It's the eye
No, 'a rib' is not a palindrome because it is not spelled the same way forward and backward.
level
Level.
LEVEL
level
eye
eye
The palindrome is Eye.
A palindrome for a rotating engine part is Rotor.
A palindrome for a part of a motor that turns or rotates is a rotor.
"Level" is a palindrome meaning "no part higher than the other."
The word rotor is used to refer to a rotating part of a machine. It is also a palindrome.
eye
rotator
level
poop (deck)
Oh, dude, a moving machine part palindrome? That's like asking for a fancy latte at a gas station. But hey, if you're into that stuff, the palindrome for a moving machine part would be "rotor." It reads the same backward as forward, just like how I feel after eating too much pizza.