Ariel Owners Motorcycle Club

Hi I have been looking on the forums for information on wether or not my 1954 needs to be converted to run on unleaded petrol. I have found lots about iron cylinder heads. Nothing so far about mk2 square 4.

Unleaded will increase valve seat wear but the increase rate of wear is very little and unlikely to be noticeable for at least 50,000 miles, why not wear the existing ones out and replace in 50,000 miles? The only reason to do an unleaded conversion is if the seats need to be replaced anyway.

Ariel valve seats in the alloy head engines are pretty hard anyway so valve seat recession is not a problem if you run on unleaded. In fact, if you manage to wear your seats out, I think you should get an award for doing so much mileage! The cast iron heads are softer, but there is still nothing like the problem you get with car engines. You can always use a lead replacement additive which I usually do, but which I haven't done on the Healey so far. This should indicate to you my lack of concern on the matter.

hi , i just use a fuel additive to help the engine from E10 or E5 petrol i use STA-BIL and it helps stop the petrol getting water in it