Stock ´86 C20 350cui octane

[Dave15]

Hello Guys n Girls

does anybody know if its "ok" to fill up my old lady with 93 octane?
reason why i am asking is because here in europe we have the 95 octane (in USA its called 91) and we have the 98 octane (in USA named 93)
the problem is that since april this year the 91 octane fuel is now with 10% Ethanol, before this it was mx. 5% and i read that the higher Ethanol level is unhealthy for older engines, the 93 octane stayes with max. 5%
for my ´05 Mustang neither the 10% ethanol or filling it up with Shell V-Power 100 is a problem, but i don´t know about carburetor engines.

 

[Rusty Nail]

Good question. I think somewhere I read that 15% was the allowable threshold limit AND that number represents a possible maximum.

There is a simple tester that uses tap water to determine the true amount of ethanol in "gasoline" I'll see if I can find a link.

Voila!
https://www.ebay.com/itm/3838255115...uid=v-sv__JbTfe&widget_ver=artemis&media=COPY

Cheap and easy, probably fun to play with too. I saw a video about these things on the Scotty Kilmer youtube channel.

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Hope this helps!

 

[fast 99]

Problems with ethanol are many. Some rubber/plastic parts aren't compatible. Ethanol evaporates at a lower temperature, sometimes resulting in fuel boiling inside carb during hot soak. Higher ethanol content may cause lean conditions. Ethanol absorbs water, causing rust and does not store well. This is just a few reasons not to use it if possible.

One thing to remember is these vehicles were not designed for ethanol. Most fuels today are not even formulated for carbureted vehicles and the octane in the 70's and 80's was much higher than today.

 

[Dave15]

ran 15 gallons of the 93 soup threw the engine and must say it is a wise choice, much smoother idle. hope my truck feels honored. this stuff costs 6,80 $ per gal.