New Cut-Out Relay . . . Not so good.

DannL

DannL

Senior Member
Learned, for the most part, why this import relay (Taiwan) stuck closed. The relay contacts are not parallel or square to each other. In fact, they're not even directly in line with one another. This left only one edge of a contact carrying all of the current. The relay "insides" looks like it was thrown against a wall, and then run over by a bus. Definitely right up there "quality wise".

Ordered some diodes to modify this one, and the original that I pulled.
 

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DannL- Consider yourself fortunate that something much worse didn't happen to you or the car.

I had the exact same problem with my 1929 Hudson. The new cutout points were just as bad.

With the engine off and the points stuck closed, the battery directly shorted right though the generator. A fire ensued in the generator, which is located directly below the updraft carburetor.

I stopped the direct short by pulling the 14 gauge wire from the cutout with my bare hand, in the flames. I then beat the flames down with my jacket and bare hands. My adrenaline was pumped so high that it took more than an hour for me to feel the pain caused by the wire cutting into my hand, and some burned off skin.

I fixed the cutout by replacing the mechanical points with a diode. This event happened more than 20 years ago, and I've never used mechanical points on a generator cutout since that event.

The failure more of a burned out diode is your generator will stop charging the battery.
The failure more of mechanical points stuck closed can be catastrophic.

I hope that other folks will learn from this experience, and replace the mechanical points on their Model A generator cutout.
.
 
Had a similar problem with my 1929 Standard Coupe where the cut-out and the generator both burned up. Repaired the generator and put a diode within the original cutout body. Been going strong now for the past 37 years.

This happened in Bakersfield, CA in 1983.

Pluck
 
My desire to stay with an original style relay, overwhelmed my sense of safety. The shorted relay completely discharged the fully charged battery without burning it up. Having just worked on the generator the week prior may have helped prevent that fire. My starter is now rebuilt, so might as well rebuild the generator also.
 
I took the windings out of original alone with the metal core, drilled a hole in the relay frame and pressed in a used diode from a first generation delco alternator,been fine for over 40 years
 
On a Model A, when you shut the engine off you should check the ammeter to see that the needle is in the middle. If it's showing a discharge and everything is turned off, there's a problem.
 
DannL said:
My desire to stay with an original style relay, overwhelmed my sense of safety. The shorted relay completely discharged the fully charged battery...
Click to expand...

I prefer original style too, but I wont sacrifice safety, and I wont be held hostage to poor Quality:
1. The generator cut-out conversion to diode is one I always do.
2. I add a battery cut-off switch.
3. With the A's, the fuel shut-off valve can be a significant hazard. :eek:

katy said:
On a Model A, when you shut the engine off you should check the ammeter to see that the needle is in the middle. If it's showing a discharge and everything is turned off, there's a problem.
Click to expand...

Exactly right. That's one of the main reasons I add a battery cut-off switch...just in case I see that ammeter needle drop, along with my heart.
.
 
Good afternoon...In the 1960's we used to drive our cars with the cover off of the cut-out so that if the damn thing stuck closed when we shut down...we jumped out...opened the hood and used a pop cycle stick to open the points, the stick lived in the corner of the wind shield where we could grab it as we jumped out! Today I run an alternator and a gel battery...the hell with the generator and cut-out. I'm pretty traditional...but not that much so...Ernie in Arizona
 
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I had replaced all of the wiring in the car with modern braided copper in the spring. The curcuit the runs from the battery and ends up at the relay was beefed up to the next larger guage. Then the circuit is fused at 30 amps. That fuse did not blow. Since the contacts stuck closed on the edge of the contact I suspect that the short was high resistance.
 
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