100LL for Classic Vehicles ?

[phiggsbroadband]

Myself and a few acquaintances run some Classic Motor-Cycles and Cars, and have been thinking of using 100LL to avoid the problems which can now exist, such as...
The use of Ethanol in fuel has caused some problems by softening Fibre-Glass Tanks. The alternative fuel is of a low octane rating and gives 'pinking' problems on some high compression engines.


On some Classic Motor Cars the exhaust valve seats really require some lead in the fuel to prevent early erosion.
I know the LL means Low Lead, but surely Low Lead is better than No Lead at all.


Some guys have been fouling plugs on two stroke engines, the use of a hotter plug cures the fouling, but causes some pre-ignition during quick throttle openings.
Has anyone used this Avgas, and does it cure most problems?

[glendalegoon]

hello from the USA... I don't know the laws in Wales, but here it is very hard to buy 100LL from an airport and put it directly into an automobile or motorcycle.

The problem is the road tax imposed on autogas vs the taxes on flying gas


so, do check. I once put 100 ll into my 1965 oldsmobile and it ran fine...no knocking!

be well

[vandereydt]

It s being done in Belgium

Old timers run fine on 100 LL

:mad::mad::mad::mad:

[Genghis the Engineer]

Whether it's illegal or not, the fuel duty in Wales (or for that matter the rest of the United Kingdom) is higher on AVGAS than MOGAS, so I can't see the powers that be getting overly irate about it.

100LL actually contains about 3 times the lead of the old BS4040 4-star, so you're more likely to have a problem with too much lead, than too little.

My suggestion would be to run your vehicle with maybe a 1/4 full tank, initially with a mix of 4 parts BS EN228 unleaded MOGAS and 1 part AVGAS 100LL, see how that works, if no adverse effects try 3:2 or 7:3 mix, and iteratively find a mix that works - which might prove to be 100% AVGAS 100LL of course.

The other thing to consider is using AVAS UL91, which is alcohol free, and lead free, but probably much closer to the fuel that old vehicles were designed around than EN228 or 100LL. If your main issue is with synthetic materials being degraded by ethanol, rather than lack of lead, that may be the better choice.

[Shaggy Sheep Driver]

The power boat community years ago used to call at Barton to load a tanker trailer with Avgas, but after a while, it was stopped. You needed to prove the fuel was for aviation use before it could be sold.

I don't know if that was a local decision by the club, or imposed by fuel tax rules (just because it's expensive doesn't mean it meets the tax laws for vehicles).

[ShyTorque]

The "Low Lead" suffix refers to how much lead it contains compared to previous blends of AVGAS, not motor fuel.

I looked into the use of 100LL AVGAS in my competition car's engine. If I recall correctly, it contains between four and five times what used to be in 4 star petrol. I added one gallon of 100LL to four and a half gallons of unleaded and the car ran very well indeed.

[Shoestring Flyer]

A more cost effective solution to running a Classic car instead of running it on stupidly expensive Avgas is to use a fuel additive like Millers sell. This is a far better solution.
Classic Fuel Additives | Millers Oils (http://www.millersoils.co.uk/automotive/classic-fuel-additives.asp)

[austerwobbler]

I used it in my 2 stroke Mx bikes with good results and a friend of mine runs a vintage BSA on it which makes it run nicer than modern pump fuel

[chevvron]

I used AVGAS 100LL in my drag-kart which had a 250cc Honda 2-stroke engine Sometimes difficult to start but when running it was superb, especially as I had a 'skimmed' cylinder head with a squish clearance about half standard (gawd knows what the C/R was!). Having said that, I understand from microlighting that any leaded fuel can be detrimental to 2-strokes in the long run, but in drag racing, you don't run the engine very long so it doesn't matter as much as (say) a circuit racer.
Several 4 - stroke operators at the drag racing used 100LL too.

[phiggsbroadband]

Thanks Shoestring for the link to the additives, one part of which forecast impending doom for all planes or kit-cars that have alloy tanks... quote....


'Ethanol is also corrosive to other metallic components including zinc, brass, lead and aluminium which will degrade over time under prolonged exposure to ethanol.'

btw, nobody seems to suffer much from 'Plug Wiskering' now, it was often found in the days of 5 Star fuel (101+ octane).

