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casting failure on Plane Power alternator, grumpy customer

IowaRV9Dreamer

Well Known Member
This is the AL12-P70 alternator from my Beech. It was bought new from PP in 2008 (before Hartzell) and lasted 480 hours. The alternator still spins perfectly and alternates fine :) but the casting has failed.

The mount design is such that the alternator pivots on the steel bushing shown. Over time and vibration, the hole in the casting has widened out such that the alternator rocks significantly on the bushing and cannot remain straight with good belt tension.

I"m grumpy because I have to buy a new alternator for about $600, and I also have to pay a $200 core charge. I've never heard of core charges on new/outright parts. Hartzell told me they require them on every purchase.

I was originally planning to keep this alternator, fix the casting (machine for steel insert) and use it in the RV... but forget it. For the price of the core charge I can buy one or even two of the Suzuki rebuilds...

I've experienced failures of both my Plane Power alternator and Sky-Tec starter due to vibration. I don't think they are as sturdy as you'd think....
 

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Usually something like this happens because the tension arm bolt is not tightened and the alternator moves, or the bracket cracks allowing the alternator to move. If the installation is correct otherwise, it is rare to see this.
 
The experimental pivot design is the same. The through bolt keeps it tight and it must be tight. No movement is tolerated, it was loose and this is the failure root cause. I would ream the housing and machine a new spacer and reinstall, but that can not be done legally I suppose.
 
Thanks Bill - you must be right. The A&P tightened the belt last year and I wonder if he didn't get it fully tight :mad: Lesson learned, it's gonna be tight this time!
 
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