What grade and type of fuel are you using for your older Lotus Seven or early Caterham 7?

[EdWills]

Here in Canada, the government regulated in 2022 that all gasoline had to contain some mix of ethanol.  Most gas stations here seem to have a 10% blend of ethanol added to the fuel.  Some time ago,  U.S. and U.K. auto magazines gave warnings regarding the effect of ethanol on rubber seals and components used in older (vintage?) cars.  Some owners advised of black goo in their fuel tanks after ethanol contamination, carb filters/fuel filters becoming blocked with a similar build up, with others advising to drain the fuel tank and fuel lines before storing the car for the winter when ethanol has been part of the fuel mix..  I tried a search of this forum for this topic, but nothing popped up.   There are a number of other vintage car sites that mentioned the problem, but the responses from the car owners are mixed and no one had a firm suggestion of what to do.. The main worry for many of them concerned valve seat recession without the lead (and consequent premature valve wear), not the possible rotting of all the rubber seals.  Some advised to use Avgas as it has a good lead content (and may not contain ethanol?), and another advised that he found a supplier of race car fuel sans ethanol.  Is it necessary to change all of the rubber seals in a Weber carb for example, along with the large rubber hose connected to the fuel tank, and the seals in the original AC fuel pump?

 

What do you owners of older Lotus Sevens and perhaps Caterham 7 cars from the 1970s use for your fuel supply?  Also, with unleaded gas in Canada only going up to 94 octane, and then only at a few locations possibly, how does the compression ratio in your engine cope with the lower octane fuel if you are running a c.r. of over 10:1 ?

 

My uprated Crossflow cylinder head was fitted with hardened seats on the exhausts, upgraded steel valves and silicon bronze guides when unleaded fuel started to be introduced.  I also inherited a large quantity of fuel additive with lead content if it is necessary.  The rubber deterioration problem troubles me, as in the process of a rebuild, there is no point assembling everything only to find that the original parts are going to suffer damage.  Advice please. Will

 

 

Edited August 30 by EdWills

[Christopher smith]

I understand that Avgas 100LL (as in low lead) does not contain alcohol and  Sunoco and VP have a variety of grades that may be ok. Extra octane beyond what is needed should be ok. They are expensive of course. All seem to work in a 1500 pre-crossflow with 10.2 to 1

[7Westfield]

I run 91 octane alcohol free, as I can get it easily here.  I add lead substitute sporadically. Next time the head is off, it will get seats.

Avgas does not contain alcohol, in general, they aren't going to allow that crap anywhere near an aircraft. But, there is a small group of aircraft rated for MOGAS.

However, the FAA, and I assume CAA, are testing lead free fuels.  100LL is on short notice. The reason for keeping lead in avgas comes down to not wanting to mess with the storage and stability qualities. The engines have had hard seats for years. 

You should replace the rubber lines with something like Gates Barricade.

I've not really heard of trouble with injected cars, their components should be new enough. Storage is the main culprit, so running the carbs dry over winter will help.

The black goo some have seem is probably from hose breakdown, usually you see a white powder in the carb. Apparently alcohol doesn't play well with aluminum. Also, if you have a fuel cell, the older bladders and foam are not resistant.

[Christopher smith]

I am thinking (hoping) that the 100LL might be around for a while for vintage aircraft such as the B17, B24 and Mustang I saw at a show in New Jersey. I suppose they follow some rules about complete overhaul every X number of hours. But better parts may not be available? It is not like those of us with old British cars stuck on the side of a road when an engine dies.

[SENC]

I use ethanol free unleaded at the highest octane level (no problem finding it in southern US states as it is heavily used for yard and farm equipment - maybe find out where farmers buy gas for their non-diesel equipment?).  I do add Redline lead substitute just as a precautions though I've been told it isn't really an issue on our engines.  

 

I've periodically bought Sunoco "race fuel" - they have a wise variety including some specifically for older (non-racing) engines.  My car loves the 104/105, but it is expensive and technically not road legal so I don't use it much.

[7Westfield]

One downside to 100LL is availability. It's illegal for road use, but there's a catch. Contrary to some beliefs, it is NOT illegal for an airport to sell it to you in a jug. Some airports try to tell you they can't sell it for non-aviation uses, but they can if they want to.  There are some airports that try to deny sales, but they are uninformed, or just don't want the hassle of small sales.

So, buy it in jugs and take it home,  If using a self serve pump, do NOT fill the car while you're there, that will be trouble

Tell them it's for a race car, or your generator

A few years ago, I took a generator in for a carb tune---the guy said the carb was plain worn out, unfixable and unobtainium, but the cleanest one he had ever seen--most of it's life on avgas cuz that's what we had at the track

 

We've run Formula Fords on avgas for years, but next year we will try pump 91 with lead substitute, mainly for convenience

just pick it up when heading out for the weekend, and put the leftovers in the driver's 911.

