photo indicates (I'm pretty visual on things like this). It's also sounding like I might be well advised to purchase an aftermarket relay and hook it in as well. For the time being, I'm okay with having aftermarket parts which don't belong until I can afford/track down an OEM starter and solenoid rig. I just know I need to get this thing up and running at least as well as it did before I decided to strip all the wiring out. If I have to "band aid" fix it for that to happen short term, that's fine; but I will be wanting to get it back as close to factory spec as I can get it in the future.

If I "go dark" for a few days, it's because I've decided to step away and clear my head, and try to soak in what you kind folks have suggested.

[jackworstell]

I read over my two previous threads on this post and realllized that I could have made things
much clearer by pointing out that there are two issues

1)    GROUND FOR THE SOLENOID......is it a)  grounded thru the case or b) do you need
        to ground it thru  the generator armature  using the third wire ?
        ( I'm assuming that the original regulator  with its "safety relay " has been
        changed out and you  no longer have have a safety relay grounding option....but even if you
         do you could  ignore the safety relay and instead ground thru the generator armature
         thru the third wire....  either grounding option should work if  the solenoid is not grounded
         thru its case. )   
         Tom gave the been explanation of the "safety relay" grounding  and generator armature
         grounding  set-ups I have seen.

2)     HOW DOES THE SOLENOID GET 6V FROM THE START BUTTON ? For many years
         ( something like 1937-1949 ?) the solenoids used by Cadillacs had a small relay
          physically attached to them.  The starter push button energized this small relay which
          then energized the solenoid in turn.   The solenoid you have does not have this small
          relay  ( unless it's built inside the solenoid which I doubt )
          So what Bob pointed out is that in the absence of the little attached relay
           you need to add-on a small relay...for exactly the same purpose...protect
          the starter button/ignition switch.  The location of the add-on relay isn't
           critical...I would put it on the firewall  within a foot or so of the starter.

it's confusing in the there are different three relays being discussed
         1)   The "safety relay"    ( Tom also describes this as the "it's already running relay" )
                mounted on the regulator  1937-1938
         2)   The relay that was attached to the solenoid in approx the 1937-1949
               time period....which had to do with getting 6V to the solenoid coil without cooking
                the starter button/ignition switch and associated wiring.
          3)   A small "add-on"   relay which it appears you need

I doubt that there is a relay bulit inside the solenoid you have.   But still I think you need the add-on relay in any event
.  If there is an inside relay then you would have a
starter button/add-on relay/inside relay/solenoid/starter arrangement...which would still work

The first step as I see it is to determine whether the solenoid is grounded thru the case ( see
my post above )  If it is...no third wire is needed   ( and you sure don't want a wire which goes to ground on one end  with the other end hooked to the armature terminal when the generator is running......!!!)

Jack Worstell

[Tom Beaver]

Here is a picture of a 38 starter showing the starter solenoid with the starter relay sitting on top at the rear (the black box with two wires attached to it, yellow and blue).  The yellow wire is the hot wire which comes directly from the starter push button (This would correspond to your number 2 wire) and the blue wire is the relay ground wire which attaches to the the generator armature, via the voltage regulator (This would correspond to your "Y x G" wire).  It is this relay which you do not have and as Jack and Bob pointed out you need to provide  in order to limit the current draw thru the ignition switch and starter push button.

Tom Beaver

[Steve Passmore]

Jim Stampler had the same trouble some years back when a previous owner had changed the Solenoid giving Jim problems with the wiring. I sent him a correct solenoid and relay which solved it.   Personally, I would replace it with the correct unit. Someone must have a used solenoid/relay lying around?   Pre 1941 Buick used a similar setup which gives a greater scope when searching parts.

[Bob Schuman]

The solenoid in Tom Beaver's photo is correct for 1936-early 1942 V-8 engines, per the MPB. The late 42-48 solenoid looks a little different, but is a direct replacement if authentic appearance is not critical. Also, the 49 solenoid is identical to the 42-48 except it is tilted slightly, but will work fine on a flathead.
As Steve said, Buicks used a similar unit, and I think those on some Packards and postwar Oldsmobiles may work also, but you would need to see one to know if it would fit.
Bob Schuman

[39LaSalleDriver]

First of all, thanks to everyone who is holding my hand through this process, it really is helping me to dimly see the light. You guys are great for helping like you have. So today I revisited all this with less frustration, and hopefully a clearer head.

To begin with, I have created a new diagram based on the original schematic modified by also showing an aftermarket relay added in per some suggestions here. When I get specifically pinned down what I need to get, I will add one of these to the circuit. At this point, an aftermarket relay that I can mount to the firewall seems to be the only real option for me, since the starter I have isn't even really for this car and a new, correct one isn't in the budget right now. The car started and operated fine before I started this project, and there's no reason I can't make it work on that level now, only adding in a functional relay to make everything more or less fit and go back together. I'll worry about authenticity on down the road.

