Ok ... so I rebuilt the generator and it works fine but it does make a slight humming sound. Having never owned a T new enough to have a generator I don't know if this is normal or a sign that I need to remove the timing cover and check the mesh between the generator pinion gear and timing gear.
The timing gear is a NOS stock iron gear. And the generator pinion looks very good. There are only two means of adjustment that I can see; the gasket between the generator plate and the bracket .... and between the bracket and the engine block.
So my question is ... is this sound normal and if not is there any way to check the "problem" without removing the timing gear cover which would be a real pain in the neck?
Look down the oil fill cap to check for enough gear lash between the timing gear and the cam gear. Measuring it down there can be a challenge, but usually I just see if I can feel for a slight generator gear movement that indicates the tolerances aren't too close.
I would say you would have more chance of a humming sound from the gears to tight rather than lose, take the brush tin cover off and with a finger rock the armature to feel for any lash.
Great idea! Thanks ... will do that. Can I move it with a finger ... or should I use a brass drift?
I meant that question for Kevin. :-) Frank ... that's a good idea too. Wish I could get a dial indicator in there. Not sure if I could actually feel a very slight difference.
Be sure the armature has free movement axialy to allow for thermal expansion. Brad.
It was a little tight when I replaced the brush end cap. Based on period writings I used a drift to extend the end of the cap from the interior.
Ha ... I just realized that if I do need to put another paper gasket inbetween the generator bracket and the block to increase the gear distance ... I don't need to remove the radiator and timing gear cover!
I would have to cut the existing paper timing cover gasket and make sure what I replace it with is the same thickness. Can't remember if I actually used a gasket or just sealer ....
See if reaching down the oil filler hole you can move the generator gear back and forth a bit to indicate you don't have the mesh too tight. If you can't move it then you need to act to reduce the mesh which is to get the generator gears further apart. Move the generator away from the block which tells you which gasket needs to be thicker or perhaps double gasketed if your gasket is too thin.
Mark, Just do as John says: stick your finger down there and feel for gear lash. You can clearly feel any movement (if at all). I mic'd the standard gasket at .008. When I installed mine, I cut two gaskets from fairly thick stuff to get enough clearance between the cam and generator gear to give me acceptable gear lash. But check with your finger first...engine NOT running, of course.
Ok guys ... so here's the latest. I tried reading into the oil filler tube and it's pretty hard to do. Next I removed the band on the back of the generator and was able to easily reach in and rotate the armature ever so slightly back and forth ... so there are a few thousands clearance in the gear mesh.
I'm thinking that most people rebuild everything before they run their cars. Me on the other hand ... I got the engine going without the starter or generator. I had block off plates in place. After I got the engine going for the the first time I installed the starter. That can't make any unsure noise when not being used. Then I drove the car for a few hundred miles ... and then installed the generator. So maybe these are sounds that are typical but I heard them sequentially.
Just got back from a two hour drive ... seems to be charging well since the charge rate is becoming lower ... but still in the positive side.
If you replaced one gear and not the others you might have noise. Unless you use new gears for the crankshaft, cam, and generator, you will have some noise because the three gears haven't worn uniform. The noise might continue or it might get less with use.
Sure, that makes sense. Too late for matching gears on this project / budget. As long as it's mechanically safe I can live with an occasional whirrr.