Inspecting the piston sleeve for major gouges—nothing here! The piston and piston ring are also clear of any gouges or scratches.
carefully detach the connecting rod from
the crankshaft while the piston was at
TDC, and I slid the piston out of the
engine. At this point you can inspect the
bearings and replace them if necessary.
With the piston and sleeve out of the
engine, I could take a close look at the
walls of each of the parts. I was looking
for any deep grooves or gouges running
vertically on the inside of the piston
sleeve, as well as on the piston wall and
the piston ring.
If there are any major gouges, this is
a sign that you’ve had an issue that has
damaged those parts. If you can find
the parts (which I have been unable to
do for this engine), you can replace the
piston ring and sleeve, as well as the
piston if it needs to be replaced. This will
basically give you a new engine that will
need to be broken in again. The grooves
and gouges reduce the compression that
I discussed earlier, robbing you of power.
Other than some tarnishing from
the fuel, I was unable to find any major
scratches on the parts. There are some
light scratches, but they are so subtle
that I can’t see them without a strong
light—not anything that would cause
concern on this engine with its history. If
you notice a light crosshatch pattern on
the piston sleeve, this is normal. There
just shouldn’t be any major scratches.
After examining the parts and not
really finding anything wrong internally,
I cleaned up some of the tarnish and
reassembled the engine.
What else could cause the lack of
power? As it turns out, a good glow plug
goes a long way—something I should
have tried ahead of time. I know that
some of you out there are rolling your
eyes right about now, but hey, I’m not
perfect! We pilots sometimes forget the
little things and I am guilty of that, but
we learn and move on.
I feel better about my engine, though,
knowing that there is still some life in
the old girl yet! In the meantime, it’s
time to consider an alternate engine.
International Radio Controlled Helicopter Association
Synergy R/C Helicopters
98 Model Aviation APRIL 2017 www.ModelAviation.com