Nothing I own MV wise is 100% stock. I have no problem making something different to fit my specific needs. I have 5 6.x powered vehicles on the road pretty much every day. Here are my observations:
The 3 24 volt starter trucks all start no matter the conditions or how long since they last ran almost as fast as I can release the key from the start position. As in I am in the habit of turning the key to start and letting go immediately.
The 2 12 volt starter trucks go R R chug, chug, chug... on start up. It is noticeably slower start up in any condition. I actually have to think about it in those trucks so I don't just flick the starter like in the 24 volt trucks. One of these engines I first test fired with a 24 volt starter. Instant start on 24 volts and 1-3 seconds of cranking on 12 volts.
That is a day to day difference. What about if the glow plugs ever start going out or the filter gets air in it or it is allowed to run out of fuel. Basically, any situation that required a lot of cranking to get things working again? A 12 volt starter on 2 800 plus CCA batteries in 70° weather probably won't be able to crank the engine over enough to get it primed again. I am referring to 10-12 second burst, wait a few minutes, 10-12 second burst, wait a few minutes, repeat until it runs. Forget about it in extreme cold or hot weather. A 24 volt starter with the same batteries can do it with ease. Just not twice within 5 minutes I have found.
I can't speak for the other posters in this thread, but the above if why I am pushing back at you about going away from a 24 volt starter system. It works better. I plan to convert one of my 12 volt vehicles over to 12/24 as soon as I can figure out mounts for a second alternator in a serpentine belt system. 24 volt starting works better.
