My first post in this thread mentioned getting a recommendation from the manufacturer for the specific engine in question.
As that post had nothing to do with a stovebolt six, I did not give specifics, only the suggestion to check with the manufacturer. The engine involved still has nothing to do with a stovebolt six; but DOES have to do with the differences in oils and why they are important.
I have been interested in boosted engines since I was a youngster. In 1979, I special-ordered a turbo-charged four cylinder from that company that rhymes with Cord.
The engineer who was kind enough to answer my call told me that while they recommended the Rotunda brand; ANY brand which then met specification SF BUT NOT specification CD would be acceptable. The specifications are stronger now.
It seems the CD spec could froth at a higher RPM. This particular turbo used crankcase oil to lubricate the turbo. I do not remember the turbine RPM, but it was significantly high enough to cause frothing.
The engineer also suggested that I allow the engine to idle for a minimum of 15 seconds to allow the turbine to "spin down" before turning off the engine; as once the engine were turned off, oil pressure would no longer effect adequate lubrication for the turbo.
I have done the suggested recommendations, with great results; and this particular engine in general does not have a great reliability record. As stated in my first post, I subsequently bought a second vehicle for the wife; and it was sold after some 200k miles and still going strong.
The point I am attempting to make is that differences in oil CAN make a difference in certain instances; and also that there is not one PERFECT answer to a generic question.
Jon.
