thinking of putting a 8 volt battery in my 21 hack to help with a tight motor what problems will I run into if any I run one in my model a with no problems
just change the generator cutout to 8V and you should be fine.
Just a little harder on the bendix, but nothing like 12V would be.
I have had a few tight engines but have never seen a need for anything more then a 6V battery. If the motor is tight then you need to run/drive the car to get loosened up.
Same with the Model A, there are plenty of guys with high compression heads that use 6V.
In both cases sounds like a ground issue or the starter need attention.
It'll loosen up quick enough. Just take it for a few short drives, letting it cool in between.
I run 8 volt battery for years, good starting and never had any problems, never blown any light globes, still the 6v cut-out and amps read in the right range.