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Wed Jan 29, 2025 7:57 pm

ok, so i know theres a bunch of threads on this subject but a lot are fairly old so i thought id start a new one and see if theres any changes to things and maybe new perspectives too.
Years ago when the automotive industry switched from R12 Freon to 134 everyone was freaking out and they said you had to change all the O rings, compressor, and really about the whole system in order to run 134 in a R12 system. Not too many years later you could change out the filter and add adapters for the fittings and you were good to go. So on that note i wondered if the rubber fuel lines ( along with other parts ) can handle E85 better now than 10 years ago?

How do carb floats hold up to E85?

Can a stock vw fuel pump handle it?

And just generally, what’d you all do when you switched to E85?

Wed Jan 29, 2025 8:47 pm

No carb here, but I have Teflon lines and no rubber in the system at all. Also my tank was coated on the inside with one of those diy 3 part processes. The car sat with fuel in it for 5 years. When I finally brought it back to life. It fired right up and burned 4 gallons or more of that old e85 without issue. No clogged filters, tank looks great.

Even 10% ethanol seems to kill the classic cloth braided fuel lines in short order these days. I can only imagine how fast e85 would do it.

I don't think rubber has gotten better in the last decade. Look at tires. 5 years is about all you'll get out of a set before the sidewalls are rotting out of them. Yet you can go find a set from the early 90s that still look decent.

Wed Jan 29, 2025 10:14 pm

Chip wrote: No carb here, but I have Teflon lines and no rubber in the system at all. Also my tank was coated on the inside with one of those diy 3 part processes. The car sat with fuel in it for 5 years. When I finally brought it back to life. It fired right up and burned 4 gallons or more of that old e85 without issue. No clogged filters, tank looks great.

Even 10% ethanol seems to kill the classic cloth braided fuel lines in short order these days. I can only imagine how fast e85 would do it.

I don't think rubber has gotten better in the last decade. Look at tires. 5 years is about all you'll get out of a set before the sidewalls are rotting out of them. Yet you can go find a set from the early 90s that still look decent.

I love it when someone has so many points of wisdom and experience in 1 post. Awesome.

Not relying on rubber is the key. I have 2 factory E85 cars, All hard lines, viton o-rings.

Wed Jan 29, 2025 10:46 pm

I just wanted to point out that E85 has quite a range of alcohol content, from 51% to 83%. I'm not sure if its is suitable for a carb engine. My understanding is that except for the coldest areas the alcohol percentage is typically at least 70%, but I have not found the regional/seasonal mix standards from any reputable source.

Thu Jan 30, 2025 1:06 am

I ran e85 daily for a year, long time ago now.

Didn't do anything special, just rejet for it.
Didn't cause any problems in the following years.

There is cheap rubber and good rubber, Gates or Dayco hoses or Michelin tires, so forth, usually last 10 years plus
My carbs were always OE italian made in the 80's

Thu Jan 30, 2025 7:10 am

As jpaul noted.....the best methodology for quite some time now is to avoid rubber in fuel lines. This is how the OEM's have been doing it for some time.

Sure, like Chip noted, if you are racing and always in full control of what you drive....Teflon lined, braided hose is great, however it's kink resistance and mechanical breakage ability is terrible (just like brake lines).

Next in line for all fuels....just as chemical resistant as Teflon, extremely high breakage resistance....decent temp range within limits....is nylon. This is why the vast majority of OEM fuel lines are nylon, metal tubes in hot places and viton rubber in flex joint areas.

Viton/fluoroelastomer based rubber is and has been the go-to rubber for both normal gasoline and ethanol and methanol blends for a long time.

The problems with rubber....not just even but maybe especially Viton...kind of like Modok noted is that first you need to have the correct formulation of Viton. There are at least four families of viton. Not all of them are adequate with ethanol, espesially once temperature and other hydrocarbons are added in.

Here is one of several decent sites with info about the different grades of viton:
https://chemours-util.my.salesforce-sites.com/CRG_...rated%20A.

The other bigger issue is that even if you have selected the correct TYPE of viton, there have been and are still, huge problems with the actual formulations for each grade from other countries. Same old issue....quality.

Thus really became a full time issue back around the last recession when certain admixture chemical companies went belly up....and there were already quality and shortage issues worldwide....so a lot of Asian rubber manufacturers went to alternate formulations.

This is about when the OEM'S went full bore into nylon instead of just partial nylon. That made the chemical shortage issue even worse because one of the main chemicals we were short of was butadiene which is used in both rubber and nylon formulations but at least the nylons could be manufactured with more exacting control and for much cheaper.

When my 412 is finally back on the road, it's 35 feet of rubber fuel line will be down to about 2 feet of rubber. The rest will be nylon.

