Check Fuel hoses

jonbills

Membership Secretary
Site Administrator
I reckon it's mainly hoses and seals, although I did read a suggestion that 'some' metals can be damaged.
 

Huw

Club Member
Apart from being a powerful solvent, which is why some rubbers and plastics will degrade. One to watch if you have a plastic float in your carb. The stuff has increased acidity, conductivity and inorganic chloride content when compared to conventional petrol which can cause corrosion and tarnishing of metal components under certain conditions. Old aluminium castings with high manganese content don’t get on to well with it.
 

Huw

Club Member
Also from the Federation of British Historic Vehicle Clubs:

Ethanol contains approximately 35% oxygen by weight and will therefore result in fuel mixture enleanment when blended into petrol. Petrol containing 10% ethanol for example, would result in a mixture-leaning effect equivalent to approximately 2.6%, which may be felt as a power loss, driveability issues (hesitations, flat spots, stalling), but also could contribute to slightly hotter running.
 
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jonbills

Membership Secretary
Site Administrator
Also from the Federation of British Historic Vehicle Clubs:

Ethanol contains approximately 35% oxygen by weight and will therefore result in fuel mixture enleanment when blended into petrol. Petrol containing 10% ethanol for example, would result in a mixture-leaning effect equivalent to approximately 2.6%, which may be felt as a power loss, driveability issues (hesitations, flat spots, stalling), but also could contribute to slightly hotter running.
that's very interesting Huw, I found this that says the stoichiometric ratio for e10 is 14.08:1, so anyone running 14.7 is a little lean.
https://www.aa1car.com/library/air_fuel_ratios.htm
 

johnymd

Club Member
I have never used the cheaper 95oct stuff in any of my cars so I guess for the time being I should be ok.
 

MCBladeRun

Club Member
"They will also require the higher-octane 97+ ‘Super’ grades to remain E5 to provide protection for owners of older vehicles. This product will be designated as the ‘Protection’ grade."

Good enough for me, but will upgrade the fuel hoses in due course.
 

racer

Club Member
It Baffles me why anyone would use cheap 95 in there classic in the first place?
Simply use the better quality Super unleaded.
 

arcdef

Club Member
It Baffles me why anyone would use cheap 95 in there classic in the first place?
Simply use the better quality Super unleaded.
Forgive me if I'm wrong but if your car isn't designed to run on 97/98 fuel then until now there was no benefit to paying the extra? I doubt that they frequently had access to high octane fuel in the 70s and the manual doesn't seem to state its required.

20210901_193026.jpg
 

AliK

Vehicle Dating Officer
Staff member
Club Member
It Baffles me why anyone would use cheap 95 in there classic in the first place?
Simply use the better quality Super unleaded.

I’m with you on this! I guess there are times when you get caught out and can’t find the good stuff.

Either way it’s best to get the hoses updated and use the lowest possible ethanol content fuel available. That way you won’t be stripping fuel tank linings, mechanical pump rubber, carb and other floats etc.
 
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Huw

Club Member
Forgive me if I'm wrong but if your car isn't designed to run on 97/98 fuel then until now there was no benefit to paying the extra? I doubt that they frequently had access to high octane fuel in the 70s and the manual doesn't seem to state its required.

View attachment 46826
Octane requirement in the manual should be seen as a minimum requirement to ensure the correct operation of the engine.
 

arcdef

Club Member
Still pretty sure you need to adjust fueling to benefit from higher octane unless the car is designed for it.
 

Huw

Club Member
Most cars including pre- war will run well on 97 without any alteration or adjustment.

It’s impossible to have too much octane quality, and older engines can operate very satisfactorily on a fuel with octane quality greatly exceeding their natural requirement. (Pinched that line from the FBHVC site, read it it’s very very enlightening)
 

racer

Club Member
Still pretty sure you need to adjust fueling to benefit from higher octane unless the car is designed for it.

If you think about what fuel we had in the 70's here in the UK, it would have been 4star leaded fuel witch was 97 Octane.
A Zed is a sports car, witch is about performance yes? As Huw says the higher octane will protect your engine.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
My understanding is that high Octane rating prevents pre-ignition so is important in high compression engines which might 'diesel'.

I don't think a standard Z would benefit from high Octane but it won't do it any harm.
 

AliK

Vehicle Dating Officer
Staff member
Club Member
View attachment 46826[/QUOTE]
Still pretty sure you need to adjust fueling to benefit from higher octane unless the car is designed for it.


So let’s not brush aside a valid point you made here. Our L6s don’t have timing dynamically adjusted based on EGT, O2, Knock sensor etc data. So it can’t detect fuel quality and give you extra performance.

But with higher octane what you get is a cooler burn (which you can argue can get some minor ponies) reducing potential for knock. Don’t forget that 4* and 5* fuels burned much cooler with their lead content.

Then there is the matter of better detergent packs that go into more expensive fuels. Case in point: my remapped diesels always smoked like a chimney when at full throttle on supermarket fuels, but never smoked on Esso, BP or Shell fuels. Even my S2000 would idle better in hot standing traffic when using super unleaded v normal stuff.

Better detergents = cleanser burn and less plug fouling etc.

As to the question of cost: if you take my average of 1000 miles a year at say a lousy 17mpg due to the lead in my right boot, it equates to 267 litres. At the current local cost of £1.48 for super and £1.37 for regular unleaded it would cost:​

Regular: £366
Super: £395

The £30 difference is worth it to me as an insurance policy against knock let alone the benefits mentioned above. How much do we spend on pointless rubbish on our cars that isn’t vital to their operation and yet we can fret about a small difference at the pump?

Finally, super unleaded fuel is “up to” 5% ethanol and if you live in the south east the Esso super is currently 0% and RON 100 (even if labelled 99).
 

arcdef

Club Member
All good points, I also run premium.

I was more alluding to the fact that until now, there was no issue running regular unleaded and was more than understandable why people wouldn't pay the extra.
 
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