17.5mm and 15mm oil pumps?
 

I have several pumps laying around. I know one is a 17.5mm with hardend gears form Mazdatrix. How can I tell them apart? Where do I measure?

the 17.5mm and 15mm refer to how wide the gears are inside the pump its obvious when they are side by side

how do you know the 17.5 has the hardened gears?the gslse came stock with the bigger pump but it wasn't hardened

Because i bought it from Mazdatrix. It just got thrown in a box with other stock pumps.

I havent seen one with hardened gears before so can't help with id but it shouldnt have much visible wear on it because its hardened