[Jodelman]

As I understand it, in the UK, the fuel duty on avgas is lower than that on motor fuel and for that reason HMCR can prosecute if they find avgas being used in motor vehicles.

Why not just use the old four star which is still available at selected locations throughout the UK and easier to buy than trying to persuade an airfield to sell you avgas in jerry cans.

[S-Works]

Its actually illegal to use Avgas as a road fuel.........

It's not just the duty difference it's also the pollution. It's lead content is way over the legal limit.

[Above The Clouds]

A more cost effective solution to running a Classic car instead of running it on stupidly expensive Avgas is to use a fuel additive like Millers sell.


Could these be additives be used in aircraft operations using old engines when 100LL is no longer available, or to provide corrosive protection from fuels containing ethanol ?

[ShyTorque]

Bose-x,

Most people are aware that it's illegal. Strangely enough, it's legal to buy unleaded fuel and add tetra ethyl lead to the fuel tank yourself.

[cockney steve]

A friend has 3 classic bikes, Gold Star, Road Rocket and Triton... kept under wraps ina heated,insulated garage. Come the spring, bad starting , worse running.. The Ethanol -containing fuel had eaten away the fine-gauze filter on the petrol tap and also blocked the carb. jets with gunge.

Boil in vinegar to clean. throw away the green-tinted stale fuel.

[phiggsbroadband]

That's bad news Steve, I have just bought some jets for Mikuni Carbs and they are made of brass, as I suspect most carb jets will be.


I read on a Racing Fuels website *, that each Petrol/Avgas has a slightly different Specific Gravity, so in theory needs different jets... Maybe not such a problem on planes with Mixture controls, but do Rotax engines have a mixture control?


* racing gasoline ? Speed Talk (http://speedtalk.com/forum/viewtopic.php?f=1&t=35270&start=45)

[PTR 175]

I have a 1980 Moto Morini that will only run well on higher octane fuel. For example the Shell V power type of fuel. I tried Avgas 100LL from the flying club. It was a good price as it was the ex daily test samples. I have used it straight and it runs brilliantly but also found that runing it with 1/4 to 1/3 100LL worked well.

I now have a lead substitute slug in the tank I think it is tin, not sure if it works or not but still no burnt out valves many years later.

[S-Works]

Bose-x,

Most people are aware that it's illegal. Strangely enough, it's legal to buy unleaded fuel and add tetra ethyl lead to the fuel tank yourself.

But not use it on the road.

My friend got fined SIX HUNDRED quid last year for using Avgas in his V8 Landrover.......

[flybymike]

Well I have to ask.

How did anyone find out what was in the fuel tank?

[S-Works]

4x4 Club green lanes day. We all got dipped, assume they were actually looking for Red. They DNA test the fuel with an analyser at the side of the road and can identify exactly what's in the tanks.

There was also one caught using heating oil!!

[flybymike]

A waiter in our local Indian restaurant, claims to use cooking oil...;)

[Shoestring Flyer]

Yes a diesel Landrover or any other diesel for that matter will run quite nicely on Chip oil!
Conversion kits:-
ATG Vegetable Oil Kit - Vegetable Oil Conversion for Diesel Vehicles (SVO/PPO/WVO) (http://www.diesel-therm.com/vegetable-oil-kit.htm)

[S-Works]

Mine runs nicely on cooking oil. First 2500 litres are duty free after that you self declare.

Avgas does not fall into this category and neither does red diesel.......

[ShyTorque]

But not use it on the road.
My friend got fined SIX HUNDRED quid last year for using Avgas in his V8 Landrover.......

No, I wasn't referring to the use of AVGAS on the road.
It's possible to buy tetraethyl lead additive and mix that with unleaded petrol.

The blue dye colour of AVGAS would tend to be a bit of a giveaway if that's all that's in the tank..


As far as using veggie or biodiesel in "any" diesel engine...not so in my car. The owners' manual specifically says it's not to be used.

