MoGas Tips, Tricks, Concerns, How To

The major Mogas concern I have is that so few have endorsed the
concept, that it may not ever get to critical mass. The engine
manufacturers ignore it or don't support it, the AOPA never mentions
it, many FBOs simply state "our insurance won't cover it", the hodge
podge of state gasahol laws are eroding the practicality of it all, and
lastly we owners of low compression engines simply are not using it
anywhere near as much as we should.

Mogas is simply assumed by most "real pilots" and mechanics to be a
substitute fuel, inferior or harmful to engines, and something that is
only used by a small minority of old aircraft owners. For those and
probably still other reasons, mogas isn't widely available for cross
country use. The advantages of Mogas are only talked about in forums
such as these.

Mogas users have to get this situation changed. Some day 100LL is
going to disappear by an EPA mandate & then where will we be? I feel
the 100LL users are whistling in the dark as no substitutes seem to be
forthcoming to their leaded fuel.

nrp wrote:
The major Mogas concern I have is that so few have endorsed the
concept, that it may not ever get to critical mass. The engine
manufacturers ignore it or don't support it, the AOPA never mentions
it, many FBOs simply state "our insurance won't cover it", the hodge
podge of state gasahol laws are eroding the practicality of it all, and
lastly we owners of low compression engines simply are not using it
anywhere near as much as we should.

Mogas is simply assumed by most "real pilots" and mechanics to be a
substitute fuel, inferior or harmful to engines, and something that is
only used by a small minority of old aircraft owners. For those and
probably still other reasons, mogas isn't widely available for cross
country use. The advantages of Mogas are only talked about in forums
such as these.

Mogas users have to get this situation changed. Some day 100LL is
going to disappear by an EPA mandate & then where will we be? I feel
the 100LL users are whistling in the dark as no substitutes seem to be
forthcoming to their leaded fuel.

Both Aviation Consumer and AOPA pilot have articles on this subject in
their current issues. They both conclude that 100LL is really not
going to be going away in the foreseeable future (the EPA has delegated
the issue the FAA and the FAA is not interested in getting rid of
100LL), and they also both describe research into alternatives that is
in fact going on now.

One statistic that interested me was that 70% of the GA fleet does not
have the high compression engines that need high octane/leaded fuel.
However, the 30% that does burns 70% of the gas.

It seemed as though the AOPA article ignored the proven success of
MoGas, but it did point out the very limited success of 100LL
alternatives. I wonder if there are any more high compression engines
running in test cells trying replacement fuels. It sounded like there
was only one.

nrp wrote:
It seemed as though the AOPA article ignored the proven success of
MoGas, but it did point out the very limited success of 100LL
alternatives. I wonder if there are any more high compression engines
running in test cells trying replacement fuels. It sounded like there
was only one.

What is the proven success of Mogas? I mean, besides testimonials
from its users on this newsgroup, what proof is there of Mogas success,
and how would it be defined?

For example in their article on fuel, Aviation Consumer had a sidebar
on mogas saying it wasn't as good as advertised. They said several
shop owners told them that when they get engines or cylinders in for
work, they can immediately tell if the owner is running mogas by the
corroded camshafts and deposits on the valves and seats. These shop
owners claimed that the extra overhaul costs eliminate the mogas
savings, and attribute it to the "varying additives" used in mogas and
to the fact that most mogas sold doens't really meet the ASTM standards
dictated by the STC.

Personally I don't know, I have no experience with Mogas, all I have to
go on is what I read here and in other sources. It would be a pity if
this was correct, especially with rising 100LL prices.

I remember traveling in 1974 with a British engine engineering
consultant who was absolutely positive the US auto manufacturers were
going to be in for a rude surprise when unleaded fuels were foist upon
them by the EPA and the 1975 catalytic converter needs. He predicted
valves and seats would quickly fail creating a massive maintenance
problem.

It never happened. Hardened valve seats were used from the beginning,
and the reduction in engine contamination has given us longer service
intervals and incredibly long lived automotive engines today.

Where are the hardened seats for aircraft engines? Even something that
recognizes some fuels don't have TEL in them? I've lived with over 20
years of autofuel in my O-320-E2D (one of the first STCs from Petersen)
using low cruise powers, hoping to minimize valve seat recession. So
far I've been very successful.

The lack of a consistent airport distribution system to assure quality
for MoGas after 20 years is crazy. There must be other forces at work
that are not obvious to me.

For example in their article on fuel, Aviation Consumer had a sidebar
on mogas saying it wasn't as good as advertised. They said several
shop owners told them that when they get engines or cylinders in for
work, they can immediately tell if the owner is running mogas by the
corroded camshafts and deposits on the valves and seats. These shop
owners claimed that the extra overhaul costs eliminate the mogas
savings, and attribute it to the "varying additives" used in mogas and
to the fact that most mogas sold doens't really meet the ASTM standards
dictated by the STC.

I read that article, and it is the closest thing to total bull**** I've
ever read on the subject. I can line up several shop owners who will
absolutely contradict the statements of those supposed "shop owners".


Nearly every INDEPENDENT shop owner I know (and that distinction seems
to be critical here) will testify that engines that have ran on
unleaded fuels are MUCH cleaner inside. They will tell you that they
can tell instantly upon teardown whether someone has been burning 100
LL in an engine that was designed to run on 80 octane avgas, simply by
the amount of crud inside.

