Hi Colin, I replied direct to your enquiry but others might also like to see this and add their views. Firstly, congratulations on your purchase and welcome to the classic MG clan. Essentially any recent valve reseating should have involved installing hardened valve seats that would negate the need for additives, but if still unsure you could use any of the commercially available brands once or twice and the coating from those should be adequate. Even in a worse case situation installing hardened valve seats is still a cheaper option than long term expenditure on additives. Petrol is expensive enough as it is, particularly as the car is likely to go better on premium 95-98 octanes.
Posted By: Terry, 29 Nov 2013 10:47 am