E85 By-product "Gum"

[Narva*2010Participant Narva*2010VC Commodore View build HERE Member since: March 5, 2015 Posts: 87]

Good morning,

I thought I’d share this with the guys running E85.  Might just be a problem particular to a servo near me, but it’s pissed me off.

It’s nothing new, but it’s new to me so if I can help anyone else with preventing this issue happening to them that would be good.  Bottom line I guess, is go to a servo with high E85 turn over and use an additive.  Lucas do one to prevent gumming.

Anyhow, look at the top of the inlet valve, second picture and you will see all the sticky shit on top of the valve.  Was flow tested, down 150hp due to the gum obstructing air flow and preventing propper cylinder fill.

 

Sorry could  only get the main one in

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

Wow, have to say the more I have to do with “pump” E85 the less I like it.  Just seems very variable on quality and make up.

• This reply was modified 9 years, 8 months ago by  VRSenator065.

[cava454Moderator 93 VR BT1 View build HERE Member since: February 20, 2015 Posts: 2 390]

Why the addictive?

 

got plenty mates running it with 0 issues?

[vs manta 218Participant Vs hsv manta View build HERE Member since: March 2, 2015 Posts: 796]

How many km has this done ??

And how long of time has it been since heads last come off

 

did you notice it was down on power to remove the heads and have a look ??

[vs manta 218Participant Vs hsv manta View build HERE Member since: March 2, 2015 Posts: 796]

i found this on a dodge forum and seams very good info

 

 

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 <span style=”background-color: transparent; border: 0px; margin: 0px; outline: 0px; padding: 0px; background-position: initial initial; background-repeat: initial initial;”>fuel </span><span style=”background-color: transparent; border: 0px; margin: 0px; outline: 0px; padding: 0px; background-position: initial initial; background-repeat: initial initial;”>tanks</span>, 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.
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Well, here is what I did just so everyone is clear. I filled a <span style=”background-color: transparent; border: 0px; margin: 0px; outline: 0px; padding: 0px; background-position: initial initial; background-repeat: initial initial;”>40mL</span> vial with E85 and blew it dry with nitrogen gas and mild heating (about 150*F). After there was no fuel left, I placed it under high vacuum to remove any remaining volatiles for about an hour. I was left with a clear sticky residue that smelled bad – like nasty frying oil. I dissolved this sample in the NMR solvent and analyzed it and it IS the same goo that was on the injector. There was smaller amounts of some other stuff in it as well, but the same peaks I saw in the black goo were in this residue. The black goo IS coming from the E85. It isn’t naturally black, though. I suspect it just has soot mixed in with it that is giving it the color.

So the next challenge is figuring out why is this crap in our fuel, and if it is in everyone’s fuel (particularly people who aren’t having this problem).
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Gum in E85!

——————————————————————————–

Ok, it isn’t chewing gum, of course. I think gum is a generic term for high MW sticky solids. Anyway, if you look at table 1 in this article, it mentions that there is up to 5mg of “solvent-washed gum content”/100mL and up to 20mg “unwashed gum content”/100mL. It think this might be what is sticking to our injectors.

Later in the article it also mentions that mixing E85 and pump gas WILL cause additives to crash out and stick to the injectors and intake runners. I don’t think this is what we are seeing since I saw the molecule in a clean sample of E85, but it does open that possibility for others who are mixing.

(link to doc that didn’t work)
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So I’m in a brief meeting intermission, but I really am convinced that this stuff is the “gum” mentioned in that article. I found another paper that defined the gum as the residue left after evaporation of the fuel. I’m going to see if I can get ahold of the author of that paper and see if I can figure out exactly what the “gum” is to verify that this is what we are seeing.
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Thiazole, I think have a lead on an exact chemical name to follow up on in solving this mystery. Read the following:

“Overuse of additives with E85 may result in poor vehicle operation. RFA has also made certain recommendations about appropriate detergent treatment of E85. Some detergents, such as polyisobutylene amine, have performed poorly in FFV operation. At some blend levels, these additives may precipitate out of the blend resulting in excessive fuel system deposition.”

This info was taken from a pdf I found while researching for a graduate project on E85 I am currently doing,http://www.afdc.energy.gov/afdc/pdfs/41853.pdf

So polyisobutylene amine might be the gum that is precipitating and this is a straight up fuel quality issue and not a fuel environment based one…
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It wouldn’t surprise me if gasoline evaporates faster than ethanol in which case you could see this stuff crash out (since it isn’t soluble in ethanol). I doubt it happens in the gas tank, though, or the entire fuel system would be covered in this gunk, which I haven’t seen. What probably happens is after turning the engine off, whatever E85 is left on the tips of the injectors and in the intake manifold evaporates off leaving behind this gum. After doing this several times, you get a significant amount of gum formation.
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It is dissolved in the E85, but just barely so that it readily crashes out at the injector tip. You can’t filter it. It would be like filtering out hard water to remove hard water stains. It can’t be done until after it crashes out, but by then it is too late.

