Petrol additives

[Dave Wheatley]

Now that we have had E10 fuel for a few weeks, can anybody point me to reviews of the various (lead replacement, octane boosting, anti ethanol) additives. Hopefully by now some classic car magazines or organisations will have produced reports.
Additives any good?, or snake oil.
Any personal experience on here?
Any recommendations?
I can only get E10 round here.

[Bumpa]

Don't any garages near you stock the super grade? Super unleaded is going to remain at not more than 5% ethanol, and some brands are zero. Round here (Ayrshire) its only Morrisons that don't keep the super grade. All the other supermarkets and small garages have it. OK it costs more but with low mileages covered by most classics it's not a big extra expense.

[Dave Wheatley]

It's a 50 mile round trip to the nearest E5 stockist at Newton Stewart. I made a special trip there last weekend, and they didn't have any!
An additive that works would be welcome.

[Ian F]

Dave, take a look at this from the fbhvc:

https://fbhvc.co.uk/fuels

Whether you need "lead replacement" additives depends on your specific engine and whether you have had hardened exhaust valve seats fitted. I used to use the Castrol additive and as far as I could tell it worked fine.

Ian F

[Dave Wheatley]

Thanks for that excellent link Ian. I'll give it a good perusal before supper.
"and as far as I could tell it worked fine." - this is the problem with these additives which is why I could do with reports from organisations like the FBHVC.

[Ian F]

I suppose what I was saying is that I had no discernable valve seat recession when using the Castrol additive - didn't have to adjust the valve clearances and the seats looked Ok when I stripped the head.
Of course the damage potential of ethanol is much more difficult to assess as it could extend throughout the fuel system and affect several different materials.
I am fortunate (here in Fife) as I have Shell station nearby and always use their Super Grade.

Ian F

[Peter Cresswell]

I did suffer from quite sudden and severe valve seat recession (over about 1000 miles) when we took the B to France in 2017, and this was despite using Castrol Valvemaster since I bought the car at the end of 2011, and running it on super unleaded. I think the underlying reason was constant speed cruising on the Autoroutes. I then built a new engine using another head and had unleaded valve seats fitted as part of the upgrade.
I haven't got much more advice to offer to all the good stuff above, but remember E5 fuel has between 0 and 5% ethanol but E10 has between 5.1% and 10%. This means E5 might not have any ethanol in the fuel but E10 will always contain ethanol. Esso have recently issued a statement that their Supreme + fuel contains no ethanol in most parts of the UK. I believe Shell and BP have some ethanol in them as I haven't seen them claim it is zero.

Also remember the MGB engine was designed to run on 98 Octane minimum so they should have always been fed with 4*or Super Unleaded fuel, but the bad effects of ethanol fuel will not be seen for some time as it takes time for the ethanol to degrade (for example) the fuel hoses. You might notice E10 affects the way the car runs as the stoichiometric ratio is lower than for pure petrol. Modern cars can cope with this because of the pre and post cat. sensors which are used to manage the correct fuel to air ratio. You will also get less MPG from E10 fuel over E5