Cadillac & LaSalle Club Discussion Forum

Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: KC Tom on December 06, 2021, 12:05:17 PM

Title: 1940 starter relay
Post by: KC Tom on December 06, 2021, 12:05:17 PM
I am having issues my the starter relay on my Lasalle.
Starts fine when cold but after running for a few miles it will not restart, no click totally dead. Sit for 30 minutes and starts fine. I believe it might be the system that prevents starter from working when motor is running.
I purchaser a new relay delco Remy 1866167 but it is totally different.
Someone on this board had mentioned that in late 1940 they switched to a updated model.
Does anyone know a part number and possibly where I might get one.
Thanks for any help.
Title: Re: 1940 starter relay
Post by: harvey b on December 06, 2021, 06:53:14 PM
is your solenoid like this one on ebay?  https://www.ebay.com/itm/264845621408?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m1438.l2649  the number you have is showing as the correct part,but it is possible the starter is changed,the only other number i see is 188 4537  1942-1949  use with solonoid 1118102 on 1942. do you have any pictres that would help too,Funny thing is i just ordered a 186 6167 relay for my car,its not here yet but i hope it fixes mine ?. harceyb
Title: Re: 1940 starter relay
Post by: KC Tom on December 06, 2021, 07:34:25 PM
That one is different then mine. When you get it if it doesn't fit let me know. I have a new old stock one that won't work for me but might for you.
Title: Re: 1940 starter relay
Post by: V63 on December 06, 2021, 09:51:46 PM

Check all your connections...Past that, the starter solonoid might be suspect?  Verify that A heat shield is in place for the solonoid.
Title: Re: 1940 starter relay
Post by: harvey b on December 07, 2021, 08:43:48 AM
When the car is running,there is a "system" in place to keep you from hitting the starter button and possibly damaging the starter,it is connected through the voltage regulator,i am unsure of the actual wiring for it.On my 37 it works as it should.it is a handy feature to have.Is it possible your voltage regulator is the problem?.I have a picture of my starter,the relay is at the end where the cables connect,it is a little bit of work to replace it,you have to be careful when you replace it,it is insulated from the live contacts,make sure you put the insulated washers back exactly as you found them?.As far as i know they only had this type of solenoid,but the one on ebay will work,it is a later type,wont be "correct" for your car.There are some tips on repairing the regulator in the shop manual too. harveyb
Title: Re: 1940 starter relay
Post by: V63 on December 07, 2021, 12:03:59 PM
Thank you Harvey, that sounds right. That 'system' sounds like a  generator circuit is used to complete the ground. Once the generator starts charging,  the ground is lost.
Title: Re: 1940 starter relay
Post by: KC Tom on December 07, 2021, 01:59:57 PM
Thanks Harvey
I hate to spend $300 for a relay if that is not the problem. You have me thinking about the regular, but I know the system is fed from the regulator and I noticed that when this happens the amp meter is not showing charge. It normally shows charge.
Maybe the points in regulator are sticking. Maybe when it does it I will tryirapping lightly on the regulator cover and see what happens
Title: Re: 1940 starter relay
Post by: Tom Beaver on December 07, 2021, 10:13:07 PM
Here are some comments I got from Doug Houston:
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 (ground) 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. (Doug Houston)

Tom Beaver
Title: Re: 1940 starter relay
Post by: KC Tom on December 07, 2021, 10:38:02 PM
I wonder if possibly they used some leftover 39 parts on my 40 car, I believe I have the earlier system.
Title: Re: 1940 starter relay
Post by: Tom Beaver on December 08, 2021, 09:42:28 PM
You could run a wire directly from the ground side of the starter relay to the ARM post on your voltage regulator or directly to the generator armature itself.  This would bypass your start/run relay in the voltage regulator and tell you if it is functioning correctly.  I wired up my 38 LaSalle this way and since it bypasses the start/run relay you can use the existing wire in the wire loom to make the connections.  I have had no issues with starting the engine, but I must admit that I have never deliberately pressed the starter button with the engine running because starter ring gears are as scarce as hens teeth and there is no need to tempt fate.

Tom Beaver
Title: Re: 1940 starter relay
Post by: KC Tom on December 08, 2021, 10:46:18 PM
Tom
Thanks for the reply
That sounds like a great idea. The connections on the starter are not where I can read what they are. Is the to or bottom connection the ground? Or could I tell with a continuity test. Where does the existing ground wire go?
Obviously electronic is not my strong suit.
Title: Re: 1940 starter relay
Post by: Tom Beaver on December 15, 2021, 12:02:31 AM
A picture may be worth a thousand words, so I have attached one of the starter relay on my 38 LaSalle.  There are two wires, a yellow one and a blue one, that attach to the starter relay.  The yellow wire comes from the starter button and the blue wire, which is the relay ground, attaches to the GEN (Armature) post on the voltage regulator.  When the engine is not running,  the Armature is, as pointed out by Doug Houston, a low resistance path to ground.  Push the start button and the relay is energized actuating the starter solenoid.  Works like a charm.

Tom Beaver
Title: Re: 1940 starter relay
Post by: KC Tom on December 15, 2021, 01:53:41 PM
Thank for the pic. I have attached a pic of mine.
I purchase a new one that is the correct part number for a 1940 Lasalle but it is different then mine. I think you said yours is a 39 so maybe my relay is from a 39.
Someone said you can test that system by running a wire from the ground on the relay to a direct ground , will that work and if so could I leave that wire until or if I am able to find a correct relay?
Title: Re: 1940 starter relay
Post by: Tom Beaver on December 15, 2021, 11:12:52 PM
Your starter relay does not appear to be an OEM style relay, so if you purchased a relay with the correct part number it wouldn't look like yours but should be similar to the one in the picture I sent and it should work just fine.  Any relay will work if you connect the ground terminal directly to ground, however, you will loose the safety feature of disabling the starter button when the engine is running.

Tom Beaver
Title: Re: 1940 starter relay
Post by: Barry M Wheeler #2189 on December 16, 2021, 12:09:00 AM
Give Terry Wenger a call. He's "done" half a dozen flatheads and can possibly help. He is in the Directory in MO. Or Brad Ibsen. I forget what state he's in, so you'll have to look through the member  listing in the back of the book. Best of luck.
Title: Re: 1940 starter relay
Post by: harvey b on January 04, 2022, 11:30:26 AM
Well i was able to fix my relay,i installed the new relay and did some cleanup and painted the outer case and all is well with it now.These starters are heavy :-\,its a job to get it in the hole,and the bolts are hard to get at,no room from top or bottom,but it is doable. Tom on your last picture it looks like a wire is not connected,not sure if im seeing it right or not?.Hopefully you have had some good luck with yours. harveyb
Title: Re: 1940 starter relay
Post by: KC Tom on January 04, 2022, 12:14:32 PM
I Harvey, thanks for the reply
All wires are connected.
I knew of the issue with trying to get that heavy starter in place so when I restored it I put a stud in the bottom starter bolt hole so it is very easy to get it on and off. Unfortunately I have been unable to find a relay that is the same as mine to replace it.