REFLECTOR:Alternator Woes.

[Dennis Martin]

Hi Scott,

I bought my alternator adjusting bracket out of Summit catalog.  It's 
also chromed.  I wonder how I can tell if it's crappy metal.  My 
friend Dennis Miller had to mill it a little to make it adjustable, 
so that weakened it.

Thanks for sharing important information.  If it would fit, I bought 
a super heavy duty alternator.  Aluminum case, weighs just under 8 
lbs and delivers 110 Amps.  It's a Denso, but beefed up by 
aftermarket tech company.  I've forgotten the brand, but if anyone 
wants to know, I'll get you the web site.

All the best,

Dennis Martin
V-6 Chevy almost ready to roar


>My alternator has been a constant pain in the ass since I bought the plane.
>
>1.)  Bolt came out that holds the adjusting arm bracket to the case. 
>Why?  It was not safety wired, no hole on the bolt head. It went 
>through the prop on the way out, no major damage.
>
>2.) The adjusting bracket cracked after 75 hours. This is the long 
>bracket with the slot in it.  I replaced it with another of same 
>make thinking it must have had a flaw.  No damage to plane.
>
>3.) The new adjusting bracket cracked after 45 hours. This bracket 
>is a universal replacement chromed bracket.  It was crap.  Poor 
>grade of steel and chromed on top of that which weakened it even 
>further. I questioned replacing it when I did it but didn't trust my 
>instincts. I scavenged a junk yard for a good quality bracket. No 
>damage to plane.
>
>5.) After installing new bracket alternator still wiggled. The 
>multiple mounting failures had caused the lower pivot mounts to wear 
>elongation's in the mounting holes.  I reamed them out on the mount 
>and alternator installed 7/16 shoulder bolts.
>
>4.) The alternator failed.  Disassembled it and decided that this 
>particular unit had seen 300,000 miles of service before 
>installation on my airplane. Didn't know what the unit had come off 
>of and my local alternator shop found a new replacement.  No damge 
>to plane.
>
>5.) One of the 7/16 shoulder bolts failed.  It was mislabeled in the 
>store as a high alloy steel, it was garden variety.  I probably over 
>torque'd it thinking it was a better bolt but it should never have 
>been used in that application anyway.  It went through the prop on 
>the way out and wholloped my Catto prop real good in 4 places(nut 
>and 3 washers).  My A&P buddy thinks it happened on the ground and 
>the fourth whap near the tip was one of the pieces bouncing back up 
>into the prop.  I'm replacing the  failed and remaining bolts with 
>true 7/16 grade 8 bolts.  Also repairing prop.
>
>All these failures can be attributed to "Pilot Error" in my opinion.
>
>No safety wire on a bolt.
>Using inferior bracket.
>Using junk yard alternator of unknown age.
>Using substandard hardware.
>
>Scott
>
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