I've been doing battle with my starter for the last week. The original starter broke the nose in half due to....... unknown. Bought another GM type starter and a TA mini starter and they both behave the same. Put it on with no shim, starter gear bumps into flex plate gears. Put one shim and it has proper clearance on gears, however it sometimes doesn't retract. Is that normal? Does the actual starting of the engine help fling that bendix gear back into it's cubby? Look at 3:30 point of video. Summit states that this result is ok and not a problem. What say you?
The drive pinion rides on the armature and they have spiral grooves. As it turns, it the solenoid pushes the drive pinion into the out position so that it will engage as well as rides up on the spiral grooves. When starter motor power is removed and the engine starts, the overrun will push the drive pinion back into the housing along with the solenoid spring that should retract it but if the drive pinion is engaged to the flywheel and the engine didn't continue to turn, it may be mildly bound up and stick. If you wiggle the flywheel and the drive pinion retracts, it should be OK. If you loosen the start bolts and it retracts, you may need a shim due to interference between the two.
I had a problem with a flat SFI flex plate, where the ring gear was too close to the starter pinion. It would grind all the time, and eventually took out my starter. My solution was a Rob Mc starter that used a separate mounting block. Those type of starters allow you to use shims to back the pinion gear away from the ring gear. That is different than the shims used between the starter and engine block to adjust gear back lash. Later on, I swapped in another SFI flex plate with the correct offset, and removed the shims. I believe the Tilton, and Powermaster starters are of this design. You can't make this adjustment with a stock starter.
