MSefi.com read only forum (Jan.15,2018)

Since E85 is now available in my area, my motivation to convert my MS-II setup to flex fuel has increased. I'm hoping somebody has some experience with components and can tell me which parts are most likely to be damaged by the Ethanol. Here is my current fuel delivery setup:

-Steel fuel tank (aftermarket) for 1990 Chevy Blazer
-Stock braided flex hoses for same
-Steel hardlines up the frame rails for same
-Brown (Viton) O-rings on fuel fittings
-Stock-replacement type in-tank fuel pump for TPI Camaro (late 80's-early 90's)
-Braided Teflon flex lines from frame to engine (this should be fine)
-Anodized aluminum fittings from flex lines to fuel rails
-Intake manifold, FPR, fuel rails are all Camaro TPI
-Ford Racing 24 lb/hr injectors with GM (Multec) O-rings (bigger injectors will be needed, but maybe I will start mixing in some E85 with these)
-Also, I think the hose inside the sending unit is rubber fuel line.

And what kind of corrosion are we talking about? Broken in a week? Broken in 10 years? How do I know there is a problem? Do the injectors get plugged or what?

Other than the rubber in the sender, you should be fine with all your components. You should find out what type of rubber it is. The type of rubber is important. Buna-N ,( Nitrile), is a very common rubber and is compatible with E85. Stay away from any silicone rubber products though. You can purchase Buna-N O-rings through McMaster Carr online. Teflon and Viton are plastics, so E85 won't affect them. Anodizing aluminum will make it corrosion resistant, since it is basically speeding up the corrosion process into a hard, ceramic type layer ,(Aluminum Oxide).
Ethanol is a solvent, so the Ethanol in the E85 is going to clean all the scum off of the inside of your fuel tank, fuel lines, etc., and deposit it in the fuel filter, so have a few extra on hand. This too shall pass.
E85 is not terribly corrosive. Ethanol is often confused with Methanol, which is very corrosive. Also, the addition of gasoline decreases it's corroding tendencies. I leave E85 in my aluminum fuel tank, (and fuel rails), for months at a time and the only problem I have is that it evaporates through the gas cap vent, over a few weeks time.
You can test your components by soaking them in Denatured Alcohol from the hardware store and then testing them. Rubber, as mentioned before, is the biggest E85 casualty, and it will get real squishy, and gummy, if is not resistant. Most rubber products in fuel systems, however, have been upgraded to be ethanol resistant since the mid 80's. Don't forget that there is Ethanol in pump gasoline these days, during the summer.

So the aluminum fuel rails and intake manifold will be OK?

The megamanual makes it sound like all that Ethanol is a big deal, but my gut instinct is that if aluminum components won't hold up there will also be problems with the valves, heads, etc. and conversion is nearly impossible. From what I have read, the only real risk of corrosion is from fuel with water in it. How often is there appreciable water in pump E85? Is there any easy way to tell?

I ran E85 through aluminum fuel rails for a long time without any problems. Never had any issues with fuel hoses, either, using generic "fuel injection hose" from Auto Zone or NAPA.

I had to change my fuel filter because the E85 dislodged all the crud from my gas tank.

Th aluminum parts in your engine will be fine, but try not to leave fuel in the fuel rails for a long time without running the engine. You could always have them plated if you're worried about it.
Back in the old days, valves would take a beating if you didn't have lead in your gas. Today's modern vehicles have superior valve and valve seat materials that do not require lead. These same valves will not be affected by E85, which is 20%,(or more), gasoline. Remember that the Model T was originally designed to run on pure Ethanol, not gasoline. Gasoline came along shortly after the Model T, and the whole world changed. The flex fuel vehicles you can buy today have the exact same engine as the non flex fuel vehicles. The difference is the ECU and the flex fuel sensor, (fuel composition sensor).
Water in E85 will stay emulsified into solution with ethanol as it readily mixes. The quality of your fuel is regulated just like any other fuel, (which is not very well). I read about a "shake test" that could be performed with Ethanol. Basically you put some in a clear test tube and shake the heck out of it, then watch as it settles, looking for small bubbles. You could use a Hydrometer too, but that will only show the amount of Ethanol in the mix, not how much of the remaining is water and/or gasoline. You could always run it through a water separation filter, kinda like diesel engines have inline. In my limited experience, water has not been much of a consideration. It's the ratio of Ethanol to gasoline that I concern myself with since this changes from station to station and time of year.