[S-Works]

The irony of the whole situation was having some toe rag nicking fuel from our aircraft for his Corsa being caught with over 200l in his car and in Jerry cans and only getting a caution.

My mate was just using the left over waste samples from his fuel bowser. Only a lunatic would pay to put savages in a V8 Landrover!!

[flybymike]

My mate was just using the left over waste samples from his fuel bowser. Only a lunatic would pay to put savages in a V8 Landrover!!
I certainly wouldn't have savages anywhere near my car....

[S-Works]

Goddam auto correct.....

[ShyTorque]

I've seen quite few savages in V8 Land Rovers.

[longer ron]

A ahem friend of mine used to put some 100LL in his Holbay engined Hillman Hunter GLS !(up to 50/50 !

It was a fairly high compression engine and the demise of 5 star fuel meant that it pinked like a ba5tard on 4 star...no such probs with some 100LL on board LOL :)

[modelman]

My old shortstroke Manx Norton use to run quite nicely on 50/50 super unleaded/avgas and a splash of proboost octane enhancer. Any avgas always made plugs difficult to read to get the jetting right though. I was told not to use 100% avgas as it is designed for quite slow revving engines and would struggle to get complete combustion in my old 7000 rpm motor.

[ShyTorque]

You have to watch some types of fuel component rubber materials with AVGAS, they can be adversely affected.

A reason not to add too much in the mix!

[cockney steve]

Try putting Veg. oil or Biodiesel through a Delphi pump-equipped diesel and you'll learn a VERY EXPENSIVE LESSON

You caneasilymake Biodiesel from waste cooking -oil...a lot of older diesels will,indeed, run well on pure "chip-fat"... otherwise , filter, titrate and convert properly.. If you get your titrationwrong, you can get a residue of NITRO-GLYCERINE instead of ordinary Glycerine. -not recommended for a longand healthy life.....YOU STILL CAN'T USE IT IN A LOT OF MODERN DIESELS especially Common-Rail.

UK pump-diesel is now mandated by law to have , IIRC, 5% bio-content.
Research the problems with the Renault engine....fitted to :- Mazda6, Volvo V40/ S40, Renault Megane /Espace..Mini diesel...........Don't take my word, it's all out there onthe motor forums....yes, I know I'm a Saab dastard as well.:O

[Mariner9]

UK pump-diesel is now mandated by law to have , IIRC, 5% bio-content

Somewhat academic really, but that is not correct.

The current legal specification for diesel (EN590) in the UK allows any FAME content between zero and 7%. Makes no difference to the rest of the points made in cockney steve's post though with which I generally agree.


As for using 100LL in classic vehicles, one thing not yet mentioned above is that they may become more difficult to start in Winter (due to the lower vapour pressure of avgas compared to winter grade 4*)

[alland2012]

I would also endorse the Miller classic fuel additives, we have clients with a range of cars from the early thirties through to modern day classics, we have been supplying and using Millers products for many years without any problems at all.

[ShyTorque]

As for using 100LL in classic vehicles, one thing not yet mentioned above is that they may become more difficult to start in Winter (due to the lower vapour pressure of avgas compared to winter grade 4*)

Which is why you should only add it to unleaded petrol, about 1 to 4.5, which brings it up to the level of the old 4*. In fact it's probably more like 5* at that ratio, due to the better basic formula of today's fuel.

Once you've got enough TE lead in the fuel to prevent pinking, there is no point adding any more; it will cause more problems than it's worth, such as plug contact whiskering. So AVGAS is best used as a fuel additive, rather than a replacement fuel by itself.

Obviously, for off-road use only, to remain legal.

[RatherBeFlying]

Back in '76 I bought a Renault 5 which required premium fuel that over the next few years became unavailable as unleaded took over the premium pumps:uhoh:

100 avgas blended in worked very nicely, but gradually airfields began refusing to sell for automotive purposes because of legal pressures.

Tetraethyl lead is said to be a nasty substance; so octane boost is better from other chemicals.

That was the last French car I bought. It required a steady diet of wheel bearings and CV joints before it rusted out:ugh:

After a move it turned out that my new landlady had an R5. She saved herself a bunch of money when she took my advice to get rid of it before 65K miles.