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green gasoline

Greetings to all, an opinion on the use of green gasoline, it is advisable to use the lead additive? wm20

email (option): marcoleo1967@gmail.com

Re: green gasoline

Always use a lead additive on cast iron cylinder side valve engines!

/simon

Re: green gasoline

Hi green gas is fine if you are only doing a few hundred miles a year, it's only if you ride very hard or travelling thousands of miles before you need hardened valve seats or additives

email (option): Johnsonsteve386@gmail.com

Re: green gasoline

By "green" I assume you mean unleaded petrol, if that's the case just carry on and pour the stuff in your tank and use your bike. There's a whole lot of nonsense about old vehicles and modern fuels to worry out on the internet but the truth is our kind of bike were happily doing thousands of miles on fuel which was much less refined that the stuff at Tesco's. Just use it and the worst that can happen is you will have to rub in an exhaust valve and you would probably have to do that anyway!
Richard

email (option): richard177smith@btinternet.com

Re: green gasoline

When these bikes were made during the war the fuel was about 70 octane with no lead additive. With the cast iron used on the cylinders you would need to do thousands of miles before you would suffer recession on the valve seats if at all.

Re: green gasoline

I've never come across the term 'Green Gasoline'...If it means fuel with bio-ethanol then best to avoid at least the higher concentrations if you can. Certainly E10 has the potential to cause problems of corrosion and water absorbtion.

If using fuel containing ethanol, you will have to make your own judgment...this is more controversial than oil type and those who insist that none of it is a problem are pretty vociferous.

My personal feeling is that if you are concerned then a corrosion-inhibiting additive which will often contain a valve and guide lubricant in the form of magnesium or similar will not do any harm and may help. Whilst wartime fuels were poor quality and low octane, modern fuel formulas are not the same and seem to remove any oils or lubricants from the valve area.

There is probably less risk to a well-used engine than a newly-built example.

Re: green gasoline

According to an engineer mate of mine lead additives are a triumph of marketing over substance. These engines never had lead in the first place. Another case of web misinformation

email (option): jeremy@clogmaker.co.uk

Re: green gasoline

thanks for the answers, yes with green petrol I meant unleaded petrol. so from what I read I can safely use it without adittivi!

email (option): marcoleo1967@gmail.com

Re: green gasoline

I stand corrected, I guess.

/simon

Re: green gasoline

I bought this booklet the other day, I had always thought that the valve problems were caused by a lack of lead, this quite clearly say the opposite, so what exactly does a lead additive do that is helpful?

Rob

b

b-8

email (option): robmiller11(a)yahoo.co.uk

Re: green gasoline

It's primarily an 'anti knock' additive that reduces pre ignition...Ian

email (option): ian@wright52.plus.com

Re: green gasoline

The lead that was in petrol acts as a cushion on the valve seats to stop recession of the valves. That is why when the lead was removed there was a great demand for hardened valve seats. Hardened valve seats are not really necessary on our old bikes as why tend not to do the mileage anymore.

Re: green gasoline

[..'Tetraethyl lead [TEL] is a petro-fuel additive, first being mixed with gasoline (petrol) beginning in the 1920s as a patented octane rating booster (antiknock agent) that allowed engine compression to be raised substantially. This in turn caused increased vehicle performance and fuel economy. TEL had been identified chemically in the mid-19th century, but its antiknock effectiveness was discovered in 1921 by the General Motors research laboratory, which had spent several years attempting to find an additive that was both highly effective and inexpensive...']

Reduction in wear of the valve/seats was an added bonus of lead use...I have found with the cooler running post war OHV B Series BSA engines the removal of lead has no discernible effect on the valves/seats under normal and varied use...

I have had problems with the exhaust side of my M20 but only after using it at sustained cruising speeds on motorways over a period of time...I experienced deterioration of the valve and seat sooner than anticipated and I put it down to that...I have read that continuous running of that type is the worst case scenario for hotter running engines...

I fitted a 'lead free seat' a number of years back and used a modified exhaust valve from an Iveco turbo diesel...Since then I've not had a problem...Many people who do not use their M20s in that way have reported no problems at all with using lead free fuel...Ian

email (option): ian@wright52.plus.com

Re: green gasoline

Valve seat recession was real and identified in extensive laboratory testing
OF AIR CRAFT ENGINES when running in lean burn conditions as is done at high altitude.

It was never ever found to be a problem in auto engines at sea level.
But the technically illiterate who write 99% of all motoring magazines got hold of it and ran hard.
Did wonders for sales as owners desperately needed to know if their precious possesions were going to self destruct.
Naturally the snake oil salesmen followed hard in the footsteps .
For carburettor engines there never was a problem.
Some blown engines could be adversely affected.

I used to do thousands of miles on my M20 and the only valve problems has been a single burnt exhaust valve.
Done enough miles to do a full series of rebores on one barrel out to +80 and no vlave problems.

The people who had problems were the clots running 11:1 to 12:1 which is right on the limits so they either had to detune or run

email (option): bsansw1@tpg.com.au

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