What cracks cylinders?
There are many things that are bad for an
aircraft piston engine.
In no particular order:
1) not flying it. This is probably the worst thing
you can do to an aircraft piston engine, and is
generally the cause of most private engine
problems and overhauls. Internal corrosion.
2) not preheating it. With some ether, you
can start an engine in very cold temps. But
you're going to see a lot of metal-on-metal,
both because of lack of lubrication and and
decreased tolerances due to differential
metal expansion and contraction rate with
temperatures (think of a bimetallic thermometer)
3) overheating it. Now we're getting back on
topic with respect to cracking cylinders. The
hotter you run an engine, the shorter it's life.
This is not hard to understand. A lot of people
think you should "baby" an engine which is totally
wrong. It does not hurt and engine to produce
it's rated torque at rated RPM. Not in the least.
What hurts an engine is running it hot. You run
CHT's over 400F, the cylinders are not going to
last as long as if you kept them under 400F. This
is a matter of cowling and baffles and seals. I
don't like running hot oil temps, either. I've seen
260F at central america airshows and I don't
like it.
4) shoving the mixture in. Everyone loves to
pull the power back in a descent and then shove
the mixture in, which shoots cold fuel into the
cylinder and cracks it, according to the engineers
at TCM. This is a very bad idea with a TCM-360,
520 or 550 but everyone does it anyways, and
then wonders why their cylinders are cracked.
Let's look at the opposite of above. If you
- frequently fly an engine
- always preheat it
- keep the CHT's below 400F
- lean in a descent
Then your engine will go far beyond TBO. Most
people either can't bother to do the above, or
they object to it on some kind of artistic creativity
basis, and trash their engines.
There was an airplane that sat at my airport for
almost a year. This is very common when an
owner gets busy, sick or dies. I told the son of
the owner that the 540 Lycoming in that airplane
cost $50,000 from Lycoming, and it was being
destroyed by sitting.
He replied that $50,000 wasn't very much money
to them.
What would I know, about operating piston aircraft
engines compared to him?