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Car runs great except for one problemūüėĬ† Car doesn't start until the starter disengages, then starts.¬† Starter turns over fine but car doesn't start until I stop the starter.¬† Is timing to retarded?

Help.

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26 minutes ago, 1939bcoupe said:

Car runs great except for one problemūüėĬ† Car doesn't start until the starter disengages, then starts.¬† Starter turns over fine but car doesn't start until I stop the starter.¬† Is timing to retarded?

Help.

What year and model are we talking about?

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You have a voltage problem. The starter is dragging the voltage down below where the ignition will function. When you release the starter the voltage comes back up while the engine is still turning over and it will start. Either your starter is taking too much to operate or more likely you have a battery cable problem, like small 12 volt cables on a 6 volt car, or bad connections or grounds.

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I've been experimenting and the problem occurs more when  the engine is hot.  I've checked the cables and grounds and they appear to be correct.

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If the cables are incorrect size, the problem will be greatest when the engine is hot. Cable should be at least as big around as your index finger. 

If the starter needs rebuilding, it could be slow and drawing too much voltage. What does your amps gauge show when the car is cranking? Does it go all the way over to "D"?

Pete Phillips, BCA #7338

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I agree, Roger is on the right track. The ignition cant really be off while cranking, because the Buick autostart system does not require you to touch the ignition switch to crank the car. I would check the battery voltage while cranking. I would also check the voltage at the starter (between the battery cable post and the starter case) while cranking.

 

The cables are the main suspect in a case like this, followed by a weak battery. I believe the positive cable goes right to the starter post, and the rest of the electrics also connect there (that would include the ignition).

 

Does your negative cable go to the frame or the engine/transmission? If your negative cable goes to the frame, there will be a third cable or strap running from the frame to the engine/transmission. It needs to be as big, and as good as the other two.

 

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Posted (edited)

Download the 1942 Buick shop manual. All of it section by section. The pdf link does not work.

http://www.oldcarmanualproject.com/manuals/Buick/1942/Shop Manual/

It is very comprehensive and has information that can be used with all straight 8’s.

It has more information than was included in older ‚ÄúShop Manuals‚ÄĚ before 1942-41

 

Has a good section on starting

 

Cables for 6 volt need to be twice the cross sectional area of those for 12 volt (as you buy now)

Edited by 1939_Buick (see edit history)
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I would also check each cell of the Battery for its acid,/loading  with a acid tester, all cells must have the same  capacity.( loaded, or unloaded doesn't  matter)

If one Cell capacity is not like the other  the  cell begins to sulfating, it can makes problems like yours.

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I had a battery cut off with the green wheel for on and off.  I've had it on the car and no problem.  Took it off the car today and problem solved.  Not sure why it became a problem all of a sudden. Also, super bonus, I've had a low end miss just above idle for about 6 months that has been driving me crazy.  I tried everything to try and solve that problem. Miss is now gone.  WTF.  Another lesson on looking for easiest solution.  I've always had a problem with the rule "Don't fix it if it is not broke".

Thanks everyone for all our help.

Frank

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1 hour ago, 1939bcoupe said:

I had a battery cut off with the green wheel for on and off.  I've had it on the car and no problem.  Took it off the car today and problem solved.  Not sure why it became a problem all of a sudden.

Sounds like the switch was made for 12 volt capacity, not 6 volts.  Lucky it worked as long as it did.  The power from you battery is only available as the weakest part allows.

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If I had a nickel for every time I have seen a battery switch causing trouble.......

 

Good starting depends on clean tight connections, and keeping the number of them to a bare minimum. Battery switches fly in the face of this idea. Some of us really do need them on our old cars. I don't think any of them are even short term reliable, let alone long term reliable. Ok, maybe one of those enormous Cole-Hersee things they used on fire trucks would be ok, but even that adds connections and another cable to the system. Also, its the size of a cantaloupe, and where would you put it?

 

I think that "Green Knob" switch is the best thing available because you aren't adding any more cables, it can be taken off easily, and you tighten the connection by hand, so you know it's tight.

 

I want a switch on my Pontiac, but the area under the floorboard is tight. It either needs to go there, or I would have to lift the hood or crawl under the car to reach it. The green knob, as built, doesn't fit. I was in the midst of modifying one to fit in the available space, and I broke it. Guess what? It isn't brass. It is some cheap white metal, probably zinc. They had just painted or plated it with something to turn it yellow. Also, the cross section of the metal where it broke was pretty thin. I thought "i'll just buy a brass one". Nope. I don't think it is made in brass. I looked everywhere. If you read the fine print, it always says "brass finish" or something similar, or it just doesn't say. If any of you know where to get one made of actual brass I would love to hear about it.

