Quote:
Originally Posted by cycleguy55
Interesting read here, albeit very long. The net of this is that he basically dismisses as myth the requirement for ZDDP (a.k.a. zinc) that many strongly believe in for flat tappet / lifter engines, and recommends certain types of high quality 5W30 synthetic pretty much universally.
https://540ratblog.wordpress.com/
The weight / viscosity of your oil s/b based upon the clearances in the engine, as indicated by pressures you're seeing. Standard guidance for many has been 10 PSI per 1,000 RPM at operating temperature, so 60 PSI @ 6,000 RPM. Running heavier / thicker oil than that not only requires more power to pump, but may also result in insufficient lubrication to tight clearances - particularly when cold (yes, even with multi-viscosity oils). |
A guy in our club is a retired
oil engineer from one of the big US refineries. A good part of his career was spent developing and providing oil for race cars, sponsored and unsponsored. When I showed him the 540Ratblog (after being pretty impressed myself), he ripped the methodology to shreds. The author is making a lot of unfounded statements that he backs up with pseudo science and testing.
The recommended oil from the guy with experience? Delo diesel when it used to have 1200ppm
zinc, now Delo diesel with ZDDP additive. Based on that I'm running Rotella 15W40 as it still has 1200 ppm ZDDP in my flat hydraulic tappet motor.