You wouldn’t want to filter this out even if you could, anyway. The E85 I’m buying has about 10mg of this gum/100mL which means it has about 6000mg per tank. The amount of gum required to clog up an injector is probably only 20mg. The amount to clog a <span style=”background-color: transparent; border: 0px; margin: 0px; outline: 0px; padding: 0px; background-position: initial initial; background-repeat: initial initial;”>fuel </span><span style=”background-color: transparent; border: 0px; margin: 0px; outline: 0px; padding: 0px; background-position: initial initial; background-repeat: initial initial;”>filter</span> would probably be about 1000mg or less. If you could filter it, you’d be clogging several filters per tank. When we scale up the synthesis of a drug, if there is an intermediate that forms a gum and requires filtration, it can actually kill that synthesis and send us back to the drawing board. Gums SUCK and there really aren’t many good ways to deal with them other than just dissolving them away.
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Q from someone: I was just thinking that if the gum is a component of the gas that’s added to the ethanol to make the E85 (the other 15% that’s not ethanol) then adding a little more gas that is more highly refined might push the cross over point far enough that we’d never see it… ?
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Yes – I suspect that when they add the gasoline to the ethanol that the gum is at or very near the saturation point. If you consider that 10 gallons of E85 only has 1.5 gallons of gasoline in it, adding another 1.5 gallons of non-gum containing gasoline like racing gas would decrease the relative concentration of the gum to gasoline by 50% away from saturation. I think this alone would make a big difference and be pretty affordable if it works

[vs manta 218Participant Vs hsv manta View build HERE Member since: March 2, 2015 Posts: 796]

And a link to the 500+ post thread i got it from

 

http://www.srtforums.com/forums/f187/ok-now-let-s-talk-about-downsides-e85-602323/

[DarrenParticipant Toowoomba Qld82 VH SS Commodore 89 Yamaha FZR1000 View build HERE Member since: March 4, 2015 Posts: 33]

wow… that’s a worry
I’d also be looking at your injectors (if you are running EFI)

[Narva*2010Participant Narva*2010VC Commodore View build HERE Member since: March 5, 2015 Posts: 87]

Morning,

Engine had done maybe 3,000km.  Half on PULP, the other 1500 on E85.  I noticed when swapping out a Come Manifold to a TP ProPaw.  Then engine out to put a bigger cam, up comp and change ring pack.

Didn’t realise it was down too much on power.  10.8 @ 125 on PULP vs 10.7 @ 126 on E85. It should’ve gone better on the E85 than it did, but it’s hard to test power on street, esp in 1st and 2nd.  Did a few dyno’s but always had ignition issues.  But yes, I did think it didn’t seem to go as hard as it first did.

It’s carby.  I reckon if injected, it wouldv’ve packed it in by now.

The additive is like a fuel conditioner supposed to lubricate pump, prevent corrosion associated with E 85 and has inhibitors that prevent the formation of Gums and Varnish.

Just out of courtisy, letting you know I have put this on another forum. (Sorry Gary) I’m looking for feed back from Melbourne lads as to where they fuel up and if they’ve had any issues.  As I said, I’m suspect on one of the servos here.  You get told when changing to E85, flush everything, the ethanol will pick up all the shit in your tank and put it through you engine… I think the boys at this servo used an old tank to put their E85 in…

[cava454Moderator 93 VR BT1 View build HERE Member since: February 20, 2015 Posts: 2 390]

Where bouts u from mate?

[Narva*2010Participant Narva*2010VC Commodore View build HERE Member since: March 5, 2015 Posts: 87]

Over the Westgate mate, Altona. I fuel up in Hoppers Crossing and Point Cook. We have heaps of E85 out this way, but I reckon I’ll stick to the Westgate Bridge United.

[VRSenator065Participant Adelaide SAVR Senator LSx454 1960 Kombi (project) 1921 Nash Hot Rod (future project) View build HERE Member since: February 17, 2015 Posts: 5 777]

No issues posting stuff on other forums mate at all, no forum Nazi’s here :)  Yea Jake @ Bain racing also recommended to me the fuel additive you are talking about with the E85.  To me the issue is you don’t really know exactly what you’re getting from “pump” E85.  Different altogether buying in drums.  I reckon if I were running the numbers you are maybe you buy ELF E85?

[cava454Moderator 93 VR BT1 View build HERE Member since: February 20, 2015 Posts: 2 390]

Ahh k. Lucky you. Non on my side of town that’s close to me. :(

[pir4teParticipant Mallala640 HP hyper-cruising SS-V Flagonwagon View build HERE Member since: March 2, 2015 Posts: 154]

Hi mate, saw this on Aussie V8s earlier tonight, if you are using United e85 it’s probably not a long term residue. Notify and change the supplier.
I’ve run flex exclusively for five years, 180k km which is close to 20,000 litres of ethanol and never had this issue on close inspection. Quite the opposite.
It may be the pump / tank at the petrol station, given you are 100% certain your car’s entire ethanol supply system is compatible.
I read that U.S. corn-derived ethanol can leave a gum residue, but not United’s Sorghum distillery out at Dalby. So I think is the retail supplier.

Naturally as-pirated, all-motor.

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