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Old 11-25-2020, 07:58 PM
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sastanley sastanley is offline
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Quote:
Originally Posted by joe_db View Post
Avgas most definitely has lead in it. Besides for being 100 octane it is formulated on the assumption it will be sitting around a while before being burned.
Airports USED to have 2 grades, 80 and 100. The 80 octane that had little lead or maybe none. That got discontinued and now 100LL is all there is. "Low Lead" is only in contrast to the old 100/130 or 115/145 octane fuel, it has a LOT of lead in it.
This really sucks for low compression airplanes designed to run on 80 octane.For a while we could run car gas, but then ethanol killed that off and now we have to use 100LL and then add TCP to the gas to prevent lead fouling of spark plugs and sticky valves. TCP is quite toxic, I am always careful handing it.
So the moral of the story is I have to use one toxic chemical to fight the effects of another one because someone had the bright idea to subsidize Big Ag and require corn in gasoline
Joe, I am almost 50, so my first car was a 78 Civic with no catalytic converter and ran leaded gas. When I was driving it in the late 80's, I used to buy the STP lead substitute. My understanding was pre-catalytic (including the A-4) liked the lead to lube the valves and valve stems. I am just asking for clarification on your post. Did the lower octane (for lower compression engines) not have much lead in them, and was it enough for aircraft engines or motors like the A4? Why would they put more lead in the 100 octane fuel?
I was always using a little MMO as my 'lead substitute', until this year when I took Dave Neptune's advice and started adding synthetic 2-stroke oil at about 100:1. That is a guess. I bloop a little bit down the tube before I dump in 5 gallons 87-90 octane E-zero (the octane rating depends on the source.)
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Last edited by sastanley; 11-25-2020 at 08:01 PM.
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