donaziza

donaziza

Well Known Member
Hey guys, like to ask a question. I'm laid up for a while, ie, can't fly. Every two weeks, I go run up my engine and because I have oil cooler shutters I can close, am able to get the oil temp up to 220* or so ( to get the water out ) Anyway, since I'm not flying, when I sump the fuel tanks, every two weeks, the 100LL fuel may be very dark blue, light blue, or you can actually see the dye spreading from the top of the fuel sump test tube to the bottom.

My question is: is this safe fuel to take off with?:eek: I'm assuming yes, but there are a lot of guys out there who know better than me.
 
It has been my experience the the fuel is beginning to deteriorate. It will eventually deteriorate to a point where it will turn to a white color and also not burn. I've had this happen more than once with avgas that I have had stored. Different batches have deteriorated at different amounts of time so beware.
 
A couple of pilots up here in the Northwest have noticed variations in blue dyes recently as well. I'm not sure when the dye is added, but my best guess is that it's a manual process and that there's variability in the amount added depending on who does it and how. All of the fuels we've seen, heavy dye or light, have burned just fine.

Aside: In order to "boil off the water" in your oil, you have to get the engine to operating temperatures, and keep it there for at least half an hour, before shutting it down. Just getting the oil to 220 and then shutting down will not do it. The repeated heating/cooling cycles will create *more* nasty things in the oil that don't get cleaned out in a ground run.
 
Do you have someone that can go fly it for you? Otherwise if you're going to be out for a while I would seriously think about having the engine pickled.
 
Really not good to run the engine on the ground. The baffles are designed to cool the engine in flight. Running on the ground does not cool the engine evenly. If you can't fly, it's better to leave the engine alone. Do not start and do not rotate the crankshaft.
 
To both Snowflake and Sig 600:

Snowflake, Thanks for your cautions. I was aware that one needs to "fly" their aircraft for a good half hour with the oil at operating temps to clean everything out. I "am" able to get the oil up above 180* in about 15 minutes, run the engine about half an hour, to 40 minutes, with the last 10 minutes or so at the 220*. I knew this wasn't as good as flying it, but I figured it was the lesser of two evils. Last flew the plane April 1st. Was supposed to be all healed by mid May, but the healing decided not to heal.

Sig 600, I thought about pickling, but as I said above, I thought I'd be flying by now. Now I'm looking at mid August to Sept. at the earliest. I had thought about someone else flying it, and just "maybe", I might know a local RV 8 guy who would do it-----since all of this is taking a lot longer that planned.

What do both of you guys think? Short of pickling or flying, with the info above, is what I'm doing indeed the lesser of two evils?:confused:
 
Mel said:
Really not good to run the engine on the ground. The baffles are designed to cool the engine in flight. Running on the ground does not cool the engine evenly. If you can't fly, it's better to leave the engine alone. Do not start and do not rotate the crankshaft.
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Thanks Mel
 
Agree with Mel

Better to do nothing with your engine at all unless you are putting it into long term storage. Steve

Slightly off topic but... While flying in Mexico I filled with Mexican 100LL. It did not have the unique smell that U.S. 100LL has but still had the blue dye in it. Smelled just like car fuel. Anyone else have any experience with this?

Steve
 
Look up AeroShell Fluid 2F. Basically mineral 100 with a bunch of corrosion inhibiting additives for engine storage.
 
donaziza said:
What do both of you guys think? Short of pickling or flying, with the info above, is what I'm doing indeed the lesser of two evils?:confused:
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I concede that what you're doing is better than what most pilots do (start up, run for 10 minutes, shut down), but it only deals with some of the moisture in the oil. It also adds startup/shutdown cycles to your engine with no operational benefit (you don't get to fly), runs your engine in a less optimal cooling environment, and bears a nonsignificant amount of risk of something going wrong while you're sitting still on the ground at high power settings. Brake failure? Stray pedestrian? Stray animal?

From a cooling perspective, as Mel says, and hence for the engine overall, you're better off just not running it and leaving it parked. Motorcycle engines in many parts of the world sit idle for 6-8 months of the year without pickling and without ill effect. Yours would sit fine for the same period while you get better.
 
Snowflake said:
I concede that what you're doing is better than what most pilots do (start up, run for 10 minutes, shut down), but it only deals with some of the moisture in the oil. It also adds startup/shutdown cycles to your engine with no operational benefit (you don't get to fly), runs your engine in a less optimal cooling environment, and bears a nonsignificant amount of risk of something going wrong while you're sitting still on the ground at high power settings. Brake failure? Stray pedestrian? Stray animal?

From a cooling perspective, as Mel says, and hence for the engine overall, you're better off just not running it and leaving it parked. Motorcycle engines in many parts of the world sit idle for 6-8 months of the year without pickling and without ill effect. Yours would sit fine for the same period while you get better.
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OK Snowflake, I will take yours and Mel's advice and "not" run it. I'm not a mechanic, thus why I asked for help here. Thanks to both of you guys.
 
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