Re: Broken Skytech pinion tooth (Q200)


Jim Patillo
 

Kevin,

The shiny spot (scrape) you saw on the side of the housing is
indicative of the pinion gear being side loaded when fully engaged
into the starter gear on the engine. Rich Chappee would immediately
diagnose that as a kickback.

I'm of the opinion that you either had an electrical kickback or a
hydraulic kickback. Given the fact that you use a mag to start
indicates a hydraulic kickback. That happens when the battery you
are using doesn't have enough amperage to get over the top (high
compression). The result is a damaged housing, shaft, seals, etc.

As I've said before, the inrush amperage required to run a permanent
magnet starter is much greater than that of a B&C starter and
requires a larger battery. I still use a 25RG even though the B&C
will start an IO540 with an 18AH battery.

The reason we initially started using the Skytec was because it was
a direct replacement for the stock unit, no modifications.

The B&C requires modification to the mag box because the solenoid is
mounted at 45 degrees or so as opposed to vertical for the Skytec.

Simply mount the B&C and determine the area to be cut out of the mag
box. Use the piece you cut out, reverse it and flox back into place.
Reglass to restore rigidity to the mag box. Cut the interfering
corner of the motor mount pad so that the starter clears on
installation. You will need about a quarter of an inch clearance
around the new starter to prevent rubbing.

Hope this helps you. I really think you're wasting your time putting
on another reworked Skytec. Rich is a really nice guy but there is
an issue that needs to be solved here.

Good luck,

Jim P.
"Kevin Fortin" <kfortin@p...> wrote:
Jim,

I know about the motor mount mods that need to be done but haven't
heard
about the "magbox" mods you mentioned. What's happening there?

Thanks for you time and I wish I had listened to you earlier
(oops).

"Experience is what you get when you don't get what you want".



Kevin

-----Original Message-----
From: Jim Patillo [mailto:logistics_engineering@m...]
Sent: Tuesday, February 22, 2005 9:24 PM
To: Q-LIST@yahoogroups.com
Subject: [Q-LIST] Re: Broken Skytech pinion tooth (Q200)




Kevin,

1. Thank Rich for all his help, send it back and try to get a
refund.
Don't waste your time trying to make another Skytec work. I tried
that three times.
2. Buy a B&C, have Bruce Bainbridge upgrade the motor to a 320, no
charge(better for high compression)and install it.
3. Go fly!

The B&C starter has worked perfectly since the install. The
modification to the mag box was simple and the motor mount only
needed to have one corner cut off the pad. About 10 hours work,
start
to stop.

As I've said before the B&C starter takes much less power to run
it.
Hopefully I've put the starter issue behind me. You can do the
same.

Sorry to hear of your troubles. I do understand!


Regards,
Jim P

--- In Q-LIST@yahoogroups.com, "Kevin Fortin" <kfortin@p...> wrote:
Brad Olsen and guys,



First off, my apologies to Brad Olsen for not responding to an
offline email
he sent me regarding the following subject. My email was
filtering
emails
without attachments and I didn't realize it.



I am responding to his email on list because I think it is of
interest to
many regarding Skytech starters.



Background: I ordered a Skytech starter on the basis of
what
Skytech
told me and after discussing what seemed to be the problem with
Jim
Patillo's starter aka. "electronic ignition induced kickback".
Upon
receiving the new starter I installed it and it seemed to work
well, but had
more of a "grinding" sound in operation than I would have
liked.
After a 10
MAXIMUM total starts, in a hurry to get the airplane to an
avionics
shop
(onfield), I forgot to turn on the fuel, and, after a very short
taxi, the
obvious happened, I ran out of gas. Duh!!! I turned the gas
valve
on,
waited about a minute, then tried starting again. The prop
turned
for
somewhere between 6 to 10 seconds before the engine caught and I
taxied on
my merry way. A couple of days later, I picked the airplane up,
jumped in to
start it, and was met with what seemed to be the grinding sound
of
gears
with missing teeth (the engine did start, however).



The following weekend I pulled the engine and the starter only
to
find a
tooth missing from the Skytech starters drive pinion gear. That
was
the bad
news. The good news, I was able to find the tooth. (I thank the
Q
god's for
that one.)



On the following Monday, I called Skytech and explained the
problem
and they
did all they could to help. I can't complain about their
customer
service.



At this point, I have received a replacement starter (new) from
Skytech, but
as of yet, I have not installed it. All my mental alarms are
going
off
related to something that can throw of a piece off big enough
that
it could
gum up my engine (read off field landing and/or a damaged
engine)
or at the
least break off a tooth on the crankshaft gear, which at the
least,
is going
to be damn expensive.



Relevant info 1. As far as I know I did not have a
kickback.

2. I was starting on left mag only

3. I believe the real problem is Skytech's
control of the
centerline distance of the pinion/crankshaft gear set. In an
effort
to
loosen the tolerances in the manufacture of the starter, Skytech
has allowed
the pinion to get too far away from the main gear on the
crankshaft. This
results in an incredible force trying to separate the gears.
This
force than
further deflects the shaft that holds the pinion, which leads to
even higher
forces on the gears, then ultimately to a broken tooth.

4. I am going to try to get some measurements
on
the
centerline distances this weekend and I will let you guys know
what
I find.

5. Item 3 is only conjecture at this point.
Please take it
as so.

6. I have high compression pistons, but I
don't
know the
ratio.

7. I usually don't write well and tonight is
even
worse.





If anyone has a better starting system idea, let me know. I am
not
feeling
to good with this right now.



Kevin Fortin

N275CH

Except for the starter, damn close to flyin'
















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