Armature end play

[dcmason69]

Purchased rebuilt large frame starter from Oreillys
Notice if I flip it end to end it feels like the armature is sliding back and forth! In my mind there shouldn’t be that noticeable.
Did not see any info in FSM on this
Iam Leary to put in.
This is the 1.8 3 and 3/4 housing can anyone confirm this is ok or needs end play shimmed up?
Thank you dcmason69

 

[RJRENTON]

Purchased rebuilt large frame starter from Oreillys
Notice if I flip it end to end it feels like the armature is sliding back and forth! In my mind there shouldn’t be that noticeable.
Did not see any info in FSM on this
Iam Leary to put in.
This is the 1.8 3 and 3/4 housing can anyone confirm this is ok or needs end play shimmed up?
Thank you dcmason69

There is a certain amount of end play involved (axial movement).....between the drive shifting fork and sliding starter drive assembly (aka Bendix); axial clearance between the shifting fork solenoid and the shifting fork; and axial movement between the starter drive and the end of the starter motor housing probably to allow for thermal movement (growth) of the entire assembly.....the starter motor gets quite hot due to location compounded when headers are used. You do not say how much movement is noted.....1/8" overall???.....there must be clearance.........just my thoughts......
BOB RENTON

 

[dcmason69]

There is a certain amount of end play involved (axial movement).....between the drive shifting fork and sliding starter drive assembly (aka Bendix); axial clearance between the shifting fork solenoid and the shifting fork; and axial movement between the starter drive and the end of the starter motor housing probably to allow for thermal movement (growth) of the entire assembly.....the starter motor gets quite hot due to location compounded when headers are used. You do not say how much movement is noted.....1/8" overall???.....there must be clearance.........just my thoughts......
BOB RENTON

Yes i agree for the bendix fork etc.
But I can feel the armature hit back and forth against the end plate feels like more than 1/8 inch.
Thanks for your input
Just my thoughts that armature should not have to much end play?
dcmason69

 

[RJRENTON]

Yes i agree for the bendix fork etc.
But I can feel the armature hit back and forth against the end plate feels like more than 1/8 inch.
Thanks for your input
Just my thoughts that armature should not have to much end play?
dcmason69

The ARMATURE needs axial movement because during cranking, the magnetic centers of the pole shoes and ARMATURE tend to self alignment (magnetic centers), the ARMATURE current tends to be quite high (300-400 amps) because it's a series wound motor .....movement is result and needs axial movement to accommodate this alignment......
BOB RENTON

 

[dcmason69]

Ok
I see how that would work. Learned something new!
Thank you Bob
Not my first choice but the cost for me to buy a used core and then pay for a rebuild, made me opt. For a china rebuild. Hope it doesn’t bite me in the butt!