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My simple solution is to remove the -ve cable from the starter solenoid when parked. It is held on with a wingnut. Just slip a little piece of rubber hose over it to prevent disastrous contact with anything. The wee piece of hose is stored tucked under the brake line on the chassis, out of sight. This also makes it easy to charge without pulling up the carpet and undermat.

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It's to bad about the cut off switch, because when we are working on the engine and it is much easier to twist the cut off wheel, then disconnecting the cable. 

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I saw a hefty disconnect switch that was remote controlled on line but I cannot find it again.

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The one in the second link looks good. (I don't have enough headroom for it, but it looks good.)

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I agree that Roger is on the right track.   I can always tell when it is time to replace my battery in my 53 Special straight eight when the engine starts when I lift my foot up from the accelerator.   I have had a Pertronix module installed and it is very sensitive to battery voltage.  I got 7 years on my last battery but my new Tractor Supply 3EH makes it sound like a  12 volt system whe cranking.   Starts in seconds.  

Joe

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I had the same problem with the green cutoff switch on my '39 Roadmaster.  In fact, it died at an intersection one day because of the cutout switch. I removed it and the engine spins much faster now.

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Posted (edited)

I have been told that Summit Racing has cut out switches that can stand up.  Used for race cars.  Here is one that might be of consideration.

 

https://www.summitracing.com/parts/sum-830050?seid=srese1&gclid=EAIaIQobChMI76WvtK2u4wIVtP_jBx3O3Ac8EAQYASABEgLzzvD_BwE

 

And here is a selection for your reading pleasure.

 

https://www.summitracing.com/search/part-type/battery-disconnect-switches?SortBy=Default&SortOrder=Ascending&tw=battery disconnect switches&sw=Battery Disconnect Switches

Edited by Larry Schramm (see edit history)

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Many cars of my Customers here too have the green Wheel Switch.

I put it in also ,in my shop if the 50 or 60 years old electric in the Cars looks 

" critical"...

Important is before installing ,to disassemble it and lube it complete with Battery-Grease.

Then they've no contact problems especially on the small point under the Wheel.

Myself use one like this :

https://www.walmart.com/ip/Heavy-RV-On-Off-Off-Trailer-Vehicles-Auto-Knife-Disconnect-24V-12V-Duty-Battery-Truck-Kill-6V-Post-Doctor-Switch-Shut-250-750-Top-Switch-Car-Cutoff-A/454957724

Looks more old style in my Compartment than the ugly green Wheel ( the ones with black wheels are rare,but then,OK ..ūüėČ).

The only Reason for have a Bat Switch in my 38 ( 12 V with complete new wiring) is only the power consumption from the original Time Watch ,if the Car parking for a week or longer.

 

 

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I experienced the exact same issue with a green knob shut off.  Now clean and dielectric greased, I know I have to really clamp it tight to not have the issue.  

 

An oldtimer said Model As did this all the time when the connections got corroded.   

 

Common 6V issue. 

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I have maybe 30 of those green cut-off switches sitting in a box under my workbench. When a car in the shop won't start and is wearing one of those, particularly a 6V car, we take it off and the problem usually vanishes. Removing the switch cures it permanently. They're just terrible. Those who are using them with success are doing it in spite of the switch, not because of it. It's only a matter of time before the switch betrays you and like the OP, you won't think to look at the switch because, after all, it worked so well for so long. It will become the last thing you check instead of the first and leave you tearing your hair out when you can't find a solution.

 

I use big, heavy disconnect switches rated for 200 amps on my cars along with 00-size cables and have no problems at all, even though installing the big switch requires two additional connections and may pose a minor risk of additional resistance. Their size seems to preclude any issues. If you use one of them on your 6V car, make sure they're the big ones the size of your fist, not the light-duty ones that are only rated for 50 amps.

 

If anyone wants one of these green pieces of crap (LOL), I'll give it to you for free. Use at your own peril.

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2 minutes ago, Matt Harwood said:

I use big, heavy disconnect switches rated for 200 amps on my cars along with 00-size cables and have no problems at all,

 

Do you have any suggestion on a make and model of switch? Something you have known to work in a 6v system for several years?

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