Petrol

mustang68

What is the story with modern petrol? I seem to remember when I used to go and fill up the car we had choices of Super Plus or whatever it was called with a higher octane rating, but now the option seems to be limited to Petrol with 5% ethanol or diesel.

The reason I started to think about this was my car was becoming harder to start and then I remembered that it had been a while since I had put fuel into it and I have read that Ethanol is hydroscopic, meaning that I'll have a lot of water content in the petrol after a few weeks. So I went to get a fuel stabiliser in halfords and found a shelf full of additives, some of them were 25 euro a tank! I got "Dry fuel" so we'll see how it goes.

So what is the octane rating of normal petrol, what performance degradation are getting and how quickly is a half talk of 5% ethanol going to go bad?

Thinkingaboutit

I've used a Lead Additive/Substitute for a Wolseley 16/60 I've had for the past five years, no issues.

v300

Modern petrol looses it's VOC's thru evaporation quite quickly. A fuel tank of a car is not a great place to store fuel for more than a small few weeks as the fuel "goes off" after that.

More info on the wiki:
http://en.wikipedia.org/wiki/Petrol#Stability
"Good quality gasoline should be stable almost indefinitely if stored properly. Such storage should be in an airtight container, to prevent oxidation or water vapors mixing, and at a stable cool temperature, to reduce the chance of the container leaking. When gasoline is not stored correctly, gums and solids may accumulate resulting in "stale fuel". The presence of these degradation products in fuel tank, lines, and carburetor or fuel injection components, make it harder to start the engine. Upon the resumption of regular vehicle usage, though, the buildups should eventually be cleaned up by the flow of fresh petrol. Fuel stabilizers (see below) can be used to extend the life of the fuel that is not or cannot be stored properly. Fuel stabilizer is commonly used for small engines, such as lawnmower and tractor engines, to promote quicker and more reliable starting. Users have been advised to keep gasoline containers and tanks more than half full and properly capped to reduce air exposure, to avoid storage at high temperatures,[3] to run an engine for ten minutes to circulate the stabilizer through all components prior to storage, and to run the engine at intervals to purge stale fuel from the carburetor.[4]"

Fishtits

OP, what is your car?

PS Its a good starting point when you've a problem...

Dades

Fishtits wrote: »

OP, what is your car?

PS Its a good starting point when you've a problem...

I'm guessing it's a 1968 Mustang.

Tigger

Dades wrote: »

I'm guessing it's a 1968 Mustang.

its a gift

W.Shakes-Beer

Dades wrote: »

I'm guessing it's a 1968 Mustang.

I wouldn't imagine you'd have to worry about fuel staying in a tank in that.

Daved_XB

It could simply be that the fuel in the carbs & in the fuel line is evaporating over time & it takes a while to get fuel up to engine… are you running the original engine mechanical pump or have you an aftermarket electrical fuel pump??

Also old carb cars can go in & out of tune depending on the weather… for example the six pack on mine has to be retuned from summer to winter or she just won’t run right