Glass fibre petrol tanks and problems with Ethanol in pump fuel.

[IanCordes]

Dicky. There are plenty of BP garages in the SE who are supplying s/unleaded 'Ultimate', so you may be unlucky with your local Commonwealth friends. I filled a couple of jerry cans on the A3 Guildford way a few weeks ago, Festival of Speed weekend. It may be a case of supply and demand local to you.

[Dick F]

HI ian, I will wait and see, but there is a lot of demand here from bike owners at least. It will in the end come about though, like everything else the car industry forces on us today, cars and bikes being out priced with repair cost due to parts availability, electronic parts out pricing the car.

As we know already fuel for Race cars and bikes etc is around at extortionate prices, i will look round for a fuel bowser second hand, and start filling up now how much cai keep at home??????????????????????

[IanCordes]

10 litres, I think..... I wouldn't dream of exceeding that, of course, despite living 200 miles from the nearest ethanol-free pump.... That excludes what is in the bike/car petrol tanks.

Have you tried checking availability of avgas at Goodwood, or Shoreham airfields? Leaded; albeit low; ethanol free, 100 octane, just the job! Should be much cheaper than race fuel, too.

Having said that, I have heard that it has slightly different burning characteristics than our pump fuel, and is recommended to be mixed 50/50 with superunleaded, so we go full circle! Unless anyone knows any different?

[John Wakefield]

The ethanol problem aside, standard unleaded is fine in two stroke engined roadster & trials bikes with low to medium compression (up to about 8:1) In fact in the old days when our bikes were new low octane 'commercial' grade petrol was recommended. In fact garages used to use this grade in those small hand operated two stroke mixture pumps remember BP Zoom?

[johnrunnacles]

I've had no problem burning "neat" AvGas in my Vale-Onslow iron-barrelled Hawkstone in a 20:1 mix with "R", Ian, nor in my 4-stroke 500 TriBSA.
It is, as you say, relatively cheap too, at less than £2/litre.

[Dogsbody]

A little more info on lead with reference to two strokes.

http://www.cycleworld.com/2015/08/11/ask-kevin-do-two-strokes-work-better-with-leaded-gas/

Dogsbody

[Dick F]

Yes When i had the Silverstone i did get it from Goodwood, as they need it Rob uses it also in his TZ racers as they run now just on straight avas , running 50 - 50 mixes he used in the past were ok but he had some expensice blow ups and has now changed, i know trials strokers can use the ordinary rated fuel but i like to use the top octane if i can, my modern road bike is happy with the cheaper fuel but they are designed for it >

[aa will]

fuel

i use std avgas in my panther sprint/hillclimb vintage special it runs great i drain it after each meeting then add a bit of oil then it goes in my scottish outfit , if i have no trials i sling it in the old mz they all seem happy , the only problem is that some of the local airfields have started asking for the planes logbook ,(sorry guv its around here somewhere),but its obvious that me getting 20litres must have a very small plane, or!!!!!!! will.

[Dogsbody]

Re Avgas, this from another site
AvGas is short for Aviation Gasoline. AvGas is of interest to motoring enthusiasts because of its availability, octane rating and low price compared to commercial race fuels. AvGas might seem an obvious choice but closer study raises some doubt.

AvGas LL100 stands for "Low Lead 100 Octane". TEL (Tetra-ethyl-lead) is added to raise the octane. When used in a motor vehicle this fuel will leave a lot of lead deposits in the motor. 100LL has a high lead content (0.5 grams per litre), even higher than leaded race fuels. The deposits left when TEL(lead) is burned are corrosive and damaging to valves, valve guides, valve seats and cylinder heads. Lead deposits will also block oxygen(lambda) sensors and catalytic converters and foul spark plugs even after only a short use. Also, 100LL has a chemical package added to make it perform at high altitude, and that isn't the best thing for motor vehicle performance here on the ground.

