MoGas Tips, Tricks, Concerns, How To

("M" wrote)
So you point is that lead scavenging agent isn't needed because there's
not that much lead in the 100LL?


My curiosity was: What quantity (by weight) of lead is in 100 gallons of
100LL?

I picked 100 gallons because I didn't want some small fraction. As it turns
out, 2 grams/gallon is not a small fraction.

I used the term "actual lead" because I wanted to know the amount of lead
left behind if "everything" else were to be distilled away.

My side point was: Lead = "ATTACK!" to the Greens ...1 gram, 2 grams, 15
grams, 0.14 grams, doesn't matter to them - it's LEAD!!!

[Thanks to Jim L]
From http://en.wikipedia.org/wiki/Avgas :
"Avgas 100LL contains a maximum of 2 grams of lead per US gallon"

1,000 grams (kilo) = 2.2 lbs
500 gallons of 100LL = 2.2 lbs of lead.

Now the world make sense to me.


Montblack
"Hello, Thielert..."

http://www.dieselair.com/
Diesel updates for airplanes

I see. My point on the other hand has nothing to do with the lack of
greeness of 100LL. My point is that the bromine in the lead scavenging
agent is corrosive to the engine after the combustian event. We live
with it because the high compression engine needs it to get rid of the
lead. But for 1:7 compression engines this corrosive compound is an
entirely unnecessary evil because the engine doesn't need the extra
octane from TEL. By getting rid of TEL we get rid of bromine in the
engine (lead bromide reacts with water to form hydrobromide acid). Too
bad mogas is the only unleaded fuel we can get for our LC engines at
this point.

("M" wrote)
Too bad mogas is the only unleaded fuel we can get for our LC engines at
this point.


What would your unleaded fuel of choice be?

How would it be different than MoGas?

Um, hydrogen? propane? 100% ethanol?


Montblack

An unleaded aviation fuel with the same quality control and tracking as
100LL would be ideal. Unfortunatley that's not going to happen anytime
soon. For the time being I'll just keep doing my own alcohol test and
filling up with mogas.

1 The octane measurement is an attempt to quantify a fuels propensity for
detonation or pre combustion. Higher octane means less propensity.
2 Precombustion and detonation are usually caused by, among other things,
engine overheating, and hot spots.
3 Precombustion and detonation can lead to further increases in CHT.
4 Precombustion and detonation can damage an engine.
5 High CHTs can damage an engine.

Let me know which of the above statements you disagree with, and I will find
a reference for it.
I stand by my statement that an overheated engine will be more damaged if it
is running lower octane fuel.

"Jay Honeck" wrote in message
oups.com...
I also agree with posters that claim that mogas can lead to early engine
wear. The fuels may be equivalent under normal circumstances, but if the
engine overheats, the low octane fuel will do a lot more damage than the
high octane fuel.

That is simply not true. Perpetuating a myth like that in this forum
is not productive.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

Perhaps a more useful comparison would be how much
lead is/was in 80/87 vs 100LL?

Those of use with older, low compression engines that were designed
to run on 80/87 may be introducing 4 times the amount of lead into our
combustion chambers by running 100LL than the original designers had
intended for.

80/87 has a maximum of 0.5 grams of lead per US gallon while 100LL has
a maximum of 2.0 grams of lead per US gallon. Unleaded Mogas is...
well... Unleaded!

In reading about this somewhere (AvWeb? EAA?) I recall words to the
effect that the refineries can get up to about 97 octane without any
lead, and they only add as much in to get to (or slightly exceed) the
100 octane rating.

I have the EAA Mogas STC for my C-170B, and the paperwork states if
you mix a certain amount of 100LL with unleaded Mogas (25% to 75%),
you get approximately the same amount of lead as you would have had
with a tank-full of 80/87.

For what it's worth, my O-300 absolutely *hates* straight 100LL (way
too much lead). Aggressive leaning, both on the ground and in the
air, can extend the time between fouled pugs and stuck valves, but
both are virtually inevitable without a lead scavenging agent (like
TCP) or using Marvel Mystery Oil, etc.

I burn Mogas on local flights and when/where I can get it on cross
country flights. When I have to fuel up with straight 100LL, I add
TCP.

Not only is the Mogas cheaper, I no longer have to worry about
fouled plugs and stuck valves! (aka a "no-brainer"). 8^)

Bela P. Havasreti

Let me know which of the above statements you disagree with, and I will find
a reference for it.
I stand by my statement that an overheated engine will be more damaged if it
is running lower octane fuel.

None of your statements are incorrect, they are merely irrelevant.

Low-compression aircraft engines were designed to run on 80 octane
fuel. Running fuel of higher octane is not going to hurt anything --
but it won't help, either.

87 octane auto gas is perfect for our low compression engines, and
certainly won't hurt them. Using "premium" (or, for that matter, 100
LL) is neither necessary nor recommended.

(Note: SOME mogas STCs do require using a higher octane car gas, but
those are the exception, not the rule.)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

I wonder about the effect of LOP on muffler life. I used just the
low-power-operate-at-peak philosophy and my 172 went thru the muffler
internal flame tubes every 450 hrs, like it could read the hour meter.

As posted before, the head honcho at Dawley Aviation (the exhaust
system folks in Burlington, WI) told me personally that running lean of
peak has been the best thing that EVER happened to their business.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

"nrp" wrote in message
ups.com...
Collins 172 engine was same as mine. Lyc O-320E2D low compression.
Only mine has been fed a minimum lead diet to get 1700 hrs TT & 30
years since new (i. e. no OH!).

And as stated elsewhere, the LOP procedure doesn't work with the crappy
fuel/air distribution systems in HO engines with carburation or FI.

Interesting RC attitudes on the GAMI observations. I think he was very
aggressive in leaning his 172 to the point of roughness - and he got
plenty of that thru the years he had it. At the time though his 172
problems sure scared hell out of us & our (then) new bird. His is
history. We still have ours.

I'm coming up on 1500 hours in mine which has been run 60LOP for five years.
That has been all 100LL. The last annual/maint showed virtually pristine
cylinders and plugs.

If someone has the right fuel availability/engine combination, then hell
yes, use Mogas. 100LL here is $4.15 a gallon and that's pricy, so using
Mogas would be "more better", but not with my engine.

The issue with Collins and the article he wrote was the situation with his
P210, not his Skyhawk. Like so many others, he jumped in without learning
the method. It was shear blockheadedness.

wrote in message
...
On Thu, 11 May 2006 10:08:01 -0700, "Matt Barrow"
wrote:


"Jay Honeck" wrote in message
groups.com...
Geez Jay, better get yourself educated on leaning. Leaning properly on
the ground means way, way lean of peak which by definition is downright
cold EGT's although on the ground at low power there's no such thing as
high EGT.

Welcome to 1952, where you have to move levers on the panel in order to
make your plane run properly while on the ground. And you say MOGAS is
bad? Strange how I have to do none of that, when I run with mogas.
The engine just purrs like a kitten, without any input from me at all.

Nice change of subject when caught with your pants down.


curious who was right there to jump on, also.

Umm...the original poster?