View Poll Results: Answer these questions about your PCV if you run E85
Voters: 23. You may not vote on this poll
Possible Ethanol Gunk Explanation
Evolved Member
Joined: May 2008
Posts: 697
Likes: 1
From: Mitchigan
Thiazole, the chemist on codsm
Explanation in other words from another poster on codsm
Alright, I finished my analysis of this stuff, and my finding is very unexpected. I think it will
probably surprise everyone else as well. This doesn't appear to be forming because ethanol
is "such a good solvent" but because ethanol is a poor solvent. I suppose it should have
been obvious when others said that it "washes right off with gasoline". Why would
something that ethanol is selectively dissolving wash off with gasoline? If this were
something in rubber or from our fuel tanks, wouldn't that imply that gasoline would dissolve it even more readily than E85? Alright, so what is this stuff? It is a appears to be a very large petroleum based
hydrocarbon, similar to Vaseline. There isn't a single hetero-atom in the molecule (ie, the
entire molecule is comprised of hydrogens and carbons), but the molecule is very large. It is
also completely aliphatic (ie, only single bonds in the structure - no double or triple bonds).
Where did it come from? I can only think of two different sources it could be coming from.
It is either something that is mixed in with the rubber hoses that is meant to dissolve away in the gasoline, or it is a trace impurity in the 15% gasoline that is in E85 that wasn't
separated during the fractional distillation process. Because it is such a large molecule, it
wouldn't be very soluble in ethanol and could easily crash out of solution at the injector.
probably surprise everyone else as well. This doesn't appear to be forming because ethanol
is "such a good solvent" but because ethanol is a poor solvent. I suppose it should have
been obvious when others said that it "washes right off with gasoline". Why would
something that ethanol is selectively dissolving wash off with gasoline? If this were
something in rubber or from our fuel tanks, wouldn't that imply that gasoline would dissolve it even more readily than E85? Alright, so what is this stuff? It is a appears to be a very large petroleum based
hydrocarbon, similar to Vaseline. There isn't a single hetero-atom in the molecule (ie, the
entire molecule is comprised of hydrogens and carbons), but the molecule is very large. It is
also completely aliphatic (ie, only single bonds in the structure - no double or triple bonds).
Where did it come from? I can only think of two different sources it could be coming from.
It is either something that is mixed in with the rubber hoses that is meant to dissolve away in the gasoline, or it is a trace impurity in the 15% gasoline that is in E85 that wasn't
separated during the fractional distillation process. Because it is such a large molecule, it
wouldn't be very soluble in ethanol and could easily crash out of solution at the injector.
So, let me see if I can wrap my decidedly non-chemist brain around this: This "very large petroleum based hydrocarbon", or vlpbh , is able to be completely dissolved into gasoline, essentially becomes part of that fuel, and is burned up in
combustion, never to be seen again except broken down as part of the exhaust gasses out
the tailpipe. However, with ethanol, the vlpbh is more or less "dislodged" from the rubber or
distilled petroleum, and is carried by the ethanol as a separate particulate of sorts, perhaps
partially burning during combustion (that which makes it into the cylinders), and definitely
being deposited on the injectors, valves, runners, etc.?
combustion, never to be seen again except broken down as part of the exhaust gasses out
the tailpipe. However, with ethanol, the vlpbh is more or less "dislodged" from the rubber or
distilled petroleum, and is carried by the ethanol as a separate particulate of sorts, perhaps
partially burning during combustion (that which makes it into the cylinders), and definitely
being deposited on the injectors, valves, runners, etc.?
That was a very interesting read. I read the whole thing and Thiazole said he was "liaison to an ethanol plant executive and have been asked to help their chemists figure out what this stuff is." That was 9-14-2009. Nothing from him posted on the that thread after that.
Where is the OP because I'd like to know why the poll involves PCV because that is the last thing that has to do with this at least in my experience.
I still stand by my theory of it has solely to do with the station the e85 comes from, explains exactly why mellon only had the problem after he purchased it from a station he didn't in the past.
Evolved Member
Joined: May 2010
Posts: 500
Likes: 4
From: Australia
It happens over here with our Australian E85 too. Some people get it some dont. Whatever it is the companies either have no idea what it is or how to prevent it (encouraging for a bunch of fuel chemists )or have no regard for peoples vehicles. It can build up so fast (within 1000kms) and results of clogged injectors can be catastrophic to the engine.
)or have no regard for peoples vehicles. It can build up so fast (within 1000kms) and results of clogged injectors can be catastrophic to the engine.
Seems real solid then!
Where is the OP because I'd like to know why the poll involves PCV because that is the last thing that has to do with this at least in my experience.
I still stand by my theory of it has solely to do with the station the e85 comes from, explains exactly why mellon only had the problem after he purchased it from a station he didn't in the past.
Where is the OP because I'd like to know why the poll involves PCV because that is the last thing that has to do with this at least in my experience.
I still stand by my theory of it has solely to do with the station the e85 comes from, explains exactly why mellon only had the problem after he purchased it from a station he didn't in the past.
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