I have been looking at O.M.'s starter conversion site (very helpful!!) what is the advantage of a 24 volt starter over a 12 volt system ? I have found the starter I need and it can be bought in 12 or 24 volt.Also are there any differences in the pitch on helical cut teeth on ring gears ? & if so how would I determine what it is ?
Thanks
Vernier

Either the 12V or 24V will work for the D2/D4 but I would recommend the 24V for the D6 and larger. The 24V is a requirement if your running glow plugs. There is no difference in the tooth pitch. The 11 or 12 tooth helical pinion works for everything from D2 to D9

Thanks for the info. O.M. that makes things easier. Started removing the pony this afternoon, will have to make some plates w/ gaskets to cover all the holes after everything is gone.
Vernier

With 24 volt you can use smaller battery cables and smaller CCA batteries.

Adding batteries in series as in 24v the CCA adds together, in a 12V system where the batteries are connected in parrallel addind more batteries adds more reserve, but the CCA is limited to battery size. Generally you need 1000 CCA for the 40MT starters.



I have both D4 & D6's running on 12v, and it starts just the same as the factory 24v tractors we have.

The reason why I went with 12 at the time is we had standerdized on GM 12si alt's, plus there is a better slection of lights for 12v. At the time of the conversion we had some large wheel tractors that had 504 CI engines, 40MT starters, GM 10si alt's and 2 group 31 batteries, I figured if it could work for such a large tractor 4 cylinders would be no problem.

The only problem is you need $$ batteries with 12v, but difference might be much.

CR;4168 wrote:

With 24 volt you can use smaller battery cables and smaller CCA batteries.

Adding batteries in series as in 24v the CCA adds together, in a 12V system where the batteries are connected in parrallel addind more batteries adds more reserve, but the CCA is limited to battery size. Generally you need 1000 CCA for the 40MT starters.



What you need to crank something is POWER. This is roughly equal to volts times amps. So with 24 volts, you can have the same power as 12 volts system with half the amps. So less CCA and cable size. Battery will roughly be the same size for the same Power output.

In a system,
Amps (current) is additive when the batteries are paralled ( multiple 12 volt batteries in 12 volt system for example)

Volts add when batteries are in series ( two 12 volt batteries in 24 volt system for example)

either way, you get more POWER by using more than one of the same size battery.

Before you go ramping up the amperage using the 12V approach, better check the rating of the disconnect and starter switches. Yes, the studs are rated for 2000 amp but the contacts for the 6-36V switches are rated considerably less, like intermittent 30 seconds on/3-minutes off, 300 amp continuous on the disconnect switch. (Colehersee switch)

Also need to verify contact amperage ratings of the starter solenoid.
The starter/generator repair industry loves to do business with those that tinker with the laws of physics.

"Old wrote:

Either the 12V or 24V will work for the D2/D4 but I would recommend the 24V for the D6 and larger. The 24V is a requirement if your running glow plugs. There is no difference in the tooth pitch. The 11 or 12 tooth helical pinion works for everything from D2 to D9

I notice Magnet is from California, probably reason for swapping out the pony motor=higher ambient temperature. During cold Indiana winters, the pony motor is a savier when the tractor has to start. We just remaned the pony on a D7 17A18692. It purrs like a kitten, always starts no matter if rain, snow, cold, or hot. I can't help but think our older tractors would be hard pressed to start below zero F without careful supply of either which we really rather stay away from. We got enough parts to complete the job from wrecker yard north of Robinson Illinois.

Hi Dave,
These starters are being installed all over the globe. I'm not doing anything that Cat didn't do just doing it with an updated starters, and yes, per Cats instructions, at temperatures below 10 degrees F. the ether option (also Cat provided) was a requirement. If pony motors were all that great, they'd still be using them.

On the later & new Cat engines the direct injection system & also the computerized systems make for easier starting on todays engines over the old prechamber low nozzle breaking pressure system.The main thing with the direct electric starting is you need to keep the batteries fully charged esp. in colder weather so they are ready to go.The only advantage with the old starting engines was (is) that you can jump the battery with your pickup or just an automotive battery to get her going.

Hi SJ,
The biggest advantage of direct start for me is that I do a lot of work alone so I'm off and on the tractor a lot doing other things. The choice then is to let the tractor idle a lot or do many starts with the pony motor. It is really nice to just hit the button and know she's going to start. If it was a case of start it once on the pony and run it all day long I might think differently if I lived in a frigid climate but I am spoiled now.