My starter randomly stopped working a little background info

I have a 13b rew with fd trans
rx8 starter mod
starter worked for a week
lightweight flywheel brand new
all voltages checked fuses and relays bypassed
when i turn the key it sounds like it try’s to engage and then stops
i thought maybe it was a bad solenoid which is unlikely because it’s brand new but took it to autozone and they confirmed the starter is working correctly
I also verified voltages for all switched and constant 12v everything checks out

my thoughts is that the starter is not aligned properly
but at the same time nothing changed from it working to not working
one minute it was cranking over and the next sounds like grinding and then just starter motor spinning

 

Never rule out a brand new part as the problem. It's crazy but new parts can be bad out of the box or fail prematurely without reason. Sometimes the odds are in your favor for stuff like that.

I would take the starter apart and check your work. If you're confident in everything else then there's only 1 variable left...... the starter itself

 

That's what I call the "newborn" syndrome - likelihood of defects is quite high when stuff is new. Then once you've gotten past that, stuff is more reliable until it starts to wear out.