The problem with the dual pulley setup on this engine is that it is very
easy to put
too much tension in the belts. I was shocked to check my belt tension after
a
hot shutdown and found it was extremely tight. The engine expansion after
running up to temp tightens the belt severely. It must be set quite loose
to get
the right tension when hot. I have also heard of cracked alternator
brackets from
the same cause. Also, the internal alternator fan is there for a good
reason!
In addition, it is a good idea to run a blast tube to cool the alternator on
very
tightly cowled units. Very sorry to hear of this accident.
Glenn
>From: Graham Singleton <grahamsingleton@btinternet.com>
>Reply-To: europa-list@matronics.com
>To: europa-list@matronics.com
>Subject: Re: Europa-List: Flying for Fun" accident
>Date: Fri, 17 Nov 2006 00:07:55 +0000
>
><grahamsingleton@btinternet.com>
>
>The N'Denso alternator is reliable if properly installed, so is the Subaru
>engine, However, the NSI /Subaru conversion has a very poor reliability
>record. The alternator failure was exactly the same as Bill Wynne's it
>seems, it wasn't "out of the blue", imho it was just a matter of time.
>I haven't looked closely at the alternator placing but my understanding is
>that the belt tension necessary to drive the alternator results in bearing
>overload. IOWs bad engineering design.
>The gear box (redrive) has a similar record, frequent failures due to
>overheating but for different reasons. These Subaru installations were
>aproved by PFA but without the benefit of hindsight. NSI marketing was very
>seductive at the time. I doubt if they would be aproved now except under
>"grandfather " considerations.
>Graham
>
>Belinda Glover wrote:
>
>>It was indeed literally an out of the blue failure almost in to the blue
>>as
>>well since I thought at one point I might have to ditch in the sea at the
>>Seven estuary to put the smoke/fire out!
>>
>>In hindsight the "Approved" installation had the normally reliable
>>Nippondenser alternator sat high aft in the cowls which proved too much
>>for
>>the grease in the sealed bearing.
>>
>>
>>
>
>
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