Next, I have determined that indeed the "#2" post in my previous photo is grounded through the case as Jack recommended I check. I think it is also a safe bet that the relay is not built into the solenoid as Jack mentioned, so I am going forward with that presumption. I would also presume that the yellow wire in my diagram becomes the de facto ground wire?

So here is my new diagram based on what I understand the schematic to be telling me. If I have something wrong, please don't hesitate to point it out. My questions based on this new diagram, if I have it illustrated correctly would be:

a) Which wires go to which terminals on the aftermarket relay? and;

b) How would they wire into the starter or connect to the posts on the starter that I have? I assume I will have to run some short pig tails from the aftermarket relay to the posts on my starter. and;

c) Will any generic 6v aftermarket relay work or will I have to seek a vintage one for similar cars as Bob and Steve have suggested? The ones for Ford tractors seem to be fairly cheap and common; and if those would work, should I get one of the three or four post variety?

Thanks again,

[jackworstell]

I'm assuming that your solenoid is grounded inside the case.

If so....then one end of the solenoid coil is grounded inside the case and the other end of the solenoid coil
should be attached to #2 terminal ( inside the solenoid)

To test this out
   put the car in neutral and have the ignition off
   take a temporary jumper wire ( something like #16 gauge or #14 gauge will work ) and
      ...very briefly.....put 6V on #2 terminal...just touch #2 with the jumper wire...
       then the starter should attempt to turn ...very briefly.

Jack Worstell

[jackworstell]

        (........ See my post just above regarding the solenoid ground............ )

About the add-on relay...you don't need a big one.   It just has to supply enough current to actuate the solenoid coil.
A little "ice cube" type will do ( but so will dozens of others }

It has be be for 6V   and normally open type.  For example  see  ebay 173173517546

......hook 85 to the starter button  and 86 to ground ( or you can reverse these two if you want )
......hook 30 to a source of 6V   and 87   goes to #2 on the solenoid....87a is not used
......with this set up...when you push the starter button...it turns on the relay and closes the contacts
           and this in turns puts 6V on #2 terminal and this activates the solenoid and the solenoid
           actuates the starter.

Tom  Bob  Steve    do you guys agree with this  ?

[z3skybolt]

Not directly responsive....

.....but if you want to replace with an original as Steve Passmore said....Buick is an anternative.  I checked my 37 Buick Special today.  The starter solenoid  is identical to my 1940 346 engine.  You might find a good one off an old Buick or rebuild it.

And ALLCADS has them.  Of course they were $500.00 over a year ago.

Bob

[Brad Ipsen CLC #737]

Just put a want request in the WTB section for the correct flathead starter solenoid.  Either early or late version as Bob stated will work.  Much easier than reengineering the Cadillac design and most likely cheaper. 

[39LaSalleDriver]

        (........ See my post just above regarding the solenoid ground............ )

About the add-on relay...you don't need a big one.   It just has to supply enough current to actuate the solenoid coil.
A little "ice cube" type will do ( but so will dozens of others }

It has be be for 6V   and normally open type.  For example  see  ebay 173173517546

......hook 85 to the starter button  and 86 to ground ( or you can reverse these two if you want )
......hook 30 to a source of 6V   and 87   goes to #2 on the solenoid....87a is not used
......with this set up...when you push the starter button...it turns on the relay and closes the contacts
           and this in turns puts 6V on #2 terminal and this activates the solenoid and the solenoid
           actuates the starter.

Thanks Jack, I went ahead and ordered one of these exact units. For $10 it will get me by for right now (I hope) until I can afford/find the right starter and solenoid unit. Just to make sure I am understanding everything correct, I have updated my illustration to reflect the above data. Does this look right to you? If so, I'll go ahead and wire it all up when I get the relay. Thanks again for your patience and assistance.

[jackworstell]

  Looks good to me.
 
  I assume that the solenoid coil:     one end is connected to #2 terminal and the other
        end of the coil is grounded somewhere inside the case.

  I note you plan to ground the add-on relay thru the generator armature.  I hadn't thought
       of this angle.....but it helps make sure the starter isn't activated when the engine is running
       so less chance of damaging the starter pinion/flywheel teeth.
       

Jack Worstell


Jack Worstel


     

[39LaSalleDriver]

Just to do a follow up on all this, today was a profitable day. I got the new relay wired in, and while yes, it isn't OEM, it will hopefully be serviceable for the time being. Best of all it is completely reversible and I didn't have to drill anything or modify any original parts. I was able to mount it directly to the casing of the solenoid, so that helped keep everything somewhat tidy.

I also got my turn signals finished up. I installed a single pole/double throw toggle switch under the dash which is so much more discreet than the ugly aftermarket job which was mounted to the steering column with a hose clamp. I had already rewired the back end of the car, and made new innards for the tail light cans which mounts two sockets. In those I was able to affix two specialty red 6v LED lights for my tail/stop and turn signals. These should draw less voltage and be dramatically brighter. I had also remounted the amber motorcycle? turn signals which were on the front bumper, and put them in behind the fender grills.

Really looking forward to doing testing this week to make sure everything works as it should!