There is, by Penrite's own specification sheet, a difference of three percent of Zinc (The main anti wear additive for our old engines is Zinc Dialkyi Dithiophosphate or ZDDP) between the Penrite Classic Mini (1610 PPM) and HPR30 (1570 PPM). Not a quantum leap in specifications over a standard base..
The give away is in the marketing. HPR is apparently provided with "DOUBLE LAYER of engine wear protection with FULL ZINC and EXTRA 10 technology" whereas the classic is a "HIGH ZINC anti-wear additive package".
And that's what they
claim. Having dealt with a few product specification issues in manufactured products, there's no one really watching. So it could be anything.
You can however use Classic Mini for a light diesel application... Maybe a BMC A Series Diesel Tractor in a mini?
I haven't found the zinc levels for Valvoline at all, however I have found an article which states that they have a 1500 PPM level of ZDDP in their racing oils only.
http://www.penriteoil.com.au/tech_pdfs/ ... ummary.pdfGraham Russel was always good for a talk about oils..