interferance starter pinion & ring gear

[glenncof]

I'm not a engine builder but trying to solve starter problem.

It appears the starter pinion gear is hitting the ring gear on my 1985 911 with 187K miles on original starter/engine (yea, hard to believe on the starter but true).

This is prevents the solenoid from fully retracing (intermittent) and powering the starter motor.

I had the starter rebuilt and it does the same thing.

I could see wear on the pinion gear which leads me to believe the ring gear has gotten closer to the pinion. I beveled the leading edges of the pinion which helped but not fully corrected problem.

I can see the wear pattern on the pinion from ring gear teeth and there is clearance. I now suspect the pinion gear teeth edges are hitting the ring gear.

It's hard for me to believe the flywheel could move this much from wear, I assume main bearings.

Is this much wear possible or is the pinion/ring gear clearance very tight ?

[john walker's workshop]

the ring gear is replacable. there is an update to a wider gear. they wear out badly and chew up starter teeth, cause noisy starter function, gash gears and sometimes hang the starter in the teeth where it keeps cranking. pretty common problem. remove engine to replace of course.

[glenncof]

Thanks John.

The problem was the rebuilt starter had it solenoid replaced but the replacement was not good. It would not retract enough to get 12V to the motor, ie. weak.

I know they changed the solenoid since I saw the old one.

They put on a brand new solenoid and pinion gear. Seems to be working fine.

This had me scared the main bearing were going on engine.