Not to throw more "fuel" on the fire, but is it possible that the large change in the general atmospheric conditions Jeff is flying could contribute to a change in"behavior" of the fuel? I.e. much higher humidity, etc...
It probably won't change how I fuel my plane, but it would be interesting to know if atmospheric conditions can significantly affect fuel that is sitting around for extended periods in our tanks...vs. relatively stable conditions in underground storage tanks. I am referring to behavior other than just condensation or evaporation, though either of those could change the percentage of any added compounds over an extended period of time. TJ -------------------------------------------- On Sun, 8/12/18, Mike Stirewalt via KRnet <[email protected]> wrote: Subject: KR> Mogas Blues To: [email protected] Cc: [email protected] Date: Sunday, August 12, 2018, 1:01 PM Based on several of the comments on this subject, some guys are missing the point of Jeff Scot's account of his gas problems. It wasn't the ethanol that damaged his fuel system components, it was something else . . . some additive(s). Jeff York makes the point that such extensive damage had to have started at some point prior to Jeff Scott's arrival in Arkansas. Since Jeff has been using his mogas/avgas mixture for many years in Los Alamos without problems, a mystery still lies at the bottom of this situation if the information Jeff York provided is accurate - that is, if the damage was cumulative, starting well before Jeff Scot left Los Alamos. I don't think so. Jeff would have noticed it. Reading the situation as it happened, Jeff Scot's fuel rig on his truck, along with the damage to tanks and tank fittings on the Cub, all happened abruptly. I would conclude it was a result of gas bought in Arkansas with some new and strange additive that is aggressively corrosive. So far it seems there's been no damage to Jeff's KR, with the same fuel. This could be that it just hasn't had time to do it's nasty work - or that the fuel tank and components in his KR are resistant to this particular mysterious additive blended into Arkansas fuel. I'd not be surprised to learn that Jeff has drained and flushed his fuel system on the KR. Jeff Scot makes the point that the lead in 100LL can cause deposits on valve stems thus causing premature wear to the guides. When I had my heads off of the GP2180, I had slight discoloration on the valve stems closest to the face. There was discoloration (a light film that came right off) also within the valve guides near the face. I threw the valves away, however I have a picture of an old valve together with a new valve and I'll attach it to this post. You'll see no accumulation of lead on the old valve. I didn't clean it up. I did clean the guides with a narrow stiff brush and they not only looked new once I'd done this, there was no play in the guide when inserting the new valve stem. In other words, I didn't have any lead build up. I had no idea 100LL had half a gram of lead in every liter. That's a hell of a lot of lead. Running lean as I do, the lead has not caused a problem with my guides despite the very high lead content of the fuel. With that much lead in the fuel, I think next time I have the engine apart I'll bump the compression ratio up from 8 to maybe 11 or 12 :-) Might as well take advantage of such great anti-detonation protection. Jeff Scot does not agree with the idea that lead acts as a lubricant as some old timers say. I tended to agree with that idea - that lead is slippery and protective. I tend now to believe what Jeff has told me about lead since he knows what he's talking about as opposed to the opinions of old timers at the hangar who base their opinions on experience and rumor and the collective wisdom of the mob and, by no means, in any case, is everyone in agreement. As it happened, my engine had suffered no accumulations of lead and the guides looked amazingly new after 500 hours, showing no wear. None. The reason for that was due to using elephant feet on the rocker arms and because I run the engine very lean at full throttle, except for takeoff and climb and, in the winter, I even lean it in the climb. Anyway, all I started this out to say was Jeff's problem has nothing to do with octane. It has to do with something strange in the mogas in Arkansas and wherever else this mysterious substance is blended into the car gas. I'll put whatever Chevron Supreme I have at the hangar in my car and even though my use of mogas has been slight, I won't be using it at all in my VW - even though the VW is originally a car engine. I have a primer, two fuel pumps, fuel valves, fuel lines, fuel filters, an Ellison carb, a fuel pressure gauge, hoses connecting all this, etc. I've never had a problem with any of these components using avgas so I'll continue to do so. I don't think they blend additives with avgas. Aviation engine manufacturers design their engines based upon the use of a fuel that doesn't bounce around with different blends compensating for the seasons. Plus, I seem to get more power out of the engine with avgas. It might be my imagination, but probably not. When I'm in the midwest buying gas for the car at those stations that sell only gas with ethanol, my mileage drops. There is less energy in gas with ethanol than in gas without it. I think it's just a matter of degree when it comes to ethanol in car gas. Premium gas probably has less ethanol than lower grades, but I suspect all gas has ethanol in it these days. I think it's something mandated by Congress to subsidize the farmers who produce it. The Chevron guy told me that on the phone if I'm remembering correctly. Mike KSEE ____________________________________________________________ 'Genius' Pill - Top 1% Didn't Want The Public To Know About The Brain Insider http://thirdpartyoffers.juno.com/TGL3141/5b707651ec20376515721st04vuc_______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/[email protected]/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. To UNsubscribe from KRnet, send a message to [email protected] -----Inline Attachment Follows----- _______________________________________________ Search the KRnet Archives at https://www.mail-archive.com/[email protected]/. Please see LIST RULES and KRnet info at http://www.krnet.org/info.html. see http://list.krnet.org/mailman/listinfo/krnet_list.krnet.org to change options. 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