Ray

Thu Jan 30, 2025 7:33 am

whether teflon, vinyl or whatever, I dont know, but I can tell you that the lines ( and a lot of the other engine bay plastics ) in most cars from the early 2000's to present cannot handle UV's and the elements at all. leave one off these vehicles sitting outside without a hood for just one summer and you can see & feel the plastic degrading. this isn't an issue for a vw with all its sheet metal or one that's garage kept but in Baja or a rail that even didnt sit outside year 'round , still doesn't have the sheet metal to protect these parts from UV's while its being driven and id be concerned about their mechanical failure from exposure just from that.
what about silicone rubber?

Thu Jan 30, 2025 8:34 am

The good IDF kits already have Viton seats on the needle valves, such as here:
https://www.ebay.com/itm/122932769850?_skw=weber+v...R6yJtP2WZQ

But Has anyone found any GFLT Viton IDF accelerator pump diaphragm's for idf's/ida's?

Thu Jan 30, 2025 9:28 am

BFB wrote: whether teflon, vinyl or whatever, I dont know, but I can tell you that the lines ( and a lot of the other engine bay plastics ) in most cars from the early 2000's to present cannot handle UV's and the elements at all. leave one off these vehicles sitting outside without a hood for just one summer and you can see & feel the plastic degrading. this isn't an issue for a vw with all its sheet metal or one that's garage kept but in Baja or a rail that even didnt sit outside year 'round , still doesn't have the sheet metal to protect these parts from UV's while its being driven and id be concerned about their mechanical failure from exposure just from that.
what about silicone rubber?

Your basic nylon fuel line is nylon 6. It is not very UV resistant. Nylon 6.6 is also common and it is roughly 50% greater UV resistance for a very small amount more in cost.

However, you can buy highly UV resistant spec nylon fuel tubing (nylon 11). As you note, the OEM'S do not use it simply because virtually all of the line in normal cars is shielded from UV.

On the other hand, as you note, a couple of summers outside with normal nylon 6 is getting chalky and brittle....and heat and freezing have no effect on it. It's strictly UV, especially in the 290nm to 300nm wavelength that affects it. It lasts about 1.5 to 2.0 years of normal UV exposure before it's a problem. Nylon 6.6 is maybe 2 to 3 years.

So, that being said, you can buy basic nylon 6 or 6.6 fuel line for so cheap that even if your car has 30 feet of fuel line....a $75 investment will buy a big enough roll to replace the lines three times. Just change them out every two years. That's one way. Or spend about 2X for nylon 11 fuel line and it will equal or exceed the lifespan of most high quality rubber fuel line these days out in the weather and UV.

Silicone is not a good fuel line for automotive fuels. It also has poor tear resistance. Ray

Thu Jan 30, 2025 12:50 pm

EVfun wrote: I just wanted to point out that E85 has quite a range of alcohol content, from 51% to 83%. I'm not sure if its is suitable for a carb engine. My understanding is that except for the coldest areas the alcohol percentage is typically at least 70%, but I have not found the regional/seasonal mix standards from any reputable source.

Here it varies not only by season, but by fuel station.
Summer mix at the large chain is 66% to 67% but where I get it is 77% to 78%.
Winter mix I'm not real sure of since mine is a fair-weather car, but the last fill up I did before calling it for the year dropped my 1/2 tank (stainless tank) or so of 78% to 70% so about 62% at the good location.

Thu Jan 30, 2025 2:41 pm

I intend to use stainless steel lines in my car for the tank i will have to use some coatings.

Thu Jan 30, 2025 6:40 pm

Depending on what material your carb float is made of it can absorb ethanol and become heavy. Also the density of ethanol and gasoline are just different enough that you might want to re-set your float level even if it doesn't absorb alcohol.

Thu Jan 30, 2025 7:02 pm

Went through so many carb and and gas lines that and running like crap.

Rich Hunt the carb guy, said Joe put in a steel line and fuel toggle switch cut off.

That was years ago steel gas line in side cabin

If I am not going to run my bug for more then a day I shut the switch and run the engine till it dies , a few minutes

No more problems, also prevents some one stealing the bug.

Thu Feb 06, 2025 8:12 pm

Im going to assume that since no one said anything about the stock pump that no one has run one with e85?

Thu Feb 06, 2025 8:15 pm

My bus had a "stock" pump when I ram e85
the type with four screws on top

But shortly after that I decided to use only electric fuel pumps

Fri Feb 07, 2025 7:55 am

the old rebuildable type?
how long was "shortly"? couple weeks or few months

Fri Feb 07, 2025 10:41 am

More like that whole decade in general.

I never did replace the fuel pump on that bus, I drove it for a few years after that, back on gasoline again. I got rid of the bus because it was too rusted out (the body, not the fuel pump)

Fri Feb 07, 2025 5:21 pm

Good to know. Thank you