Morning,
Am using redex lead replacement additive, how much should you add to a gallon of unleaded ?,when I bought the car was told to add a cap full (250ml bottle) per gallon, is that about right. Leads on from my smokey engine post would to much have an effect on performance and smoke ?
Thanks Cliff

Location: Luton

Is lead replacement really necessary with side-valve engines? The seats are much less exposed to the combustion chamber and less susceptible to burning. I would perhaps be more concerned by the use of ethanol in lead-free fuel than the lack of lead. I use super petrol grade in my period cars to avoid the dreaded ethanol/water/petrol compounds which attack brass,Zamac and rubber with equal ferocity and disastrous results.

Cliff, I have never used lead replacement additives in my RP. It may be advisable in higher performance Austin engines but a stock road going seven should run fine on unleaded - leaded petrol didn't exist in the 1930s.

Location: Gard, France 30960

Ok cheers,I have read so many things about,should have shouldent have, I thought I better use it,I am pretty much certain it hasent had hardened valves fitted so that's my reasoning for using it again possibly old wives tale ? I shall start putting neat unleaded in and see how it goes.
I have brakes Bruce ,not brilliant but I have some .

Have a good day

Location: Luton

If you take it off the road over winter be sure to drain the fuel system…

Ok Duncan thanks,
Was hoping to run it on dry days through winter so should be ok to leave it in ?

Location: Luton

I think that Duncan Grimmonds post may be more relevant regarding the avoidence of ethanol.
I have also only used the super stuff since becomming aware of the damaging effects of ethanol.

Location: Near M1 Motorway Jtn 28

Forgive my ignorance but do yo mean the super unleaded ?

Location: Luton

For 20 years I have run a high revving 1960s car without inserts as everyday vehicle, including regular 360 mile trips at around 60 mph. When lead was phased out I used an expensive additive but tried a few trips without and no problems so quit. Slight recession on one occasion followed weak jets installed for an economy run and overlooked.

A previous different car regularly run with weak jets gave a lot of recession, and that with lead. The same car later run on CNG with no problems.

Older engines generally cannot tolerate excessively weak mixture without jerky running etc. Most Seven owners today use every available mousepower, and it seems that to be a Seven owner in UK today saving on petrol hardly a concern, so weak mixes unlikely.

Considering how frequent burned valves and valve grinds were in the past, it is surprising that Seven blocks are often not excessively pocketed.

Location: Auckland, NZ

Location: Near M1 Motorway Jtn 28

I can understand wanting to use premium fuels to avoid ethanol, but what about the possible damage caused by the higher octane?

I believe the higher octane means the fuel 'burns' slower and can still be 'burning' on the exhaust stroke, resulting in raised exhaust valve temperature.

I have heard of folk running on premium petrol reducing the octane rating by adding other compounds - paraffin for example.

There are two kinds of unleaded available with or without Ethanol.

They are marketed as Unleaded 95, Unleaded 98; E10 95 and E10 98. The basic 95 unleaded is fine in an Austin. Most motorway outlets generally now only supply E10 fuel. The normal stuff is usually still available at supermarkets.

On the subject of draining down, I have never had any problems with ageing of unleaded fuel. My car usually has a full tank all year round as it gets used on fine winter days and starts no problem.

I doubt if short term use of E10 would have any effect on an Austin but some later cars prior to 2000 (such as my 1997 MGF) cannot tolerate E10 because it rots the seals in the fuel management system.

Adding paraffin is probably not recommended as it can increase bore/ring wear and will find its way into the sump ultimately diluting the oil...

Location: Gard, France 30960

Have to agree ,I don't believe in fuel going off,maybe in years but not months, my petrol lawnmower would be finished by now and restarted in the spring no problem,equally had a motorbike before the 7 ,wouldn't use it through the winter,would start on the button months later no problem,also a generator for work might not need it for months but when I did ,again no problem .

Location: Luton

My experience has been that ethanol fuel has rotted supposedly E-proof fuel line. My Pembleton Brooklands was left with fuel in the tank and lines for 12 months and the water has been absorbed by the plastic floats and every union pees petrol. I have to replace the flexible line and fit new floats to replace the "sinks" which settled at the bottom of a can of fuel when I tested them They have absorbed water taking them from 10g to 13g.

A pal with an Alvis had his brass mesh screen on the fuel pick-up tube dissolve over one winter, filling his fuel line with green crud.
I avoid fuel with Ethanol to be on the safe side.

I think the question is what fuel that is available today that best suits what the A7 was supposed to have for fuel originally.

Every countries fuel is different according to local requirements so one has to be careful for sure.

If you are not using the car for any length of time over two months add fuel stabilizer to the fuel to prevent the problems associated withthe current fuel they sell us.