Morris Minor Owners Club

As above, my current advice ranges from cheap mineral 20/50 to modern fully synthetics. It's a recon 3.5 litre with about 30k on the clock,running well,but a slight leak from the rocker gasket.
Suspect that there's no right or wrong answer to this one...just different opinions?

20W50 from Morrisons - plenty good enough - just don't expect it to last 'for ever'.

As far as I can make out from what has been said on the subject the only advantage to using synthetic oil in an old design engine is that it will extend oil change intervals but as it costs more in the first place it will only gain you time for the oil change. The other service items will still have to be done anyway so as BMC says use ordinary 20/50 and stick to normal service intervals. It's a shame that my Morrisons don't stock it or I would use it as well, I get mine from Halfords.

I don't understand why anyone would want to economise of one of the most important aspects of engine health? What API grade is Morrisons oil? Halfords Classic 20w/50 is API SE and is blended exclusively by one of the reputable oil companies (I have seen the blending operation).

The original 1958 948 engine in our Minor needed a rebore at 30,000 miles and an exchange crank at 43,000 miles, not long after my mother bought it. After that, using the best quality oil available it ran up to 99,000 miles, getting well modified on the way, with no further major work and now in a new home (Frogeye Sprite) it is still doing good service - low oil consumption and excellent oil pressure.

Our 1380 runs on Castrol 10W/60 full synthetic and has done >60,000 enthusiastic miles, including many track days, on the same crank with 50 lbf/in2 at hot idle, and up to ~65 lbf/in2 at 3,000 rpm plus.

I would recommend using a good quality 20W/50 mineral oil to API SE/SF or better and change it annually, or earlier if the mileage is more than ~10,000.

I can't get it at any of the supermarkets either. The cheapest I've found is in B and Q for a tenner. Half the price of Halfords. I do intend to use better oil once I get my new engine in though.

Whatever grade you use, Use a quality branded oil, it's the life blood of the engine. The only good use for Morrisons or Adsa own branded oils is the oil can.

b and q do a fully specked 20/50 for about £12 i use that

The more basic 20W50 oils are fine for old motors - the important thing is to make sure there IS oil in the sump. I doubt the engine is going to be thrashed ! Fuel consumption will soon put a stop to that....

Quite right, it won't be thrashed! And even I can look after regular oil changes. Really interesting all the different opinions though!