petrol

[cherokeegraham]

I've been told that it's ok to run the series 2a on regular unleaded, is this right or should I use an additive?

[Canada Al]

A standard 2 1/4 petrol is not designed for unleaded fuel . you can run this engine on unleaded but eventually you will burn the valve seats . you can use an additive or run one tank out of four with leaded petrol .
Alternatively you could fit hardend valve seats when you next have the head off .

[Robbo]

I agree with Al, but that said if you only do about a 1000 ayear it'll be ok for your retirement, but that said I'd go with unleaded and use the additives rather than super which seems to run a little lumpy sometimes...

yours currently switching from super to ordinary, 31 year block with unleaded head.

[muddyweb]

Main thing for running on unleaded is to make sure your ignition timing is right for the grade of unleaded you run.

I can't remember off the top of my head, but I'll dig out the various timings for the engine (unless someone has them to hand :-))

As said, unless you are doing loads of miles, don't rush out and get an unleaded head conversion for it..   Run it on unleaded until you have problems...   I haven't had any issues yet, even without additives.

[cherokeegraham]

Cheers guys. Muddyweb, that would be really usefull, thanks.

[Devon-Rover]

On the 7:1 engine the static timing for 90 - 95 RON fuel should be 6'BTDC
on the 8:1 engine the static timing for 90 - 95 RON fuel should be TDC.

[Spacemud]

I use additive in my old MG and SIIa and haven't had any problems as yet. I was told additive in one out of four tanks would be fine and I haven't managed to prove that wrong so far!

[MisterC]

I fitted an inline fuel catalyst thingy I got from ebay for a fiver and stopped putting the additive in.  I do around 8000 miles a year commuting to work every day in my 72 S3 petrol.  I know this won't really lubricate the valve seats like lead/an additive, but no problems so far.  I hope those aren't famous last words....