Hartzell starter pinion damaging ring gear

[Bluebeard]

About 2 years ago I installed a Kelly (now Hartzell) MZ-4204 starter in place of the original Prestolite lead-ballast model.

The starter pinion is being thrown forward with such energy that the backs of the teeth of the ring gear in the positions where the engine naturally comes to rest are being eroded.

Has anyone else encountered this?

The wear can be spread by starting the engine with the prop in varying positions, but this is not a real solution.

[Steve Barnes]

As I recall, there are two common tooth counts on the the starter ring and the pinion has to be matched to it.

Steve

[Bluebeard]

Yes the pinion is matched to the number of ring gear teeth.

[schristo@mac.com]

What you are noticing is not likely erosion; the ring gear is machined with some relief on the back side of the teeth to aide with starter engagement...

[Bluebeard]

No, it is damage, it appears only in the range of positions 180 degrees apart where the starter would engage the ring gear after the engine has come to rest in one of its normal two preferred positions (i.e. with the 2 blade prop in the 8 oclock- 2 oclock position seen from the cockpit).

I am not clear how to post a photo here.