AvGas is blended for large-bore, long-stroke, low RPM engines which run at high altitude. While AvGas' higher octane is useful, smaller-bore, shorter-stroke, high RPM engines will perform better on racing fuel or high quality octane boosters. AvGas has lower volatility so when used in proportions higher than about 40%, part-throttle drivability and cold starts may be compromised. AvGas has a lower specific gravity so it will require a change in air-fuel ratio calibration for the engine to perform at its best. LL100 is blended with a high percentage of aromatics causing reduced throttle response which is not an issue with an aircraft engine but certainly an issue in a high-performance automotive engine. These high levels of aromatics will also damage rubber components in automotive fuel systems such as fuel lines, fuel pump seals and injector washers.

The sale and use of AvGas is heavily-regulated. Most aircraft fuel dealers refuse to put AvGas into anything other than an aircraft fuel tank. There is a legal grey area that has some vendors willing to dispense AvGas into "approved" containers if they believe the end use of that AvGas is fueling an aircraft engine. This loop-hole is how some may obtain AvGas for automotive use. Because AvGas has no taxes and duties on it, use on public roads is illegal and if found could result in your vehicle being impounded.

Apart from availability problems as none of the local airports will sell it to non aircraft owners, it burns too slow for high revving, high compression engines ( not really an issue for most two stroke owners ) but mixed 50/50 the lead content is beneficial for older four stroke engines.
However my reasons for using Sunoco race fuel are it's guarantee of being Ethanol free, stability, and it's consistency.
Dogsbody

[johnrunnacles]

Thanks Dogsbody. Useful info.

[IanCordes]

Cheers Dogsbody, that is an interesting article. It is more or less what I was refering to in an earlier post, but I had only heard it anecdotally.

To pick the bones out of it; it is interesting that it is described as LL; low lead; whilst the article states it has a high lead content. Also that it warns of the effects of lead on engine internals. I thought lead was meant to be a good thing in 4-strokes, lubricating valves, preventing valve seat recession etc. If harmful, why would they use it in aircraft engines?

Being formulated for slower-revving long stroke motors should be ok for our 2-strokes, and old 4-strokes, Nortons, Triumphs etc etc, and if mixed 40/60 as the article suggested, and as you conclude, it should be beneficial.

We still need a reliable supply of ethanol-free superunleaded to mix it with! Good old BP....

[Dogsbody]

This article gives more specifics,
http://www.clubdbsa.org/forums/showt...d-the-hard-way!
When I was speaking with Sunoco ref jetting it came as a surprise that with R6SR I would need to go down a couple of jet sizes not up as I thought. The reason is that pump petrol has about 1.8% oxygen, R6 has none, although they do some fuel up to 12.9% oxygen and others up to 120 RON!
It really is a minefield. Dogsbody

[Stuart Baskill]

All supermarket petrol whether 95ron or superunleaded; Tesco's being 99ron; contain ethanol. Just 3 litres of Tesco s/unleaded stripped the paint off the inside of the filler in my Norton petrol tank overnight; that was just the fumes.
The only superunleaded you can be sure still contains no ethanol is BP, but even then, that does not apply to all regions of the country. ALL pump petrol in the south west; Cornwall, Devon, Somerset etc contains ethanol; period. Also, I believe, in Scotland. In the south-east, Midlands and oop north, you will be ok with BP Ultimate, but that is about it.

Apparently you can buy an ethanol tester for £19.90 from Frosts (part number Z600) and the man who wrote the article said that all the super fuels that he had tested were free from ethanol.

[Dogsbody]

Or you can test for free, taken from an aviation website.I have done this with surprising results. Dogsbody
HOW TO TEST FUEL
FOR ETHANOL

To determine if ethanol is in the gas:

On a test tube or olive bottle six or seven inches long, make a permanent line about two inches from the bottom.
Fill with water to this line, then fill the tube to the top with gasoline.
Cover the tube, agitate it, and let it stand.

The ethanol and water will mix and separate out together. If the water level appears to have increased, the fuel contains ethanol and should not be used. Ethanol percentages of less than 5% can sometimes give a reading below the line. Therefore, any deviation in the water line indicates the presence of ethanol and should serve as a basis for rejecting the fuel.

[Colin Sparrow]

What exactly was surprising about the results, Colin? Or was the surprise the fact that it actually worked?

Useful dodge if it does!