starters

I have three Farmall M tractors. All have been converted to 12 volt, electronic ignition. I have been reading recently about ring gears getting stripped from the 12 volt conversion starting aggressively. Mine kick over really fast. I have also read about a different starter gear that might eliminate that problem. Would you guys mind addressing this problem in very simple terms that a non mechanic might understand? Especially converting the starter? Thanks and Merry Christmas. Ellis

Run it like it is.They will work along time.

What I understand. The original starter designed by Delco, has a pinion that is moved into engagement with the ring gear by the inertia of the pinions mass. Inertia is the resistance to movement caused how much it weighs. In this case it is the fact that the starter motor is a very aggressive type of motor with quick spinup when it is given battery voltage. The pinion is mounted on a spiral spline that is part of the motor shaft. The Motor quickly drives the pinion out along the spiral splines, stretching the big flat coiled spring. As the ring gear now turns and the engine starts, the speed of the ring gear teeth exceed the speed of the pinion teeth and that motion releases the pinion to be pulled back on the spiral splines, to it's resting position, away from the ring gear.
The new style drive is similar, but uses a cushion in the pinion assembly, and a much weaker spring. The return from starting the tractor engine is more driven by the speed of the ring gear teeth pushing the pinion back away from the ring gear, with retraction fully made by the lighter spring.
The new style seems to be more rapid in extension to engagement, allowing a more likely stab into the teeth of the ring gear while nearly not rotating.
The new drive also seems a little more centered and less likely to get jammed if the teeth don't slide into place perfectly.
A worn end frame bushing on the starter snout will also allow either drive to get crooked.
No one has done high speed (slowmo) photography in the housing to compare the two, so my story can't be substantiated other than they seem to be a reasonable and less expensive solution. One person on this site has indicated that the one he used failed soon after installation. Others seem satisfied. A worn spiral spline, and bushings may also contribute to any repair being inadiquate. Jim

John T and others also recommend the use of smaller battery cables to mellow out the force applied at 12v. #2 cables are smaller than the 00gauge cables originally on the tractors. Starter motors can last longer on 12v because the engines are started with much less cranking. Jim

(quoted from post at 07:58:27 12/25/19) John T and others also recommend the use of smaller battery cables to mellow out the force applied at 12v. #2 cables are smaller than the 00gauge cables originally on the tractors. Starter motors can last longer on 12v because the engines are started with much less cranking. Jim

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My 1940 M, converted to 12 volts, was equipped with #4 cables when I got it. It ALWAYS started just fine. NEVER a problem. I eventually replaced those cables with #1, simply because the old cables were falling apart, and I already had the #1 cables.

Incidentally, my 1950 H, still on 6 volts, also uses those #1 cables, and it also starts just fine every time. #0 or #00 gauge cables are totally unnecessary.

My M and H have been 12V since the 70's. No problems yet. Just how long do I have to wait?

Best thing you can do for them is to treat it exactly opposite of what you would do for 6v.

The smallest cca 12v battery you can find along with 4 gauge battery cables.

As said, small cables and a low cranking amp battery will help.

If the old starter and flywheel are in good shape, it will last a long time. If they are worn, the added power will hasten the failure. Everything needs to be right, a bad flywheel gear will quickly damage the best starter.

But the most effective precaution is to listen closely to what's happening when starting.

Have everything ready before hitting the starter. Keep the engine well tuned and ready for quick starts. Be sure the timing is right, no kick backs.

But above all, listen and watch the engine to be sure it is totally stopped before engaging the starter. The last thing you want is to hit the starter while the engine is rebounding off a compression stroke!

Have read the others. You can take it to a service shop and have 12 volt fields put in. My 1955 6volt lasted till two years ago. The bendix broke into three pieces. The guy totaly rebuilt the starter like new for under 80.oo.