Model A questions

MikinInd

Member
My 1944 model A I'm currently working on came to me with a few "farmerized" additions. Most of which I'm guessing are from a late A or model 60.

It was a running and driving machine when I purchased it from a guy that deals in old tractors out of Wisconsin. It came to me with what I assumed was a 6V system. At least it had a 6V battery in it with a positive ground and 6V lights which weren't hooked up. The generator is 12V according to the tag though. Model number 00955 as best I can make out. What do I really have here? I'd like to change the whole system over to a 12V negative ground but what all does that entail with this setup?

I've also found the all to common worn splines on the clutch end of the crankshaft. They aren't quite as bad as some that I have seen though. I have a new clutch driver and it does fit tightly when installed but it fits tightly almost flush with the end of the crankshaft. I was pretty sure I heard that the driver needs to fit with a bit of room from the end of the crankshaft to the outer end of the driver when installed for proper clutch operation. Is that correct? Is it possible to gain that little bit by shimming it out with some thin material?

I may be moving soon and I'd like to have the tractor back together and operational by that point. I really don't want to tear it all the way down and find another crank for it if I can get by with what's in it. Its not a working tractor anymore so it wouldn't be pushed hard with this repair.

All thoughts are appreciated.
 
Providing the generator is actually a good one, you would need a 12 volt voltage regulator for it. Then reverse the ammeter leads if it was positive ground before. And look to the coil for proper resistance in it at 3 ohms roughly. It will also need it's leads reversed if positive ground before. For negative ground coils, the coil post marked - for negative goes to the distributor's points. 6 volt lights won't last long on 12 volts but they are not sensitive to the change in ground polarity. You may find the voltage regulator by searching with the generator tag numbers. To know if your generator is good, a motoring test after a basic 'ohming' out of the various leads should suffice. John T has several posts that outline these procedures, here is an older one until he shows up.
<a href="http://www.yesterdaystractors.com/cgi-bin/viewit.cgi?bd=jd&th=458733" target="_new">John T diagnosis</a>

Yes, the clutch driver should be proud of the end of the crankshaft by some safe margin and this can be increased by means of a properly sized washer that does not contact the crankshaft. I'm thinking valve spring shims might be a good choice here, they often are available off a display board in certain shops dealing with a lot of head work such that you get a vast array to select from both in thickness and sizes. .050 clearance should be fine if the crank isn't too messed up as that is a tapered fit and over time the driver will tend to work up onto the crankshaft further as it's used due to the retaining bolt's torque. Not a bad idea to recheck that torque and clearance issue on fretted crankshafts either from time to time.
 

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