Edited August 30 by 7Westfield

[wdb]

I use 10% ethanol pump gas at the highest octane I can find. Haven't had a problem, knock wood. My car is a 1995 build but the engine is a 60's twincam. Nothing in the fuel system is 50 years old I guess.

[bsimon]

Can't help you with octane.

 

When I lived in Colorado, I would go to marinas and boat docks to get alky-free petrol. Watercraft and E10-15 don't go good together, so marine suppliers won't even sell it.

 

If all else fails, you can separate the alcohol from petrol by mixing with tap water and draining the water after it settles. I used an inverted VP jug on a plant stand. The alky bonds to the water and settles to the bottom (top) of the jug and can be drained away. 1 quart or more of water to 5 USG of petrol.

 

Here in Wyoming, we can buy alcohol-free petrol at about half the stations in town. Lots of boats, mowers, and motorized toys 'round these parts...

 

[Carz01]

I’m currently using 110 leaded. Here’s a link to sites offering e-0, in various grades by state in case you haven’t seem it.  https://www.pure-gas.org

[MV8]

Also, separating the ethanol results in around 80 octane fuel. Running e10 or worse with no changes leans the mixture and reduces the range. Never use it in a 2 stroke or a rotary.

[Christopher smith]

Just a reminder on safety. Boosting octane without lead may mean adding organic ( chemist definition) compounds like toluene and xylene. So please be careful to avoid significant skin contact and breathing since there may be some residual benzene content and that is super bad. Not that lead is great, but aromatic hydrocarbons may cause issues years after contact. So I am a bit wary of very high octane no lead fuels. Sorry for organic chem 101-- I know almost everyone hated it.

[IamScotticus]

Is a synthetic lead substitute a proper abatement?

[Christopher smith]

did a quick look using perplexity search for history of octane improvement and chemicals in lead substitutes. The latter looks a bit like alchemy with magnesium complexes so it looked a bit shaky. Not sure I would fully trust the info sources fully since a lot of the test data was probably proprietary.

But it did sort of confirm the idea that aromatics ( benzene, toluene etc.) are common now with only a few unmodified vintage motors asking for lead. Way back  (1960s) Amoco premium  used to claim lead free way before Federal mandates but I recall very poor spark plug life with my 340 Barracuda. Adding benzene on purpose rather than just as a trace from refining, seems very irresponsible but I suppose they like the evaporation characteristics ( low boiling point) perhaps for colder climates in winter. Somewhere I heard that unhardened valve seats could benefit from lead early in life but once the seats were lubricated that lead was not critical. Probably no way to confirm that so might be risky.

[jbcollier]

Getting back to the original question about what to run if you are in Canada.  Well, that depends.  What engine are you running?  And, in what tune is that engine?

I have a 69 Lotus Seven S3 with a somewhat modified 1600 Ford crossflow.  It has a stupidly-lumpy cam (not my idea), larger valves, and mildly ported.  I run premium rated 93 or 94 (rating on the pump in Canada) with no issues.  Ford crossflows have very good swirl flow and can run high compression ratios with few issues.  Lotus Twin Cams are not as good in that regard.

 

The issues with ethanol have little to do with running and performance.  The issues are with humidity, long term storage, and reactions with other materials.  I live in dry Alberta and do not fuss much but I will drain my tank and run the lines, pump and carbs completely dry before winter storage.

 

First, regardless of fuel you are running, if you can’t remember changing the fuel lines, change them ALL.  Use ethanol-proof lines and change them at least every five years, whether the car is run or not.

 

If you live in a dry climate, do the above two and relax and enjoy your car.  If you live in a humid climate, then you still need to do the above but also add a fuel additive specifically designed to stabilize ethanol fuels.  For winter storage, still drain and run dry your pump, lines and carbs but leave the tank full to the brim with the fuel + additive.  Come the spring, do not run that fuel.  Drain it off and run it in your commuter.  Only use fresh fuel in your Seven.

 

Lastly, ethanol and old, lined tanks do not mix well.  Getting tanks cleaned out and lined is getting difficult these days.  I’d recommend  either acid dipping the tank and properly repairing any leaks.  Or, fit a new tank.

Edited September 2 by jbcollier

[7Westfield]

UNVERIFIED AS YET    but, given that it's CA, no surprise

 

 

[Christopher smith]

That sounds long enough for many of us who might have put off hardened valve seats and alcohol resistant parts to get them in place.

