Orvilfox --
First a disclaimer: I'm not an AME or A&P but only a lowly pilot with
lots of engine management experience. I'd seek out a knowledgeable
A&P on the topic -- and there are a couple of recommended sources of
information at the end of this answer.
Both fuel and lubricants are very specific to engines, as indicated
your own experience with auto gas additives. Also, by the question
whether or not there is a catalytic converter on your engine?
Catalytic converters are easily damaged by lead:
Toyota Motor Sales
"Emission Sub-systems" (undated)
http://www.autoshop101.com/forms/h64.pdf
Even more sensitive are oils, which contain additives to protect
specific types of metals found in aircraft (or auto) engines.
Aviation Today
"Piston Lube Principles"
http://www.aviationtoday.com/cgi/am/show_mag.cgi?pub=am&mon=1200&file=1200piston.htm
---
Terry Edwards, who does hold a Canadian A&P, wrote an excellent
article for Kitplanes Magazine on the differences between auto engines
and aircraft engines -- and what's likely to be an issue with 100LL
Avgas. The article includes a chart with vapor pressure, lead,
sulfur, gum and octane differences that will be useful in your
technical discussioins with others:
Kitplanes Magazine
"Auto Engines for Airplanes" (Edwards, August 2001)
http://www.kitplanes.com/features/content/AutoEngines2.htm
The major difference, of course, is the presence of lead in Avgas at
levels 100 times higher than in "lead free" formulas for cars.
Edwards notes "However, on lower-compression engines that do not need
the octane rating, the lead content can cause lead fouling and erosion
of spark plugs, valve erosion, and valve and ring sticking."
Beyond those considerations, the prime question that I would seek
counsel on from an A&P is: will the auto engine be more susceptible to
icing, given the different vapor pressures?
But others have put engines on the market designed to run both mogas
and Avgas, including the CAM100 from Firewall Foreward, an engine
modifier:
SportFlight.com
"Kitfox Engines"
http://www.sportflight.com/kfb/engines.htm
And lots of work is being done by Honda and Toyota (quietly) to adapt
auto engines to aircraft use:
PrimeMover.org
"Aviation and Engines Home Page" (Travis, undated)
http://www.prime-mover.org/Engines/GArticles/article2.html
Finally, you might be interested in the perspective of a racing
person. He notes the differences in weight, which though slight will
effect your gross weight and possibly the aircraft's center-of-gravity
(CG):
Osborn's Automotive
"Racing Gasoline Verses Aviation Gasoline" (Wusz, Nov. 16, 1995)
http://www.osbornauto.com/racing/race2avgas.htm
---
Finally, some good resources on the issue would be the Experimental
Aircraft Association (EAA) or Aircraft Owners' & Pilots Association
(AOPA), if you're a member of either. Both have telephone help lines
for members that I've found useful.
EAA
http://www.eaa.org/
AOPA
http://www.aopa.org/
In the case of the EAA, some of the best technical information is
often right at your back door, in local chapters:
EAA
"Welcome to EAA Chapters"
http://www.eaa.org/chapters/default.asp
Google search strategy:
Avgas + "auto engines"
"catalytic converter" + lead
Best regards,
Omnivorous-GA |
