leaded or unleaded

[Budgie]

Ok I know this has been spoken about adnausiuosly in the past , not sure if that's spelt right or even a right word, but I will be going to see a four door saloon shortly and she still runs on leaded so no hardened valves in this one but the guy reckons he uses super unleaded and was told to by a local motor engineering firm of which I know well and is highly thought of in the field. So my query again is , does this sound fine or can she be run on unleaded without any "interference"!

[panky]

Personally I haven't used additives for a number of years and all is well. As long as you're not doing mega miles or towing a caravan constantly then it should be fine.
A couple of examples I know of. A good friend meticulously put the measured amount of additive in his car over a number of years until the engine started loosing power and popping, when we took the head off the exhaust valve on number three was sunken and seat badly drawn. Luckily a spare head was at hand and he now saves his money and doesn't bother with additive.
Another friend re-built his head with hardened seats, 35000 miles later the seats were fine but the valves had buried them selves into the seats they were so badly worn. Neither of these vehicles are Minors but are ordinary iron head engines driven carefully and sparingly.

[JOWETTJAVELIN]

FBHVC published a list of additives which have stood up to scrutiny, I use Castrol Valvemaster when I must.

http://www.fbhvc.co.uk/legislation-and- ... formation/

[bmcecosse]

The additives are 'snake oil' - some may boost the Octane rating slightly to help prevent pinking - but that's about all. Just set the exhaust valve gaps at 15 thou - and check/reset at 3000 mile intervals and all will be well. Just use standard petrol - no need for the expensive stuff in this low power engine. It's all quite the VERY LEAST of the worries when considering buying a car !

[Gareth]

In my experience, if you use unleaded petrol in a car designed for leaded, you'll have to make some adjustments (as BMC says) but be prepared for the soft valve seats to wear.

How quickly that happens will depend entirely on your driving style and the condition of the engine. I've had to replace the valve seats on No.3 twice... Leaded heads are available: I'd suggest saving your money from additives and put it towards the 'Lead-Free Head fund'.