This looks like it is an old study on a Cummins engine using CG4 oil. Maybe late 1990's? The delay in getting oil to the rocker shaft, which is at the most remote spot in the lube system, is eye-opening. Even with Oil D, it takes 60 seconds. With the worst oil in the test, it took almost 180 seconds.
vino_neuro - Thanks for publishing this for all to see. Regardless of the age of the data it is of course still most relevant
This is one reason why I commenced using a 5W-40 synthetic over 15W-40 mineral lubricant in my OTR vehicles during the mid 1990s. In field testing some years earlier this was an obvious conclusion! As well I used centrifuge "by-pass" filters and SS FF screens - previously synthetic media FF filters
I've published my results many times on BITOG and described them at the 10yr BITOG function
I believe that Daimler AG commenced new used lubricant pump ability tests a year or so ago - this was as a result of used lubricant gelling under harsh Euro winter conditions. A new ACEA/MB Test protocol will most likely be the end result