Rebuilding generator

[1928 Sport Coupe]

I am trying to rebuild a generator for my 1928. It has a long nose generator on it now. I put on a fan shroud to help keep the engine cool. The current generator pulley walks ahead enough to rub the shroud while driving it. There is almost no clearance with the engine not running.

I have 2 short nose generators that that match. I was hoping to use the best of both generators to make 1 good one. I have already ordered the needed parts. The one generator has a newer armature, brushes and fields in it. Who ever rebuilt it way back when ran the two wires out to the cutout and ground and epoxied the wires in the terminal hole. The weld on the case is rough and looks terrible. The other looks dirty inside but the case is much nicer, not pitted and the weld is hard to see.

The 2 generators I have to use have different size pulleys. One pulley is about 3-1/8" diameter the other is about 3-1/2' diameter. Both will fit either armature ok. Which pulley would be the best to use?

Thanks for any advise.

[ndnchf]

3.5" is typical. Of more concern is the pulley walking ahead. That should not be happening. It sounds like the bearing retainer plate is loose or missing.

[rotorwrench]

Keep in mind that a 1928 model A would have has a powerhouse generator originally.

The later Autolite designs should still work to align the belt. The generators of the Model B era were a bit different than the model A and one way is the lack of the terminal protruding out the case. In some cases, the little insulator bushing was deleted to exit a wire but the two wire set up may require a larger exit in the case. If the terminal insulator will still fit in the case then A person can get the parts to use a stud terminal. The 3-brush generator really didn't need the ground wire to exit the case but different types of cut outs were available that used the ground wire. These were the two stage current type set ups that had a cut out and a two stage relay to up the current output when the headlights were used. They are oval shaped instead of just a round can design. These were not available in the model A era but were available in the model B era. Cars equipped with a radio set had them.

Smaller pulleys would be used in applications where the engine is run at lower rpm. This keeps the generator rotational speed in the sweet spot for low rpm engine operation. Larger diameter sheaves are for higher rpm operation to slow the rotational rpm of the generator.

[1928 Sport Coupe]

Thanks for the information.
I will use the larger pulley and the short shaft generator I have. That should give me about 1/4" clearance from the fan shroud. The shroud is a Snyders repro.
The picture is the generator that was in the car when I bought it. I know it is not a powerhouse generator but it has been in the car for 45 to 50 years.

[Marshall V. Daut]

Try a shorter fan belt, which would change the relationship between the pulley and the shroud as the generator is pulled closer to the engine. The gap between them would be increased. The fan belt in your photo appears to be too long, allowing the generator to tilt too far out and downward. The fan belt is almost touching the return pipe hose. Too close for comfort...
Marshall

[old31]

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x2 with Marshall

[katy]

What's the difference between a "long nose" and a "short nose" generator? How does one tell them apart?

[ndnchf]

Long nose vs short nose.

[katy]

ndnchf, thanks

[1928 Sport Coupe]

Is the generator rear brush plate with a bearing interchangeable with the plate that uses a bushing, as long as I use the armature that uses a rear bearing, and the correct bearing? I do have a rear bearing plate and armature that matches.
I thought I saw somewhere the long generator with a rear bearing was used from Oct 1928 to April 1930 on Model A's. My car is marked 11-??-28 on the gas tank, the day may be a ?4.

Thanks for any help

[rotorwrench]

The bushing type armature is used with the bushing type rear support cover. The armature has a larger diameter and a longer dimension at the bushing end. It has the short taper at front.

The bearing type armature is stepped on the rear bearing end to fit the bearing and is shorter in dimension on the rear bearing end. It has the long taper at front. The bearing rear support will only work with the appropriate armature.

Some early tube type housings have the terminal closer to the front support cover. The later tube types have the terminal closer to the rear access cover toward the rear of the housing.

I've never tried mixing and matching housings, armatures, and supports. With the different armature dimensions, it would be doubtful that they interchange. The bearing type tube generator with the longer taper at front was the first type used in late 1928 but it was a fairly long draw down since both the 3-brush Powerhouse and the early tube type were both in production during that time. The assembly plants just used what ever they were supplied with during the slow transition. Henry was always worried about labor strikes with his suppliers so he used as many different suppliers as he could to hedge his risk factors in that respect. They were building a million cars per year so there was always a risk of shut down.