100 LL has FOUR TIMES the amount of lead that my engine was designed to
run with. As a result, spark plugs foul with lead far easier, making
it necessary to aggressively lean the engine. Which, of course, in
turn leads to much higher exhaust gas temperatures, and unnecessary
wear and tear on the engine.

The ONLY time I've ever had engine trouble with Atlas' O-540 was on a
road trip where I was forced to run exclusively 100LL for days on end.
I fouled a cylinder so badly that BOTH spark plugs ceased firing,
requiring a quick return to the airport landing, (Not QUITE an
emergency, but close...)

I would run 87 octane unleaded car gas in my engine if it cost MORE
than 100LL. My engine simply runs better and cleaner on it, and I will
not run 100 LL unless I am forced to use it.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

On 10 May 2006 13:24:27 -0700, "xyzzy" wrote:

For example in their article on fuel, Aviation Consumer had a sidebar
on mogas saying it wasn't as good as advertised. They said several
shop owners told them that when they get engines or cylinders in for
work, they can immediately tell if the owner is running mogas by the
corroded camshafts and deposits on the valves and seats. These shop
owners claimed that the extra overhaul costs eliminate the mogas
savings, and attribute it to the "varying additives" used in mogas and
to the fact that most mogas sold doens't really meet the ASTM standards
dictated by the STC.

Junk science from the aircraft maintenance industry. Since auto gas
STCs generally prohibit commercial operations, you can expect that if
an airplane is being flown on auto gas that it's probably going to be
on weekends by pilots who have to work for a living the rest of the
week. That's the kind of operation that has already been documented to
cause corrosion on camshafts, regardless of fuel. And as for deposits
on valves, how could auto gas deposits be any worse than the deposits
caused by 100LL? Lead deposits have been documented to cause valve
burning, valve sticking, ring sticking, spark plug fouling, and
in-flight engine failure. That's a major reason why we're running
mogas. A claim like that might make sense if they noted a lack of
deposits as being the indicator of auto gas operation.

I'd be more impressed if these people would publish objective,
scientifically controlled studies instead of anecdotal observations.
As it happens, the only people who have done studies have found no
problems with auto gas.

It is noteworthy that the FAA has given its blessing to 82UL avgas,
which, being based on auto gas, contains no lead. It's FAA approved,
so it must be ok, right? Of course I doubt that anyone now living will
ever see it at our local airports.

And then there's NASCAR. After years of noise from environmentalists,
NASCAR has announced that they've developed and are beginning to use
an unleaded alternative to the leaded racing gasoline they'd been
using, which was essentially the same stuff we fly with. Once the
environmentalists get through with NASCAR, don't you wonder how long
it'll take for them to draw a bead on us? They may ask that EPA start
testing air quality around airports just like they asked the EPA to
test air quality at NASCAR races. EPA says they're not interested in
doing anything about avgas, but that could change with a single
election or a single court decision.

RK Henry

People seem to ignore the fact that lead dibromide, the byproduct of
burning 100LL, is acidic highly corrosive when mixed with water, which
is also plenty as a result of combustion.

Lead dibromide is formed when Tetra-ethyl lead react swith lead
scavenging agent ethylene dibromide during the combustion. The lead
scavenging agent is a necessary evil to get rid of the metalic lead
after TEL does it job of retarding the combustion. Without it the
metalic lead will quickly accumulate in the engine as slush.

Other than its high octane value (which isn't needed in 1:7 compression
engines), 100LL isn't such a good fuel to begin with.

"nrp" wrote in message
oups.com...
It seemed as though the AOPA article ignored the proven success of
MoGas, but it did point out the very limited success of 100LL
alternatives. I wonder if there are any more high compression engines
running in test cells trying replacement fuels. It sounded like there
was only one.

GAMI has been running a Lycoming GTSIO-540 on a test stand using rot gut gas
using it's PRISM system without a burp, and hoping for an STC when they can
work out vibration tests.

http://www.gami.com/prism.html

"xyzzy" wrote in message
oups.com...

nrp wrote:
The major Mogas concern I have is that so few have endorsed the
concept, that it may not ever get to critical mass. The engine
manufacturers ignore it or don't support it, the AOPA never mentions
it, many FBOs simply state "our insurance won't cover it", the hodge
podge of state gasahol laws are eroding the practicality of it all, and
lastly we owners of low compression engines simply are not using it
anywhere near as much as we should.

Mogas is simply assumed by most "real pilots" and mechanics to be a
substitute fuel, inferior or harmful to engines, and something that is
only used by a small minority of old aircraft owners. For those and
probably still other reasons, mogas isn't widely available for cross
country use. The advantages of Mogas are only talked about in forums
such as these.

Mogas users have to get this situation changed. Some day 100LL is
going to disappear by an EPA mandate & then where will we be? I feel
the 100LL users are whistling in the dark as no substitutes seem to be
forthcoming to their leaded fuel.

Both Aviation Consumer and AOPA pilot have articles on this subject in
their current issues. They both conclude that 100LL is really not
going to be going away in the foreseeable future (the EPA has delegated
the issue the FAA and the FAA is not interested in getting rid of
100LL), and they also both describe research into alternatives that is
in fact going on now.

Somehow I don't believe the oil companies are going to base their business
on what the FAA and AOPA think is going to happen.