Strange Electrical Problem

[Robert/Texas]

I’m experiencing a problem starting the engine in my ’28 roadster. This problem occurs about every three or four times that I go to start it.

When I turn on the ignition switch the ammeter shows no discharge and when I step on the starter nothing happens. The horn and lights work though. I’ve been able to solve this problem by putting the transmission in third gear and pushing the car a few feet forward and the car starts like it normally does.

All thoughts and suggestions will be greatly appreciated.

Thanks, Robert

[1931 flamingo]

The Bendix may be hanging up.
Paul in CT

[Tom Endy]

Check the ground cable on the battery where it attaches to the frame. This area is prone to corrosion, and you can lose battery connection. Remove the bolt and wire wheel the bolt and nut. Clean the corrosion off the boss on the frame and wire wheel the end of the cable. This is the most neglected electrical connection on a Model A.

Tom Endy

[MAG]

X2 on post 2.
The starter shaft could be bent slightly causing the Bendix to hang up.

[Brentwood Bob]

A stainless lock washer can be added.

[nkaminar]

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Adding to what Tom and Bob said: A star lock washer will bite into the components and provide a good ground. Plus a little electrical grease will keep the corrosion down.

Adding to what Flamingo and Mag said: Modern Bendix drives are available that work better for me in my car.

[Robert/Texas]

Thanks everyone for your help and advice.

I think that there is a Bendix problem and plan to order one, but I don’t understand why the ammeter doesn’t show discharge when I turn the ignition switch on as it has always done in the past.

I replaced all the car's wiring last year including a new braided ground strap. I cleaned the frame where the strap goes with a wire brush on my drill, so I don’t think that is a problem, but I’ll check that anyway.

Robert

[MAG]

If the points are open when the ignition switch is turned ON there will be no current flow through the coil, consequently no movement of the ammeter.

[HDowse]

Another way to check your ammeter drop is with the ignition on pull the spark advance lever down. That shifts the plate and points so that they close and you'll see the ammeter drop. Put it back up before starting…..

[Robert/Texas]

MAG, I realize this but I have two Model A's and two early V8's. Both Model A's were purchased in 1989. I assume that all four cars always have their points closed when I stop their engines because their ammeters always indicate discharge when I start them and fluctuate while cranking. I don't know if this is unusual or typical.

Thanks, Robert

[jerrytocci]

You said "nothing" happened. If the started spun, then something happened.

[nkaminar]

Where the engine stops after you turn it off depends on the compression and how tight the engine is. A loose engine with good compression will rock on compression. That will lead to the points being open or closed when the engine stops.

On an antique brass car with the trembler ignition, you can sometimes get a free start just by turning the ignition on and then perhaps retarding the spark. It will ignite the gasoline fumes in the cylinder. When growing up, a neighbor had a Overland with an acetylene tank for the headlights. The car was rigged so that you could fill the cylinders with acetylene by hand cranking and then turn on the ignition to start the car.

[Badpuppy]

Originally Posted by Robert/Texas

I don’t understand why the ammeter doesn’t show discharge when I turn the ignition switch on as it has always done in the past.

I replaced all the car's wiring last year ...
Robert

How far in the past? Before you rewired? The black wire from the ignition coil should be connected to the generator side of the junction block, not the battery side as shown on the original drawing. Then you will see discharge through the ammeter into the coil.

[Robert/Texas]

Jerrytocci
To clarify. When I press on the starter switch the starter does not engage or spin and the ammeter does not register but the horn and lights work. This leaves me to believe that there is something wrong with the starter, likely a Bendix/starter problem.

Nkammer
A little off topic but I have two Model T’s. Both were purchased in 1988 and both have the original type of ignition systems. One car had the head milled and low mileage on it’s rebuilt engine. I have never gotten a free start with that one and it is hard to start with the hand crank. The other one has a well-worn engine. I got free starts nearly every time until it got a ring and valve job. I still get free starts with it but not so often.

Badpuppy
It was about a year and a half ago that I rewired my ’28 roadster. All the wiring was replaced including the two cables and ground strap. Everything electrical worked fine until now. I just went to my barn and checked the coil wires on the roadster and on my early ’28 OCPU. Both are wired with the red wire on the coil marked +. I think that my problem has to do with the starter, probably the Bendix.

Thanks to all of you, Robert

[burner31]

Do you have a gremlin chaser in your tool box?
Harbor freight may have one in the back if you ask nicely

[nkaminar]

I have another thought. I don't know if you have the fuse that mounts next to the starter, but if you do, check to see if the fuse makes good contact with the holder. I added a little electrical grease there. Also, check to see if the electrical cable from the battery is not loose on the starter switch. If you have a battery cutout switch, check that too. Electrical grease on all the connections will help to reduce corrosion. It could also be your starter switch. Cleaning the contacts and adding the electrical grease to the switch will cure problems. I use the electrical grease that has some copper in it, available from McMasters-Carr.

Regarding the Model T's: Getting a free start all depends on where the engine stops. With the added friction of a new ring job it will stop in another position. If this is important to you, you could hand crank the engine to just past top dead center and then try the ignition. Move the timing lever up and down to see if it will start.

Burner has a good point. The multi meters are low cost and help chase down faults. Checking resistance or the voltage at the starter switch when trying to start the car will tell a lot. If the voltage does not drop when pushing on the starter switch it means that the switch or starter are bad.

[Badpuppy]

Originally Posted by Robert/Texas

Jerrytocci
I just went to my barn and checked the coil wires on the roadster and on my early ’28 OCPU. Both are wired with the red wire on the coil marked +. I think that my problem has to do with the starter, probably the Bendix.

Thanks to all of you, Robert

The red wire is from the ignition switch. It's the other one that should be connected with the yellow-black wire from the generator.

You're right, that's not causing your start problem, just the failure of coil current to register on the ammeter.

[Ernie Vitucci]

Good day...You might want to jump around your amp meter and see if the problem still exhists...you might have an amp meter that is not happy...or just loose terminals on the back of it or loose terminals on the ignition switch...Ernie in Arizona

[Dave in MN]

Originally Posted by Robert/Texas

I’m experiencing a problem starting the engine in my ’28 roadster. This problem occurs about every three or four times that I go to start it.

When I turn on the ignition switch the ammeter shows no discharge and when I step on the starter nothing happens. The horn and lights work though. I’ve been able to solve this problem by putting the transmission in third gear and pushing the car a few feet forward and the car starts like it normally does.

All thoughts and suggestions will be greatly appreciated.

Thanks, Robert

Guys, Please help me out here as I have not rebuilt a Model A starter motor in all the years I have worked on Model A's....
Is it possible he has a bad spot on the commutator of the armature resulting in no action or draw when the starter switch is closed? Could this situation along with open points be the exact description he is conveying?
Thanks for any comments.
Good Day!

[Big hammer]

Why would pushing the car in third gear allow the car to start??? After a no start not turning over??? A guess of a bad connection and the bouncing then the connection comes back. I would after cleaning battery terminals ground connection would then proceed to the starter switch! If bad brushes or amateur in the starter smacking the starter with a big hammer may Indicate a starter problem if it starts then.