Reply To: Which oil?

[wristpin]

“Straight” or mono grade SAE30 comes in two versions, detergent and non-detergent. The former mono grade 30 complies with the requirements for modern air cooled four strokes and used to be the recommended oil for Briggs etc although they now also allow multi-grade oils. The non detergent presently marketed for many classic cars is probably the equivalent of the SAE30 that was recommended for making up two-stoke mix .
Morris and Millers both market detergent and non detergent SAE30 oils and Millers also market a specific non synthetic two-stoke mixing oil for older engines.