VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1933-1936 34 Generator Cut-out

I've changed out the Cut-out on my 34 with the correct 29-37 Cut-out. Previously had a 23-28 Cut-out which worked. Now with the new one, which looks good, it does not charge. I've polorized the Generator, moved the third brush, cleaned the points but still does not show a charge. Any suggestions?

Hello Jon, So we have a 28, 29, 36, and a 40. Each of the earlier cars use slightly different cut outs. Sometime between 29 and 36 the base of the cutout was changed to a much heavier angle style instead of the little tabs of the earlier ones. All of them should have similar internal components. What a lot of people are doing now is removing the coil/contact setup, and soldering in a heavy duty diode in its place under the cover of the cutout. This eliminates the potential sticking contact of the cutout. Works well and should last forever. As long as you do not remove the cover you will be the only one who knows. If you really want a voltage regulator there at least two types that will not change the look of the generator permanently. One is a type that replaces the band strap that covers the brushes. I think there was a tech article on it in the G & D some years back. Another uses your cut out and its internals are replaced with electronic components that control the voltage, and current output. A third style uses the case of your generator and the internal components are replaced with an alternator. I think it can be configured as either 12 volt or 6 volt. As with anything on these cars just throw money at it and you can have it any way you want. Sounds like the coil is not working on the cut out. Use a volt ohm meter with the car battery disconnected to see if there is continuity through the coil. If not it is a prime candidate for a diode, or a rewind. Keep us posted. Art

I hooked up my old cut-out which I'm sure worked before and it shows no charge. I'm now thinking it may be my generator.

With the car running put a volt meter on the terminal of the cut-out where the generator wire is connected and see if you have voltage.

I agree with Junkyard Dog.

First I would check to see if you have voltage on the wire coming directly out of the generator.

Are you sure you have the cut-out connected properly. They will not work if you put them in backwards with the wires connected to the wrong cut-out terminals

I'm sure it's connected correctly. I'll work on it again in a couple days if it warms up.

Does it charge when the headlights are on? The resister on the back of the light switch may be burned out

I've installed both the Generators I have, one rebuilt the other with new brushes. Used three different cut-outs. None of which shows a charge. I know this can't be that complicated! It shows a discharge with lights on wheather the Engine is running or not.

With the engine running remove the battery cables.

If the engine dies with the battery out of the circuit then the generator is not putting out and/or there is a ground/short in the system's wires.

1. I would carefully look at the splash pans below the generator where the wire lays to see if there are rub marks [places of no paint where an electrical discharge can occur.] back towards the cowl.

2. I would carefully check the wiring between block and gen. where it bends when you tighten the belt.

3. Where the headlight wire runs in the brace under the radiator to the passenger side headlight.

4.One place I found most of all is along the frame where the wire runs through the clips to the rear tail light. The area near the cross member to the transmission is where I have found a lot of wear. Pull the wire past the clip and look at it.

5. One time I had a rat chew the wires where they went through the fire wall.

Or remove the gen out of the circuit and see if engine runs on the battery only.

The idea is to isolate the areas part by part to see when it restores to normal. Then you can look at that area to see what is going on.

Hope this helps.

When replacing a generator always polarize it by quickly touching the output terminal (or other place directly connected to it) with positive voltage from the battery. Once polarized the magnets will produce a strong enough field to induce power when the armature rotates next to it.

From Jon's post on January 17th: " I've polorized the Generator".

Missed that in my review. If it worked prior to addition of latest cut-out(s) then output connection or wiring maybe the problem if they were harmed with the changes. There has to be a reason that it now does not work. This is not rocket science.

I'm sure the solution will be simple and I won't give up until I find it. I may have a loose wire on my Amp. Gauge, I'll check that tomorrow.

I'm sending both Generators wit Cut-outs back to the Generator shop next to have them tested. If both show to be good then I'll start looking else where. I don't think the Amp. Gauge is bad.

Did you try the above test to see if the generator is putting out voltage, and if so, how much?

I did not and I'm not sure if I know how to use the Volt Meter?? I used the Meter agaain and got a reading but I don't know what it means. The dial was set on x10 OHM and the needle went to around 20. I got another reading earlier but was not able to get it later.

When working on a vintage car knowing how to use a volt meter is a must. You had your meter set to Ohms and not volts so the reading that you received is not accurate. Set your meter to Volts, DC on a voltage scale that is higher than the volts that you want to read. Put the negative probe on ground and the positive probe on the generator terminal of the cut-out. With the car running read the voltage that shows on the meter. Go here for instructions on how to use both an analog multimeter and a digital multimeter, depending upon which meter you have:

Analog meter: https://www.wikihow.com/Read-a-Multimeter

Digital meter: https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter/all

Thanks, that's a lot of help. I'll try it today. I have both, an analog meter and a digital meter.

Great! Let us know what voltage you come up with at the generator with the car running at a higher RPM than idle.

Did you switch the leads to the cut out when you replaced it. HAVING THE LEADS BACKWARDS WILL NOT ALLOW IT TO WORK!!!!

I did not switch the Leads. The HOT wire is on the Bat. side and the wire coming from the inside of Gen. is on the other.

From your description, you have the cut-out connected correctly.

I started my Coupe again, hooked up the Meter but I get a reading that flashed all over the place. So again, I guess I don't know how to use it.

I tried the Voltage Meter again. I get a reading on the BAT. side of the Cut-out but no reading at all coming out of the Generator. That's with both Generators. I'm going to have the Generators back in the Shop next week to see if they are indeed putting out current.

I may take the Generator off my 35 and install it on the 34. If it shows a charge I'll know it's the Generators. Then put the two off the 34 on the 35 and see if they charge??