[inchoate]

in my experience e10 is ok in older cars/bike as long as it doesn't sit for any length of time.  If I know I'm going to use the gas I happily fill up with gas station 93 octane e10.  If I even suspect that something is going to sit for more than a week or two I drain the fuel system.  I'll put some race gas in the tank if I have some around or if I'm feeling fancy.

 

I've cleaned and rebuilt so many carbs that I'm entirely sick of it.  The extra work and expense with the gas is well worth it for me.

[IamScotticus]

I was able to get zero Ethanol at a Philips 66 in Houston tonight at $3.40/gal.  It is 87 octane. I could have gone further and gotten 90-92  but this is storage gas with Stabil added.  It will probably be used in the lawnmower and generator. And for carb cleanings.

@Carz01 thanks for the link.

Edited September 7 by IamScotticus

[oilteq]

In 1981 I put "gasohol" (E10) in my 1979 Suzuki 750.  It was not long until I had to grind on the clutch for half a block to get it going.  I switched back to straight gasoline, and it ran fine within one tankful.  The shop said it dried out the O-rings in the carburetors.  Gasoline mixed with alcohol becomes more aggressive than either by themselves.

 

As MV8 mentioned, alcohol enleans the air to fuel ratio, but you can compensate by enriching the mixture.  With no ECU to change the AFR when burning different fuels, it is often recommended to tune for whatever you choose and stay with it.

 

In my opinion, there is no lead substitute.  In 1988, as the wide nozzle system was practically gone, the EPA and USDA reported the results of a joint study Report to the President and Congress on the Need for Leaded Gasoline on the Farm.  The pages were not numbered, but I would guess it is about 200 pages long.  The intent was to prove that lead substitutes could replace lead.  They proved the opposite.  They tested products from Du Pont, Polar Molecular, and Lubrizol, which dominated the market and sold to blenders for a hundred different brands of lead substitutes.  Lubrizol’s additive was the only one to have a partial success, when used at four times the recommended rate in a 454 with induction hardened seats, but still more valve recession than 0.1 grams of tetraethyl lead per gallon.

 

Gasoline stabilizers are good, but I would stay away from those that claim to stop phase separation.  If 10% alcohol does not keep the water suspended, adding a pint of additive in 10 gallons makes little difference.  Look at the SDSs and you will find they are mostly alcohol anyway.

 

I would not worry too much about aromatic solvents in pump gasoline because the limit to Reid vapor pressure is regulated.  Octane boosters on the other hand, are mostly aromatic solvents and do not raise octane much anyway.  I have never experienced it, but excessive vapor pressure in a carbureted engine can cause vapor lock.

 

If avgas or racing fuel is available, I think those are your best choices.

 

 

 

 

[Christopher smith]

3 hours ago, oilteq said:

In 1981 I put "gasohol" (E10) in my 1979 Suzuki 750.  It was not long until I had to grind on the clutch for half a block to get it going.  I switched back to straight gasoline, and it ran fine within one tankful.  The shop said it dried out the O-rings in the carburetors.  Gasoline mixed with alcohol becomes more aggressive than either by themselves.

 

As MV8 mentioned, alcohol enleans the air to fuel ratio, but you can compensate by enriching the mixture.  With no ECU to change the AFR when burning different fuels, it is often recommended to tune for whatever you choose and stay with it.

 

In my opinion, there is no lead substitute.  In 1988, as the wide nozzle system was practically gone, the EPA and USDA reported the results of a joint study Report to the President and Congress on the Need for Leaded Gasoline on the Farm.  The pages were not numbered, but I would guess it is about 200 pages long.  The intent was to prove that lead substitutes could replace lead.  They proved the opposite.  They tested products from Du Pont, Polar Molecular, and Lubrizol, which dominated the market and sold to blenders for a hundred different brands of lead substitutes.  Lubrizol’s additive was the only one to have a partial success, when used at four times the recommended rate in a 454 with induction hardened seats, but still more valve recession than 0.1 grams of tetraethyl lead per gallon.

 

Gasoline stabilizers are good, but I would stay away from those that claim to stop phase separation.  If 10% alcohol does not keep the water suspended, adding a pint of additive in 10 gallons makes little difference.  Look at the SDSs and you will find they are mostly alcohol anyway.

 

I would not worry too much about aromatic solvents in pump gasoline because the limit to Reid vapor pressure is regulated.  Octane boosters on the other hand, are mostly aromatic solvents and do not raise octane much anyway.  I have never experienced it, but excessive vapor pressure in a carbureted engine can cause vapor lock.

 

If avgas or racing fuel is available, I think those are your best choices.

 

Great info- thanks