Morris Minor Owners Club

Not at all - ideal 'upper cylinder lubricant'!
beware - it's not cheap - I got some from a Castrol rep who used to visit me at Work! Oh dear - the W word - make me come over all faint!

I believe if you start using it you have to always use it unless you strip the engine as it repells ordinary mineral oil meaning your bearing shells effectively run dry.It is based on castor oil so has different properties.It's a bit like the trouble caused by putting silicon brake fluid after mineral stuff.A no-no.

If the engine is run on Castrol R - then yes, to change to normal mineral oil requires a strip down to clear it all out. And vice versa of course! My tiny amount of UCL will not be doing any damage - and it does smell nicely when the engine is working hard.

Oh yes you can't beat the smell especially at a hill climb when cars with it in are being ragged to within an inch of their lives.