“Upper cylinder lubricant“ in the form of Red-X was a penny a shot per gallon of petrol I think, but the dispensers seemed to disappear from petrol stations in the late sixties.As engines became more long-lived it fell from use.
Designed a hundred or so years ago, the ABC engines are from a different age -did ABC owners use UCL In the 20 ‘s and later?
Are present day of ABC users advocates for UCL it in an effort to provide some petrol- borne lubricant to the cylinders and valve stems ?