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1. 01:07 AM - Re: SV: IO-240 alternator drive coupling (Keith.Miller@esa.int)
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| Subject: | Re: IO-240 alternator drive coupling |
Hans
I posted quite a bit on this point back in July 2012 , when mine failed at
about 400 hours . I didn't follow the post up with my solution (Sorry) ,
but in the end I went for an overhauled part through Aircraft quality
accessories in the USA ( see OC posting for the Link ) they were very
fast at sending the unit to me ( Too fast in my opinion as they used an
expensive courier service ) , Part itself is expensive for what it actually
is, but they returned the $500 deposit as soon as they received my old core.
I did all the research (as per Johns note) about replacing the unit with the
old mechanical solution , and I agree with John. The old mechanical design
should not fail due its simplistic design, whereas the new one piece
coupling is always going to fail eventually as the rubber gets old , and
once it starts to slip it will rapidly wear out- but good news is is that
it can not damage the engine , just a bit of fine rubber residue in the
oil .
When I spoke with Aircraft quality accessories, they said it was a regular
replacement part ( 2 to 3 per week ) ,and they did quite good business out
of this part. ,they also told me that they get more orders in the hot
summer months , when owners are switching on the Airco and loading the
alternator to a max before they get into the air, and that it is unlikely to
survive for long periods when there is a max current draw from the 60amp
TCM alternator.
In my case I put my failure down to my decision to switch to a Lithium
Phosphate main battery without first redesigning the charging circuit ,
since these batteries demands huge currents from the alternator just after
start up.
Replacement process is quite easy , took me about 4 hours in total
( requires the removal of one magneto to get to one of the bolts - no way
around that )
Good luck with your decision and replacement,
Keith
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|"Hans Christian Erstad" <hans-chr.erstad@c2i.net>
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|03/03/2013 21:00
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| Subject: |
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|SV: KIS-List: IO-240 alternator drive coupling
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|owner-kis-list-server@matronics.com
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Thanks OC
Yes, it sound like I have identified all options - and there are quite a few.
Looking at the failed on-piece coupling, I think it is not designed to last,
only to make money :-)
I think the best option is to find used parts for the multi piece coupling,
but buy new the bushing and retainer that according to SB95-3B is to be
replaced every 500h.
This Service Bulletin have been useful providing information on part numbers,
torque etc. However it seems like the one-piece coupling never reaches 500h,
so the SB is to no help there, apart from stating "The one piece coupling may
be substituted for the coupling assembly shown in Figure 1." Maybe they
issued the SB to infrom about this substitution when they realized that the
one-piece is flawed.
The SB calls for the couling to be tested for 100 inch punds of torque.
Probably all 500h couplings will fail this test? and will require replacement
with the substitute. Anyone know about a 500h coupling that have passed the
test?
Regards
Hans Christian
Fra: owner-kis-list-server@matronics.com [
mailto:owner-kis-list-server@matronics.com] P vegne av Owen Baker
Sendt: 3. mars 2013 14:08
Til: ERSTAD HANS-CHRISTIAN; KIS-LIST MATRONICS
Emne: KIS-List: IO-240 alternator drive coupling
3/3/2013
Hello Hans Christian, I am sorry to read of your alternator drive coupling
problem. The attached copy of TCM SB95-3B provides some relevant information.
I think that you have a very good grasp of the four solutions to the problem.
They are: a) purchase and install the multi piece coupling, b) convert to a
front drive alternator, c) purchase and install a one piece coupling from CMI
(Continental Motors Inc. -- new name), purchase and install an aftermarket
rebuilt one piece coupling.
Regarding each solution:
a) The multi piece coupling was replaced by the one piece coupling as the one
piece coupling was considered superior. That point may be debated.
b) The IO-240 B3B engine in the Diamond DA 20-C1 airplane uses the front
mounted alternator. One could maybe source the parts needed from a Diamond
aircraft dealer. I dont know if that model airplane was ever introduced
outside of the USA and Canada. In addition to obtaining and installing the
front of the engine parts needed one would also have to seal off the left
open alternator drive access hole in the rear of the engine.
c) Purchase a one piece coupling from CMI. The most expensive initial course
of action.
d) The aftermarket one piece coupling can be purchased from these people:
http://www.qualityaircraftaccessories.com/Default.aspx?A=ProductSearch&ID=/search-results&SE=True&q=635796
for an initial cost of $1,095.00 US. They are supposed to refund $500 US of
that when they receive your returned old one piece core.
Please let me know if I can be of further help.
OC
'O C' Baker says "The best investment you can make is the effort to gather
and understand information."
==========================
From: Hans Christian Erstad
Sent: Mar 2, 2013 12:55 PM
Subject: KIS-List: IO-240 alternator drive coupling
I have read several
postings about early failure of the IO-240 alternator drive coupling (P/N
635796).
The coupling failed
now at 337 hours in my IO-240 powered KIS. From other postings, it seems
like this part never reaches 500 h, and cost a fortune to buy new (more than
$2000), but may be overhauled for $600.
The failure rates
indicate to mee that this part (too) is a bad design.
Apparently it is
possible to replace the one piece coupling, with one that contain of several
parts (531325, 530407, 632050, 653982, 653983) and have been used on other
Continental (e.g. O-200).
What have the
experience been for you that have IO-240 ?
Any suggestion for
best place to get the one-piece overhauled? or suggestions for where to buy
the serveal-piece alternative?
Regards
Hans Christian
Erstad
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