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The following question was posted on a forum at HomeBuiltAirplanes.com from a member "I have a 503 on my PPC and a 582 on my Slipstream. I would like to replace the 503 but would like to try another engine beside the 582. My friend has a hirth and I won't get one based on his success. Anyone flying the MZ202 or MZ202i Comments?"
Below is my response to the posted question and editorial after my original post
Leon Massa owner of
Compact Radial Engines provided more insight I thought I should update my post
with his comments, which are inserted below in "Red"
But, I got in the last word with my rebuttal posted in "Green"
The MZ201 engine has a long history. It is an
Italian design dating back ~ 12 years. The really big difference between the
Hirth and the MZ is how they are made. The Hirth is a cast molding process that
uses vibration to remove any air trapped in the pouring process. This type of
casting leaves the aluminum more brittle and less dense than other methods. Case
in point, it is very common to strip the spark plug threads in the Hirth heads.
Talk to owners and you will find many have had to put some form of thread
reconstruction to fix the problem.
The MZ201, MZ202, MZ301 are manufactured using a high pressure injection molding
process. This makes the crankcase, cylinders and heads more like billet
aluminum. Injection molding assures no air introduced during the molding process
because only liquefied aluminum is passed into the mold, no vibration is needed.
The result is a stronger engine able to transfer heat more efficiently to the
cooling fins.
The MZ201 was designed as a free-air engine and worked fine in a tractor
configuration, however, cooling proved to be a problem in a pusher setup.
(No, this is incorrect. The 201 only has one carb,it
runs at less rpm and produces less hp than the 202,therefore it produces less
heat as it is not working as hard, max power is achieved at 4700-5000 rpm.It can
be used in tractor or pusher config)
Thus the introduction of the MZ202. I am unclear who
introduced the MZ202 fan cooled engine. However, Leon Massa purchased the
manufacturing rights for the engines. His company, Compact Radial Engines, Inc.
is located in Surrey, BC Canada. Leon still
has the engine's major components molded in Italy. When he receives the
components they are then CNC machined to within 2 mil
(0.0005" depending on the part and the fit needed)
tolerances for final fit. I know of no other
company that uses this good of a specification.
The MZ cylinders are
Nikasil, which is a ceramic coating
(and nickle)
on the cylinder
bore. This type of cylinder is much stronger and heat resistant than pressed in
steel cylinders. The Nikasil bonded to the aluminum allows the more efficient
transfer of heat from the cylinder wall to the cooling fins. Should you have the
misfortune of a piston seizure a Nikasil cylinder can better stand up to the
overheated piston. With a steel cylinder a piston seizure will, more often than
not, require it to be bored to clean up the melted aluminum that fills in the
voids in the steel.
When Leon first started marketing the MZ202 in the USA there were some problems.
Some were created by Leon
(not likely)
(OK Leon, your pride is
showing)
and some
(all) (
)
were caused by the
end user.
Leon's biggest problem was the final assembly setup that left the factory. That
problem caused most engines to run rough and often times "4 stroking" which is a
term used to described a condition similar to running with the choke in the full
on setting. It was not an easy problem to overcome for most owners.
The problem itself was simple to correct after discovering that Leon was
shipping the MZ202 with the carburetors jetted two full steps below sea level.
(This carb setup was
done on purpose and was "setup" by a "Bing" rep right from the Bing factory.The
setup was that the carbs were set rich at sea level so that customers could run
the engine right out of the box without worrying about "running it to lean", all
customers need to "tune" the engine for their own conditions so the factory carb
settings were in most cases too rich.We could not possibly setup every engine to
suit everybody)
A fact that Leon forgot to
tell his customers about.
(No, It should be obvious
that you would have to "tune" the engine to your own conditions and enviorment)
(if that is the case,
the customer still needs to know the engine is tuned way rich!)
His reasoning for
the very rich carburetor setting was to assure a problem free engine break in
procedure and he never knew at what altitude the engine would be put into
service. (more on the break in procedure later)
Several owners and dealers ended up sending their engines back to Compact Radial
Engines because the engines would not run good. I was one of those owners.
However, rather than sending my engine to him, I loaded it in my car and drove
to the factory.
Leon was very accommodating and spent his entire day disassembling, inspecting
with a micrometer and caliper and then reassembling the engine. I spent the full
day at his side and learned a great deal about the full manufacturing process. I
was very impressed indeed.
Each cylinder after final CNC machining and Nikasil coated is inspected for
tolerance and is given one of three classifications (A, B, C). The pistons are
also made to match each of these A, B, C, classifications. The result is a
cylinder and a piston that match the MZ clearance specification. I will tell you
these variances from cylinder to cylinder are very small but one that Leon was
concerned about. After all this was to be an engine for aircraft, not land
locked vehicles. He knows first hand that a pilot can't just pull over to the
side, get out and fix a problem
(yes,
I'm a pilot too (GA and PPG)
My problem was
nothing more that an engine with way to rich jet settings throughout the rpm
range. Once that was corrected by jetting, re jetting and re jetting again, I
got it right. My MZ202 in a pusher configuration does not vary more than 30
degrees F from idle to full power or anything in between. The transfer from each
jet's range to the next jet's range is near perfect. And, the MZ202 runs great!
