Fuel additive

[Stevo19677]

My 88 GLT has the B230E engine fitted. Should I be using fuel additive or will it be ok if I use super unleaded. I can’t find out whether it has been modified or otherwise. If it has, would putting the additive in causeany damage?

[Bob Meadows]

I have the same car & engine: ~ never found any difference between super/premium- so mainly just the normal one. No additives are required but I do keep a fairy liquid bottle handy filled with Red X and when I fill up it gets a couple of squirts at times. (3 classics get the same secret formula)
Bob.

[Stevo19677]

Bob, thanks for this. I’ll stick some Redex in each time I fill up.

[Stephen Edwin]

Recent opinions on Redex vary. I used to earn pocket money selling shots. Nobody has ever convinced me that "upper cylinder lubricant" is worth a penny ....



How much lubricant survives combustion in to the upper cylinder?

Doubtless adherents will prove me wrong and I will be delighted.




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[Clifford Pope]

Other fuel additives undoubtedly do work. Lead tetraethyl for example wasn't added for nothing - it really did increase the octane number and allow higher compression ratios.
It also had a spin-off effect of providing lubrication that prevented valve seat erosion. When lead was outlawed other additives were developed, as a substitute for use in classic cars that needed it. This too worked - my Triumph 2000 pinked badly on unleaded fuel, but ran perfectly when one of the manganese additives, I forget the name now, was added at the rate of a small bottle every tankful.

As to whether Redex confers any benefits is a moot point. But whether it does or not, the principle is sound, as demonstrated by lead and manganese additives. Additives can and do survive the combustion process, and in some cases therefore can be beneficial.

[Stephen Edwin]

Thank you Clifford. So the additives you mention are [in part] lubricants and effective as such. Point taken.

I still have my reservations about Redex.


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[classicswede]

No 240's need any additive to run on unleaded, they were designed for to be run on unleaded and even be safe with LPG. It is also common to run them on E85

Redex failed to work when tested

For cars that do need leaded fuel then have a read here on what has been tested and works

https://fbhvc.co.uk/fuels

[Clifford Pope]

Originally Posted by classicswede

Redex failed to work when tested


https://fbhvc.co.uk/fuels

But what exactly is it meant to do? Provide "upper cylinder lubrication"? Why - presumably engines are designed to receive proper lubrication anyway, and have been for a hundred years.
It was also sold, or at least bought, as a way of giving an engine "a good clear out", whatever that is supposed to mean. It was certainly very impressive in action - lots of smoke, and revving the engine did appear to expell lots of muck. It always felt better afterwards, but was that entirely psychological, of no practical value?

What I can however attest to is the injection once in a while of water vapour as a way of decoking a gummed up combustion space. If you've ever observed the effect of a small water leak into one cylinder, you'll have seen how clean and shiny it makes the combustion space and the valves. You can't dismiss that as just imagination - water in tiny quantities as an additive demonstrably does clean an engine.

Of course another benefit of Redex, or any small degree of oil burning, was to deliberately or accidentally coke up the engine a little to improve compression.
Remember the advice to place a piston ring on top of a piston when cleaning it during decoking, so as not to disturb the ring of carbon that accumulates and helps to provide the gas seal? Many an engine was cleaned over-enthusiastically and then suffered higher oil consumption as a result.

[classicswede]

Originally Posted by Clifford Pope

But what exactly is it meant to do? Provide "upper cylinder lubrication"? Why - presumably engines are designed to receive proper lubrication anyway, and have been for a hundred years.

With the introduction of 4star petrol manufactures found they could use softer materials for valves and guides that would close faster. The fuel reduced knock, lubricated the intake and also coated the exhaust side reducing wear. Take that away and some engines like the BMC A series will be eating into the exhaust valve seat within as little as a 1000 miles! There is some debate as to how it protects exhaust valves as by that point the fuel is burnt. What is known as ashing coats the mating surfaces preventing them from micro welding

[AndrewBrown]

Originally Posted by classicswede

No 240's need any additive to run on unleaded, they were designed for to be run on unleaded and even be safe with LPG. It is also common to run them on E85

Does that include all 244 245 models, as in b21 engined models from 1974 onwards?