Scudrunners

I like both the TCM IO-360 and Lyc IO-540 -
I have had many of them for many years.

Very different engines.  Do keep in mind
that there is no replacement for displacement  ;D

A better straight-up comparison might be
the TCM IO-520 or IO-550 vs Lyc IO-540
(remember there are both parallel and
angle-valve Lyc variants, with a staggering
54 lb weight difference!)

You can do things to the Lyc that you would
never do to the TCM, and vice versa.

Another interesting comparion is the early
Maule airframes vs the later Maule airframes.

Huge differences!  Early Maule airframes are
very light, with very small vertical fin and
very large rudder, while later Maule airframes
are very heavy, with very large vertical fin
and very small rudder.

While I love them all, I really prefer the earlier,
lighter versions with the big rudder.

The amazing thing about your comparison
is how well the tiny 360 did against the huge
540!

A power-off descent with rich mixture is
a really bad idea with a TCM.  Lycoming
will tolerate such abuse.

If you look at a Lycoming sideways, it's
cam lobes and lifters will spall and it will
start making metal.  A friend of mine was
pretty depressed today - his RV-8 started
making metal, and he flies very frequently
and uses camguard.  Told him it was time
for roller lifters.

However, you can park a TCM for decades
without pickling and it will be just fine.  I
have mentioned a Bonanza here at my
airport that sat for a couple decades and
the engine was fine.  Incredible.

Photofly over on AvCan picked up a 182
in the USA that had sat for years.  It
runs fine.  He didn't overhaul it, even
though it was past flight time TBO and
sat for years.  He flew the North Atlantic
in it, instead.  I guess going back home
with a C-reg aircraft has some street
cred  ;D

Remember that most private aircraft
engines don't wear out.  They corrode
internally and rarely make flight time
TBO - unless they are TCM.

There's a cute little C-85 on the field
with 3400 SMOH.  Uneithical AME's of
course all say it's junk and needs an
overhaul but it makes great power
and flies just fine.  At least that's what
a very unscrupulous AME just north
of me said - he was trying to fool the
owner into selling it to him for cheap.
This is the same AME that steals
dataplates.

True.  The (parallel-valve) Lyc is de-rated
from 260hp at 2700 rpm to 235hp at 2400
rpm. 

I know there are 235 Maule owners out there
that have tweaked the governor to get that
extra 300 rpm (and 25 hp) back.  Paper-pushers
avert your eyes.

In fact, Maule eventually even started selling
the 260 hp version of the 540, it was such a
popular (if unauthorized) mod!

If one is so inclined, it is not difficult to
get 310 or 320hp out of the 540, if one
is interested in high-compression pistons,
cold air induction, etc.  Many people do
this (Monty Barrett, Lycon, etc).  A friend
of mine has ferried Patty Wagstaff's
airplane and he says you wouldn't believe
how powerful that engine is.  I forget the
RPM it wound up to.

Hell, even Lycoming will sell you a 540
like this (see the Thunderbolt program). 

I met a nice young man at Oshkosh (he
seemed to be barely old enough to shave)
that built them.

The TCM IO-360 is a fine engine, though.
So smooth, and it makes great power
(at 2800 rpm!) for such a little engine.

I know a lot of hamfisted pilots have
bad things to say about them (like the
GTSIO-520 in the C421) but that's just
a matter of ignorance and mostly a
complete lack of competent training,
which is what people want.

I have been flying the same TCM IO-360
for 44 years now.  No cylinder cracks.
Never been overhauled.  And I use it
for tailwheel training!  I don't let four-
bars fly it, though.

On the subject of de-rating ...

Cessna similarly de-rated the TCM IO-360
from 210hp to 195 hp (2800 to 2600 rpm)
when they put it in the 172 XP.  Again,
another airplane/engine that has a bad
reputation because of ignorant, ham-fisted
pilots that like to wear white shirts and
gold bars.

In the USA, you need a special endorsement
to fly an aircraft with 200+ hp (I am not making
this up) so Cessna dodged that with the de-rating.

Again, people tweaked the governor to get
the RPM (and hp) back.  Hell, there's even
paper for it!

Some years ago I went down to Seattle with a client to fly a Maule on amphibious floats with the turbine engine.

It was by far the most bizarre handling and flying device I ever had the misfortune to experience.

Both on the water and in the air.

Oh yeah, the 420hp Allison C250.  They
didn't make too many of those.

You want a bizarre experience on floats,
try a Challenger ultralight amphib.  Scary.