The other problem Leon has seen is poor lubrication. There are a great deal of
different 2-cycle oils on the market. According to Leon most are marginal at
best. Therefore, Leon has elected to use oversize ball bearings on the
crankshaft. These large roller bearings on both ends of the connecting rods help
protect the engine from poor performing 2-cycle oils.
During my visit Leon addressed the oil issue in great detail. He showed me two
MZ202 engines that experienced engine failure due to lack of lubrication.
The first engine was disassembled with the crankcase halves exposed. I could
easily see that the connecting rod bearing had been overheated to the point the
rod itself turned blue from heat. Interesting thing is the air and oil/fuel
mixture enter the engine at the position of the connecting rod bearing on the
crankshaft. At this juncture the rod bearing would be the first thing the air
oil/fuel mixture would come into contact with. It looked to me as though the
owner forgot to mix oil with his fuel.
Don't take bets that the customer ever admitted to doing that, because you would
lose.
The second engine failure I saw was due to a rod bearing failure on the piston.
This is a crucial area where good lubrication is a must. Leon let me feel the
underside of the piston and it felt like it was rubber coated. He then showed me
the wrist pin. It was blue from high heat. Leon stated this area of any 2-cycle
engine gets the least amount of lubrication, therefore the oil used must be of
the highest quality or failures will occur. Leon then went on to teach me about
2-cycle oils.
I have been a
believer of high quality synthetic 2-cycle oils for years. I used them in my
racing snowmobiles. Anyhow, Leon told me about an environmental requirement in
the USA for new oil sold in the USA. All new oil must contain 10% recycled
product
Thank you Ralph Nadir. Leon said he highly recommends Castrol TTS synthetic oil
because it is made in Italy from 100% virgin stock. He then went on to state
lubrication is never an issue with the TTS oil. He has not had an engine failure
to date with owners using this oil. That doesn't mean that other high quality
oils won't work, he just has a lot of faith in TTS oil.
Leon used my engine to show me another advantage of TTS oil. I had been using
Red Line Racing Synthetic 2-cycle oil. Leon took a scraper from his pocket and
pushed it across the top of one of my pistons. The crud just pealed off in a
soft gob of black. Leon said this was unburned oil and would be the reason
de-coking would be needed often. He then showed me a piston and head using TTS
oil. There was a complete absence of carbon build up and you could see the
jetting of this piston and head had been right on. Would you care to guess what
brand of oil I use now? Problem is Castrol TTS oil is hard to find. For more
information where to get TTS oil, send me a private email. I am not telling you
this just to sell oil.
Final thing - the engine break in procedure is well detailed in the owners
manual and full break in takes less than 10 minutes. With this step completed,
re-jet the engine using Bing carburetor's jetting charts and go fly.
As far as being a test pilot for the MZ202, that phase has been done. In fact a
single place light weight helicopter called the Mosquito uses the MZ202 as it's
only engine option. In this setup the engine is running at full sustained power
all of the time it is in flight. Now that is reliability!
(yes, and I think I have shipped
about 60 MZ202's so far to the Mosquito guys, maybe more I lost count)
(one last comment..... you must run premium or high octane gas to prevent
pre-ignition)
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This past April at Sun-N-Sun I had a chance to
observe two versions of the Mosquito helicopter in flight and on the ground. In
both cases I was most impressed with the on the ground operating conditions of
the MZ202. The engine is started and warmed up like any other 2 cycle engine.
After the engines were up to operating temperatures the engines were brought up
to operating rpm which is full throttle. That is right full throttle with no
load on the engine. That's right a free running engine with no load against
it for more than 5 minutes. Unbelievable, but true! As I watched the two pilots
would sit on the ground with no collective applied to the rotor. The engine was
running to the point I could hear the reed valves flutter. As soon as a pilot
applied a bit of collective to the main rotor the flutter would be gone and the
engine purred ever so nice. The engine never changed pitch, such as labor, when
lift-off collective was applied. They would fly around the pattern, land and sit
there for more than 5 minutes at full throttle with no collective and then do it
all over again. I watched this cycle go on and on for over an hour on one of the
Mosquito's all of the time running at full throttle. I have never seen a 2 cycle
engine run that hard. I asked how many hours were on the two Mosquitoes I saw.
One had 42 hours and the other had 45 hours at the start of Sun-N-Fun and had
been flying every day during their flying window. I never did get to talk to the
second pilot because he was having to much fun flying and had not stopped by the
time I left. I would have to estimate the second Mosquito topped 50 hours before
the End of Sun-N-Fun.
Test Pilot, I think
not.
Rocky
Just telling it like it is
