Morris Minor Owners Club

I'm sure that it's been asked before, but what is the collected opinion on running a standard 1098 minor engine on unleaded fuel?

I tried searching but I could not find a definitive answer.

Thanks

just do it,all it causes is valve seat regression and exhaust valve burning ,but only after very high milage and constant high speed(If you can get one to high speed ) motorway use. Do the head with hardened seat inserts when the head/valves have gone beyond re seating'/grinding or when you decide to have the head off for refurb .I have run my 55s11 ever since leaded was removed,not had a problem. Def not worth modifying head just for the sake of doing it. And don't bother with additives don't really have much effect except mentally your "head "

Do you mean standard as in state of tune or original (without fitted valve seats)?

Former - fuel consumption would be marginally higher. Requires different timing setting.

Latter - with original valve seats - as kennatt.

Sodium filled exhaust valves as well as hard seats would likely be overkill, but that would remove any problem of burned valves and seats.

As above the common wisdom is that it's fine if you're not doing high and fast mileage.

If I recall correctly, Roy (RIP), recommended increasing the tappet clearances on the exhaust valves to 15 thou rather than 12 thou. You may also want to tweak the timing.